Chinese Version Light学术出版中心
Latest Issue
Issue 11 ， 2008
-
Study on optical system of high resolving
Abstract：The dimension and configuration of space camera is mainly dependent by the optical system of the camera. It is useful for the space camera get small, light weight and stabilization that to study several optical system configurations for one application purpose. This paper describes high resolving visible space camera which takes sun synchronization orbit and TDI CCD push-bloom imaging method. Assume the orbit height is 500 km, the grand sample distance is 0.5 m. Analyzed six kinds optical system configurations using the CODE V optical design software, the obtained results have different F number and FOVs(field of view) of each others, and presents useful optical design data. In the practical applications, according to the ground swath width determine the FOV, then choice the optical system configuration which can satisfy the needed FOV and small dimension.Keywords：space camera;high resolving visible camera;optical system design;optical transfer function- 66
- |
- 19
- |
- 53
Published：2020-08-13 -
Study on the quantitative analysis of the cotton in cotton-terylene textile by near infrared technique
Abstract：In order to establish a calibration that can determine the concentration of cotton in cotton-terylene textile precisely. First, near infrared spectra of 50 cotton-terylene textile samples were collected using self-designed accessory. Savitsky-Goaly filter smoothing, first derivative and second derivative pretreated the spectra. Calibration models for cotton content were established with PLS, The results indicate that Savitsky-Goaly filter smoothing spectra treatments couldn’t effect the performance of the model in this case; NIR technique could analyze the contents in the textile precisely, RMSEC is 0.022，RMSEP is 0.018 and the error of analysis is restricted ±0.05;In addition, several key aspects of this application were expressed.Keywords：near infrared spectroscopy;textile;partial least squares;spectra treatments- 52
- |
- 11
- |
- 5
Published：2020-08-13 -
Vacuum ultraviolet radiation characteristics of diffuser for space ultraviolet remote sensing instrument
Abstract：Changes in diffuser reflection ratio will directly affect the radiometric calibration results and exploration results of space ultraviolet remote sensing instruments in orbit. Build up a device to study vacuum ultraviolet radiation characteristics of diffuser by simulating space ultraviolet radiation environment, and carry out the researches on the vacuum ultraviolet radiation characteristics of AL + MgF2 diffuser for space ultraviolet remote sensing instrument. The experimental results show that, vacuum ultraviolet radiation accelerates the degradation of diffuser reflection ratio; diffuser reflection ratio has degradation at 160-300nm; the degradation value increases with the increase of radiation time; the degradation varies with linearity at 160-300nm and the rate of degradation differs with the wavelength. Analyze the factors which may cause the degradation.Keywords：vacuum ultraviolet radiation;AL+MgF2 diffuser;space enviroment;degradation- 41
- |
- 9
- |
- 8
Published：2020-08-13 -
The Design of spectrally tunable LED light source
Abstract：Light-emitting diodes are compound semiconductor devices that convert electricity to light. In optical radiometry and calibration, LED has good performance of high luminance, energy-cost savings, long life, no pollution and small bulk. It is new reference source of radiometry, photometry and colorimetry. In this text, design of spectrally tunable LED light source has been described. It composed of an integrating sphere with a large number of LEDs. The source is designed to have a capability of producing different spectral distribution in the visible region, and it can mimic various light source. A series of simulations have been conducted to predict the performance of spectral distribution of the designed tunable source. The source has designed a power control box, it can control every LED module accurately. This new type source will be used as a transfer standard for radiometric application.Keywords：light emitting diode;tunable source;radiometry;Spectral distribution- 52
- |
- 7
- |
- 14
Published：2020-08-13 -
Study on imaging system with harmonic diffraction element in terahertz multi-band
Abstract：Terahertz wave is an electromagnetic radiation area with significant scientific value. This paper has integrated 14-50µm terahertz wave into multi-band imaging system, based on the special large dispersion capability of harmonic diffractive element. The longitudinal aberration is simultaneously limited less than 0.75mm in the five harmonic wave bands (15.8-16.2µm, 18.5-20µm, 23-25µm, 30.5-33.5µm and 46-50µm). In each harmonic wave band, the magnification changes as a function of wavelength, which creates image registration error. To compensate for this shortcoming, the zoom optical system is designed by means of optical two- component. The problem is solved successfully in the theory. The design results show that the image height keeps 6.74mm in every harmonic wave band and the zoom optical system still realizes aberration compensation action. In the five bands, each optical transfer function approaches the diffraction limit in 10 cycle/mm. Finally, the system realizes the requirement of portability, minitype and ease fabrication.Keywords：terahertz;harmonic diffraction lens;multi-band;zoom optical system- 69
- |
- 12
- |
- 12
Published：2020-08-13 -
Molecular Dynamics Simulation of AFM-based Nanoindentation
Abstract：Three-dimensional molecular dynamics (MD) simulations are utilized to study the AFM-based nanoindentation process of monocrystalline copper film. The Morse potential is used to compute both the interactions between the specimen atoms, interactions between specimen atoms and indenter atoms. Nanoindentation processes are conducted to evaluate the indentation depths on the indenter’s stress and variations of system potential energy. The results shows that the plastic deformation via amorphous transformation is the mechanism of nanoindentation of monocrystalline copper film. With the increase of indentation depth, both of the variations of system potential energy and stress increase, indicating a strong size effect.Keywords：AFM;indentation;molecular dynamics;monocrystalline copper- 76
- |
- 7
- |
- 1
Published：2020-08-13 -
A Novel Element Frequency Selective Surface
Abstract：A novel element Frequency selective surface (FSS) composed of an improved cross element is presented in this paper. By applying modal matching approach, the novel element FSS is compared with the traditional cross element FSS theoretically. The influence on the center frequency for changing angles of TE incidence and polarizations of large angle incident waves is researched. With filming technology and lithography, FSS samples with improved elements are made. The tests are made in the microwave darkroom. The measured curve shows good agreement with the emulated curve. It is shown that the traditional cross element FSS can not have angle independence for TE incident waves or polarization independence for large angle incidence, the drift of the resonant frequency is 300MHz for 45°TE incidence, and 800MHz for different polarizations of 45°incident wave; In our modified structure, the resonant frequency of the FSS remains independent of incident angles, the drift of the resonant is only 100MHz for 45°incident wave, also, the resonant frequency maintain the stabilization for different polarization.Keywords：Frequency selective surface (FSS);polarization independence;the resonant frequency;independence of incident angles- 30
- |
- 4
- |
- 8
Published：2020-08-13 -
Design of diffractive optical elements for off-axis illumination in lithography system
Abstract：Being one of the very important RETs (Resolution Enhancement Technology), OAI (Off-axis Illumination) is widely applied to optical lithography system. The advantages of adopting DOE (Diffractive optical element) to realized OAI are not only the flexible illumination shape available but also the controllability of the intensity profile in addition to the higher efficiency of light source. In this paper, the four DOEs that have 8 phase level are designed by using the step-iterative algorithm, and the four elements can realize dipole, quadrupole, annular and Bulls-Eye illuminations respectively. The simulation results show that their efficiency of light source are all better than 80% and the RMS (Root-Mean-Square) of intensity profile compared with the ideal ones are all smaller than 7%.Keywords：DOE;resolution enhancement;illumination;beam shaping- 54
- |
- 10
- |
- 12
Published：2020-08-13 -
Design of large aperture refractive-reflective zoom lens
Abstract：This paper introduced an optical design method for large aperture zoom optical system. The optical system divided into two segments which called front and back with this method. The front optical system used reflect system to meet the request of large aperture and the back optical system used the converse zoom objective. The two segments would be assembled at the first imaging of the optical system. It would assure the imaging quality of the optical system through optimized the converse zoom objective of the back. This method had been proved feasible from the design results through an example. This method also could assured the configuration simple and compact and solved the matter which hard to design zoom lens with the large aperture.Keywords：zoom lens;optical system;large aperture;imaging quality- 58
- |
- 10
- |
- 13
Published：2020-08-13 -
Application of fiber optic sensor measurement system in spin superconducting rotor instrument
Abstract：A spin drive principle of superconducting rotor and a fiber optic sensor measurement system used in spin superconducting rotor instrument were introduced. The measurement system includes displacement fiber optic sensor, speed fiber optic sensor, motor control fiber optic sensor and signal readout pattern. It not only can gauge suspension micro-displacement and rotation velocity of rotor, but generate some necessary motor control signals to drive rotor. The experimental results of rotor suspension and rotation at liquid helium temperature (4.2K) show that the measurement resolution of superconducting spherical rotor suspension micro-displacement is 10 um and the rotor speed is 1013 rpm, which give some useful references for the further application of fiber optic sensor measurement system to monitor rotor’s operating position accurately.Keywords：fiber optic sensor;cryogenic environment;superconducting rotor;electromagnetic- 52
- |
- 8
- |
- 4
Published：2020-08-13 -
A New Type Optical Waveguide Matrix Switch
Abstract：On analysis of the basic structure of Mach-Zehnder interferometer (MZI), two switch units were defined. A new type optical matrix switch based on Banyan network was proposed, and the multiport interconnection 1:k (k＞1) can be realized with two types of Mach-Zehnder interferometer (MZI) units. Taking the 2×2 and 4×4 optical matrix switches for example, the constructions and characteristics of this new type optical matrix switch were provided. With the optimization and the design of the MZI construction, the influences of the intersection angles among the waveguide links and the excess loss of the MZI units on the total optical loss of system are studied, and the insertion loss of systems is discussed. Based on planar lightwave circuit (PLC) technology, SiO2-based MZI units, 2×2 and 4×4 optical matrix switch were fabricated. A basic agreement between experimental results and theoretical calculation was obtained and the response time of less than 1 ms was obtained, then the multiport switch function fulfilled.Keywords：integrated optics;banyan network;multiport optical matrix switch;SiO2 waveguide- 44
- |
- 10
- |
- 0
Published：2020-08-13 -
Wavefront aberration of cubic phase in propagation and Order Separation by the CGH
Abstract：When making a design of the cubic phase plate testing system using computer generated hologram as the null lens, two very important questions are emerging. They are the wavefront aberration of cubic phase in propagation and the separation of the diffraction orders. The opinion is presented in this paper that the cubic phase introduces higher order aberration as it propagates. And the expression of the aberration for the cubic phase when propagating is given in detail. From the formula we can see that the high order aberration increase as the propagation distance l increase. The theoretic foundation for the diffraction orders separation of the testing wavefront diffracted by the CGH. To prove the theories, we take a design of the cubic phase plate testing system for example. The results coincide with the theoretical formula we got.Keywords：optical testing;CGH;cubic phase;wavefront aberration;diffraction order separation.- 37
- |
- 6
- |
- 3
Published：2020-08-13 -
Enhancing correlation peak value in VLC based on diffraction characteristic of SLM
Abstract：The multilevel diffraction spectra of target image is obtained on the filtering plane because of the periodic structure of SLM in VLC,. Matched filters can be loaded at the position of different diffraction spectra on the filtering SLM to perform matched filtering of multilevel diffraction spectra. Theory analysis shows the correlation spots of different diffraction spectrums are at the same position of the output plane, and then the correlation peak value is enhanced by coherent superposition. It is verified by experiments that the output correlation peak of VLC can be effectively enhanced using this method.Keywords：optical correlation recognition;Vander Lugt correlator;spatial optical modulator;correlation peak;Interference;diffraction- 40
- |
- 8
- |
- 1
Published：2020-08-13 -
A New Method for High Accurate Determination of Refractive Index of Optical Glass
Abstract：High accurate determination of refractive index of optical glass has become more important aspect to ensure imaging quality of optical systems. In this paper, we introduce the measuring method of refractive index of optical glass, both foreign and domestic actuality of development .We bring forward a new method to calculate refractive index by measuring the three least deflection angle of three vertex angle of prism , the characteristic of method is that accuracy of the refractive index measurement improve with refractive index augment. Accuracy of the refractive index measurement is more than 1x10-6 by goniometer which accuracy of angle measurement more than 0.5². Formula of new method is deduced ， the accuracy of measurement are analyzed in the theory. New method have better application foreground because of its high accuracy.Keywords：refractive index;high accurate determination;least deflection angle- 65
- |
- 7
- |
- 17
Published：2020-08-13 -
Thermal Effect of Nd:YAG Slab with Diode Bar Side-pumped
Abstract：In order to solve the thermal effect problem of laser slab by diode bar side-pumped, temperature modeling of laser slab was investigated. By the analysis of working characteristic of laser slab, a thermal model according to the practical situation was introduced. Based on the heat conduct theory, a novel solution of the Possion equation was established and the general analytical solutions of temperature field and thermal distortion field of laser slab were obtained. This analytical solution not only solved the problem of calculation error in temperature field caused by the assumption of radial heat flow in laser slab, but also overcame the problem of low precision induced by the numerical analysis method. The results show that when the yttrium aluminum garnet doped with a mass percent of 1.0 % of Nd-ion is side-pumped by a diode bar with output power of 30W, and the Gaussian spot radius coupled on the side-face of laser slab is 150μm, the slab can get a maximum temperature rise of 102.3 oC，1.54μm maximum thermal distortion on the side-face and 2.66μm maximum thermal distortion on the end-face. The temperature field distribution of Nd:YAG slab under different pump power and coupled radius were quantitative studied. The results can be applied to the design of resonant cavity in diode bar side-pumped slab lasers and offer theoretical basis for reducing the thermal effect in laser systems.Keywords：solid-state-laser;side-pumped;Nd:YAG slab;thermal effect;analytical analysis- 30
- |
- 6
- |
- 13
Published：2020-08-13 -
Calibration of distortion for three-mirror off-axis
Abstract：To obtain the distortion of three-mirror off-axis, the calibration method and procedure of the system are presented, the principle and composion of calibration system are also introduced. An analysis for the distortion of three-mirror off-axi is carried out on the basis of the distortion mathematically. The distortion is settled in the mathematical model by means of least square poly-regress method. The results show that calibration accuracy of the absolute distortion is less then 2μm（1σ）, and the calibration accuracy of relative distortion is less then 1×10-4（1σ）. This method is fit for the request of high accuracy calibration of the distortion for three-mirror off-axis, It is valuable for the practical application.Keywords：three mirror off-axis;distortion;mathematical model;calibration- 44
- |
- 7
- |
- 10
Published：2020-08-13 -
Research on Scheme of Torsion Angular Distortion Measurement Based on Moiré Fringe
Abstract：In order to accurately measure the three-dimensional deformations between large photoelectricity measurement equipments, a high-precision optical angular measure method is proposed based on the moiré fringe produced by the double diffraction grating interference. Through collimator to simulate equipment and the fine-tuning mechanical structure to adjust collimator to simulate the torsional flexibility of three-dimensional objects, the measurement experiment is made on the independent foundation platform. Through comparing different design proposal in experiments, use of the scheme of CCD target surface installed in the image surface of parallel light is come to use. The image processing technology of filtering thinning is made used to obtain the stripe width by treating with the collected moiré fringe. According to the changes of stripes width, the torsional flexibility value is work out through the mathematical model. The experiments results show that, when the fine-tuning institution makes the collimator circumgyrate in the field of view of ±7', the clearer moiré fringe image can be gotten in the scheme. And after the algorithms process, the angle of torsion measuring accuracy is 4.3"(3 ) when the moiré fringe width is 1615~1712 . This method meets the measurement requirements of high-accuracy angle of torsion between equipments, and it lays the foundation to enhance the photoelectric precision of measurement equipment.Keywords：torsional flexibility;angular distortion;Moire fringe;program analysis;image processing- 51
- |
- 8
- |
- 8
Published：2020-08-13 -
The extraction method for missile bullets’multiple targets of opto-electronic theodolites
Abstract：The system of opto-electronic theodolites for measuring missile bullet provides parameter of missile bullet trajectory and affords primacy scientific data for completing campaign assign and obtaining ideal result of destroy. This article researches extraction arithmetic for missile bullet’ multiple targets. Above all, adopting OSTU method change numeral image into binary image, and bstract separately center position of targets and area of targets, at the same time, mark target region; enactment threshold of area, according to area of target, judge conglutination and obstruct; then separate targets in term of wave crest and trough’s variety of grey histogram of conglutination region; obtain grey average of target; acquire middle axes of target by adopting Hough transforming and pproximating and calculate obliquity angles of targets. In course of matching, forecast searching region of target matching by using Kalman filter; accomplish missile bullet’s multiple targets data association of serial images by making use of improving eigenfunction and achieve extraction of missile bullet’s multiple targets after obtaining center position of targets, area of targets, grey average of target and obliquity angles of targets. The experimental result shows that right ratio of the extraction targets reach to 90%.The article use correct mathematical model and reasonable arithmetic and obtain effectively parameter of missile bullet’ multiple targets.Keywords：Opto-electronic theodolite;missile bullet’ multiple targets;OSTU method;Kalman filter- 46
- |
- 6
- |
- 5
Published：2020-08-13 -
Image stitching of multi-lens with large visual field in range instrumentation
Abstract：Objective: In order to get the video image with large visual field in range instrumentation, a system of auto-stitching multi-lens image with large visual field is established and its applied algorithms such as image matching, marking the area of lapping, seamless stitching and etc is investigated. Method: First, the theory of wavelet transformation and wavelet-packet are presented. The image-matching algorithm based on wavelet-transformation by matching wavelet parameters of image is analyzed. Then, marking the area of lapping by comparing and rotating algorithm is analyzed, marking the only lapping area by matching the sub-lapping areas after rotating. Finally, the image seamless stitching algorithm by wavelet-packet transformation is analyzed: after image wavelet-packet transformation, merging the wave-let parameters by frequency and then using the result to rebuild the image. Result: Experimental results indicate that the system gets an image with 3.3°×1.76°large visual field by stitching four image with 1.1°×0.88° visual field, the image after stitching is smooth and seamless ,the speed of the system can reach 10F/S. Conclusion: It can satisfy the range instrumentation requirements of getting image with large visual field.Keywords：Large visual field;Wavelet transformation;wavelet packet;image matching;Seamless stitching- 40
- |
- 6
- |
- 4
Published：2020-08-13 -
Application of real-time feature level multi-sensors data fusion system in Photoelectric Theodolite
Abstract：To satisfy the requirement of real-time in photoelectric theodolite and guarantee tracing precision and reliability, a new servo-control system according to MIMD (multiple instruction multiple data stream) structure was proposed. Kallman filtering was adopted to implement data fusion of multi misdistances. Operation principle of theodolite was simply introduced. Mathematic derivation of data fusion in a theodolite with multi imaging systems was given. It showed that solution of data fusion needed large quantity of numerical calculations. To satisfy the calculation requirement and real-time processing demand, a special parallel calculation system with three arithmetic units which was composed of two DSPs and single FPGA. Chaining mode of three arithmetic units was described and time outgoing of real-time calculation for each one was analysis. Hardware simulation was carried out on the special calculation system. The simulation result showed that the system can satisfy the real-time requirement with 1.25ms in theodolite with three imaging systems, while the CCD sampling frequency was 50 Hz and sampling frequency of photoelectric encoder was 800 Hz.- 70
- |
- 6
- |
- 3
Published：2020-08-13 -
Structure stability study for carbon fiber composites precision component in a large aperture space optical remote sensor
Abstract：In order to study the structure stability of precision support components made of the carbon fiber composites (CFRP) in the large-aperture space optical remote sensor, a CFRP joint cylinder between primary mirror and second mirror was designed and manufactured. The mechanical model of the joint cylinder was established. The material’s laying way of the component and relevant parameters were calculated based on the method of finite element analysis. The structure stability of the joint cylinder was validated through the test. First, The maximum deflection was calculated according to the angle changed between primary mirror and second mirror. The mechanical model of the joint cylinder was established according to the true load. Then ,the axial elastic modulus based on the model was calculated. Following, the material’s laying way of the component was determined by the composite laminate theory. Second, the angle between the two mirror, and the modal distribution of support structure were calculated based on the software ANSYS. Finally, the structure stability was validated by the mechanic test and optical measurement method. The results show that the angle between primary mirror and second mirror was less than 10″, the first-order natural frequency of CFRP support components is greater than 75 Hz. CFRP support have better structure stability, having reached to the requirement of general technology index.Keywords：space optical remote sensor;Carbon fiber composites;Structure stability;optical measurement- 44
- |
- 8
- |
- 22
Published：2020-08-13 -
Application of quantitative fault tree analysis for space camera software development
Abstract：Quantitative fault tree analysis (FTA) is very effective in analyzing the reliability and safety of space camera software system. It is difficult to get knowledge about system’s faults and construct the structure of fault tree. A method of software fault tree establishing based on Rough set is put forward. Because software failure cause is anfractuous and available data are got hard, an approach to model for bottom event based on vague set is proposed. The relative probabilistic importance of bottom event and the occurrence probabilistic of top event can be calculated using the model. The outcome is very useful to guide design of software reliability and decide the emphases of software test. Experimental results show that the new approach of software fault tree analysis can help designer advance system reliability develop by fault tolerance and error design. The results also show that the new method makes software quantitative analysis possible which is unable to deal with as a result of reliability data getting difficult.Keywords：software reliability;Fault tree analysis;Rough set;Vague set- 60
- |
- 8
- |
- 4
Published：2020-08-13 -
Study on the Thermal Control of High-power Focal Plane Apparatus
Abstract：In order to realize the thermal control of high-power focal plane apparatus (FPA), the thermal design of FPA is studied based on the method of simulation and experiment according to the structure characteristics of the FPA. First of all, the main requirements of the thermal design of high-power focal plane apparatus are introduced and the feature of thermal design of focal plane assembly was analyzed. Then, the thermal performance is simulated by means of code TMG. The thermal test is conducted and the fit curve of temperature of FPA according to the thermal test is given. Finally, how to choosing the thermal control mode rationally is put forward according to thermal design example. The results show that the temperature of 50W high-power FPA can be controlled lower than 35℃ when it is worked in 2 minutes continuously and have the 12℃ cool source. It can meet the design requirements of FPA.Keywords：CCD;Focal plane;focal plane apparatus;focal plane assembly;Thermal control- 57
- |
- 8
- |
- 12
Published：2020-08-13 -
The realization of high-frequency chopping control stepper motor based on ICL7667
Abstract：ICL7667 is used as a power MOSFET drivers in stepper motor drive system,for increasing switching speed of the power MOSFET and realizing high-frequency chopping control stepper motor.First, study on the gate capacitance,switching time of the power MOSFET due to the problem of power MOSFET is not in cut-off or deep saturation.The results showed that the gate capacitance of the charge and discharge process affected the power MOSFET switching speed.Then introduce the method to increase the switching speed of the power MOSFET. Finally, ICL7667 is used as a power MOSFET driver to achieve a high-frequency chopping control stepper motor .Simulation and test results showed that:the drive circuit with voltage division by resistors in the frequency of not more than 20 kHz ,power MOSFET can to be in cut-off or deep saturation;ICL7667 can guarantee that chopping frequency of 200 kHz, the power MOSFET can to be in cut-off or deep saturation. The chopping frequency of the drive circuit used ICL7667 is increased 10 times than the drive circuit with voltage division by resistors. After using the ICL7667,stepper motor can run correctly under control of high-speed chopping signal.Keywords：ICL7667;Power MOSFET;stepper motor;MOSFET driver;switching property- 59
- |
- 9
- |
- 1
Published：2020-08-13 -
Effect of aerocraft attitude on image motion compensation of space camerasystem
Abstract：In order to realize high precision image motion compensation, analyzing the effect on image motion compensation of aerocraft attitude, it may put forward the requirements of space camerasystem. First, to analyse the image motion match character that the modulation transform function of camera requires, and decide permitted errors of image motion matched. Then, the Mento-carlo method (statistic distribution method) is used to analyse and calculate the errors of image motion velocity. Finally, it is decided that the attitude accuracy meets the requirements of image motion compensation.The conclusion can be drawn by calculating, that the requirements of that attitude and the stability of attitude measure accuracy is 0.1°and0.005°/s meet errors of image motion matched of 96 TDI-CCD integration progression. The method is simple and easy to implement, which is suitable for the study of image motion compensation of space camerasystem.Keywords：space camera;Attitude;image motion compensation;MTF;Mento-carlo method- 40
- |
- 8
- |
- 28
Published：2020-08-13 -
Research of Laminated Photoresist Sacrificial Layer Technology and Residual Stress in Micromirror Fabrication
Abstract：This paper investigates the laminated photoresist sacrificial layer technology and residual stress in micromirror fabrication. Different problems in electroplating related to the photoresist sacrificial such as pollution are discussed and their solutions are proposed．Through experiments, it was found that the solvent of the upper photoresist penetrates the electroplating base metal layers and dissolves the sacrificial layer behind it; a new fabrication process is developed. The residual stresses in thin metal films can affect the device properties. And the investigation of the residual stress origin and how to control are shown. Some valuable experimental parameters were obtained. Employing the new technologies, we fabricate perfect flat micromirror with the size of 620×500×2 μm3, air gap’s height of 12μm.Keywords：Micromirror;Laminated photoresist;sacrificial layer;residual stress- 61
- |
- 10
- |
- 2
Published：2020-08-13 -
The analysis of flexible wheel’s accuracy in great speed ratio frictional transmission
Abstract：Great speed ratio frictional transmission is a new kind transmission device, which has high precision and great speed ratio. Flexible wheel is one of the key components in great speed ratio frictional transmission. It will has micro-deformation by load. In this paper, flexible wheel is modeled with elastic mechanics theory and finite element analytic method. And its different amounts of deformation caused by different load are analyzed by ANSYS software. The device of testing flexible wheel’s amount of deformation is designed and fabricated. The angle amounts of deformation by different loads are tested with 0.2 angular second electronic leveler in micro-deformation. The disparity between theoretical amount of deformation practical amount of deformation is putted forward. At last, we considered in this paper that the theoretical amount of deformation can be used in program of the driving system to eliminate the deformation in order to improve transmission precision.Keywords：flexible wheel;micro-deformation;deformation accuracy- 68
- |
- 7
- |
- 0
Published：2020-08-13 -
CFD Analysis for the Effects of the Hydrogen—Air Ratio on Combustion in a Micro Combustor
Abstract：Based on the six wafer combustor used in the MIT micro-gas turbine engine, an idea was presented that two-dimensional numerical simulations were performed to investigate the effects of hydrogen/air ratio on the combustion characteristics in a micro combustor when the mass flow rate of the mixture was constant. The CFD model of the micro combustor included hydrogen/air flow path, combustion chamber as well as solid walls used to construct the combustor. The simulation analysis included not only the detailed elemental reactions occurred in the combustion chamber, but also the fluid flow dynamics, heat transfer within the combustor and heat loss to the ambient. Through such systematic numerical analysis, the calculating results are considered to be compatible with the experimental results from the overseas, which may be used as the guideline for micro combustor design.Keywords：Equivalence ratio;Micro combustor;Combustion characteristics;CFD- 54
- |
- 9
- |
- 2
Published：2020-08-13 -
Fabrication of In-line Micropipettes and Digital Micro-jetting Experiment
Abstract：Abstract ：Micropipette fabricated from pulling of glass capillary have problems such as easily brittle fracture, hardly controlled length of microchannel and low efficiency of micro-jetting. Therefore a new Non-IC method for fabricating micropipettes has been designed. Round cross section with lower flow resistance is chosen the shape of the nozzle. Multi-microchannels are embedded tightly into the plastic pipe, by employing the rheologic flowing of plastic and the different shrinkage ratio of the two materials when cooling. Conical pipes which connect microchannels and plastic pipe formed by capillary and corrosion action, and meanwhile the length of micronozzles reduced. The method has the characteristics of low cost, simple manipulation and safe process. Micropipettes with 4 and 10 micronozzles have been fabricated. The inner diameter of micronozzle is 50μm, and the length is 2.5mm. The length of the conical pipes is 750μm. Experiments of micro-jetting of aqueous liquid into oil phase and gaseous phase were carried out by employing digitalization of microfluids technology with the micropipettes. Micro-droplets with diameter of 80μm and microarray were prepared. The micropipettes have proved to be well working with digitalization of microfluids technology by the experiments.Keywords：microfluidic;micropipettes;digitalization of microfluids technology;microarray;micro-jetting- 41
- |
- 6
- |
- 2
Published：2020-08-13 -
Installation Method of a Sub-mechanism on the Dropping Device of Aeronautical Weapons
Abstract：In response to erroneous dropping of external stores on the dropping mechanism of aeronautical weapons, finite element technique is adopted to conduct analysis to the hook, sector rocker and sector wheel, and fundamental reasons for it are found out, and the installation method of a sub-mechanism is put forward to without changing the structure of the dropping device. The sub-mechanism applicable in micro spaces is designed with computer-aided 3-dimension motion analysis and interference detection techniques.Structural stability of the sub-mechanism is studied in aspects of dropping sequence, energy requirements, rigidity and intensity of the stop as well as thermo-elasticity with computer-aided statics, dynamics, thermo-elasticity and stability engineering analysis (CAE) techniques. Results of calculations, experiments and aerial embarkation flights show that, the theoretical power value consumed by the stop is 10 w, and measured value is 14w; the measured value of tripping voltage is 7V, and the theoretical value of the time sequence is 0.0038s, greatly less than the performance index of the dropping device itself. The sub-mechanism acts safely and reliably, and avoids mutual interference between all moving accessories of the main body, which provides evidence for engineering application.- 28
- |
- 4
- |
- 0
Published：2020-08-13 -
New technology application research of ship distortion measure
Abstract：A new vessel distortion measure method based on image network-transmit technology is presented, the theory and the actual application of the new method is validated. The article introduces the distortion measure system of the ship, contrasts the aggregative processing system with the distributed processing system and indicates the technology advantage of the new system. The article analyses the time characteristic of the new system, demonstrates the system technology feasibility. The system expend 16ms to complete a image data capture and process cycle of 16 cannel.Keywords：distortion measure;image network-transmit;time characteristic- 40
- |
- 5
- |
- 8
Published：2020-08-13 -
Task specific uncertainty estimation of large-scale measurement
Abstract：It’s necessary to specify the uncertainty for the measuring results. It’s difficult to evaluate some uncertainties of large-scale measurement by conventional analysis method and standard comparison method, especially for special fitting task. For special large-scale measurement, we research its uncertainty based on Monte Carlo evaluation and denote this uncertainty as discrete point-clouds through computer visual. The measuring uncertainty is evaluated by off-line simulation for an optimum sampling strategy. The optimized measurement idea including point symmetry, equal distribution and radius constraint is given, taking the example of analyzing large-scale circular section part by laser tracker. This is applied to measuring practical tunnel components by laser tracker. It’s proved that the uncertainty of given measuring objects is evaluated accurately and intuitively by Monte Carlo evaluation and discrete point-clouds representation, which also build the optimum sampling strategy for better measuring precision.Keywords：Large-scale measurement;uncertainty;Monte-Carlo;Task specific;laser tracker- 57
- |
- 8
- |
- 14
Published：2020-08-13 -
Optimal Design of Radial Magnetic Couplings
Abstract：The precise Permanent Magnetic Couplings (PMC) is a core component of the vacuum robot. Accurate analysis and efficient optimal design are essential to improve transmission performance of vacuum robot and avoid costly trial. The state-of-art of the related research was firstly reviewed. Then a practical mathematical model with a novel criterion was set up. Furthermore, two typical analytical methods, the Equivalent Magnetic Charge (EMC) and the Current Sheet Model (CSM) were improved and compared with the 3D FEA method on efficiency and accuracy. Last but not the least, the Design of Experiments (DOE) was introduced and an effective and practical optimizing process was proposed. The results showed that the accuracy of the improved EMC was increased by about 6% and the efficiency was increased by 117% compared with the original EMC method. The error of the CSM method was 30% bigger than that of the 3D FEA, though the efficiency of CSM was much higher. It is very important to provide proper initial parameter guess to ensure a rapid convergence on optimizing process. The proper initial values can be obtained only by using nine simulation models with the DOE method. Multiple sets of optimizing cases were gained easily through standard optimization methods. The proposed optimizing method can satisfy the requirements of practicability, higher precision, as well as strong stabilization.Keywords：magnetic couplings;EMC;CSM;FEA;orthogonal test- 51
- |
- 8
- |
- 1
Published：2020-08-13 -
Research on Embedded PPPoE Access Method based on Highly Secure VPN
Abstract：In order to provide high quality information security service in public network, a new scheme is developed for constructing secure VPN. In this scheme, security protocols are separated from operating system and integrated into the network equipment-Safe Ethernet Card. When a program makes use of network equipments, the protocols cannot be bypassed. The scheme can be used to provide security communication and prevent active attack. Hardware platform and inner software structure of the card is introduced, and multiple access manners link into the VPN are discussed. An accessing the VPN method of implementing ADSL dial-up based on PPPoE in the card is presented. Experiments results show that this method achieved expect purpose.Keywords：VPN;PPPoE;network security;secure tunnel- 42
- |
- 6
- |
- 2
Published：2020-08-13 -
Full-automatic light adjustment control for CCD camera by external trigger
Abstract：In order to improve the deficiencies of automatic light adjustment methods for traditional CCD camera system in engineering, a new full-automatic light adjustment method for CCD camera system is presented. Light is adjusted by couple of external trigger electronic shutter and iris diaphragm, with electronic shutter adjusting light mainly, and iris diaphragm adjusting supplemented. By adopting external trigger mode, electronic shutter time adjustment of CCD camera is realized. The aperture of iris diaphragm is adjusted by motor under the control of single-chip to make the image illumination moderate. Feedback control quantity is obtained by the mean level of the image’s target region, and full-automatic light adjustment is implemented. The composition and working principle of the new light adjustment system are narrated briefly. Matlab simulation results show that histogram related to image of the new light adjustment system is wide and uniform, and the value of its power spectra is more than 7.5dB. The image of the new light adjustment system is clean and high-contrast. The new light adjustment system is effective and satisfies requirements of the optimal full-automatic light adjustment for modern CCD camera system.Keywords：external trigger;CCD camera;light adjustment system;electronic shutter;Iris Diaphragm- 39
- |
- 4
- |
- 6
Published：2020-08-13 -
Blind Image Restoration Algorithm Based on Space-adaptive and Regularization
Abstract：Based on original nonnegativity and support constrains recursive inverse filtering (NAS-RIF) algorithm, an improved algorithm is proposed in this paper. In order to control the trade-off between fidelity to the observed image and smoothness of the restored image and to prevent noise amplification, a newly cost function of the NAS-RIF algorithm can be obtained by adding space-adaptive terms and a regularization term. The space-adaptive terms can be calculated through the local properties of the observed image and the noise variance. An estimating method of noise variance is also proposed in this paper. This improved algorithm uses conjugate-gradient routine to calculate the optimal result. The experimental results show that the improved NAS-RIF algorithm provides a better restoration result.Keywords：Blind image restoration;space-adaptive;regularization;nonnegativity and support constrains recursive inverse filtering (NAS-RIF);estimating method of noise variance- 54
- |
- 7
- |
- 6
Published：2020-08-13 -
Space Code Projection Method for Shape Measurement of 3D Large Objects
Abstract：3D image merging technique is a key technique in measuring large scale free form surface. Based on image-control-point-restrain theory, the paper presents a new method of 3D image merging technology. In this method, a pseudo-random space code is first projected on a large object surface, and the images of the object are taken from different angle of views. By matching the window interest points on the overlapping region, the coordinate transformation matrix was obtained and 3D measurement of large- scale free-form surface was realized. Experiment result shows that by this new method of space code image merging technology, large-scale 3D shape can be successfully measuredKeywords：space code;3D measurement;3D image registration;3D image merge- 48
- |
- 4
- |
- 3
Published：2020-08-13 -
Calibrating Multi-vision Sensor System with One Dimensional Target
Abstract：Based on the invariance of cross-ratio and the property that all points of the one dimensional target are collinear, a global calibration method of Multi-vision system is proposed. The global coordinate frame is constructed based on the coordinate frame of one of the vision sensors, which is called the base vision sensor. The one dimensional target is positioned arbitrarily, for at least twice, in front of both the base sensor and the sensor to be calibrated. For each vision sensor, according to the invariance of cross-ratio, the image coordinates of the target feature points out of the view field are computed, utilizing the image coordinates of at least three feature points captured by the vision sensor. The transformation matrix from the coordinate frame of the sensors to be calibrated to that of the base sensor is solved, and optimized using non-linear optimization method. The global calibration of multi-vision sensors system is realized by pair-wise calibration between the base vision sensor and each of the vision sensors to be calibrated. The proposed method can be carried out without any high-accuracy 3d measuring equipments. It is simple, flexible and applicable in various situations. Experimental result shows that the error of the global calibration method is 0.041mm.Keywords：Global calibration;One dimensional target;The invariance of cross-ratio;Multi-vision sensor- 58
- |
- 4
- |
- 2
Published：2020-08-13 -
Research on the Evaluation Algorithm of Curve Profile Based on the Image
Abstract：According to the imaging characteristics, for achieving high precision measurement in linear profile of micro-parts, an evaluation algorithm of linear profile which based on discrete points is proposed. Firstly, edge detector is used to obtain the edge of the micro-parts. After that, a series of points which has tiny interval can be calculated by the expressions of designed profile. In addition, a system of coordinates is build for corresponding the point of actual profile and the point of designed profile. Finally, for every point of actual profile，we can calculate the minimum distance between it and the points of designed profile as the linear profile error of the point. The experimental results showed that the error is less than 1.5 pixels，so the proposed algorithm can significantly improve the precision and efficiency in measurement of linear profile.Keywords：linear profile error;micro-parts;method of minimum distance;discrete points- 43
- |
- 8
- |
- 2
Published：2020-08-13 -
Initial Target Region Estimation Suitable to Optical Tacking
Abstract：Due to be sensitive to noise for unsymmetry target, General center of mass can not locate well for optical tracking, and the macro divided method has good anti-noise capacity, but it is too computationally intensive. The macro-pixels method was used to reduce calculation time. For the unsymmetry target of 4×4 pixels in 128×128 pixel spot picture, the value of r could be optimal as 36 pixel of Micro pixel dimensions and target macro-pixels enlarged to 2 pixel according to less calculation time and better in anti-noise capacity. The value of r is 1 when SNR is 5 dB. Dynamic picture test shows that the improved arithmetic has 18~20 frame/s of processing speed.Keywords：Optical tracking;center of mass;Macro pixels;macro divided method- 59
- |
- 4
- |
- 3
Published：2020-08-13 -
Research on improving Resolution of Ultrasonic Image Based on Wavelet Image fusion
Abstract：Abstract：Ultrasonic imaging technology is a remarkable new technology in modern nondestructive testing (NDT), however, the main problem is that its resolution is lower at present, especially transverse resolution, directly affecting the application value of ultrasonic image. Aiming at the application characteristics for ultrasound image, for obtaining contrast test, making several experiments with the methods proposed based on combining interpolation and wavelet image fusion which are used to process ultrasonic images, results indicate that: it is feasible for improving the resolution of ultrasound image with the method of comparing the region energy to determine in which image the object is clear，The wavelet decomposition is used to decompose images interpolated to two different parts, namely, the low frequency part and high frequency part, then the low frequency part is processed with the method of average, and the high frequency part with the largest region energy, finally, better results have achieved from application of this method to improve the resolution of ultrasound images.Keywords：image fusion;Ultrasonic imaging;Image spatial-resolution;Super-resolution;Wavelet transformation- 52
- |
- 8
- |
- 7
Published：2020-08-13 -
A rendering algorithm based on Ray Casting for medical volumetric data
Abstract：Ray Casting algorithm is usually used in medical volume visualization, but there are a lot of limitations inherent to this algorithm, like high computational demand, low quality images, or a fixed classification. In these respects, a schedule for assigning optical attribute to resampling points is defined, and the schedule is reasonably associated with distance between the object and the viewpoint, as well as the object and the light source. Based on this, an efficient and accurate rendering algorithm for medical images is presented in this paper, and the algorithm classifies volumetric data into the foreground voxels and background voxels, and the former voxels are resampled using LOD (Layer of Detail) technique, then optical attribute of the resampling points is determined by the above-mentioned method. At the same time, the background voxels are displayed by the accelerated method based on space leaping resampling. The results show that the presented algorithm can achieve up to 2.5 fps on PCs for 512×512×482×2 Byte volumetric data. Meanwhile, tissues or organs can be displayed clearly, which is more coincident with the human vision.Keywords：medical volumetric data;real-time rendering;Ray Casting;resampling;LOD- 47
- |
- 5
- |
- 1
Published：2020-08-13 -
Intravascular ultrasound image segmentation based on active contour model and contourlet multiresolution analysis
Abstract：It is valuable to segment intravascular ultrasound (IVUS) images of atherosclerotic plaques during the diagnosis of atherosclerotic diseases. Aiming at two problems of traditional IVUS segmentation methods, i.e. the contour initialization and robustness, a novel scheme is proposed to segment IVUS images of plaques based on the active contour model and the contourlet multiresolution analysis. With the contourlet transform, the original image is decomposed into lowpass components and bandpass directional subbands. The template matching is adopted in lowpass components to yield initial contours of the lumen border and the media-adventitia border. The anisotropic diffusion is then utilized in bandpass directional subbands to suppress the noise as well as preserve vascular boundaries, and the contour evolution in the boundary vector field is used to obtain final contours. The method is evaluated via 100 simulated images and 120 real images, and results demonstrate that it can automatically and accurately extract two vascular borders. For real IVUS images, it outperforms the traditional active contour model by 3.04 pixels in terms of the mean distance error, and 6.30% in terms of the percentage of area differences.Keywords：active contour model;Contourlet transform;multiresolution analysis;intravascular ultrasound image segmentation- 48
- |
- 7
- |
- 14
Published：2020-08-13
Article
Loading...
0