Chinese Version Light学术出版中心
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Issue 10z ， 2015
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Simulation of characteristics of cloud and fog echo for pluse laser fuze
Abstract：Pulse laser fuze is susceptible to the interference of natural environment, such as cloud and fog, and easy to produce a false alarm. Therefore, this paper researches the cloud and fog echo characteristics of the pulse laser fuze. On the basis of Mie scattering theory, a pulse laser transmission model for the cloud and fog is established by using Monte Carlo simulation. The cloud and fog echoes in two conditions are simulated. The first condition is that both pulse laser fuze and target are in the inside of cloud and fog, and the other is that the target is in the inside of cloud and fog and the pulse laser fuze in the outside. At the first condition, the echo signals are acquired when the distance between pulse laser fuze and target is 10 m and the visibility are 1,3,5 and 10 m, respectively. At the second condition, the dynamic echo characteristics are obtained when the distance between pulse laser fuze and target is 10 m, the visibility is 3 m and the cloud and fog boundaries are 0,1,3,5,7and 9 m, respectively. Moreover, it analyzes the influences of cloud and fog parameters and position, on the cloud and fog echo, and the waveform difference of cloud and fog echo and target echo. This research provides the theoretical support for the anti-interference of pulse laser fuzes.Keywords：pulse laser fuze;cloud and fog echo;Monte Carlo method;simulation- 57
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Published：2020-08-13 -
Description of continuous surface deformable mirrors by using orthogonal polynomials
Abstract：By taking a piezoelectric Deformable Mirror (PDM) and a Micromachined Membrane Deformable Mirror (MMDM) as examples, a method to accurately characterize the surface of continuous surface deformable mirrors was discussed. The description characteristics of Zernike polynomial and Q polynomial methods using different fitting parameters were compared and the influence of higher polynomial terms on fitting accuracy was researched. By activating one or more actuators, the two groups of five surface data were obtained for PDM and MMDM respectively. Then, the number of sampling points and the number of polynomial orders were set as variables. The ten surface data were fitted using the least square method based on five types of sampling grids;either the Zernike polynomial and Q polynomial were adopted. The experimental results show that the edge-clustered sampling grid outperforms the four uniform grids in terms of fitting accuracy. The Q-polynomial fits produce smaller fitting residuals than Zernike fits when the polynomial order goes beyond 40. Moreover, the RMS(Root-Mean-Square)of fitting residuals stays in the 1×10-5 mm order of magnitude when the polynomial order increases from 10 to 80, while the residuals away from the aperture edge decrease significantly. The above results can guide the choice of fitting parameters in deformable mirror applications, describe the surface characteristics of deformable mirrors and improve wavefront control accuracy.Keywords：optical freeform surface;surface fitting;deformable mirror;Zernike polynomial;Q-polynomial- 58
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Published：2020-08-13 -
Multiple linear CCD pose measuring optical system
Abstract：For the high precision attitude measurement of flying objects in a suspension test field, a multiple linear CCD attitude measurement system with an area array CCD as auxiliary recognition was proposed. Aspecial imaging lens consisting of cylindrical lenses was designed for the linear CCD . Three red Light Emission Diodes(LEDs) were mounted on a flying object to be as cooperation targets, while two area array CCDs and three linear CCDs were utilized to image for the light spots. Finally, the attitude angles of the fly object were obtained by measuring the space position of the light spots. The working region of the linear CCD optical lens is at wavelength (635 ± 15) nm, the full angle of view is 19° and the focal length is 90.04 mm. Seven pieces of cylindrical lenses and a piece of red filter were used to compose a telecentric optical path of image space, which effectively eliminates the aberration and completes the measurement for a larger depth of field. The results show that the lens distortion is less than 0.05%, and the depth of field is up to 1.5 m. The designed system achieves high accuracy measurement by combining linear array CCDs and special imaging systems.Keywords：attitude measurement;Linear CCD;telecentric optical path of image space;cylindrical lenses- 63
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Published：2020-08-13 -
Orthogonal two-component multi-point interferometric Rayleigh scattering velocimeter
Abstract：To obtain the flow field velocity of an engine with high dependability at extreme combustion condition, the velocity of gas flow field was measured by using Fabry-Perot etalon to detect the Doppler frequency shift of molecular scattering. The working principle of a multi-point interferometric Rayleigh scattering velocimeter was introduced, and the correlation between collecting direction of scattering light and the direction of measured velocity component was analyzed. Then, an orthogonal two-component multi-point velocity measurement system was set up. Based on the measured interference fringe image, the center of interference fringe was measured by template match, the Doppler frequency shift of Rayleigh scattering was obtained through a fitting spectrum curve by with Levenberg-Marquarat algorithm and the corres ponding velocity was calculated. The orthogonal two-components with a Mach air flow of 1.5 were obtained at an x-y plane, and the multi-point velocity vector graph in the x-y plane was given. The research results show that this velocity measurement system can simultaneously measure the orthogonal two-component velocities with high dependability.Keywords：Rayleigh scattering;multi-point velocity measurement;flow velocity measurement;Doppler frequency shift;Fabry-Perot etalon- 68
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Published：2020-08-13 -
Laser feedback confocal tomographic system based on microchip Nd:YVO4 lasers
Abstract：Based on the theory of frequency-shifted laser feedback and confocal technology, a laser feedback confocal tomographic system is designed. The light source in the system is a single longitudinal, linearly polarized Nd:YVO4 microchip laser worked at the wavelength of 1 064 nm. It can magnify the frequency-shifted feedback signal by a factor of 106 and can realize optical tomography with a greater depth on the premise of high resolution. With the technology of scanning and image processing, the system can fulfill the three-direction imaging of a sample. The system has a lateral resolution of ~1 μm and a vertical resolution of ~15 μm. A two-dimensional imaging experiment for polyfoam and a foreign matter detection for inside onion are performed and the inner information images of the samples are obtained. The results show that the system designed has well tomographic ability and also good location ability for the foreign matter inside biological samples.Keywords：Nd:YVO4 microchip laser;frequency-shifted laser feedback;confocal tomography;image processing- 44
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Published：2020-08-13 -
Real-time calculation of statistical regression atmospheric transmittance profile
Abstract：As many single remote sensing images have extended multiple latitudes, their remote sensing information retrieved by several simple atmospheric transmittances will generate to many big errors. To solve above problems, a real-time calculation method of statistical regression transmittance profile was proposed. Firstly, a regression prediction equation and an equivalent optical mass calculation method were established based on the Curtis-Godson(CG) approximate method of homogeneous atmosphere. Then, by taking the MODTRAN's 6 types of atmospheric transmittance profiles and the corresponding atmospheric profile data as samples, statistical regression parameters were calculated, and the model's precision was verified. Finally, a correction formula for transmittance zenith angle was presented and the slant path transmittance profile calculation was implemented. The simulation results show that the average biggest error of transmittance profile is 1.39%, and calculation time of single band is less than 0.08 s. Combined with measured data of temperature and humidity, this model can calculate the transmittance profile at the observation point in real-time, thus not only improves effectively retrieval accuracy of remote sensing image.but also expands the model's application ranges.Keywords：atmospheric remote sensing;atmospheric transmittance;statistical regression;zenith angle correction;MODTRAN- 46
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Published：2020-08-13 -
Fiber-optic semiconductor laser transmission welding system for thermoplastics
Abstract：A transmission welding system with an optical fiber laser was established to realize the seamless welding of thermoplastics. The structure, laser source, beam collimation and focusing for the welding system were studied. The method of laser transmission welding was discussed according to the characteristics of plastic welding. Then the laser transmission welding system was designed by using the fiber laser as a source. By considering the divergence of the fiber laser source, the light beam collimation and focusing system was designed. The welding experiment of polypropylene specimen was carried out by using the designed fiber laser transmission welding system, and the tensile test of a welding specimen was performed. The results show that the welding strength of specimen is 379 N by the semiconductor laser transmission welding system, while the laser power is 40 W, the welding speed is 50 mm/s, and the content of carbon black is 0.1%. It satisfies the system requirements of practical applications.Keywords：semiconductor laser;laser welding;transmission welding;thermoplastics;optical fiber- 86
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Published：2020-08-13 -
Portable fluorescence blend oil measuring system
Abstract：To measure quantitatively each single vegetable oil in blend oil, a portable fluorescence blend oil measuring system was established and an algorithm for the measurement of each single vegetable oil in the blend oil was investigated. Firstly, the hardware was designed for portable fluorescence blend vegetable oil measuring system. Then, sunflower oil, soybean oil and peanut oil commonly sold in the market were mixed into blend vegetable oil. The fluorescence spectra of different proportions of blend oil were measured and the content of each single vegetable oil was tested. A corresponding mathematical model was established based on partial least-square regression model to be used as a standard database. Furthermore, spectral data of the blend oil under the test was taken into the partial least-squares regression model established before to calculate and to obtain the content of single vegetable oil in the blend oil. Experimental results indicate that deviation of test accuracy of calculated content of each vegetable oil in the blend oil is within 10% based on the partial least-squares regression model. The measuring system has higher measuring speed, good accuracy and needs a few samples, and it satisfies the system requirements of the quantitative measurement for each single vegetable oil in blend oils.Keywords：fluorescence measuring system;portable measuring system;blend vegetable oil;quantitative measurement- 70
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Published：2020-08-13 -
Color analysis of iron surface structure fabricated by circularly polarized femtosecond laser
Abstract：A method to induce multi-colors on an iron surface by using Circularly Polarized Femtosecond Laser (CPFL) processing was proposed. The subwavelength ripples were fabricated by CPFL scanning over the iron surface where covered by randomly distributed nanoparticles with diameters from 50 nm to 190 nm. A while light was used to irradiate the treated iron surface, and the relation between surface colors and incident angles was explored. By changing the incident angles of a white light from 0° to 80°, diverse colors were displayed on the laser-treated iron surface. In order to understand the underlying mechanism of the experimental results, a model of spherical nanoparticles spread randomly on ripples of the iron surface was built by Finite-difference Time Domain (FDTD). The experiments show that the surface reflection spectrum is varied from blue to red by increasing the incident angle of white light, which is consistent with the experimental results. Furthermore, it is found that the reflection spectrum shifts towards blue and the peak increases by decreasing the sizes of nanoparticles. This work may find potential applications in the fields of information storage, identifying codes and anti-counterfeiting patterns.Keywords：laser induction;femtosecond laser;circularly polarization laser;iron surface;multi-colors;Finite Difference Time Domain(FDTD)- 50
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Published：2020-08-13 -
Coating optimization and SPR wedge probe with single mode fiber
Abstract：A method to coat a 50 nm golden film with a plasma sputtering apparatus was proposed. By considering low sensitivity on Surface Plasmon Resonance(SPR) mode mixing of multimode fibers and simulation difficulty, a SPR sensing probe of single mode fiber with the wedge structure was introduced experimentally. Firstly, the effects of parameters such as vacuum degree, electric current, distance and time on film properties and film depths were studied. The film thickness was calibrated by a profilometer and the effect of film thickness on SPR exciting phenomenon was measured by a modified SPR measurement system with a space prism. The 630 nm single mode fiber was polished into a wedge structure by fiber grinding technology, and the 50 nm golden film was coated on the inclined plane of the wedge to realize the Kretchmann prism structure on the single mode fiber. Under a microscope, the end face of multi-mode fiber with 105 μm diameter of fiber core was directed at a total reflection beam and fixed to collect the reflection light of SPR, where the sensing property and reflective index of SPR single mode fiber with the wedge structure were studied. The results show that the golden film is well coated with (50±5) nm film thickness under the conditions of 2×10-1Pa vacuum degree, 5 mA electric current,1 cm sputtering distance and 3.5 min sputtering time. When grinding angel is 15°, the SPR sensor of single mode fiber with wedge structure is sensitive to liquid with refractive index between 1.333 and 1.385 and the working range of resonance valley is between 693 nm and 924 nm with the mean sensitivity of 4 442 nm/RIU. The proposed ion sputtering equipment meets the demand of SPR experiment and the SPR probe of single mode fiber with wedge construct is characterized by high sensitivity, simple procedures and great application potential.Keywords：golden film;plasma sputtering;Surface Plasmon Resonance(SPR) probe;single fiber with wedge construct;refractive index sensing;coating optimization- 52
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Published：2020-08-13 -
Qualitative analysis of KCl composition for skin secretion based on near infrared spectroscopy
Abstract：As KCl composition at human body surface has a direct relationship with the human physiological condition, a detection method for the KCl composition of skin secretion at the normal body temperature 36.5℃ was explored, The near infrared spectroscopy was adopted to measure the solution concentration of KCl. After analyzing the solution concentration of K+ based on near infrared spectroscopy, the least square method was used to fit the absorption peak. Fitting results show that the absorption spectrum for KCl composition of skin secretion varies with temperature and KCl concentration, and the determination coefficient of least square method (r2) can reach to 96.28%. The results indicate that KCl composition qualitative analysis for skin secretion based on near infrared spectroscopy can clearly give the relationship between the absorption peak and solution concentration of KCl near the normal body temperature. At the same temperature, the absorption peak gets bigger with increasing the solution concentration of KCl . At the same solution concentration of KCl, the absorption peak gets bigger with increasing the temperature.Keywords：solution concentration;KCl;composition of sweat;Near-infrared spectroscopy;least square method;qualitative analysis- 51
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Published：2020-08-13 -
Application of wavelet denoising in distributed optical fiber interferometric vibration detection and location system
Abstract：The phase modulation and positioning principle of a Distributed Optical Fiber Interferometric Vibration Sensing (DVS) system are discussed and the wavelet denoising principle for interferometric signals is introduced. As the DVS system is vulnerable to environmental noise interference and easy to produce false alarms or larger positioning errors, the paper uses the wavelet analysis method to implement the denoise of interferometric signals and the exact detection and accurate position of vibration signals.The experimental results show that proper wavelet analysis method selected for time-frequency characteristics of vibration signals improves the signal-to-noise ratio (SNR)of the detection signal and variation detection accuracy obviously, and decreases the false alarm rate of the system. Meanwhile, it ensures the system positioning error within ±50 m. As compared with other denoising methods, the application of wavelet transform in signal processing improves the accuracy and spatial resolution of the vibration detection and reduces the system positioning error. The method is applicable for the same types of distributed vibration sensing systems.Keywords：fiber optics;distributed optical fiber interferometric vibration sensing system;sagnac interferometer;wavelet transform;wavelet denoising;position determination- 57
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Published：2020-08-13 -
Applicable conditions of phase retrieval based on transport of intensity equation
Abstract：As phase retrieval based on the Transport of Intensity Equation (TIE) is selective about lighting, recording systems and samples. This paper analyzes the applicable conditions of phase retrieval based on the TIE through theoretical analysis and numerical simulation, and verifies the effectiveness of the applicable conditions. It points out that the phase retrieval is suitable for objects with little intensity variation especially. The generalized phase of the light need to be a constant. and the recording systems are of infinity optical structure. Two experiments are conducted in a 4f system and an infinity optical microscope system for a micro-engraved glass sample. The results show that recovered average depth of the 4f recording system is 1.41 μm and that of the infinity optical microscope system is 1.56 μm. The result of the infinity optical microscope system is very close to that of the laser scanning confocal microscope. It concludes that the phase of the object can be effectively recovered by the 4f recording system and the infinity optical microscope system, and the phase retrieval accuracy of the microscope system is higher.Keywords：microscopic measurement;phase retrieval;Transport of Intensity Equation(TIE);4f system;microscopic system- 61
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Published：2020-08-13 -
PF-OFDM dimming control for indoor visible light communication systems
Abstract：To achieve reliable high-speed data transmission and high quality lighting for an indoor Visible Light Communication (VLC), a new indoor visible light high-speed communication dimming control scheme was proposed based on a Pulse Width Modulation (PWM) technique and an Optical Orthogonal Frequency Division Multiplexing (O-OFDM). First, the working principle of Parallel Flip OFDM(PF-OFDM) was introduced and its good compromise performance in power efficiency, spectral efficiency and bit error rate were verified. Then the dimming performance of PF-OFDM system with the PWM technique was adopted and analyzed. Experimental results indicate that the spectral efficiency of the proposed dimming control scheme approximates the DC-biased optical OFDM(DCO-OFDM) system, the dimming range is slightly better than that of the DCO-OFDM system and the Bit Error Ratio(BER) has improved by 3 dB for 16QAM. Therefore, PF-OFDM dimming control scheme obtains better spectral efficiency and BER performance in the mean time without sacrificing illumination quality.Keywords：Visible Light Communication (VLC);dimming control;Parallel Flip-orthogonal Frequency Division Multiplexing(PF-OFDM);dimming range- 51
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Published：2020-08-13 -
Analysis of camouflage jamming effect on spectral imaging by using correlation function
Abstract：To investigate the effectiveness of wider broad-band camouflage jamming on spectral imagers and to evaluate the jamming effect on spectral imaging quantitatively, camouflage jamming tests were carried out with a kind of broad-band camouflage net and a hyperspectral imager. Then,the camouflage jamming effect on the hyperspectral imager was analyzed quantitatively by using correlation function. The results show that, under the test condition, the correlation function between the spectral images before and after camouflaging varies between 0.68 and 0.98 with the target characteristics before being camouflaged, camouflage net layers and the spectral band, thus it can reflect the camouflage jamming effect on spectral images sensitively and accurately, and demonstrate the change of jamming effect with spectral bands conveniently. The evaluation results of jamming effect also accord with that obtained by observing spectral images. So the correlation function could be used to evaluate the jamming effect on spectral imaging quantitatively and impersonally.Keywords：spectral imaging;electro-optical countermeasure;camouflage jamming;evaluation of jamming effect;Correlation function- 49
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Published：2020-08-13 -
Compensation of chromatic aberrations for microstructure press-on prisms
Abstract：As high astigmatism press-on prisms have weak ability to compensate chromatic aberrations in the adjuvant therapies of children strabismus, a method to compensate the chromatic aberrations of press-on prisms was proposed by using a diffraction prism array. The pres-on prism device was composed of a refraction prism array and a diffraction prism array. Both the device structure and the principle of chromatic aberration compensation were discussed, Then, the device was simulated and its aberration compensation ability was analyzed. Theoretical analysis shows that the optimal range of element width of the refraction prism array is 600-800 μm, while the optimal range of element width of diffraction prism array is 15-20 μm. Software simulation results show that the light transmittance of the press-on prisms made of polymethylmethacrylates(PMMA) is 95%, 83% of the spots in the diagram locates inside the Airy spot rings. It concludes that the proposed method is well practical and suitable for compensating the chromatic aberrations in high astigmatism press-on prisms.Keywords：press-on prism;diffraction prism array;chromatic aberration compensation- 37
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Published：2020-08-13 -
Phase shifting fringe profilometry based portable 3D measurement system
Abstract：A portable 3D visual measurement system based on stereo vision and a phase-shift grating was established to implement global 3D profile measurement for a free-form surface object and some corresponding algorithms were analyzed. Firstly, the local data were calculated by using the stereo vision principles, phase shifting profilometry and a multi-frequency heterodyne method. Then, multi-view registrations were achieved by using a target plane. Finally, global measurements were achieved through noise filtering, optimized registration and redundancy filtering for measurement data and complete data were obtained. The experiments were performed to verify the feasibility and accuracy of the system. Experimental results show that the measurement accuracy is about 0.04 mm;single view measurement costs are approximately 10 s;data processing and registration of two neighbor views consume almost 20 s. It indicates that the system can rapidly and completely acquire 3-D surface data of an object with high precision and it can satisfy the application requirements of general objects.Keywords：phase-shifting fringe profilometry;3D measurement system;fringe projection measurement;free-form surface measurement;multi-view registration;data fusion- 47
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Published：2020-08-13 -
Position resolution of quadrant detector for uniform spot
Abstract：To precisely analyze the performance of a position detecting system based on a quadrant detector (QD), the main factors affecting QD position resolution for a uniform spot model were studied. The basic principle of the QD position detection was firstly analyzed. Based on the approximation formula of spot position and according to the error theory, an approximate mathematical model was derived to characterize the relationship between the position resolution and the beam radius, the spot centroid position and the total signal to noise ratio. Finally, an experimental system was designed to verify the validity of the mathematical model. The research results show that the estimation error of position resolution using the mathematical model is about 12% for various radii when the distance between the center of QD and the position of spot is in a half radius range and the total signal to noise ratio is 63.04 dB. Furthermore, the mathematical model could exactly and directly estimate the position resolution of detection system of the QD, which brings great convenience to engineering applications.Keywords：position detection system;quadrant detector;position resolution;uniform spot- 47
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Published：2020-08-13 -
Effect of different liquid and filling modes on thermo sensitive characteristics of photonic crystal fibers
Abstract：By using different methods to fill different types of thermo sensitive liquids, the thermo sensitive characteristics of a high birefringent Photonic Crystal Fiber(PCF) based on hybrid lattices was researched. The relationship of birefringence properties and temperature was investigated using Comsol software in finite element method. The numerical results show that the thermo sensitive characteristics of the PCF are influenced by liquid types and filling methods. When the ethanol is filled in the circular air holes in a core area, the sensitivity of the PCF worked at an excitation wavelength of 1 550 nm is up to 2.5×10-5/℃ with pitch of holes in 1 μm, the diameter of a circular air hole in 0.96 μm and the aspect ratio of rectangular air holes in 4. As compared with that of corresponding PCF structures, the fiber proposed and liquid filling method have higher thermo sensitivity and broader application prospects for high sensitivity temperature sensors.Keywords：photonic crystal fiber;hybrid lattice;filling mode;thermo sensitive liquid;temperature sensing- 59
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Published：2020-08-13 -
Rapid-testing system for intensity spatial distribution characteristics of LED
Abstract：A set of rapid-testing system for intensity spatial distribution characteristics of light-emitting diodes (LEDs) was designed to screen out LEDs with light distribution defects before they leave the factory. This system used optical fibers for collecting light and a contact image sensor for photoelectric conversion. The relationship between sensor output and its corresponding light intensity was established and the intensity distribution properties could be obtained and corrected by comparing with the data of a reference sample. The correlation coefficient was proposed to quantitatively evaluate the difference between tested sample and reference sample. Experimental results indicate that this system can effectively reflect the differences of intensity distributions of light sources. When the correlation coefficient is greater than 0.995, the tested light source can be screened out as a highly correlated one. When the correlation coefficient is less than 0.995 but greater than 0.99, the light source can be screened out as a low correlated one. When the correlation coefficient is less than 0.99, the light source can be screened out as a non-conformity one and should be eliminated. As the system gives up the traditional mechanical transmission, it provides a new measurement method with a high speed, and meets the demands of on-line intensity distribution testing very well.Keywords：Light Emitting Diode(LED) source;spatial light distribution;rapid measurement;screening correlation coefficient- 80
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Published：2020-08-13 -
Solution of plenty of marks in photogrammetry by bundle adjustment
Abstract：How to calculate a plenty of marks in close range industrial photogrammetry was discussed. The optimization method of bundle adjustment was proposed when the number of marks was large. Firstly, the application of the elimination point by point in adjustment calculation was analyzed. The accuracy of adjustment optimization was improved by introducing 10 camera intrinsic parameters of lens distortion. Then, the random function was used to select many marks in the space for bundle adjustment. After several times of partial adjustment optimization, the result could be very close to the level of global adjustment optimization. This way of adjustment not only overcomes the difficulty on out of memory and calculation interrupt in traditional calculation, but also has a high computation speed. Finally, two experiments with 1 360 and 896 marks were performed and the results show that reprojection errors are 0.076 and 0.107 1 after reconstruction respectively. It indicates that the method has a great accuracy and can be used in the actual measurement.Keywords：photogrammetry;point to point method;elimination;bundle adjustment;forward intersection- 43
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Published：2020-08-13 -
Prediction of Crystal structure and electronic structure of CuInS2
Abstract：The structure of CuInS2 crystal at 0 GPa was successfully predicted by using the CALYPSO software in developed particle swarm optimization algorithm. The result shows that the CuInS2 crystal under atmospheric pressure is a tetragonal crystal system, and its space group is I-42 d. The elastic constant matrix of the CuInS2 crystal was calculated, and the obtained elastic constant meets the mechanical stability conditions of the crystal. On the basis of the elastic constant, the volume modulus, young's modulus and shear modulus were calculated. Finally, the hybrid functional method was used to calculate the band structure of CuInS2 and projection state density, respectively. The results show that the CuInS2 crystal is a direct band gap semiconductor with a band gap of 1.22 eV. In order to further analyze the properties of the CuInS2 crystal, the charge density and electron local function were calculated. The results show that the Cu bonding process in CuInS2 has charge transfer, the covalent bonding is between Cu atom and S atom and the ionic bonding is between In atom and S atom.Keywords：CuInS2 crystal;predicted structure;electronic structure;chemical bond- 66
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Published：2020-08-13 -
Detection of optical zero position error for scanning mechanism in spectrometer
Abstract：To detect the error of optical zero position in scanning mechanism of a grating scanning near-infrared spectrometer and to increase the wavelength accuracy of the spectrometer, an image processing method was proposed for measurement of the vertical errors of pendulum and screw in the scanning mechanism when the grating scanning system was in the optical zero position. Firstly, the image of optical zero position was acquired by the image acquisition system. Then, spatial coordinates of relevant elements were calibrated by pixels, and centerlines of screw and pendulum were extracted by using the edge extracting method and least-square curve fitting algorithm. Finally, the angle between screw and pendulum was calculated by equation parameters of fitting centerline, and thus the error detection on optical zero position was realized. The experimental results indicate that the error of the zero position is 1.544° and the measuring precision is 0.083°. The proposed method satisfies the testing requirements for simpleness, non-contact and higher precision. Moreover, it provides theoretical data for compensation of wavelength errors for grating near-infrared spectrometers.Keywords：infrared spectrometer;grating scanning mechanism;error of optical zero position;image processing;measurement accuracy- 44
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Published：2020-08-13 -
Plastic optical fiber evanescent wave sensor for accurate measurement of microalgae biomass
Abstract：A plastic optical fiber sensor with double U-shaped probes (i.e. the sensor and reference probes) was created to accurately measure microalgae biomass. Firstly, two D-shaped fibers were created by a grinding method. The D-shaped fibers were subjected to numerous rounds of heating-cooling treatment to obtain U-shaped ones. One of the prepared U-shaped fibers was employed as the sensing probe and to sense the algal cells and changes in the liquid-phase (concentration and composition), and the other prepared U-shaped fiber coated with a hydrophilic mixed cellulose ester membrane was used as the reference probe to separate the liquids from the cells and to measure the liquid concentration and composition. Furthermore, the plastic optical fiber sensor with double U-shaped probes was implemented based on the sensing probe and the reference probe. A theoretical model was established to examine the performance parameters of the probes and the response properties of the sensor for the microalgae biomass. The measuring results show that the output signal of the prepared sensor is a function of the biomass and is not affected by changes in the liquid-phase composition or concentration.The developed sensor can accurately measure the low and high level biomasses. When the biomass of the chlorella pyrenoidosa in the range of 0-598.998 mg/L (the absorbance at OD680 nm in the range of 0-2.986), the maximum relative error between the fitted curve and the experiment results is 2.46%, and the relative error mean is 1.28%.Keywords：plastic optical fiber;optical fiber sensor;evanescent wave sensor;double probe;microalgae biomass- 62
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Published：2020-08-13 -
X-ray computed laminographic system for plates and shells
Abstract：A Computed Laminiography (CL) imaging system was developed based on the rotation scanning of tilted objects to realize tomographic imaging inspection of plates and shells. The system structure was outlined and the adopted X-ray source, detector and mechanical system were described. Then, according to the X-ray with matter interaction principle, the rotation laminiography scanning mode based on tilted objects was designed and its operation mechanism was analyzed. Furthermore, the algebraic iterative reconstruction algorithm and system geometric calibration method were discussed. Finally,the system was adjusted and the performance testing and the application experiments were carried out. Experimental results indicate that the imaging spatial resolution of the developed system reaches 3 lp/mm and the density resolution is 0.3%. It satisfies the high-precision tomographic imaging inspection requirements of plates and shells and the laminiographic testing performance for plates and shells is superior to that of traditional TC method.Keywords：X-ray Computed Laminiography(CL);image reconstruction;plate and shell;spatial resolution;density resolution- 70
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Published：2020-08-13 -
Sidewall precision analysis of metal part formed by selective laser melting
Abstract：To improve the precision of side wall forming in additive manufacturing of metal parts, a process method was explored in selective laser melting of metal parts. Some phenomena effecting on sidewall precision like powder adhesion, molten pool-end bulge, and thermal deformation were analyzed and corresponding process methods to obviously improve the precision were proposed for different sidewall types. It points out that the precisions of vertical sidewall and sidewall with upward normal can be improved distinctly by using the alternating direction spiral edge-scanning plus inside-filling scanning strategy and maintaining a lower edge-scanning speed. The precision of sidewall with downward normal is strongly affected by thermal stress, but this kind of thermal deformation can be avoided through the appropriate design of scanning strategy and sidewall support. According to process analysis, a metal part with different types of sidewalls was manufactured using selective laser melting technology. Test results show that the size precision of this part reaches ±0.05 mm/10 mm and the surface roughness Rz is 26.7 μm.Keywords：selective laser melting;Additive manufacturing;sidewall forming;metal part;precision analysis- 37
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Published：2020-08-13 -
Preparation and characterization of Eu3+ doped silver borate glasses and their applications in white light emitting diodes
Abstract：The feasibility to produce white light emitting diodes by using glass phosphors was explored, and a series of Eu3+ doped silver borate glasses with various silver contents were prepared via a melt-quenching technique. The structural, spectral and chromatic properties of the glasses were studied. X-ray diffraction (XRD) patterns indicate that there are no silver particles in glasses in the identifiable level that the XRD could reach, but absorption spectra exhibit the existence of silver nanoparticles in the glasses with higher silver contents. Furthermore, the excitation and emission spectra show that the glass samples can be effectively excited by near ultraviolet and can generate emissions covering almost full visible region. Fluorescence decays demonstrate that there are many types of silver aggregates in the glass samples. The color coordinate was calculated, and it shows that white light generation can be obtained from Eu3+ doped silver borate glass samples with certain composition. Finally, a white emitting device was produced by using the glass with the color coordinate of (0.312,0.336) and a color rending index of 0.88 and a 390 nm diode.Keywords：silver borate glass;Eu3+ doping;Ag aggregation;white Light Emitting Diode(LED)- 50
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Published：2020-08-13 -
Optimization of cascaded parabolic compound X-ray refractive lenses
Abstract：To get Compound X-ray Refractive Lenses(CRL) with a short focal length and high gain, the structure parameters of CRL were optimized. And a novel cascaded parabolic CRL made of poly methylmethacrylate(PMMA) was developed by two refractive structures. The main optical performance of cascaded parabolic CRL was derived. And optical properties of the CRL with single structure and the cascaded CRL with two structures were numerically analyzed. The results show that the cascaded CRL imposes a smaller focal length and a higher gain as compared with the CRL with single structure for the same geometric aperture and the radius of curvature. The focal lengths of the designed three cascaded CRLs are shortened by 33.3%, 66.7% and 40.5%, and the gains are increased by 23.9%, 60.9% and 27.6%, respectively. The cascaded CRL is expected to have the ability to adjust the focal performance of ID X-ray beam and has a better application prospect in the micro beam X-ray analysis.Keywords：parabolic lens;cascade X-ray lens;compound refractive lens;optical properties- 45
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Published：2020-08-13 -
Effects of precursor impregnation on mechanical properties of reactive bonded silicon carbide
Abstract：To improve the mechanical properties of the gel-casting reactive bonded silicon carbide, furfuryl alcohol was selected as the precursor, and the porous state green body after degreasing at high temperature was processed by precursor impregnation. It is expected to improve the performance of the silicon carbide by improving its content in the body after reaction sintered. The density and the microstructure after the impregnation process were investigated. The results show that the average density of the sample without impregnation process is 2.93 g/cm3 after reaction sintered, namely the silicon carbide content is 68.2%. The average density increases to 3.06 g/cm3 after impregnation, namely the silicon carbide content is 83.0%. The silicon carbide content increases by 21.7%. The scale of β-SiC generated by furfuryl alcohol pyrolytic carbon is fine. Under the light microscope, the appearance of β-SiC is difficult to distinguish from the original α-SiC, but the distribution of β-SiC is not uniform in the body. A performance test was conducted with the samples. It shows that the average flexure strength has increased from 343.3 MPa to 382.0 MPa after impregnation, and strength increased by 11.3%. The average elastic modulus has increased from 303.5 GPa to 353.8 GPa after impregnation, the elastic modulus increased by 16.6%. These data indicate that the mechanical properties of the silicon carbide have been improved in varying degrees.Keywords：Silicon Carbide;reaction bonding;precursor impregnation- 57
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Published：2020-08-13 -
Performance test of Fourier transform infrared imaging spectrometer
Abstract：The paper researches the measurement methods of key parameters of Fourier transform imaging spectrometers. Firstly, the physical meaning of the key parameter Noise Equivalent Spectral Radiance(NESR) was introduced and corresponding calculation model, test principle and data processing method were given. Then, a calibrated black body was used as radiation source, the performance parameters of Fourier transform imaging spectrometer for mid-wavelength and long-wavelength were tested experimentally, including the NESR, radiometric accuracy and spectral errors. Test results show that the average NESRs of infrared imaging spectrometer for long-wavelength at 10 μm is 21.4 nW/(cm2·sr·cm-1) and that for mid-wavelength at 4.6 μm is 4.6 nW/(cm2·sr·cm-1). The radiometric accuracies of the spectrometer is less than 0.4 K and 2 K for long-wave and mid-wave, respectively. The spectral errors of the spectrometer for both mid-wavelength and long-wavelength are less than half of the spectral resolution. These parameters are all in the normal range, which verifies the feasibility of test method. It provides references for the periodically measurement of imaging spectrometers.Keywords：Fourier transform infrared imaging spectrometer;Noise Equivalent Spectral Radiance(NESR);temperature measurement accuracy;spectral error- 81
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Published：2020-08-13 -
Influence of laser speckle average size on ghost imaging
Abstract：The influence of speckle average size on the ghost imaging with pseudo-thermal light was investigated. A binary image and a grayscale image were used as images of an object to be reconstructed. The reconstruction quality was quantified by Peak Signal to Noise Ratio (PSNR) as the measure, while three sets of reconstructed pictures with different size speckles from small to large were compared intuitively. Four correlation imaging methods including Ghost Imaging (GI), Differential Ghost Imaging (DGI), Compressive-sensing Ghost Imaging (CGI) and Pseudo-inverse Ghost Imaging (PGI) were simulated. Then, several groups of speckle fields with a growing size were used to reconstruct respectively by these methods. The simulation result shows that the PSNRs of GI, DGI and PGI are improved to 7 dB remarkable as the speckle size increasing, while the PSNR of the CGI enhances little. Besides, when the object arm and reference arm are not quite symmetrical in the experiment, the speckle size of two arms are deviated slightly. The reconstruction PSNRs of four methods are decreased as the bias increasing and indistinguishable finally. For a distinguishable reconstruction, the allowable deviations of GI and DGI could be bigger than that of the CGI, in which the PGI is the smallest.Keywords：correlation imaging;laser speckle;ghost imaging;speckle size;two-arm symmetry- 62
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Published：2020-08-13 -
Twin-core fiber SPR sensor with cone angle structure
Abstract：A novel Surface Plasmon Resonance (SPR) sensor was developed based on the twin-core fiber. The fiber grinding technology was employed to fabricate the sensor probe. The twin-core fiber was grinded into a incline plane shape (building the taper angle structure) and was plated the 50 nm thickness gold film on the end surface and 300 nm thickness gold film on the side surface of the fiber. A normal single mode fiber was used to launch the light source power into one core of the twin-core fiber, and a multimode fiber with a core diameter of 110 μm was emplogyed to receive the SPR reflected spectrum. The experiment shows that the SPR sensor based on the twin-core fiber can measure the refractive index of 1.333-1.385, and the testing average sensitivity is 4 769 nm/RIU. As compared with the traditional optical fiber SPR sensor, the novel SPR sensor based on the twin-core fiber has the diameter of 125 μm, which is convenient to integrate in a 5# Syringe needle to monitor bio-information in vivo. The diameter of the fiber core is 8 μm, therefore the beam mode is few, which helps to improve the sensitivity. Besides that, The working range can be moved by changing the fiber grinding angle, and sensitivity can be improved, so the sensor has a great potential applications.Keywords：surface plasmon resonance(SPR);fiber SPR sensor;twin-core fiber;taper angle structure- 54
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Published：2020-08-13 -
Precision conveyance of microwave photon transmit electricity
Abstract：A precision conveyance of microwave photon transmit electricity was researched. The principle of microwave photo transmit electricity and its advantages were introduced. Then, a element configuration and mathematical algorithm models of energy conversion based on the system of remote microwave photon transmit electricity were established. The energy conversion relationships between the blast-off carry and the take-over carry in microwave photon transmit electricity were analyzed. The power SOC (State of Charge) of precision conveyance was researched under ADVISOR software, and power capability was tested on the system of microwave photon transmit electricity. Experimental results show that the system of microwave photon transmit electricity designed and parameter matching are relatively rational, thus the efficient operation of precision conveyance of the purely dynamoelectric type has been achieved. The research helps to enrich and develop the science of microwave photon transmit electricity, and plays an important role in the research and development for new energy precision conveyances.Keywords：microwave photon transmit electricity;precision conveyance;energy conversion- 45
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Published：2020-08-13 -
Application of VirtualLabTM in performance analysis of miniaturized GRIN lenses
Abstract：The application of field-tracing physical optical software VirtualLabTM to the performance analysis of a miniaturized gradient-index (GRIN) lens were investigated. and the basic properties of the miniaturized GRIN lens was introduced, the lens optical model of miniaturized GRIN lens was established in the platform of VirtualLabTM. Then, focusing properties of GRIN lenses with different lengths were simulated. The simulation results show that the miniaturized GRIN lens has a period of 1/2 pitch length and appears strong focusing performance at the length of 1/4 pitch, which is consistent with related theory. The experimental results verify that the research on periodicity of focusing performance for GRIN lenses can provide theoretical basis and effective methods for design and fabrication of smaller optical probes. Moreover, the VirtualLabTM is confirmed to be an intuitive and effective tool to optics design and analysis and is applicable to miniaturized investigation of GRIN lenses.Keywords：Gradient Index(GRIN) lens;focusing performance;field-tracing;VirtualLabTM;pitch- 32
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Published：2020-08-13 -
Progressive approach characteristic window filtering for HTV background suppression in supersonic combustion field
Abstract：To improve speed measuring accuracy of Hydroxyl Tagging Velocimetry(HTV)in a complex and special supersonic combustion flow field, a progressive approach characteristic window filtering was proposed to do the meticulous measurement. Firstly, the influence of background noise of the supersonic combustion flow field on the image processing of the HTV measurement was analyzed. Then, on the basis of the background suppression by the window filtering, the deformation, distortion, blur of HTV tag line caused by the flow rate change in fuel flow field significantly in some locations were processed by taking the partition processing method, the filter window was gradually narrowed, and the tag line along the width direction of the image within the window for each partition was approached to Gaussian distribution. By combined with image analysis methods in median filtering, the HTV background removal method was achieved for the combustion flow field. The feasibility of the method was analyzed and discussed, and corresponding parameters were determined by the experimental processing. Comparison of experimental data shows that after optimization, the Signal to Noise Ratio(SNR) is greatly improved, the accuracy has increased by 18.8%, which satisfies the system requirements of the HTV application for the SNR and measurement precision.- 45
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Published：2020-08-13 -
Spectral detection with high spectral resolution and high signal-to-noise ratio based on remote sensing monitoring
Abstract：To invert precisely the CO2 concentration in atmosphere by the green-house gas information obtained by satellite remote sensing, this paper researches the high spectral detection technology with high spectral resolution and high Signal-to-Noise Ratio(SNR). A method of fine spectrum splitting was demonstrated using a large area diffractive grating at three spectral bands of 0.76,1.61,2.06μm. According to the theory of remote sensing detection, the theoretical SNRs of the three bands were deduced to reveal the restrict relation between the spectral resolution and the SNR. The detectors with large pixel sizes and high quantum efficiency were selected to detect the weak signal with high SNR by using methods of pixel combination and blind pixel correction. A spectral calibration facility was established to measure the instrument line shapes(ILSs) of the three bands, and the center wavelength and the full-width at half maximum(FWHM) of each spectral channel were determined with a Gaussian fit to the core of each ILS. The results of the spectral calibration indicate that the spectral resolution is 0.04 nm. The above-mentioned study provides the basis for the realization of accurate detection of absorption spectra and 1-4×10-6 reversion precision of CO2.Keywords：spectral resolution;signal-to-noise ratio;spectral calibration;satellite remote sensing- 40
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Published：2020-08-13 -
Improvement of depth calibration for digital projection 3D measurement system
Abstract：On the basis of measuring principle and existing calibration technology, an improved depth calibration method was presented. After analysis of the coordinate transforming relation between reference plane and imaging plane of an ordinary geometry setting system, the mapping relation between the depth and the phase difference was established. Then, the reverse calibration process was given. The position restriction of a projection system and an imaging system was relaxed by the new calibration model. In the calibration process, calibration parameters were irrelevant to pixel coordinate values, so every pixel did not need its calibration parameters. Compared with the original method, the new method greatly reduces the calculative complexity and storage space of calibration parameters. Two calibration methods were used to calibrate the measurement system respectively. Then, a flat object was measured by different calibration systems, the results were compared and measuring errors were analyzed. The results show that the measured PV value of the object with the new method is smaller than that of the original method. In the Z direction(0 to 48 mm), the standard deviation of PV values is 0.0036 mm, which verifies the validity of the improved method. This research has positive significance on enhancing calibration efficiency and operability for digital projection measurement systems.Keywords：optical measurement;three dimensional measurement;digital projection;depth calibration- 42
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Published：2020-08-13 -
Measurement of ship distributed deformation based on embedded system
Abstract：To detect distributed deformation angles in real-time for large measuring and weapon devices mounted on large ships, as well as to improve the ability of controlling and real-time monitoring to each measurement point, a measuring system for the distributed deformation was realized based on an embedded system.The hardware design, the realization of software and corresponding algorithm were explored. Firstly, comparing to the previous measurement method with distributed sampling, central obtaining data and calculating data, a new model of distributed measurement was proposed. And Simple Network Manegement Protocol(SNMP) was selected to realize the remote control of all devices. Then the structure of the protocol and its composition were introduced. A hardware platform was designed for the distributed deformation devices of each measurement point based on ARM+DSP+FPGA structure. After that, the software was developed on the WinCE operation system and the flow process was discussed. Finally, the experiment of system was executed both on deformation measurement and SNMP control. Experimental result shows that the device can obtain the precision within 5" without network congestion problems caused by image acquisition as the previous devices. And the capability of extending and administrating has been enhanced.Keywords：ship measuring platform;distributed deformation measurement(SNMP) protocol;embedded system- 82
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Published：2020-08-13 -
Efficient hybrid white organic light-emitting devices based on ambipolar blue fluorescent material
Abstract：Efficient hybrid White organic Light Emitting Devices(WOLEDs) were developed using an ambipolar blue fluorescent emitter 2-diphenyl-amino-7-(2,2"-diphenylvinyl)-9,9'-spirobifluorene(DPV) and the yellow phosperescent material(BT)2Ir(acac). By using two different materials for a Hole Transmitting Layer(HTL) and analyzing the curves of normalized EL spectra and efficiency, the effects of the energy level, triplet energies and charge transporting properties of the ambipolar blue materials on the performance of the devices were obtained. The white device with higher efficiency, better roll-off efficiency and a stable color coordinate also was obtained. Then 4,4',4"-tris(N-carbazolyl)-triphenylamine(TCTA) was introduced as an exciton blocking layer between blue and yellow light emitting layers, the high triplet energy and hole transporting characteristic of the TCTA were utilized, and the white light emitting efficiency of the device was improved. The WOLED has a maximum current efficiency of 10.15 cd/A, furthermore, it shows a efficiency roll-off of 35.7% from the brightness at maximum current efficiency to 10000 cd/m2.Keywords：Fluorescence/Phosphorescence White Organic Lightemitting Device(F/P WOLED);ambipolar blue fluorescent material;Hole Transmitting Layer(HTL);exiton blocking layer- 42
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Published：2020-08-13 -
Automatic precision assembly system for trans-scale miniature parts
Abstract：An automated precision assembly system for the part with a trans-scale structure is developed in the paper. Based on the analysis of assembly task, the system uses a modular architecture, including computer control and human-machine interaction module, 3-DOF(Degree of Freedom) operation manipulator module, 1-DOF operation workstation module, 4-DOF visual measurement and screw assembly module, 1-DOF charging module and operation tool library module. According to the characteristics of the trans-scale part and assembly accuracy, the visual measurement module of this system is based on the Look and Move mode control strategy. To solve the problem of blind spot detection, the manipulator module is based on impedance control strategy to control the force of part assembly and the screw assembly module adopts the torque/time control method to realize the consistency of the pre-tightening force of the screw assembly. The results of assembly experiment for a miniature device show that the error of the coaxial degree is less than 13μm and the parallelism degree is less than 10μm. The assembly accuracy meets assembly requirements of miniature devices.Keywords：Micro-electro-mechanism System(MEMS);trans-scale miniature part;precision assembly;machine vision- 58
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Published：2020-08-13 -
Experiment on main factors affecting surface roughness in ultra-precision fly cutting
Abstract：To optimize the surface roughness in ultra-precision fly cutting machining, a number of experiments were conducted to analysis on the changes of main factors affecting the surface roughness. On the basis of the processing principle of ultra-precision fly cutting machine, the main factors affecting surface roughness were analyzed theoretically. To obtain an optimized parameter combination, the experimental results were compared with the theoretical results of different cutting parameters by using the control variable method. Experimental results indicate that the surface roughness and blade ripples are sensitive to low spindle speed and high feed rate, but is not sensitive to cutting depth. Meanwhile, under the cutting conditions in spindle speed of 400 r/min, feed rate of 60μm/s, cutting depth within 6μm, the surface roughness is better than 7.5 nm, and shows a smooth surface. It concludes that choosing reasonable processing parameters allows to optimize the surface roughness and improve the machining efficiency.Keywords：ultra-precision fly cutting;surface roughness;spindle speed;feed rate;cutting depth- 56
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Published：2020-08-13 -
Coupled feed phased array antenna integrated with MEMS phase shifter
Abstract：The structure design of a MEMS(Micro-electromechanical System) phase shifter used in phase array antennas was studied and its integration method with a coupled feed phased array antenna was given. The length of the transmission line according to the phase shift principle and the beam scanning principle was calculated. Then, the cantilever MEMS switch was designed and the optimization method of the switch was summarized. Finally, the integration method of the MEMS phase shifter with the coupled feed antenna array was presented. The results show that the insertion loss and the isolation of the optimized switch are less than 0.2 dB and more than-15 dB within 25 GHz, respectively. The phase shifter has a good impedance matching in 15 GHz-20 GHz, and its phase shift characteristics vary linearly. The shift phase is 45° with a maximum phase error of ±5°. The 2×2 MEMS coupled antenna array integration with this phase shifter can complete a beam steering angle of ±30° at 17.3 GHz. The highest gain of the array is 9.3 dB. This phase shifter meets low-cost monolithic integrated demand of the phased array antennas.Keywords：Micro-elecromechanical System(MEMS);MEMS phase shifter;switched-line phase shifter;MEMS switch;monolithic integration;phased array antenna- 47
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Published：2020-08-13 -
Mounted dynamic characteristics of washer type piezoelectric six-axis force sensors
Abstract：To research dynamic characteristics of a washer type piezoelectric six-axis force sensor in a practical measurement, simulation method and calibration method of the mounted dynamic characteristics were presented. According to the working principle and the structural characteristics of the washer type piezoelectric six-axis force sensor, the research methods for mounted dynamic characteristics of the sensor were analyzed. Then, in accordance with experiment prototype parameters of the pre-stressed washer type piezoelectric six-axis force sensor, its numerical model was established, and the numerical simulation method and mounted dynamic characteristics were investigated. Finally, the dynamic calibration method for mounted resonance frequency of the sensor was developed. Experimental results indicate that the mounted resonance frequency of washer type piezoelectric six-axis force sensor is more than 3.9 kHz, and the results of the numerical simulation method are consistent with calibration results. The mounted resonance frequency of the sensor is superior to that of the available technology. The proposed simulation and calibration methods can be used in the prediction and calibration of the mounted resonance frequency of this kinds of sensors.Keywords：piezoelectric six-axis force sensor;mounting;Finite Element Method(FEM);calibration;dynamic characteristic- 40
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Published：2020-08-13 -
Droplet-based encapsulating of shrimp oocyte actuated by microfluidic pulse inertial force
Abstract：The existing droplet-based single cell encapsulation technology controlled by micro-fluidics is usually used to encapsulate micro cells with the scale of 10 micrometer and it shows disadvantages of low single cell encapsulating rates and low survival rates. In consideration of the microfluidic pulse driving technology can produce aqueous phase droplets in an oil phase environment and can precisely control the droplet size, this paper proposes a droplet-based encapsulating method of shrimp oocyte actuated by microfluidic pulse inertia force and establishes an experiment device for encapsulating large scale cells into single micro droplet. It researches the influence of microfluidic driving parameters on the droplet size and single cell encapsulating rate. By adjusting the size of a micro-nozzle and driving voltage, the aqueous phase micro droplet with a diameter of 70-180μm is obtained, and the regular arrangement of shrimp oocyte in the micro-nozzle is implemented in different locations on the axis direction of the nozzle arrangement. A single droplet randomly encapsulated with one, two, three or four cells is realized. The single cell encapsulating rate has reached by 40%. The results can provide references for larger scale cell encapsulation method.Keywords：micro fluidic pulse actuation;pulse inertial force;Micro-droplet;cell analyzing;oocyte- 44
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Published：2020-08-13 -
Fabrication of microelectrodes based on microfluidic pulse inertial jetting technology
Abstract：A fabrication system for microelectrodes was set up based on the microfuidic pulse inertial jetting on-demand technology. The conductive ink was used as a jetting meterial and it was jetted on a cleaned cover glass substrate to form the designed microelectrode pattern in a certain overlap rate. Then the pattern on the cover glass substrate was sintered to form a microelectrode in an oven at 140℃ for 25 min. The influences of the micro-nozzle diameter and driving voltage on the droplet diameter were researched, as well as the influences of droplet diameter and the overlap rate on the width of the microelectrode pattern. Finally, several different microelectrodes with various shapes were fabricated. The conductive uniformity and the stability of the microelectrodes were measured. The experimental results indicate that the fabrication of microelectrodes based on the microfuidic pulse inertial jetting on-demand technology has many advantages on the simple fabrication process, lower cost and non-surface treatment. Furthermore, the microelectrodes have several merits such as size controllability, good conductivity uniformity and the stability of morphology and resistance.Keywords：microfuidic pulse inertial jetting;microelectrode;cover glass substrate;various shape- 63
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Published：2020-08-13 -
Technological experiments of laser high-speed impact spot welding
Abstract：A solid state spot welding technique based on the laser induced shock waves was proposed to achieve the solid-state spot welding between dissimilar metal combinations with the thickness less than 100μm. An experimental platform of laser impact spot welding was designed and built. In welding, 30μm Ti and T2 pure copper were chosen as the flyer plates, and 100μm Al as the base plate. Parameters including collide angle, impact velocity and the standoff distance, which mainly affect the welding quality, were investigated theoretically and experimentally. The Smooth Particle Hydrodynamic(SPH) method in AUTODYN was applied to simulation of laser impact spot welding process. It is shown that with the increases of impact velocity and standoff distance, the interface morphology turns from straight to small wavy and finally to vortex wavy. Finally, a central un-bonded region and a circular bonded region are duplicated. Moreover, it is shown that when the shear stress direction is opposite and the effective plastic strain is above 0.4 at the interfaces the successful bond can be achieved.Keywords：laser impact spot welding;laser induced shock wave;collision angel;standoff distance;impact velocity;weld interface- 60
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Published：2020-08-13 -
CMAC/PD-based compound control of inertially stabilized platform for aerial remote sensing
Abstract：For improving the standard of stability and precision of an Inertially Stabilized Platform(ISP) for aerial remote sensing, this paper introduces a modified Cerebellar Model Articulation Controller(CMAC)/Proportional and Derivative controller(PD) compound control method of the ISP frame servo system for aerial remote sensing based on variable confidence coefficient. First, the frame servo system model of ISP three-axis is established for aerial remote sensing. Then the modified CMAC controller and the PD controller are established. In order to enhance the precision of servo system, the modified CMAC controller and PD controller are respectively added in the feedforward and feedback paths. Finally, the parameters of modified CMAC/PD compound controller are adjusted. Experimental results indicate that the pitch frame angular position maximum precision of the system's by modified CMAC/PD compound controller is 0.2154°, and the RMS of angular position is 0.0775°. As compared to the normal PID control method, they respectively reduce by 42.97% and 29.86%. The mentioned modified CMAC/PD compound control method of ISP frame servo system observably reduces the influence of unknown disturbances, and efficiently improves the control precision of ISP servo system for aerial remote sensing.Keywords：aerial remote sensing;Inertially Stabilized Platform(ISP);frame position servo system;Modified cerebellar Model Articulation Controller/Proportional and Derivative Controller(CMAC/PD) compound control;system control precision- 55
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Published：2020-08-13 -
Fault component extraction of engine based on abnormal sound
Abstract：An approach of fault component extraction for abnormal sound was proposed to realize the online automatic diagnosis of engines. In the method, an overlap superimposed method was proposed for noise elimination, and the correlation analysis and the beginning position of dislocation superimposed interception signal searching method were used to establish the signal analysis system. Firstly, the local extreme value of abnormal sound was used to determine the beginning position of abnormal sound appearance and to calculate the length of interception signal according to the separation distance of the adjacent starting points. Then, these intercepted signals were linearly superposed together to acquire the fault component. Furthermore, the error of extracted signal was analyzed and the effect factors on the errors were obtained. Finally, the cross-correlation analysis method was adopted to identify the results. Experimental results indicate that the relevance among several extracted signals reaches to 75% by the dislocation method, which can be used for fault diagnosis. The method is no complicated time frequency conversion process in extracting fault components and has advantages in simple operation and high accuracy.Keywords：engine;abnormal sound;fault component extraction;overlap superimposing;cross correlation- 55
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Published：2020-08-13 -
Experiment and simulation on porous aerostatic bearing based on material properties
Abstract：To improve the numerical simulation accuracy of a porous aerostatic bearing, porous material characteristics were investigated. For typical porous graphite materials, permeability and pore characteristics were measured, and a hydrodynamic lubrication model for inertial flow and velocity slip was established. Then the numerical simulation model was established to solve the hydrodynamic lubrication model and to analyze the influence of permeability and porosity on the thrust stiffness characteristics of bearing. Finally, an experiment platform was constructed to measure the thrust stiffness of the bearing. The experimental results show that thrust stiffness characteristics of porous aerostatic bearing are predicted accurately by numerical simulation model proposed, and the accuracy of numerical simulation can be improved significantly when appropriate material characteristics are input in the hydrodynamic lubrication model.- 72
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Published：2020-08-13 -
Vibration error compensation of high speed and high precision positioning platform
Abstract：A macro-micro-combined positioning system was built to reduce the vibration error of the positioning platform in the Z direction and to realize its high precision positioning. It was driven by a high performance linear motor. The micron-level large-stroke position was done in the macro-moving platform supported and guided by a static pressure gas guide rail. The position accuracy in Z direction was compensated by the micro platform driven by piezoelectric ceramics installed in the macro-moving platform. Then the Z direction vibration model of this positioning system was established, where the fuzzy PID control strategy was used. Furthermore, the output position signal of the positioning terminal detected by a capacitive small-displacement sensor in real-time was treated as the input signal of micro-moving platform to achieve closed loop feedback control of positioning system, and the real-time compensation of vibration error of the macro moving system was ultimately impletemented. Experimental results indicate that the micro compensating platform designed has good dynamic characteristics and real time error compensation effect. For Z direction positioning, the vibration range is reduced from 6μm to 2μm after compensation. The results show that the vibration error compensation method studied in this paper can efficiently reduce the vibration error of the positioning system and improve the positioning accuracy.Keywords：macro micro positioning platform;vibration model;piezoelectric ceramics;error compensation- 40
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Published：2020-08-13 -
Spiral-driving linear piezoelectric actuator based on exponential amplitude transformer
Abstract：To miniaturize the driving unit in a micro-electro-mechanical system, a spiral-driving linear piezoelectric actuator based on an exponential amplitude transformer was designed. the operation mechanism of the actuator was analyzed, and the screw pairs of stator and the exponential amplitude transformer were designed. Then, the stator vibration modes were analyzed by finite element software in simulation. At last, the dimension of actuator was determined, the prototype was made, an experimental platform was established and the actuator output performance was tested. Under the conditions of an effective voltage of 300 V, resonant frequency of 15.6 kHz, the phase difference between two driving voltages of π/2, the actuator reaches a maximum linear velocity of 3.392 mm/s, and the output force of 15.02 N. The test results indicate that the actuator has a good output performance, and it can be employed in MEMS driving unit to meet the demands of subminiature equipment for the micro feed.Keywords：linear piezoelectric actuator;exponential amplitude transformer;spiral-driving;bending vibration- 60
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Published：2020-08-13 -
Resistance detection method for microfluidic oil detection chip
Abstract：To improve the measuring accuracy and sensitivity of a microfluidic oil detection chip in detecting the non-ferrous metallic debris in oil, this paper presents a resistance analysis method based on the inductive analysis method adopted in previous measurement. Then it researches the resistance signal output characteristics of the detection chip. The principle and defects of the inductive analysis method are introduced. The detection chip and detection system are designed. Finally, the resistance signal output characteristic of microfluidic oil detection chip is analyzed on the basis of experiments. The experimental results show that the detection accuracy of the proposed method is higher than that of the resistance analysis method when copper particles have the size under 80μm. The resistance change is 0.2093Ω with the inductance coil of 800 turns when the other parameters are constant. Moreorer, The resistance change of coil is 0.1857Ω when the micro-channel has a diameter of 230μm. In respect of detecting copper particles with a size under 80μm, the accuracy of resistance analysis method is higher than that of the inductive analysis method. Meanwhile, there is a linear relationship between the resistance change and the inductance coil turns of chip, and the same is true for the relationship between the channel diameter and the resistance variation.- 47
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Published：2020-08-13 -
Geometric error identification and compensation of complex CNC grinding machine
Abstract：A complex Computed Numerical Control(CNC) grinding precision machining equation was established to improve the machining precision of the composite CNC grinding machine. A software for the corresponding compensation was developed, and the precision modeling, error identification, error compensation, etc. for the complex CNC grinding machine were researched. Firstly, the multi-body system modeling theory was used to analyze the CNC thread grinder modeling. The precision machining equation of CNC grinding machine was established. Then all the composite errors of CNC grinding machine were identified by using a laser interferometer. Finally, the error before and after error compensation were forecasted and the feasibility of the theory for geometric error compensation was finally verified. The simulation results show that errors have been decreased by 66.55%, 66.65% and 66.35% in X axis, Z axis and C axis, respectively, and the integrated error for three axis has reduced by 66.51%. It concludes that the error compensation technology can be used in thread processing fields and can improve the machining accuracy of the CNC grinding machines.- 60
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Published：2020-08-13 -
Load spectra of NC machine tools considering multiple influence factors
Abstract：A method to establish the representative load spectrum for probability-reliability design of Numerical Control(NC) machine tools was proposed by considering multiple working conditions and multiple influence factors to improve its reliability essentially. Firstly, the ratio of feeding length to feed speed was set as fatigue loading cycles, the ratio of loading cycles to total loading cycles was set as relative loading cycles, and the ratio of working load to the specified load of machine tools as relative load. Then, the load distribution function of a relative load vs. relative loading cycles was established using statistical analysis. In view of the situation that the load data obeyed different distribution functions, a data envelopment analysis method in which multiple error information was taken as evaluation factors was proposed to determine the best distribution model. The application results show that load spectrum of NC machine tools can be accurately established using this method. The load data of tested NC machine tools follow the gamma distribution with α=0.37 and β=0.53. The load spectrum meets the requirements of probability-reliability design of NC machine tools.Keywords：numerical control machine;machine tool;load spectrum;Data Envelopment Analysis(DEA);Reliability- 42
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Published：2020-08-13 -
Fabrication of multicomponent microcapsule based on pulse driving microfluid injection
Abstract：A method for multicomponent microcapsule molding was proposed by combination of pulse driving microfluid injection with glass micro fluid devices. The electromagnet acuator was exerted a periodical field, which allowed the solid wall of micro mozzle conneted to the acuator to move periodically and the pulse micro fluidic and jetting of different flows were implemented. Firstly, the influences of the system parameters on the stable micro injection of shell material sodium alginate solution were researched. The driving voltage amplitude range is from 6 V to 15 V. Then the multicomponent microcapsule molding experiments were carried out. The glass bead and olive oil were multilayered and encapsulated by using coaxial type micro nozzle, the "θ" structured compartment microcapsule were encapsulated by using the Y type micro nozzle, and the two core materials and compartment microcapsule was encapsulated by using the Y-coaxial type micro nozzle. Experimental results indicate that the multicomponent microcapsules molded by pulse driving microfluids injection have regular appearance, the multiple components can expand the function of single component capsule, and the multi compartments can protect each of the core ingredients from each other and from the environment. The technology has advantages over simple process, no high voltage electric field and the multi core materials including powder and liquid can be encapsulated.Keywords：microfluid pulse driving;micro injection;multicomponent microcapsule;combined micro nozzle- 46
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Published：2020-08-13 -
Preparation of flexible concave microlens array based on micro-jetting and liquid molding method
Abstract：The the flexible concave microlen array was fabricated based on the micro-droplet jetting and liquid molding methods. By using jetting fabrication system of micro-droplet array, the glycerin solution was jetted on the glass substrate coated with the hydrophilic film treated by TiO2 nanoparticles, and a micro-liquid array under the Wenzel state was formed on the glass substrate due to surface tension and hydrophilic effect. Then, the flexible concave was obtained by a liquid molding process using the polydimethylsiloxane(PDMS). The result shows that the micro-droplets are highly homogeneous and are well aligned. The final fabricated concave microlen arrays still have good geometric characteristic. The influences of the PDMS mixed liquid casting process on the Wenzel state micro-droplet and Young state micro-drolet were studied and the result shows that the micro-droplet under the Wenzel state keeps an original shape after the mixed PDMS liquid was casted on them. Through the projection image experiment of the concave microlens array, the clear, erected, shrunken and virtual image of the concave micro-lens array was obtained. The experimental process and result indicate that the jetting fabrication of the concave micro-lens array using the micro-droplet jetting technology and liquid molding method has many advantages, such as the simple fabrication process, low cost, low environmental requirements and the final fabricated PDMS concave micro-lens has good geometry and optical performance.Keywords：concave microlen array;micro-jetting;liquid molding- 60
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Published：2020-08-13 -
Vibration detectors with carbon fiber cantilever
Abstract：Many kinds of grating vibration detectors have been developed to predict earthquakes in recent years. Based on carbon fiber cantilever, a fiber Bragg grating vibration detector was fabricated in this paper. Then, four different vibration detectors were made based on three different carbon fiber cantilever structures, involving in cantilever beam, narrow cantilever beam and the trapezoidal cantilever. By introducing a mass body in 3.0486 g, the vibration detectors were tested in the same temperature. By analysing the vibration data and curves of the four vibration detectors, the best cantilever beam stucture was chosen. After analyzing the effects of different cantilever structures on the response ability of detectors, the antilever vibration detector with good static and dynamic curves of the response to the vibration detector were realized by further optimization of the bob-weight, fiber grating fixation and the proportion of rubber compound. The sensitivity of the vibration detector is 200 V/m·s-1 at work wavelength of 1550 nm.Keywords：fiber Bragg grating;vibration sensor;cantilever;carbon fiber;seismic survey- 61
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Published：2020-08-13 -
Data amalgamation of coarse and fine channels and error correction of inductosyn
Abstract：In order to improve the measurement precision of on inductosyn and to reduce the impact of noise and craft of the system on the output angle data, the paper discusses the data arithmetic and implementation on the amalgamation and correction of the actual system of inductosyn. Based on the problems from zero warp of dual channels of inductosyn, the amalgamation algorithms using correction table for dealing with the leaping dot of coarse data are presented. Then a data amalgamation method is proposed for the actual system to process the variational channel numbers. It confirms the beginning dot using actual measurement data and judges the validity using four quadrants. Finally, the angle error correction method based on the piecewise linear interpolation is discussed as well. A Field Programming Gate Array(FPGA) is used to implement and verify the proposed method. Experimental results indicate that the precision of the system of inductosyn is 3" after using the two methods above. It can satisfy the system requirements for reliability, precision, stabilization, as well as strong anti-jamming.Keywords：Inductosyn;angle measurement;data amalgamation of coarse and fine channels;error correction- 48
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Published：2020-08-13 -
Response surface experiments of effect factors on temperature in high speed cutting
Abstract：On the basis of the response surface method, the influences of main high speed cutting factors on cutting temperatures in AISI1045 steel cutting processing were researched. A high-speed cutting temperature measurement test system was established. The tests with four factors and three levels were designed by applying Box-Behnken Design(BBD) response surface experimental design method considering the cutting speed, feed, axial cutting depth and the radial cutting width. Then, the effects of various factors on high-speed cutting temperature and temperature range were analyzed. Results show that when the feed is 0.05-0.11 mm, the cutting temperature rises slowly with cutting speed increasing; when the feed is greater than 0.11 mm, the cutting temperature decreases slowly with cutting speed increasing. However, when cutting speed maintains unchanged, the cutting temperature increases linearly with axial cutting depth increasing. When axial cutting depth is less than 1.5 mm, the cutting temperature first decreases then increases with radial cutting width increasing; when axial cutting depth is greater than 1.5 mm, the cutting temperature increases with radial cutting width increasing linearly. Comprehensive analysis shows that feed and axial cutting depth effect on cutting temperature changes more significant.Keywords：high speed cutting;cutting parameter;temperature measurement;response surface analysis- 45
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Published：2020-08-13 -
Detection system of small particles in hydraulic oil
Abstract：To help the fault prediction and diagnosis of a hydracelic system, a simple and effective optical detection system was designed to detect rapidly small particles in hydraulic oil. The light blocking optical method was used in this paper, the microfluidic detection chip for hydraulic oil detection was designed and fabricated, and flow speed and the trajectory of oil in a focus area were simulated by ANSYS software. The experiments of particle detection, counting and particle concentration detection were performed in the optical detection system, the data and signal in the experiments were analyzed with optical detection principle. Experimental results indicate that the signal-to-noise ratio of 20μm particle is higher, and the counting of particles is realized by JAVA program. The amplitude of signal increases with increasing particle concentration, and the signal amplitude caused by 2000×10-6 is 6 times as high as that caused by 100×10-6. The miacrofluidic chip and the detection system designed in the paper realize the rapid detection of small particles with the diameter larger than 20μm in hydraulic oil, and the oil with different particle concentrations can be distinguished.Keywords：hydraulic oil;microfluidic detection chip;particle detection;fault diagnosis- 46
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Published：2020-08-13 -
Micro-channel shapes and obstacle layout in passive micromixers
Abstract：This paper focuses on optimizing the micro-channel shapes and obstacle layouts in the micro-channel to enhance the mixing effect of a passive micromixers. Experiments show that changing the channel shape and setting obstacles can enhance chaotic convection in the passive mixer, and they are simple methods to improve the sample mixing efficiency. Six kinds of channel shapes and two kinds of obstacle layouts have completed and simulated. The mixing efficiency in sequence is:the square-wave >the multi-wave >the zigzag >the T-shape >the mouth shape >the loop. Finally, the obstacle layout in the best microchannel-the square-wave microchannel is compared and its effect on the mixing effeciency of the mixer is studied. So the asymmetry layout of obstacles has been obtained, which can be applied to the fluid mixing at Pe less than 750. Simulation results show that optimized design of the channel shape and obstacle layout can improve effectively sample mixing efficiency in the passive micromixer. It is verified that the optimization of the structure is an effective design of microfluidic devices.Keywords：passive mixer;micro-channel shape;obstacle layout;simulation- 52
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Published：2020-08-13 -
Electromechanical system in ultra-precision cutting machine tool and its application in processing of Fresnel lens mold
Abstract：For processing micro groove Fresnel lens mold, the cutting technology and electromechanical system of an ultra precision cutting machine tool with a B rotary axis were designed. Mechanical modules of the machine tool were presented, and a motor drive and an encoder feedback system were designed. By applying linear motor direct drive, the Heidaenhain nano-scale linear encoder signal subdivided by the motor driver was used for closed-loop feedback. Electric control system of the ultra precision cutting machine tool was designed, of which the NC system was open whole soft type PA NC. The straightness error of a guide is 0.15μm/200 m. For the B rotary axis, its positioning accuracy is 3", and the rotary displacement resolution is 0.036". In the cutting experiments, flat surface(Ф280 mm), semi-sphere(Ф100 mm), complex curved surface was machined. And the Fresnel lens mold was processed by the method of rotary B-axis. The experiments show that the surface roughness Ra of flat surface is 5 nm, and the surface roughness Ra of Fresnel lens mold is 7.3 nm. The results show that it is feasible that the process technology of Fresnel lens mold is based on the high precision rotary B-axis.Keywords：Ultra precision cutting machine tool;Electromechanical system;PA Numerical Control(NC) system;Mirror finish;Fresnel lens;mold processing- 47
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Published：2020-08-13 -
DRNN feedforward-PD feedback control for precision positioning stage based on giant magnetostrictive actuator
Abstract：The Jiles-Atherton hysteresis model and the Dynamic Recurrent Neural Network(DRNN) feedforward-PD feedback control strategy were adopted to improve the positioning accuracy of precision positioning stage based on a Giant Magnetostrictive Actuator(GMA). An accurate hysteresis nonlinearity model of the precision positioning stage was established with the Jiles-Atherton model. A dynamics inverse model of the precision positioning stage was established with the DRNN learning method to compensate the hysteresis nonlinearity characteristic. The closed-loop PD feedback control was used to compensate the mapping error and to suppress the disturbance of DRNN. Using these control methods, the positioning accuracy of the precision positioning stage was improved. The research results show that the Jiles-Atherton hysteresis model can describe the hysteresis nonlinear characteristic of the precision positioning stage, and that DRNN feedforward-PD feedback control strategy can eliminate the nonlinear characteristics of the system, which has practical significance for improving positioning accuracy of the precision positioning stage based on the GMA.Keywords：Giant Magnetostrictive Actuator(GMA);hysteresis nonlinearly;Dynamic Recurrent Neural Network(DRNN);positioning stage;positioning accuracy- 65
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Published：2020-08-13 -
Compliance analysis for thinned right-circular flexure hinge with three degrees of freedom
Abstract：As common flexures in a parallel mechanism usually are machined in different directions, and it is difficult to integrate with a monolithie configuration, this paper proposes a thinned right-circular flexure hinge with three degrees of freedom. The flexure hinge can be fabricated merely along one direction, and is benefit for the spherical hinge applied in positioning mechanism with monolithic configuration. Based on Castigliano's displacement theorem, the compliance formulas of the thinned right-circular flexure hinge were derived. Finite element analysis was adopted to verify the compliance formulas and analyze the effect of the structure parameters on the compliance of the flexure hinge. Two cases on the compliance design for the application of the flexure hinge were discussed. The results show that the maximum variance between the theoretically calculated compliance value and the finite element analysis compliance value is within 20%. The parameters with the greatest impact on the compliance of the flexure hinge are the thickness b, the minimum notch spacing t, and the fillet radius r, successively. The above conclusions provide principles for the design and application of the thinned right-circular flexure hinge with three degrees of freedom.Keywords：thinned right-circular flexure hinge;three degrees of freedom;compliance analysis;Castigliano's displacement theorem- 67
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Published：2020-08-13 -
Application of waveform correlation algorithm in ultrasonic thickness testing
Abstract：The pipe wall of Compressed Natural Gas(CNG) storage well will be thinned locally because of the corrosion of drain fluids and underground water in the well for a long time, and the remaining thickness of the pipe wall can decide the service life of pipe. This paper proposes an improved thickness measuring method to overcome the shortcoming of the traditional ultrasonic detection method in larger data mounts, much interference and lower measuring accuracy. In the proposed algorithm, the eigenvalue search and waveform correlation algorithm are exploited for echo time acquisition and theoretical analysis. The detection principle and corresponding algorithm are described, and effect factors on measuring accuracy is analyzed. By taking a sample tube as the testing object, the experiments are carried out. Finally, the algorithm is used in the field detection of the CNG storage well. The CNG storage wells of 6 gas stations in Jiangsu Province is detected, and the feasibility of proposed algorithm based on waveform correlation was verified. The results show that the accuracy of thickness measuring is up to 0.03 mm, which is better than others in pipe erosion thickness testing.Keywords：storage well;Pipe;pipe wall thickness;ultrasonic thickness testing;waveform correlation algorithm- 53
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Published：2020-08-13 -
Cutting force test for ultra-precision flycutting optical crystal
Abstract：To reduce the impact phenomenon in flycutting machining of an optical crystal and to improve the surface quality of the optical crystal, a prediction model was set up experimentally for the relationship between cutting force and machining parameters. Based on the processing principle of flycutting machining, the prediction model for cutting force was built by response surface methodology(RSM). Then, a cutting force experiment for the optical crystal was conducted under the parameters designed by Taguchi method. After that, the prediction model was achieved by using the experimental data, and the accuracy of the model was analyzed by analysis of variance(ANOVA), R2 value and residual analysis. In addition, the influences of machining parameters on the cutting force were analyzed. Finally, validation tests were conducted to verify the model. Experimental results demonstrate that the model is adequate at 95% confidence level, and its accuracy is better than 2.5%. Futhermore, the cutting force decreases with the increases of spindle speed, while increases with the increase of feed rate and cutting depth. Moreover, the cutting depth and spindle speed are the main factors on cutting force, whereas the feed rate has the smallest influence. In the finish machining of optical crystal, the spindle speed should be as large as possible, while the cutting depth should be decreased, and the feed rate can be adjusted by processing efficiency under 180μm/s.Keywords：ultra-precision flycutting;optical crystal;cutting force;response surface methodology;prediction model- 45
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Published：2020-08-13 -
Design of electromagnetic compatibility for vehicular optic-electronic equipment
Abstract：The design method of electromagnetic compatibility of the vehicular optic-electronic equipment and corresponding electromagnetic anti-interference measures were proposed to improve its electromagnetic interference ability and operating reliability at the complicated electromagnetic environment. The components were introduced based on the vehicular opto-electronic equipment in this paper. At the same time, the electromagnetic compatibilities of the mechanism and electricity were designed, including opto-electronic equipment and the shielding shelter. To overcome the electromagnetic interference between wires in interconnect cables, the electromagnetic anti-inference measures, such as the cable choice, cable layout and earthing mode were introduced emphatically. According to the characters of weak electromagnetic interference resistance in the poor electromagnetic environment, the specific settlement measures were proposed in detail. Finally, the design method of electromagnetic compatibility was discussed as well. The tests were performed at an electromagnetic environment of RE102(10 kHz-18 GHz field radiation). Experimental results indicate that the vehicular opto-electronic equipment can work successfully and reliably in this condition above mentioned. It provides important design methods of the electromagnetic compatibility for the kindred opto-electronic equipment and can satisfy the system requirements of strong anti-jamming and stabilization.Keywords：vehicle optic-electronic equipment;Electromagnetic compatibility;shelter;electromagnetic shielding- 39
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Published：2020-08-13 -
Heart beat classification based on feature fusion by principle component analysis
Abstract：For lower accuracy by a single feature and too high dimensionality by a combined feature in heartbeat classification, a new heartbeat classification algorithm was proposed based on the feature fusion by using Principle Component Analysis(PCA). With proposed algorithm, each single feature was normalized, then all kinds of features were combined together to a new one with high dimensionality and more information. In order to reduce dimensionality of combined features, the PCA was employed to remove redundant components. Finally, the Support Vector Machine(SVM) was used as a classifier to classify different heartbeats. By taking time domain feature, Discrete Wavelet Trans form(DWT) feature and Discrete Fourier Transform(DFT) feature as examples, the experiments were performed in MIT-BIH database. This study was compared with the new feature mentioned above, three single features and combined feature without Principle Component Analysis. The experiments results indicate that the accuracy of the new features is 97.389% when its dimension is 100. The new fusion feature has lower dimension than combined feature and higher classification accuracy than single feature.Keywords：heart beat classification;classification accuracy;feature fusion;Principle Component Analysis(PCA);MIT-BIH database- 42
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Published：2020-08-13 -
Mean Shift tracking algorithm using joint histogram of colors and oriented gradients
Abstract：The single orientation feature gets ineffective when tracking rotational object. For the sake of fulfilling object tracking in the scenes of illumination variation, rotation and partial occlusion, a joint histogram of colors and oriented gradients based Mean Shift tracking algorithm is presented. The joint histogram fuses the features of colors and oriented gradients by expanding the dimensions of the histogram. In this algorithm, IVF(illumination variation factor) is calculated by the model of illumination, which detects the degree of illumination variation. In the process of tracking, if IVF is below a certain threshold, color feature is taken as the principal feature so that the algorithm is robust to rotation, otherwise choose oriented gradients as principal feature for its robustness to illumination variation. The problem of partial occlusion can be figured out by dividing the object template into sub areas, and the position of object can be determined by the area that obtains largest similarity coefficient. The presented algorithm shows good performance in the experiments when dealing with complex scenes such as target rotation, illumination change and partial occlusion.Keywords：object tracking;Mean Shift tracking;joint histogram;illumination variation;partial occlusion;object rotation- 68
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Published：2020-08-13 -
Matching extension for structured scenes based on homography constraint
Abstract：Structured scenes have uniform texture and the matching method based on local features can get few matches in a wide baseline case. Therefore, a matching extension method based on homography constraint was presented. Firstly, initial matches were divided into several groups and each group was corresponded to different planes based on the homography constraints. The homography matrix for each group was estimated using RANSAC based strategy and the outliers out of the plane constraint were removed. Then, the nearest candidate correspondences for unmatched features such as corners and blobs were searched by homography transformation and the SURF descriptor was used to further reject outliers. Furthermore, the homography constraints were updated using extended matches and outliers are removed. Experiment results show that the proposed method can adapt to a certain degree of scale and viewpoint changes and obviously illumination change. The initial matches are greatly enriched, and matching growth rates all achieve to 100%, which lays a good foundation for accurate epipolar geometry estimation and three dimensional reconstruction.Keywords：image processing;image matching;matching extension;homography constraint;structure scene- 66
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Published：2020-08-13 -
Truck box volume measurement under constraint of circle projection and vanishing points
Abstract：To reduce the cost of truck's box volume measuring system, some calculation methods were discussed in detail, such as the solution of intrinsic parameters of a camera, the estimation of truck's position and orientation and the calculation of vertex coordinates on the truck's box. A method focusing on single image measuring was proposed under the constraint of orthogonal vanishing points and circle projection priori from the single image. Firstly, three orthogonal vanishing points were detected from the image and the intrinsic parameters of the camera were figured out according to the vanishing points. Then, the world coordinate system was established at the center of the wheel, then, the position and orientation of the truck relative to the camera were calculated with the intrinsic parameters of the camera and the prior of single circular projection of the wheel and the external facade equation of the truck's box was solved. Finally, the vertex coordinates of the truck's box were calculated with the external facade equation and matrix equation of imaging algorithm, and the volume of truck's box was figured out. Experiment results show that the measuring error of the truck's box length is less than 0.3 m and the error of the truck's box volume is within 5%. The proposed approach is more effective and lower cost as compared with other state of art methods, and is suitable for real-time measurement of truck's box volume.Keywords：single image;vanishing point;circle projection;posture calculation;volume measurement- 44
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Published：2020-08-13 -
Chessboard corner detection based on black-white detection operator
Abstract：According to the requirement of the high-precision calibration of a CCD camera for corner detection in the calibration plate, a sub-pixel corner detection algorithm of black-white chessboard based on black-white operators(referred to BW operator) was proposed with the analysis of the gradation characteristic of a chessboard image. The algorithm checks firstly out the gray values in 4 directions as defined. The CBW(the response to BW operator) was calculated to obtain the coordinates of corners with the precision at pixel level. Then the sub-pixel location algorithm based on the gray information of corner neighborhood was proposed to improve the precision of coordinates to sub-pixel level. The simulation experiment was performed in the MATLAL evironment and the experimental results show the algorithm detects completely and accurately corners of chessboard with a precision of 0.1 pixel level. The detection algorithm provides a basic condition for the high-precision of CCD cameras.Keywords：black-white(BW) operator;chessboard;corner detection;sub-pixel location;camera calibration- 44
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Published：2020-08-13 -
Shadow detection in high spatial resolution remote sensing images based on spectral features
Abstract：To accurately detect shadows in high resolution remote sensing images and to improve the accuracy of target identification and information extraction from remote sensing images, this paper studies how to detect shadows in high-resolution remote sensing images based on the spectral characteristics of the shadows. The Normalized Blue and Red band Indexes(NBRI) was proposed according to the different decrease amplitudes of radiance in blue band and red band. Then the Normalized Difference Vegetation Indexes(NDVI) were calculated to distinguish the vegetation from the shade. Finally, a single index-shadow intensity(SI) was constructed by subtracting the NDVI from the NBRI and the shadow was easily segmented from the SI image by an appropriate threshold. The proposed method was tested on Woldview-2 multispectral images with a spatial resolution of 2 m, experimental results indicate that the overall accuracy of shadow detection is above 85%.It concludes that the method proposed in this paper has excellet performance in detecting shadow, needs less computation and is easy to be implemented.Keywords：shadow detection;remote sensing image;normalized difference vegetation index;histogram thresholding segmentation- 53
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Published：2020-08-13 -
Image reconstruction of cone-beam differential phase contrast CT using phase line integral retrieval
Abstract：For the image reconstruction of an X-ray cone-beam differential phase contrast CT, a reconstruction technique based on the derivative property of Fourier transform and the FDK algorithm frame was proposed. By which the X-ray cone-beam differential phase contrast CT and absorption-based CT could share the reconstruction software and hardware. On the basis of the phase line integral filter function, the two dimensional differential contrast projection captured by an area array sensor at each rotation sampling view angle was filtered row by row, and the line integral cone-beam projection dataset of phase function for an object was obtained. Then three dimensional phase contrast CT images were reconstructed by applying the classical absorption-based FDK algorithm to the retrieved dataset. With the well-known three dimensional Shepp-Logan phantom, a numerical simulation was performed to validate the proposed method. Finally, the experimental reconstruction was verified by the dataset of a plastic sphere sample and compared with the current methods. Experimental results indicate that normalized root square error of the new method is less than 0.2586 and the reconstruction accuracy is improved by 88%. It satisfies the high-accuracy reconstruction requirements of X-ray cone-beam differential phase contrast CT.Keywords：X-ray Computed Tomography(CT);difference phase contrast imaging;image reconstruction;phase retrieval- 44
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Published：2020-08-13 -
Automatic measurement system of tire tread length based on image processing
Abstract：To measure the tire tread length on-line automatically, a length measurement system was established for the tire tread, and image processing and measuring algorithms used in productive process were investigated. For the purpose of removing the influence of light in a real field, several methods such as median filtering, gray stretching etc, were used to preprocess the image, and the OSTU algorithm was used to accomplish the image binary process. The edge of the tire tread is straight line, so linear fitting algorithm was used to fit the linear equation in the image plane. To avoid the inconvenience in installation caused by calibration on the site, a couple of measurement reference points were reserved. The coordinate transformation parameters were obtained using the multiple linear regression method. The line equation of the tread head and the tread tail in the physical coordinate system were determined by the coordinate transformation. Therefore, the length of tire tread could be calculated. Experimental results indicate that the precision of the measuring system proposed in this paper is less than or equal to 2 mm for multiple measurement of various tire treads, and the 3σ value is less than 1.1 mm. Although the tire tread is elastomeric, the measuring system can satisfy the production requirement. The system is characterized by convenient installation and testing, system stable operation, etc.Keywords：tire tread;length measurement;edge detection;multiple linear regression;coordinate transformation;image processing- 67
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Published：2020-08-13 -
Satellite image fusion using RPCA combined IHS transform
Abstract：The traditional Principal Component Analysis(PCA) and IHS satellite image fusion technology may have spectral losing and feature detail distortion. A fusion method using Robust PCA(RPCA) combined with IHS transform was proposed to solve the problem. First, multi-spectral images were converted from a RGB model into an IHS model. The 'I' component of IHS was converted into low-rank matrix L0 and sparse matrix S0 by RPCA transform. Then, the histogram of panchromatic images was matched with the histogram of the L0 component, and the L0 component was replaced by the panchromatic image. Finally, the fused multi-spectral image was converted back to the RGB space. Testing results show that of the information entropies preserved by RPCA combined IHS method are 7.5275 and 7.4772, which means that the method proposed in the paper gives better results than conventional methods, such as PCA and IHS transform.Keywords：satellite image;image fusion;Principal Component Analysis(PCA) transform;IHS transform;PCA transform- 49
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Published：2020-08-13 -
Road extraction from high-resolution remote sensing imagery based on local adaptive directional template match
Abstract：An approach of road information extraction for the high-resolution remote sensing imagery was proposed based on local adaptive directional template match. The remote sensing imagery was segmented by means of the local adaptive directional template match and a binary image of the coarse road was obtained. Guided by the principle of local gray-scale consistency, the consistency of the input images was tested and the test results on local gray-scale of all the pixels in the image were received. Afterwards, the preliminary segmented results and the results of local gray-scale consistency test were fused to get a better original part of the road. Finally, the results after information fusion were filtered according to the different features of the road shapes and the original part of the road was attained. The areas of the road in the image are not too small as the road is successive from the space aspect. Accordingly, the parts of smaller area were removed on the basis of area index and non-road information was also removed based on the length-width ratio, so that the exacted results were obtained. The algorithm was verified by two high-resolution remote sensing images and it was compared with known road information exaction methods were accomplished. The results show that the road information can be more successfully exacted by this approach as shown in the experiment results.Keywords：road extraction;high-resolution remote sensing imagery;local gray-scale consistency;local adaptive directional template match- 70
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Published：2020-08-13 -
Fusion image assessment based on local variance and singular value decomposition
Abstract：Image fusion is not only relative to the transfer of quantized information, but also should take if the information transfer can be accepted by human vision into account. Therefore, this paper designs a fusion image objective assessment method based on local variance and singular value decomposition to combine various human visual system sensitive information into an image. In order to assess the improvement of information, the local variance was used to describe the structure information of the image. As the local variance was sensitive to image details greatly, the singular value decomposition was used to obtain a energy matrix to display the local variance distribution. Then the mutual information was taken to measure the structure difference of source image and fusion image. Finally, the comparison above mentioned was taken as the assessment results. Experiment results show that the proposed method gives the best performance for the wavelet and pyramid methods, and the assessment results are 2.8790,1.9225 and 2.6298,1.9103,respectively, which has better consistency as compared with those of traditional human visual systems.Keywords：image fusion;quality assessment;local variance;singular value decomposition- 41
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Published：2020-08-13 -
Registration of moving fuzzy image in high dynamic environment
Abstract：In matching the under-registration images in a high dynamic environment, there is large rotation distortion meanwhile the images may turn into blur in motion states, so traditional algorithms fail to match the images accurately in real-time. To solve these problems, a registration algorithm of fuzzy image in the high dynamic environment was designed in this paper. Based on the analysis of the cause of the Scale Invarian Feature Transform(SIFT) algorithm's poor timeliness, the gray-scale transform was chosen as a threshold to change the pixels of image and to reduce the number of feature points. Then, simplified feature points were chosen to implement the feature matching to improve the accuracy of the registration. Finally, an experiment was performed to demonstrate the effectiveness of this method. Experimental results indicate that the number of matching-pairs and feature points are 10% that of the original algorithm; the stability is stronger than that of the original SIFT algorithm, and the ratio of matching-pair and feature points are reduced from 0.1505 to 0.1365. Compared with the traditional SIFT algorithm, this method owns better efficiency and stability, and can satisfy the requirements of image matching in the high dynamic environment.Keywords：motion blur;image matching;gray-scale transform;Scale Invariable Feature Transfor-mation(SIFT) algorithm- 46
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Published：2020-08-13 -
Influence of cooling on imaging quality of EMCCD camera
Abstract：After the readout noise of an Electron Multiplying Charge Coupled Device(EMCCD) camera is reduced as low as 1 e-, the dark current noise becomes a primary noise source of the EMCCD camera. As the cooling can reduce the dark current noise of EMCCD camera remarkably, it has been one of the important factors influencing imaging quality of EMCCD camera. This paper analyzes and compares advantages and disadvantages of different cooling systems in the EMCCD camera, then it proposes a new cooling system for the EMCCD camera which is fitful for space-borne applications. By establishing a noise model of EMCCD camera, the influences of different cooling effects on imaging quality of EMCCD camera were analyzed. Analysis results indicate that Signal to Noise Ratio(SNR) of EMCCD camera is improved from 82.9 to 87.2 as the temperature of focal plane is lowered from 30℃ to-40℃. In addition, imaging quality of EMCCD camera can be improved effectively. The research results provides design references for development of EMCCD cameras used in space sciences.shen.Keywords：cooling;space camera;Electron Multiplying CCD(EMCCD);imaging quality- 68
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Published：2020-08-13 -
Curvature surface registration in virtual try-on garment
Abstract：This paper focuses on applications of 3D measurement to the human body measuring and curvature surface registration of virtual trying on garment. In which, the binocular vision was used to get 3D human body data of 1:1 scale; then the 3D human data were processed to obtain a precise human model; finally, the garment data were taken to implement the trying on garment. To simplify the try-on method, the human model and the garment model were treated as a rigid, and the extremum point of the Gaussian curvature and the mean curvature of the two models as a matrix of coarse matching. To reduce the registration error, nonlinear minimum distance optimization algorithm, Levenberg-Marquardt algorithm, was used, and the model of key feature points of minimum distance was taken as error parameters to obtain optimal transform matrix of corresponding feature point sets. Experimental results verify that Levenberg-Marquardt optimization algorithm for surface registration is effective, where the error setting is 10 mm and the iteration number is 33 times. It is a simple, effective and stable fitting algorithm for promoting the research of 3D garment Compute Aided Design(CAD) and personalized virtual try-on.Keywords：3D optics;surface registration;virtual try-on garment;curvature surface;Levenberg-Marquardt(LM) algorithm- 52
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Published：2020-08-13 -
Image fusion algorithm for vein enhance display
Abstract：The existing subcutaneous vein display system usually uses a near infrared image to outstand vein distribution. However, it may loss the true color and detail feature of human skin. To solve the problem, a probable method is proposed to capture the infrared image and color image at the same time and to fuse the two images. This paper proposes a new image fusion algorithm related to the best mapping of histogram, Principal Component Analysis(PCA) and image bilateral filtering. The fusion experiments are performed by proposed method, and the final fusion image shows that it can display the vein distribution clearly and keep the epidermis color and detail features unchanged. Through the calculation, the average correlation coefficient, average gradient and the average spectral distortion to original color image are 0.8431, 1.730 and 8.6429 respectively. The results show that the proposed fusion algorithm is better than several other algorithms. It concludes that the proposed algorithm has an important application value in the field of vein display of the human body.Keywords：vein display;image fusion;principal component analysis;histogram mapping;bilateral filter- 61
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Published：2020-08-13 -
Stereo matching based on support points
Abstract：A stereo matching method based on stable support points was proposed to improve its computing speed and disparity accuracy. With the method, a canny edge operator was used to detect the edge points of the image and act them as 'supporting points. Then those points were processed by a Delaunay triangulation algorithm to divide the whole image into a series of linked triangular facets. These facets were used as matching elements to compose the basic modules to perform a rude estimation of image disparity. Finally, according to the triangular property of shared vertices, the estimated disparity was refined and the disparity map was obtained. The method was tested by Middlebury stereo pairs on the platform, Experimental results show that the time cost of the method is about 1 s and the matching accuracy is 93% as compared with ground truth map. The proposed method has higher positioning accuracy and lower error mathing rate, and improves both the computing speed and computing accuracy. It forms a steady foundation and good application prospect for robot's path planning system with stereo camera devices.Keywords：stereo matching;edge detection;support point;Delaunay triangulation;disparity map- 39
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Published：2020-08-13 -
Face recognition based on Gabor reduction dimensionality features and singular value decomposition features
Abstract：For the disability of traditional Gabor filter bank on poor global feature representation, Gabor reduction dimensionality features are combined with the Singular Value Decompasition(SVD) global features of an image to characterize the facial features. On the basis of compensating the DC component in the Gabor filter, the scale retractable performance of the filter which varies with its center frequency is optimized to extract multi-scale, multi-orientation of face images. The features were added in same scale of different directions to reduce the dimensionality of features. Meanwhile, the SVD features in the whole image and block image were extracted respectively, then local Gabor features and the SVD feature mentioned above were joint to characterize the face image respectively. In order to improve computational efficiency, the face image was sampled to obtain a sample image. Experimental results show that the proposed method maintains image details and reduces the redundance of feature data better. It shows greater recognition rate and calculation rates than the traditional Gabor filter, and the recognition rate in ORL face database is up to 98.21%.Keywords：face recognition;Gabor feature;Singular Value Decomposition(SVD);local feature;gobal feature- 27
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Published：2020-08-13 -
Simultaneous localization and mapping implementation based on improved iterated unscented particle filter
Abstract：For particle filter inconsistency in mobile robot Simultaneous Localization and Mapping(SLAM),an improved unscented particle filter algorithm is proposed in this paper. To overcome this phenomenon mentioned above, the algorithm utilizes an iterated sigma point particle filter to generate more accurate proposal distribution, which fuses the robot's odometer information and laser information into sequential importance sampling routine through iterated update processing. The algorithm effectively improves the filter consistency and state estimation accuracy, and requires smaller number of particles. Based on the robot operating system, this algorithm is performed on a platform of Pioneer3-DX robot equipped with a URG laser range finder to compare with the traditional fast SLAM algorithm. Experimental results show that it creates a same consistency map and the improved algorithm with only 10 particles and consumes 325 s reduces the number of particles needed and improves the mapping efficiency. At the same time, the robot heading error is-1.4861°, showing a lower uncertainty of the robot pose. In addition, it indicates that the stability of the improved algorithm is higher than that of the FastSLAM algorithm by comparing their variances.Keywords：mobile robot;Simultaneous Localization and Mapping(SLAM);iterated unscented particle filter;importance sampling;laser range finder- 50
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Published：2020-08-13 -
Multi-sensor based infrared image super-resolution
Abstract：On the basis of complementary and relevance between a visible image and an infraved image, a new method which is called multi-sensor super resolution method was proposed. Firstly, an adaptive edge detection algorithm was used to extract the edges of the infrared image, and edges were divided into related edges and nonrelated edges according to the relevance of the edges of infrared image and corresponding visible image area. Then, a quadratic relationship model was built to estimate the high frequency patch of infrared image in the related edge region. At last, Iterative Back Projection(IBP) method was used to optimize the estimated super-resolved image. Experimental results indicate that the Peak Signal to Noise Ratios(PSNR) of the community image, crossroad image and the road image in this method are respectively 2.9 dB,1.44 dB and 1.11 dB, higher than that of the Choi algorithm. Experimental results also show that the proposed method enables reconstructing images to be better visual results and closely resembling the original high resolution images. The reconstructed images achieve better results on subjective visual effects and objective assessments.Keywords：image restoration;image processing;infrared image super resolution;multiple sensor super resolution- 60
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Published：2020-08-13 -
Determination of fast inter depth for HEVC based on dimensional similarity
Abstract：A fast depth decision algorithm for High Efficiency Video coding(HEVC) based on dimensional similarity in video sequences is proposed to improve its coding efficiency. As the difference between adjacent frames is in temporal, it implys strong dimensional similarity in inter-frame prediction. This paper analyzes the similar probability in Coding Unit(CU) depth between adjacent frames to pre-determine the depth of current CU. When the current CU does the depth splitting, its reference frame's CU depth information can be used to estimate the current CU depth. Then, it will jump over or stop some unnecessary deep splitting and to decrease the number of CU splittings and the coding computational complexity. The SKIP fast mode is also adopted to perform the fast determination. Experimental result shows that proposed algorithm reduces coding complexity by 52% as compared with original HEVC algorithm. Meanwhile, the average Peak Signal to Noise Ratio(PSNR) only decreases 0.09 dB and the average coding rate is decreased by approximately 0.58%.Keywords：High Efficiency Video Coding(HEVC);inter prediction;depth decision;Coding Unit(CU);dimensional similarity- 54
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Published：2020-08-13 -
Particle filter tracking based on saliency histogram
Abstract：A particle filter tracking method based on the saliency histogram was proposed to improve the stability of target tracking in a complex background. The saliency weights of hues in the histogram were determined by comparing the distribution of the hues in the target and the background. Then, a saliency histogram was established. The saliency histogram could restrain the disturbance from the background to the target by strengthening the recognition role of the hues existing only in the target. Thus, the accuracy of the target location could be improved. On the saliency histogram, the particle tracking algorithm was implemented and a simulation experiment was performed.The experimental results show that the method proposed in the paper can be applied to performance of the target tracking in the complex background with the low computation cost. Furthermore, the sizes of the particles are small because the model is accurate. As compared with the traditional particle tracking method, the proposed method has low tracking computation time for the single frame, and its average tracking computation time is less than 5 ms, which well satisfies the real-time requirement.Keywords：targer recognition;target tracking;saliency histogram;particle filter- 54
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Published：2020-08-13 -
Point cloud registration with normal feature histogram
Abstract：To reduce the time cost of point cloud registration and to decrease the dimension of a descriptor, this paper proposes a pre-processing method to look up the overlap region of a point cloud. This method uses the region growing variant K-means clustering based on octree structure to block the point cloud, and then get the overlap region of point cloud by the triangle & point number decision formula. Moreover, a lower dimension descriptor named Local Dot Feature Histogram(LDFH) is also created based on a point cloud feature histogram in the key point description. The pre-processing method decreases about 10%-20% data volume of point cloud and removes some unnecessary redundant operation. As compared with the Fast Point Feature Histogram(FPFH) descriptor, the proposed LDFH algorithm just has 24-dimension and takes the computation time by 15%. When the methods proposed in this paper are used to register point cloud data in practice, the proposed method can complete small geometry solid registration for one cubic meter in less than five minute. The proposed algorithm achieves the goals of reducing the cost time, lowering descriptor dimension, and has a good effect in actual registration.Keywords：computer vision;point cloud registration;normal feature histogram;descriptor- 81
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Published：2020-08-13 -
Linear MIMO precoder optimization with maximizing channel capacity under joint power constraints
Abstract：When the sum-powers and peak powers of transmit antennas are constrained, the linear precoders of multiple-input multiple-output(MIMO) systems can not well adapt to the practical applications. Therefore, this paper proposes a linear MIMO precoder optimization algorithm with maximizing channel capacity under joint power constraints(sum-powers and maximum eigenvalue) based on the convex optimization theory. By mining the internal property of the eigenvalue-decomposition of the power matrix, an exact closed-form of eigenmode is given and a two-dimensional searching method for deriving the values of the eigenvalues is proposed. As the searching points in every dimension are less than the number of the transmit antennas launched by the system, the algorithm has lower computational complexity and higher computer efficiency. Finally, simulation results verify the efficiency of the proposed method.Keywords：multiple-input multiple-output(MIMO);precoder;joint power constraint;channel capacity- 42
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Published：2020-08-13 -
Particle filtering algorithm for DOA tracking with acoustic vector sensor array
Abstract：According to the shortcomings of Direction of Arrival(DOA) estimation methods and subspace updating algorithm, this paper proposes a particle filtering algorithm combined with the DOA estimation algorithm for DOA tracking with an acoustic vector sensor array. First, the observation model based on the acoustic vector sensor array was set up, and the state equation was deduced on the basis of the second-order model of uniform velocity. Then, the quaternion Multiple Signal Classification(MUSIC) algorithm was used to improve the observed likelihood function of the particle filtering algorithm and a improved tracking algorithm was proposed. Finally, the performance of each algorithm was simulated. Experimental results show that the mentioned algorithm achieves DOA real-time tracking. As compared with the subspace tracking algorithm and particle filtering algorithm, the tracking error of the proposed algorithm is smaller. When a Signal to Noise Ratio(SNR) is less than-10 dB, the tracking errors of tracking algorithms based on the particle filtering algorithm are within 4°, thus they can adapt to a lower SNR environment.Keywords：Direction of Arrival(DOA) tracking;particle filter;acoustic vector sensor;state space model;quaternion MUSIC- 46
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Published：2020-08-13 -
Measuring algorithm for tool wear of circular saw blade in automatic cutting machine
Abstract：To measure the wear of circular saw blade of an automatic magnesium oxide board cutting machine on line, this paper designs a circular saw blade wear measuring algorithm based on machine vision. Firstly, the possible corners of circular saw blade are found using 8 neighborhood gray similarity sifting algorithm based on an adaptive threshold. Then, some pseudo corners which are not the only one or its corner response function values are not the largest among the neighborhoods are removed. The tip points of circular saw blade are determined among the corners according to whether their value is the maximum, and the sub-pixel coordinates of tip points of circular saw blade are calculated using cubic surface fitting. The radius of the circular saw blade is calculated with least square method. Then, through the known relationship between camera coordinate and world coordinate, the actually wear value of circular saw blade is obtained. At last, tool wears for two kinds of circular saw blades are calculated using the classical Harris algorithm, improved Harris algorithm and the proposed algorithm in the paper respectively. The results show that the detection time of the algorithm proposed is only 29.9% and 29.7% that of classic Harris algorithm respectively, and 145.7% and 126.5% of that of improved Harris algorithm respectively. The correct ratios of classic Harris algorithm are 100% and 50% respectively, and those for improved Harris algorithm are 71.4% and 37.5%, for proposed algorithm are 100% and 100% respectively. Therefore, the algorithm proposed in the paper is much better than other two algorithms and it is an effective and efficient method for measuring the tool wear.Keywords：automatic cutting machine;circular saw blade;cutting tool;wear detection;computer vision;corner detection;sub-pixel- 34
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Published：2020-08-13 -
Fusion of infrared and visible images based on improved fuzzy rules in multi-scale domain
Abstract：On the basis of shift-invariant Shearlet domain fuzzy processing, an image fusion method with improved fuzzy rules was proposed. First of all, infrared and visible light images were processed by Shift Invariant Shearlet Transformation(SIST)to decomposed into low-pass and high-pass subbands. For low frequency subband coefficients, the rules of local area information entropy was used. For high frequency subband coefficients,the Shearlet transform frame redundancy was considered. To solve the redundant information of the high frequency subbands, the infrared and visible light image membership degree, non-belongingness degree, the hesitation degree of high-frequency sub-band figure and the optimal entropy were calculated. The two coefficient images were decomposed, then the total count of blackness, whiteness of two corresponding blocks are computed. Finally, the block of the blended coefficient image was constructed and the infrared and visible light images were obtained by using the SIST. This method effectively eliminates the Gibbs phenomenon, and offers an edge keeping degree more than 0.85.Keywords：infrared image;visible light image;image fusion;shift-invariant Shearlet transform;fuzzification correlation chart;local area information Entropy- 67
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Published：2020-08-13 -
Star image matching by using geometric invariants
Abstract：To match rigidly star images with multi-screens, a shape context based registration method by using geometric invariants was proposed. First, denoise methods, segmented method and morphology method were applied to star images to extract star points, so that centroid of star points could be calculated. Then, feature descriptors for every star point were calculated based on geometric invariants among all stars. Each descriptor was used to represent the relationship between this star and others. A price function to evaluate the similarity between star points was constructed to get a star match pair set between the two images. Finally, random sample consensus robust method was used to remove wrong star match pairs and calculate registration parameters for the space transform. Experimental results demonstrate that proposed method can successfully match the image with different number of feature points and different brightnesses in a sub-pixel level. For two group images with the size of 4608*3072 and different ISOs, the proposed method can offer the registration accuracy near 0.5 pixel, which meets the requirements of the registration.Keywords：astronomical image;star image matching;geometric invariant;shape-context- 49
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Published：2020-08-13 -
Noise analysis of high bandwidth sparse signals processed by AIC
Abstract：On the basis of modern radar signal processing, this paper explores the feasibility of high frequency and large bandwidth sparse signals processed by Analog-to-Information Converter(AIC) and analyzes the noise effects of the AIC in practical applications. It explains the low bandwidth characteristics of the radar signals and the resolution and performance limitation of Analog-to-Digital Converter(ADC). Then, this paper evaluates the impact of signals with jitters and aperture noise on the AIC in signal processing, and compares the performance between the AIC and the ADC. It points out that the jitter and aperture noise limit the achievable ADC resolution. Finally, a system evaluation framework for examining these limitations is proposed. The evaluation shows that the performance of AIC is better than that of the ADC obviously when the aperture parameter T is fixed and the sparsity S is less than 0.35. However, when S is larger than 0.35, the influence of aperture will be serious. But the AIC is still implementation well through cross validation. It concludes that the currently proposed AIC benefits over high-speed ADC in near future.- 47
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Published：2020-08-13 -
Correction of random shift of rotation center for nano-scale CT system in X-ray microcopy
Abstract：To correct the random shift of rotation center of a full field transmission X-ray microscopy nano-scale CT and suppress the reconstruction artifacts, a method based on the calculation formula of mass center and the least square sinusoid fitting was proposed and investigated. First, the projection sinogram was obtained by the logarithm operation on the original data captured by a detector. Then the mass center position was calculated out in row by row at each view angle and the sinusoid curve was fitted by least square method. Finally, the random shift of the mass center was obtained and inputted to the image reconstruction formula to correct the shift of the rotation center. The results from the numerical simulation with the Shepp-Logan phantom and the experiment by a micro-nano composite with a diameter of 60μm at the full field transmission X-ray nano-scale CT system of Beijing Synchrotron Radiation Facility indicate that the normalized root square error after correction is less than 0.3412 and the reconstruction accuracy is improved by 82%. The proposed method can correct the random shift of the rotation center and suppress the reconstruction artifacts. Compared with current methods, it shows better practicability.Keywords：full field transmission X-ray microscopy;nano-scale CT;rotation center;shift correction;least square fitting- 57
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Published：2020-08-13 -
Heart rate acquisition system on facial image
Abstract：The extent of face absorption light changing along with the heart beat rate was verified, and a heart rate acquisition system based on the facial image processing was designed. Human face images were sampled in a video form by the system and they were processed in two steps. The first step was the processing of a single image. Firstly, an achromatic color model was built to correct the color of the original image and to remove the interference from light brings. Then, the sample area was positioned using a histogram and facial features, and the image was enhanced in space and time domains. Furthermore, narrowband gray input values were mapped to the output value broadband and to separate the illumination component and the reflection component, so the interference caused by uneven light irradiation could be further erased. Finally, the mean reflection of single image was calculated. In the second step, the wavelet transform and Hilbert algorithm were used to process the mean curve consisting of all the images and to eliminate the baseline drift wave, making the R wave more likely to be detected and to get the heart rate finally. Experimental results under many conditions show that the heart rate error is no more than 8% under a good light condition, and that is no more than 20% at a poor light condition. Basically, the system achieves the functional requirement of the heart rate calculation by sampling the light of some face region changes. Due to limitations of the camera sampling rate, the real-time performance of the system is updating every 5 s in the case of signal integrity ensured.Keywords：facial image;image processing;video acquisition;heart rate acquisition;algorithm design;mean reflection;anti-jamming design- 31
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Published：2020-08-13 -
Application of image quality evaluation and mutual information in laser image registration
Abstract：To obtain the three-dimensional laser images of moving targets, this paper establishes a range-gated laser active imaging system, and puts forward a laser image registration algorithm based on image quality evaluation and mutual information. The principle of ICCD imaging and imaging systems based on range gated were introduce. On the basis of the mutual information, the entire process of registration algorithm was described in detail. For how to choose the slice images as a reference image in moving target range gated imaging, the standard of quality evaluation was introduced before the registration, and the laser image registration algorithm based on image quality evaluation and mutual information was implemented. Experimental results indicate that brightness, Signal to Noise Ratio(SNR), average gradient and edge strength have obvious distinction, which can be as standards to select a better image in laser range-gated slice image. The reference image selection based on the image quality evaluation can effectively reduce the error registration, and the entire registration algorithm accuracy reaches to 0.01 pixel. The algorithm offers high precision and strong robustness, and is especially suitable for the laser image registration of moving targets.Keywords：image quality evaluation;moving target;laser image;image registration;range gated;mutual information registration- 79
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Published：2020-08-13 -
Measurement of truck volume by virtual reality projection matching
Abstract：An automatic measurement method by using a single image is presented based on image processing to reduce the cost of truck's box volume measurement. The method locates feature points of a target with an Active Shape Model(ASM) algorithm and calculates the ground surface that the truck is placed and establishes virtual reality environments by using the camera's intrinsic parameters and a 3D model. Then, the truck's initial pose is estimated with EPnP algorithm, and a geometry correction algorithm is used to correct the geometry of the 3D model to match the truck automatically. Under the constraints of ground surface's equations and control points, the 3D model in a virtual reality enviroment is the same as the real truck. Finally, the truck's box volumes is figured out by calculating the 3D model's box volume. Experiment results show that the proposed method can measure the volume of the truck's box automatically with a single truck image and the error of truck's box volume is within 5%. The measuring system is simple, and has good real-time performance and important practical values.Keywords：single image;Active Shape Model(ASM);EPnP algorithm;geometry correction;Virtual reality;projection matching;volume measurement- 79
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Published：2020-08-13 -
Perceptual hash algorithm for integrity authentication of multispectral remote sensing images
Abstract：A perceptual hashing algorithm for multispectral remote sensing images based on the synthetical characteristics of each band content was proposed to realize the authentication of multispectral images and to locate the tamper at the concrete band. Firstly, the multispectral remote sensing image was preprocessed and the feature extraction method for each band was determined by the information richness of the band. Then, the content feature of each band was extracted by edge extraction method and Discrete Cosine Transformation(DCT). Finally, the extracted feature was constructed based on the further compressed and normalized features, and the final perceptual hash value for the multispectral remote sensing image was obtained. The authentication was realized by comparing the difference between the recomputed perceptual hash value and the original hash value. The experiments indicate that the proposed algorithm can realize content integrity authentication for multispectral remote sensing images, and can locate the tamper at the concrete band of the image, which overcomes the defects of the existing perceptual hash algorithm without considering the feature of multispectral remote sensing images, and guarantees the effective utilization of multi-spectral images.Keywords：multispectral image;remote sensing image;perceptual Hash;integrity authentication- 53
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Published：2020-08-13 -
Multi-modal image registration based on P system with differential evolution
Abstract：A multi-modal image registration algorithm under the framework of P system was proposed by combining the parallel property of membrane computing with Differential Evolution(DE) algorithm, which was named as DE-MCIR(Differential Evolution-Multi-modal Computing Image Registration) algorithm. A cell-like P system of membrane structure was designed, and each object in membranes represented a group of transform parameters of floated images. All objects of each elementary membranes were evolved by modified DE algorithm. At the same time, the designed two exchange rules were used to update the best parameters. Finally, the global optimal object was stored in the skin membrane. The approach was tested on satellite images and infrared and visual images. For the experiment of satellite images, the average mutual information of DE-MCIR is 1.4306, and the standard deviation is 0.00341; For the experiment of multi-modal satellite images, the average mutual information of DE-MCIR is 0.0402, and the standard deviation is 0.00016; For the experiment of multi-modal real images, the average mutual information of DE-MCIR is 0.0125, and the standard deviation is 0.00187. These results reveal that DE-MCIR algorithm has better registration accuracy, global convergence, and robustness, and its performance is better than that of the Genetic Algorithm, Particle Swarm Algorithm(PSO) and PSO Powell algorithm.Keywords：differential evolution algorithm;membrane computing;multi-modal image registration;transformation parameter;P systems- 37
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Published：2020-08-13 -
Automatic camera calibration based on coded marker
Abstract：3D calibration targets have higher cost and are difficult to be fabricated. When they are calibrated, the control points for calibration should be extracted by manual intervention. Therefore, this paper designs a calibration stereo target with two parallel calibration planes by taking coded markers as the control points. The calibration stereo target is applied to camera calibration to improve its automation level. The two calibration planes of the new calibration target are placed by a parallel mode, so that the camera observes the two calibration planes with small viewpoint change and the perspective distortions can be reduced. Each control point is constituted by a circular coded marker, which is utilized to realize automatic recognition without manual intervention. Experiment results show that the calibration target can be correctly recognized under a large illumination and viewpoint change. When it is applied to stereo camera calibration, the mean re-projection errors of both cameras are less than 0.075 pixels and the position measurement error is less than 1 mm. The calibration target reduces the complexity of the calibration and is suitable for the engineering applications.Keywords：calibration target;coded marker;camera calibration;vision measurement- 60
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Published：2020-08-13 -
Human action recognition based on Kinect data principal component analysis
Abstract：To improve the efficiency and accuracy of human action recognition in the home environment, a method of action recognition based on Principal Component Analysis(PCA) of Kinect data was proposed and realized. Firstly, the time series data of human action feature description was collected by Kinect, and human pose description vector was constructed. Then, the PCA method was used to analyze the difference between the feature values at different time points and to obtain the recons-tructed eigenvalues, by which the distinction between different types of actions can be more obvious. Moreover, the action discription feature of the redundancy was filtered to reduce the redundancy and noise, which was conducive to the judgment and recognition for the human action. Finally, the recognition and classification of the action were performed based on the features of the reconstruction and the nearest neighbor principle. The experimental results show that the accuracy of this method is more than 80% for the simple human motion recognition. The identification time of a single sample is 1.67 ms and 3.93 ms, respectively. It can satisfy the human action recognition requirements for higher precision, strong anti-interference ability and real-time recognition.Keywords：robot;Kinect data;action recognition;Principal Component Analysis(PCA)- 50
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Published：2020-08-13 -
Image synthesis of arbitrary virtual viewpoint based on two viewpoints
Abstract：The synthesis precision of an arbitrary virtual viewpoint image and the movement range of a virtual viewpoint were mainly studied. A novel and effective method to synthesize a new arbitrary virtual viewpoint image based on two images was proposed. The simplified model of the viewpoint images was established in a proper coordinate system to analyze the projective geometry relationship of the corresponding points between the input viewpoint images and the arbitrary virtual viewpoint image. Each image was processed by the feature point extraction, correspondence matching and view parallel, triangular segmentation, texture matching, perspective projection transformation. An arbitrary virtual view image was generated in the space only using the positional ratio parameters between input viewpoints and virtual viewpoint. Using this method, complex three-dimensional reconstruction and camera calibration are avoided, and the limitation of the movement range of the virtual viewpoint based on traditional View Morphing technology also is solved. The experiments and simulation results show that the arbitrary virtual viewpoint images can be obtained only using the positional ratio parameters between input viewpoints and virtual viewpoint through the method proposed in this paper, even if the two input images can't be parallel completely. The proposed method is reasonable and effective.Keywords：computer vision;virtual viewpoint;image synthesis;projective geometry;epipolar geometry;view morphing- 54
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Published：2020-08-13 -
Super-resolution reconstruction of remote images based on three level training BP neural network
Abstract：To further improve the effect of the super-resolution reconstruction(SRR) of remote sensing images and reduce its time-consuming, a three level training BP Neural Network(BPNN) was established. The research was focused on the acquisition of training samples, selections of input-output training samples, and the design of BPNN structure and training algorithm. A remote sensing image degradation model was set up. Then, training sample images were got by undersampled and subpixel-shifted method. The input-output training sample images were selected by variance comparison. Finally, three groups remote sensing images with different super-resolution mapping modes were used as the input-output training samples for the same BPNN. The net was continuously trained and learned three cycles, and image size and spatial resolution were improved three times. Experimental results indicate that the three level training BPNN for the SRR of remote sensing image can obtain better SRR effect and higher spatial resolution in the process of fitting remote sensing image SRR mapping, and the Peak Signal to Noise Ratio(PSNR) is improved about 6 dB than that of other ordinary super-resolution algorithm. For preserving more image details and reducing reconstructing time, it is more suitable for practical applications of remote sensing images.Keywords：three level training BP neural network;remote sensing image;image reconstruction;Super-resolution- 48
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Published：2020-08-13 -
Simulation system of high accuracy star images based on star sensor
Abstract：A star image simulation system was designed to test the performance of a star sensor on the ground for satisfying the requirement of accuracy and reliability of the start simulation. According to technical index, the fundamentals of star simulation were discussed, and then the system overall scheme was determined. The process of star map simulation method was established, and the fundamentals and implementation method of auxiliary field calibration, converting the magnitude into grayscale, coordinate transforming and star map display were described in details. The linear brightness correction and the nonlinear correction method based on measurement data were proposed to solve the problems that exist in the traditional conversion between magnitude and gray. The corresponding model was established and then was put forward the distortion correction method to solve the star positional deviation caused by distortion of the optical system. Finally, the star simulation was implemented with static and dynamic displays, and a double-screen was used to synchronize display by the thumbnail and an external monitor. The FK5 star catalogue was used in experiment, and the simulating results indicate that the system implements the simulation on the field of view of 10.5°×7.5° and star magnitude of-4.6~6 accurately, meanwhile the star location distortion error keeps within 0.017%.Keywords：star sensor;star image simulation;distortion correction;magnitude;coordinate transformation- 46
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Published：2020-08-13 -
Optical image stitching for UAV based on weighted adjustment and regional separation
Abstract：When the images from an Unmanned Aerial Vehicle(UAV) is stitched, it will produce a lot of accumulated errors because of the large image quantity and image distortion. Therefore, a method to efficiently reduce the accumulated error was researched. Firstly, a general matching area was calculated according to the record center position in the stitching process to reduce the matching time. Then error equation was listed to carry on the regional network, and different terrain feature areas were given to conduct the area weighted adjustment. Finally, UAV images were used to the experiment for proposed method in this paper and the traditional direct splicing method. The experimental results on the proposed method show that the ghost and dislocation phenomenon are decreased by 12%, stitching efficiency increased by 15%, and the area of the stitching after expanding has improved by 8%. It concludes that the method can stitch UAV image better in the error control and efficiency.Keywords：Unmanned Aerial Vehicle(UAV);optical image;regional separation;weighted adjustment;image stitching- 52
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Published：2020-08-13 -
Electrocardiogram beat classification based on kernel principal component analysis and support vector machine
Abstract：To increase the electrocardiogram(ECG) classification accuracy, this study focuses on a method of ECG beat classification and proposes a KPCA-SVM(kernel principal component analysis-support vector machine) classification algorithm. Firstly, the kernel function was used to perform high dimensional transform for the ECG beats to form a kernel matrix. Then, the ECG beat kernel matrix was perform the principal component analysis under a high dimensional space to implement the dimension reduction and denoising of kernel matrix. Finally, a linear SVM classifier was employed to classify beats according to the dimension reduced kernel matrix. In order to evaluate the effectiveness of the algorithm proposed, it was applied in MIT-BIH-AHA dataset for ECG beat classification, and then compared with KSVM(Kernel Support Vector Machine) and artificial neural network such as Back Propagation(BP), Radical Basis Function(RBF), and Learning Vector Quantization(LVQ). The results show that the proposed algorithm improves the classification accuracy of KSVM by 1.16%, reaching 95.98%, which is much higher than that of the artificial neural networks mentioned above. Consequently, it is verified that the algorithm proposed can effectively improve the classification accuracy.Keywords：electrocardiogram;beat classification;kernel principal component analysis;support vector machine- 54
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Published：2020-08-13 -
Multi-source matching of multi-sensor images based on edge line features
Abstract：A novel multi-source image matching strategy based on line feature extraction algorithm was proposed to overcome the shortcoming of point feature matching algorithm. Firstly, image edge points were detected and connected into curves, and the edge line segment was extracted by utilizing multi-scale strategy. Then, based on the spatial proximity and relative significance, the edge line segment was divided into lots of groups, and each of them was regarded as a feature of line called line labels. Finally, the similarity between the lines was computed according to the line geometry. Consequently, whether the two line labels are similar could be verified and then they were matched by the fast matching algorithm. Similar to local feature, the line feature is robust and adapted to changes of angle of view. Compared to matching approaches based on existing local features, the proposed method is more suitable for the images with low-texture scenes, blurring-texture scenes, high changing of illumination or multi-source scenes. Experimental results indicate that the proposed algorithm has scale invariant, rotate invariant and illumination invariant and can solve the situation in which point feature matching algorithm is not available and the matching accuracy is within one pixel.Keywords：multi-source image matching;edge point;spatial proximity;relative significance;line labels;Line Feature- 38
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Published：2020-08-13 -
Target recognition based on multi-feature correlation from star image taken by drift-scan CCD
Abstract：To improve the detection precision of a geostationary satellite orbit determination system, a target recognition method based on local region multi-feature correlation was proposed by analyzing the characteristics of a star image taken by a drift-scan CCD. A morphological filter method was used to suppress the background of star image and eliminate its non-uniformity. After homogenizing the image background, the correlation coefficients of three features(pixel values, contrast ratios and linear correlation) in local region were analyzed. On the basis of correlation coefficients, the optimal threshold was determinect to isolate the pixels of the satellites and the background stars and ultimately to identify the pixels of the satellite targets. The star images of geostationary satellite were processed, the experimental results show that this method removes the influence of background stars on target recognition, decreases error detection rate and accurately detects geostationary satellite targets. It can fulfill the requirement of reliability, stabilization and accuracy of geostationary satellite orbit determination.Keywords：star image;target recognition;drift-scan CCD;geostationary satellite recognition;morphology filter;multi-feature correlation- 62
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Published：2020-08-13 -
Generation method of partitional horizontal uneven fringes
Abstract：As the oblique angle projection of horizontal even fringes on a reference plane will generate uneven fringes with bidirectional distortion, this paper proposes a method to generate horizontal partitional uneven sine fringes to reduce the measuring errors of horizontal even fringes. With the proposed method, this kind of uneven fringes' pixel-phase relationship was described by partitional function. When this kinds of fringes were projected, the even fringes with uniform distribution could be obtained on the reference plane. So the nonlinear relation between the pixel and the phase could be improved in phase unwrapping results and the measuring accuracy would be optimized. A simulation experiment on a plane with a height of 50 mm shows that the mean value of uneven fringe projection measurement error is 0.4099 mm, and the mean value of even fringes is 2.5235 mm. Moreover, that for a globe with a height of 50 mm shows that the symmetry error ranges from 3.1% to 9.3% for projecting even fringes, whereas that ranges from 0.03% to 1.6% for projecting uneven fringes. The measurement accuracy has be increased by horizontal partitional uneven fringes projection.Keywords：Three dimentional measurement;grating projection;partitional horizontal uneven fringe;pixel-phase relationship- 55
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Published：2020-08-13 -
Object tracking based on affine transform and uniform sampling
Abstract：A target tracking method based on the affine transformation and uniform sampling was proposed to solve the issues that targets may generate different geometric transformations such as scaling, rotating and beveling in the process of image tracking. Based on the particle filter algorithm, six affine parameters were set as the stable variables to predict likely deformation of the target. Then, the target modeling and candidate target modeling were constructed by uniform sampling in the affine parameter area. A similarity measuring function was selected for calculation of gray differences between two sampling sites to create a monitoring model, thus the optimal estimation of the state variables was obtained and then stable tracking of the target was realized. The simulation experiment demonstrates that the proposed method can stably track geometric deformation targets,and the deviation is less than 10 pixel. The robustness and accuracy of the method are definitely superior to that of traditional target tracking method as well as other tracking method based on affine transformation and feature modeling.Keywords：object tracking;affine transform;uniform sampling;particle filter;geometric transfor mation- 61
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Published：2020-08-13 -
Accurate recognition of work-pieces based on Gauss-Newton image registration
Abstract：To improve the recognition accuracy of a machine vision system for work-pieces, the Gauss-Newton algorithm was employed to the intelligent robot`s machine vision and the vision's recoginition accuracy was improved by sub pixel. Firstly, a rigid transformation model between template and target was built and the residual similarity between template and target image was established.Then Sobel algorithm was used for folded operation of the images detected in the x direction and the y direction to get the directional diagram of the images. The Jacobian matrix of the images to be detected was calculated using this directional diagram, as long as the transformation matrix was calculated using BI-linear interpolation after image rigid transformation. Finally, the target location of sub pixel where the residual similarity between template and directional diagram reach the minimum was detected using Gauss-Newton algorithms, and the recoanition accuracy was in sub-pixel. Experimental results show that the precision of work-piece recoanition is 0.1 pixel, which satisfies the requirement of high accuracy recognition on work-pieces.- 48
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Published：2020-08-13 -
Detection of arc surface defects in microscope lens detection system
Abstract：A detection system for arc surface defects of the microscope lens was proposed to improve the manufacturing quality of the lens. The image preprocessing and image edge detection were introduced the morphological operations to realize the contour extraction of a target. The image preprocessing and edge detection were added into the traditional edge detection. Then, VC ++ object-oriented programming tools were combined with the image detection for simultaneously processing the qualified lens and the defect lens to find out the faults of the defect lens. Finally, according to the results from the image processing for qualified lens and the defect lens, the difference between the qualified and the defect lenses is judged, thus the arc surface characteristic contour of the defect lens was extracted. The experimental results show that the accuracy of the designed system is 5.37μm and the accuracy of the defect detection is 96%. The system can realize the edge extraction and edge detection of arc surface of the microscope lens.Keywords：miniature microscope;Lens;arc surface defect;image preprocessing;edge detection;VC++- 77
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Published：2020-08-13 -
Enhanced sensing method for 3D scene in UAV ground station
Abstract：For low-flying,landing and hovering of a Unmanned Aerial Vehicle(UAV), a method of 3D scene enhanced sensing method for an UAV ground station was proposed. In consideration of a complex low flying environment, a multi-level calling guideline was established for the terrain data of the 3D scene, and then the local details of the 3D scene were increased. Then, a 3D conformal symbol of the obstacle from the database was designed, the enhanced sensing of the obstacle was achieved. A dynamic perception idea was introduced, and the vertical profile display, route presentation as well as the protection symbol were designed for flight safety in real time. Finally, enhanced synthetic vision was proposed, and the 3D scene enhanced sensing system was implemented. The low-altitude approach and near ground investigation were selected as experiments. Results show that the proposed method can provide the enhanced sensing for 3D scene display of the UAV ground station and the frame of scene display is at least 32 Hz. This method simplifies the data from the 3D scene, reduces the difficulty of understanding the scene information, improves recognition speed, and effectively promotes situational awareness of the UAV control personnel.Keywords：situational awareness;Unmanned Aerial Vehicle(UAV) ground station;three-dimensional scene;enhanced sensing;three-dimensional conformal symbol- 63
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Published：2020-08-13 -
Target recognition of perimeter intrusion defense system based on wavelet packet and BP neural network
Abstract：The seismic signals generated by recognizing targets in a perimeter intrusion defense system based on a seismometer are very weak and difficult to be directly identified. So the signal features of the targets need to be extracted before target identification.This paper presents a new method of target recognition based on wavelet packet analysis and BP neural networks.Firstly, target motion signals captured by a front detector were proposed by using wavelet denoising. Then, the signals were decomposed and reconstructed with wavelet packet analysis, and the feature values of reconstructed signals were extracted to construct feature vectors. Furthermore, the feature vectors were used as the inputs of the BP neural networks to carry on learning and training various types of target characteristics.Finally, the trained neural network were used to identify the targets on-line. Recognition result for 30 groups of data from the seismometer(6 kinds of distance, 5 sets) shows that the desired output vector of the network and the actual output vector of the network is consistent, and the target recognition accuracy reaches to 99%. It concludes that this method can effectively identify the target of perimeter intrusion defense systems.Keywords：intrusion defense;target recognition;BP neural network;wavelet packet;seismic signal- 46
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Published：2020-08-13 -
Prediction and interference of navigation star
Abstract：How to capture the directions and distribution of refraction stars in refraction starlight navigation was researched. To obtain the information of the refraction stars, a method to analyze the distribution of refraction stars on standard orbit was proposed. By proposed method, the direction of refractive starlight from a spacecraft at a special position could be obtained by adjusting the attitude of a star sensitive sensor. On the basis of star information gotten in specific time interval, three kinds of influences on refraction stars' number and distribution were calculated according to the geometric positional relationship of the sun, the moon and the earth. Comparing the stars' number and distribution before and after the interferences, a navigation simulation was analyzed. The experimental results show that the largest source of interference is the earth, followed by the sun, the moon. Under the three interferences, refraction navigation, blank section may exist for the spacecraft. In the range of navigation blank section navigation error increases rapidly, instantaneous position error in r direction could be 20 times larger than before. It is verified that the method proposed to analyze interference on refraction starlight navigation has important practical significance, especially in design of navigation methods, adjusting star sensor's attitude, and predicting navigation blank section.- 46
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Published：2020-08-13
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