Chinese Version Light学术出版中心
Latest Issue
Issue 3 ， 2008
-
Design of Signal Processing System for Detecting the Transformation of Oxyhemoglobin and Blood Flow Based on Fiber-Optic Sensor
Abstract：This article presented a system of detecting the transformation of oxyhemoglobin(Hbo) and blood flow of inner ear for the research of motion sickness. Based on the different absorption parameters of oxyhemoglobin and deoxyhemoglobin with a near infrared spectroscopy (NIRS) wavelength:660nm and 805nm, a set of engineering formulae were derived for detecting oxyhemoglobin(Hbo) and blood flow from Lambert—Beer Law. The sensor can detect and transform two kinds of transformation human physiology parameters：blood oxygen saturation and blood flow of inner ear. Through transportation data to PC, the system real-time displayed the curves of two parameters and offered forceful theoretic proofs for estimation of vertigo.- 80
- |
- 7
- |
- 2
Published：2020-08-12 -
Study of Si modified coatings on SiC substrate with ion beam assisted
Abstract：Ion beam assisted deposition (IBAD) based on End-Hall source was introduced to fabricate a Si coating on RB-SiC substrate. High-quantity surface photograph, surface scattering at 635nm and reflectance spectrum were measured at room temperature. The results showed that films became loose under fast deposition rates. The coefficient of surface scattering was decreased from 3.56% to 1.46% after surface modified polish by Si coating, which was approximate to the scattering level of Zerodur glass. The temperature and surface tensile experiment indicated that Si coating was combined well with the SiC substrate.Keywords：RB-SiC;IBAD;End Hall source;Coefficient of Surface Scattering- 49
- |
- 7
- |
- 13
Published：2020-08-12 -
Laser Diode Array Pumped Yb:YAG Thin Disc Laser With Four-Pass Optical
Abstract：The laser diode array (LDA) pumped Yb:YAG thin disc laser with a 10 mm diameter and 300μm thickness crystal bonded to Cu heat sink by Indium soldering has been demonstrated. The doping concentration is 10 at. %.The temperature of Yb:YAG crystal was controlled by water-cooled system. The pump-beam radius was calculated by Monte-Carlo method. Considering mode matching, the angle between pump light and bundle was controlled under 120. The four-pass optical coupling system was well designed with two spherical imaging mirrors(Φ=30mm,R=50mm). When the incident power was 4.13W, a cw output power of 670mw at 1030nm has been obtained. The optical conversion efficiency was 16.2%.Keywords：laser technique;laser diode array (LDA) pumped;Yb:YAG crystal;Thin disk laser- 49
- |
- 6
- |
- 3
Published：2020-08-12 -
The design of the low loss 193nm HR mirrors
Abstract：The main effective factors of the properties of 193nm HR mirrors were analyzed. It revealed that the electricity field strength decreased quickly from the outer layer to the center layer. So the outer layer next to the air side possessed the biggest electricity field strength. The absorption losses of the high refractive index layers were higher than that of the low refractive index layers. The absorption loss decreased sharply with the changing rate related to the ratio of the refractive index of the high-low refractive index materials from the outer layer to the center layer. The surface scattering loss increased proportionally to the ratio of the refractive index of the high-low refractive index materials. But the low ratio of the refractive index would require more layers to gain the certain reflectance which would result in the higher surface roughness and other loss. So it is useful for reduction of the scattering loss to select relatively high ratio of the refractive index. The HR mirrors were designed according to the alternate high- and low-refractive index layers with quarter-wave optical thicknesses. The designing reflectance was more than 98%.Keywords：193nm;HR Coating;Electricity Field Strength;absorption;scattering- 21
- |
- 6
- |
- 2
Published：2020-08-12 -
The feasibility research of LED light source in spaceborne calibration
Abstract：Light emitting diode had never been used as spaceborne calibration source before. In this paper, the feasibility of using LED as calibration source was studied. Discussing the Characteristics of LED, we used aging experiment to measure the LED long term working stability. Then, the LED current characteristic was discussed. As the calibration source characteristics would be changed in space environment, LED’s temperature characteristics, vacuum and anti-radiation characteristics were analyzed at the same time. Experimental results showed that continuous lighting for 1200 hours, LED’s attenuations were less than 1.2%., and LED on-off tests’ results showed a good reproducibility, but a period of 10 to 15 minutes instability. Changed LED’s currents had different effects on their radiant intensity and wavelength. Changed LED’s ambient temperatures would affect their radiant intensity, forward currents and peak wavelength positions. Under vacuum, as different conductive media, LED’s radiant intensity increased, and the volatile of LED’s packaging materials have little impact; In the case of radiation protection, LED’s radiant intensity change was no more than 0.5% / year in space radiation effects. General speaking, LED was competent for using as spaceborne calibration light source.Keywords：calibration;LED;luminescence;space- 52
- |
- 6
- |
- 7
Published：2020-08-12 -
The Development of New Optical Particle Counter
Abstract：This paper introduces a new Optical Particle Counter(DLJ-06 OPC) with 90 scattering angle, DLJ-06 OPC is of a LED(ight-emitting diode) as its light source, which has the character of suitable channel and long-use periods. This paper also introduces the principle of the DLJ-06 OPC. The DLJ-06 OPC was used in the experiments conducted at Xiamen for measurement of size distribution. The extinction coefficient and scattering coefficient were computed according to size distribution measured by DLJ-06 OPC were compared with the ones measured by Aethalometre and Integrating Nephelometer(wre designed by TSI). The comparison indicates that the size distribution measured by DLJ-06 OPC are reasonable.- 65
- |
- 8
- |
- 7
Published：2020-08-12 -
The pinhole Fraunhofer diffraction method of calibrating CCD optics-electron characteristic
Abstract：The precision of calibrating the CCD’s optics-electron characteristic will directly affect the measured result. A new calibrate method was introduced after the analysis of several methods of calibrating CCD’s optics-electron characteristic had been performed. The ration relationship between I/I0(the relative light intensity distribution of Airy pattern in theory) and n(the position of CCD’s pels) had been deduced. In the data processing, the conics fitting method was adopt to locate the peak value of grey scale curve and the alignment of the peak of theory light intensity curve and that of measured grey scale curve was completed. In practical experiment， a given CCD was calibrated using this method and the result was reliable.Keywords：CCD;Optics-electron Characteristic;Method of Calibrate;Pinhole Fraunhofer Diffraction- 44
- |
- 8
- |
- 6
Published：2020-08-12 -
The analysis that spectrum not matching of source affects remote sensor precision
Abstract：In the calibration of remote sensor, spectrum not matching of calibration source affect the sensor measurement precision. Computer has simulated calculation with the method of multiple trapezium. It prove the relative error of measurement has existed, and the relative error proportion to bandwidth of sensor. Remote sensor with bandwidth 20nm, it is negligible for spectrum not matching of calibration source. For moderate resolution remote sensor and the whole band remote sensor, the relative error of measurement is 7.9% when the bandwidth is 300nm. It is important that adopt calibration source with spectrum matching.Keywords：spectrum matching;relative error;remote sensor;simulated calculation- 43
- |
- 6
- |
- 33
Published：2020-08-12 -
Theory analysis of aspherical testing using the digital moiré patterns base on the sub_region stitching method
Abstract：With the characteristics of un-touching, high-automatic and high-speed, we measured 3D shape by digital moiré patterns. And it can measure 3D shape without compensator, auxiliary mirror, hologram and other assistant modules. So it is widely used in measurement of 3D shape. But with the negative effect of grating area and CCD resolution of the camera, it has some problems in large aperture, steep aspheric surface, even off-axis asphere testing. Focus on these problems; this paper established a sub-region stitching measurement of asphere by using the combination of digital moire patterns and digital phase shifting technology. This paper also illustrated the basic theory, and the mathematical implementation procedure. In all, sub-region stitching digital moiré patterns can be considered as another method, which beyond compensation tests to measurement of asphere.Keywords：asphere;digital moiré patterns;sub_region stitching;least squares fitting- 28
- |
- 8
- |
- 1
Published：2020-08-12 -
Realize width-field in Michelson interferometer for wind measurement
Abstract：The material and thickness of arms determine wide field of Michelson interferometer for wind measurement. According as four width-field conditions, the perfect two-glass is selected from Chinese glasses through analysis and calculation and the thickness of arms is gained. The choice satisfies the condition of width-field by validating. These parameters are inputted into computer and the configuration of interferometer is simulated. The interferogram of width-field is achieved through ray tracing. The wind velocity is attained by data reversing and coincident with theoretical value.Keywords：wind measurement;width-field;wind velocity reversing- 58
- |
- 6
- |
- 4
Published：2020-08-12 -
Stray light study on a WFOV absolute radiometer
Abstract：Abstract: Solar irradiance is measured while the sun scans over the FOV(field-of-view) of the WFOV(wide-field-of-view)absolute radiometer. The result contributed by the stray light entered into the receiving cone has an effect on the measurement precision. There are three aspects, the model analysis, outfield measurement of FY-3 and correction for orbit data of SZ-3, were analyzed to make the distribution of stray light with the change of incident angle of sun light. 1) The effect of stray light increases with the incident angle in a liner way. 2) The slope angle of FY-3 is about 18.4 degree. The analyze result reaches 0.63% in an incident angle of 7 degree and the result of measurement from ground is about 0.79%. 3) The slope angle of SZ-3 is about 10.4 degree. It’s smaller than that of FY-3 and uses more baffles. So the effect of stray light is very little. The correction for the orbit data of SZ-3 with the result of SZ-3 analyze obviously reduces the system error.- 24
- |
- 6
- |
- 5
Published：2020-08-12 -
Development of an Optical Coherence Tomography Imaging System in Ophthalmology
Abstract：Optical coherence tomography (OCT) is a high resolution biomedical imaging method, allowing for non-invasive and contace-free detecting of internal tissue structure and physiology. Ophthalmology is still the dominating field of biomedical OCT. The most important reason for that is the high transmittance of ocular media. An OCT system with broadband source (SLD) centered at 854 nm wavelength is applied for imaging in ophthalmology. Based on Fourier-domain rapid scanning optical delay line, the system is capable of imaging depth of 3mm. A device detecting the signal of eyeground is provided in this article. This device constitutes of the optical path for OCT imaging in the eyeground, the optical path for lighting of the eyeground, the optical path for obtainning photograph of the eyeground. The OCT images of macular region and optic nerve in the eyeground have been obtained.Keywords：optical coherence tomography;rapid scanning optical delay line;macular region;optic nerve head- 84
- |
- 7
- |
- 6
Published：2020-08-12 -
A Novel permanent magnetic bias radial magnetic bearing in magnetically suspended flywheel application
Abstract：According to the defects of the present radial hybrid magnetic bearing, the configuration and fundamental principle of a novel permanent magnetic bias radial magnetic bearing are introduced in this paper. The flux path was analyzed by using equivalent magnetic circuit, and the mathematics models of magnetic bearing were deduced. The parameter’s design method was also presented. Finally, the radial magnetic bearing was simulated and calculated by using FEM so as to check the decoupling characteristic of the excitation magnetic flux between X and Y direction through two methods, one was magnetic field distribution and the other was the influence to force Fy while plus current ix in X direction’s coils. The influence was testified very little that the force Fy was less than 3% of the force Fx which almost can ignored. The theoretic analysis and simulation have shown that this novel radial magnetic bearing can avoid the coupling between X and Y direction effectively compared to the existing structure. As a result, the control will be more easier and the performance can also be improved.Keywords：equivalent flux path;parameter design;FEM- 50
- |
- 6
- |
- 13
Published：2020-08-12 -
Uniformity study of Ni Microstructure Deposited by Through-Mask Plating
Abstract：This paper investigates the thickness uniformity and the cross-sectional profiles of electroplated individual nickel microstructures as a function of electroplating conditions. Factors which influence the thickness uniformity of microstructures were discussed. It was found that the thickness uniformity and the cross-sectional profiles of microstructures could be controlled by varying the process conditions. When no additives in electroplating solution, the polarizability were applied to explain the changes in the thickness uniformity and the cross-sectional profiles of electroplated individual nickel microstructures; with additive, coexisting adsorption states of additive in electroplating is believed to be responsible for the change in the thickness uniformity and the cross-sectional profiles of electroplated individual nickel microstructures. At last, a uniform thickness distribution and microstructures with flat profiles could be obtained at optimal plating conditions of 6±2mA/cm2 and 25°C.Keywords：uniformity;micro-electroplating;coexisting adsorption states- 72
- |
- 6
- |
- 9
Published：2020-08-12 -
Research on Gas Flux Control of Micro/Miniature Fuel Cells Testing System
Abstract：Based on the requirement of Direct Methanol Fuel Cell testing, the subsystem of gas flux control was established with the subassemblies composed of multiplied function data collection board, industry control computer, proportional flux solenoid valve，and digital display flowmeter. The control programme was made with LabVIEW, including the improved autotuning PID algorithm. The accuracy of gas flux control for Micro/Miniature Fuel Cells Testing System was improved, and data record and display were realized during the experimental process. The structure and design method of gas flux servo control system were investigated. The driver of proportional flux solenoid valve was designed and fabricated according to the principle of the voltage controlled constant-current source. Based on the character of the driver, the autotuning PID algorithm was improved and realized under the environment of LabVIEW. With the adjustable PID parameters, the steady state accuracy of gas flux control was improved, which is up to ±0.1L/min. The rise time of step response for 0-5L/min, 0-10L/min, 0-20L/min, and 0-50L/min is 0.9S, 4.9S, 5.2S, and 6.6S, respectively, and the overshoot is less than 0.23L/min, which is acceptable.Keywords：Fuel Cell;Servo Control;Voltage Controlled Constant-current Source;Autotuning PID Algorithm- 69
- |
- 6
- |
- 8
Published：2020-08-12 -
A global calibration method for multi-vision measurement system with coplanar targets
Abstract：A unique world coordinates based global calibration method with coplanar targets is proposed, in which laser tracker is taken to establish the general measurement coordinate frame and fitting the standard plane to set up calibrations points, the system is used to directly sample calibrations points for each camera in the multi-vision inspections system, the whole cameras in the measurement system can finish global calibration without medi-coordinate-frames. The accuracy loss from transformation times of coordinates frame decreases and calibrations process is facilitated. Finally, the global calibration experiment on a real aircraft attitude measurement system that is made by high speed multi-cameras is conducted, under conditions of large measurement range, root mean square error of the system is not more than 0.8mm.Keywords：global calibration;vision measurement;laser tracker;coplanar targets- 39
- |
- 6
- |
- 16
Published：2020-08-12 -
Experimental research on the micro electroforming of microstructure array
Abstract：Discussed the characteristics of the micro electroforming process systematically and analyzed the property of the electric field and flow field. The asymmetry of the electroforming and the effect of the stirring mode, current density on the microstructure were studied in detail. From experiment it can be concluded that the effect of the pure stirring reach the entrance of the micro groove only, diffusion is the control factors of micro electroforming. The equipotential line curvature of electric field grew with the increasing aspect ratio of the deposit. Which result in the discrepancy of ion transferring capacity in the reaction area. The results showed that the stirring velocity could not improve transferring condition, while complex stirring (assistant with ultrasound) could help to the deposit velocity and get the perfect microstructure. The optimal current density was less than 0.9～1.0A/dm2 in the process. Based on the research high resolute electroforming microstructure with vertical wall was fabricated.Keywords：SU-8;UV LIGA;microstructure;Micro electroforming;simulation- 43
- |
- 7
- |
- 4
Published：2020-08-12 -
Dynamic Analysis and Experimental Research of a Wall Climbing Robot
Abstract：Objetive: The transient sucking process was analyzed since the value of negative pressure plays an important role in robot’s safety, locomotion ability, parameter selection of mechanism and power. Method: A mathematical model of the transient sucking process was made and analyzed with bond graph theory since studying the process is key to improve the performance of the wall climbing robot. Firstly, the suction system is analyzed and designed keeping in mind requirements of a wall climbing robot with the Computational Fluid Dynamics (CFD) tool. Secondly, by reasonable assumptions and fluid dynamics theory, parameters of the sealing system are equivalent to rigidity and damp by bond graph theory. Then, the relationship between the negative pressure generated by the fan and the motor’s input voltage is simplified to a first-order expression. Result: Simulation result shows the transient process of a wall climbing robot’s negative pressure generating dynamic process is a first-order expression. Conclusion: At last, a bond graph model was made, and simulations by 20sim software and experiments were carried out to confirm its validity.Keywords：Wall-climbing robot;Negative pressure generator;Dynamics;Bond graph- 45
- |
- 9
- |
- 1
Published：2020-08-12 -
Dual-mass resonant output silicon microelectromechanical gyroscope
Abstract：The MEMS (Micro Electromechanical System) gyroscopes are being considered for use in a number of application areas such as stabilization, general rate control, and autopilot systems in aircraft and missiles. The benefits of MEMS gyroscopes compared with conventional gyroscopes are well known and include low cost, potential for miniaturization and low power consumption. The resonant output gyroscope, as its name implies, utilizes resonant sensing as the basis for Coriolis force detection. Resonant sensing has several advantages such as a lower capacitance noise, large dynamic range, good scale factor linearity and a direct frequency output. However, the mechanical noise resulted from vibrating mass and the error resulted from external acceleration can not be canceled. In this paper, a new device called the Dual-mass resonant output silicon microelectromechanical gyroscope is described and consists of two proof masses vibrating in the tens of kilohertz and two resonating sense elements designed resonant frequency an order of magnitude higher than that of the proof masses. The function of Coriolis force versus the angular rotational rate was analyzed by dynamics analysis. The resonant frequency of beam subjected to an axial time-varying Coriolis force was described by the Rayleigh-Ritz energy method. Appling the Mathieu Equation, the dynamics of the DETF (Double-ended tuning fork) resonator and the scale factor of gyroscope were analyzed. The gyroscope overcomes several of the problems compared with single-mass resonant output gyroscope, such as cancellation of acceleration effects can be achieved through two mechanically coupled masses vibrating anti-phase to each other.Keywords：Micro Electromechanical System;gyroscope;dual mass;double-ended tuning fork resonator;frequency output- 67
- |
- 6
- |
- 6
Published：2020-08-12 -
Portable Positioning System Design for Micro Gastrointestinal Invasive Diagnosing Devices
Abstract：Since micro invasive diagnosing devices came out, they have shown their potency in international medicine. But the positioning problem restrains development of the micro invasive devices. For this reason, the paper, aimed at gastrointestinal physiological parameters detecting capsule, designs a portable positioning system design for micro gastrointestinal invasive diagnosing devices, and details the operation principle, system configuration, positioning algorithm, and experiments in the article. The author makes the quasi-static magnetic field model computing magnetic flux density, and solutes the positioning equations based on the simulated annealing algorithm, so gets the good positioning effect. Based on the analysis of the experiment’s results, the portable positioning system for micro diagnosing devices has the benefits of high accuracy, low cost, no-harm to human, and freedom of users. Thus, the positioning system has great potential in medical application.Keywords：electromagnetic positioning;quasi-static field;micro invasive diagnosing devices;gastrointestinal;portable;the Simulated Annealing algorithm- 26
- |
- 7
- |
- 1
Published：2020-08-12 -
The influence of postbaking temperature on the thermal swelling and the internal stresses of SU-8 photoresist
Abstract：The influence of different post exposure bake (PEB) temperature on thermal swelling and the internal stresses of SU-8 photoresist were investigated. Large internal stress of SU-8 layer can result in cracks and deformation. Moreover, the feature width of microchannel will be reduced after electroforming mainly due to the thermal expansion and swelling of patterned SU-8 in electrolyte. The high-aspect-ratio and dimensional precision of micro structure were greatly affected by these two problems. When other parameters were constant, the micro channels’ width at different swelling time were measured under different PEB temperature. Experimental results show that, the swelling deformation of SU-8 became larger when at a lower PEB temperature, and thermal swelling was mainly occurred during the beginning 30 minutes, and then its deforming rate was slow down and tended to be saturated. Internal stress of SU-8 layer was measured after the PEB by the theory of curvature method. It proves that lowering the PEB temperature can greatly reduce the internal stress. Therefore, on consideration of the two effects above, parameters of PEB should be settled by the demand of micro-structure to be made.Keywords：SU-8 photoresist;micro electroforming;thermal swelling;internal stress- 42
- |
- 8
- |
- 6
Published：2020-08-12 -
Nanoscale Measurement Technique of MEMS In-plane Motion Based on Block Matching
Abstract：Motion measurement was a key method to get characteristic and dynamic parameters of MEMS resonator in every moment. The results of measurement gave important reference to MEMS designation. In this paper, an algorithm based on block matching was designed so that it was insensitive to frame-to-frame intensity variations. MEMS motion process is analyzed using the algorithm. The offered solution achieved nanoscale accuracy by always employing a small and fixed number of computations, independent of the iterative method. The amplitude-phase curve of MEMS in special driving frequency was got. Experimental results indicate that the repetition of measurement is 5nm.Keywords：MEMS resonator;dynamic characteristic;block matching;sub-pixel- 32
- |
- 6
- |
- 2
Published：2020-08-12 -
Feature Analyzing Based on Weighting Combination for Lip’s Image Sequences
Abstract：Data fusion considers discriminate performance made by different features, and gets a new discriminate vector which had higher classifiable power. To get better effect of combination, weighting combination was used to form the parts of with balance. Geometrical features of lip region and the descriptors of lip contours by Discrete Cosine Transform were combined to get a new discriminate vector. With this new vector, the HMM model was used to training and recognizing. The experimental results based on isolated Chinese words show that the new discriminate vector by weighting combination can produce better recognition result than using single characterize parameters when applied to lipreading. A maximum recognition rate was improved by 2.5% with different weighting factors.Keywords：feature fusion;Geometrical features;Discrete Cosine Transform descriptors;weighting combination;hidden Markov model- 31
- |
- 7
- |
- 1
Published：2020-08-12 -
Color Components Prediction Based on Rotated Principal Component Analysis
Abstract：Aiming at the problem of negative index in the spectral color space built by means of traditional principal component analysis, a method of color components prediction based on rotated principal component analysis (RPCA) is proposed, which performs the linear transformation from initial eigenvectors to a set of all-positive vectors as the physical basis color components while retaining the cumulative ratio of the variance contributions of principal components to the original spectral space information to the maximum extent. The rotated column vectors should be also polarized between zero and unity. The experimental results show that the novel method of prediction not only uncovers the real color components of the target image better but reconstructs the normalized spectra data set with a high colorimetric and spectral accuracy.Keywords：color match;RPCA;all-positive vector;varimax;metamerism index- 34
- |
- 8
- |
- 7
Published：2020-08-12 -
Target trace acquisition method in serial star images of moving background
Abstract：Abstract：For the CCD serial star images, while the space target is moving, the background is still moving because of the CCD flat is moving. At the same time, because of dithering of CCD flat and some other reasons, the gray value of target is not invariable, so much as to disappear in the background noise. In other words, the trace may be discontinuous. The paper put forward a target trace acquisition algorithm in serial star images of moving background. The algorithm can detect the discontinuous trace of small space target with high accuracy. Originally, the cross projection method is used in background star and target area acquisition. Then, a group of N brightest stars in every image is used to estimate the moving vector of the whole background. Finally, put forward a target trace acquisition method. The simulation experiment is done with two small targets in 16 frame serial sky images (8-bit gray scale image). Results of trace acquisition show that the algorithm can detect both trace of the two targets with high accuracy. The algorithm provides a good way for target trace acquisition of small targets whose trace may be discontionuous.Keywords：image process;star image;cross projection;trace acquisition- 58
- |
- 6
- |
- 12
Published：2020-08-12 -
Research on the Fast Stitching Algorithm of Sequence Images in the Auto Rack Girder Detection
Abstract：According to requirement of the auto rack girder detection, the real time visual detecting system is designed. Sequence images having features need to be real-time stitched and an improved Fourier field stitching algorithm which is applied to stitch sequence images of the Auto Rack Girder is put forward in the paper. It is selected within overlapped areas of image at first large region and two-dimension pulsing signal is gotten after cross-power spectrum is counted. Registration parameters are gained through maximum of pulsing signal. To bundle images, a new weighting image smoothing algorithm based on Canny is put forward. To some extent, the algorithm has general adaptability to some factors such as lamination variation, noise and so on. With the fast stitching speed, the algorithm is adopted to fast stitch a lot of sequence images.Keywords：Auto Rack Girder;sequence image;Image stitching;frequency domain;FFT- 35
- |
- 6
- |
- 1
Published：2020-08-12 -
Measuring Code-bar Grade Rod by Vision Collimation and Laser Interferometer
Abstract：In order to inspecting stripes error of code-bar grade rod, a method of visual collimation and double-frequency laser interferometry is discussed. Precise measurement system of code-bar grade rod is designed and the method of collimation and measurement is investigated. When image of code-bar edge presents on collimation area, the image and the data of laser interferometer are collected rapidly, needing not move worktable carried grade rod tardily. Then collimation and measurement are completed by software program. Image detection of code-bar edge is discussed. First, the algorithm of maximal square deviation is used to image segmentation. Then a way named image edge-tracking is presented to obtain code-bar edge directly, avoiding the difficulty of noise filter. Finally, a fine division method based on probability and statistics theory is applied to locate code-bar edge, improving the resolution of visual collimation. In the practice, the criterion deviation of vision collimation is 0.23μm and the criterion deviation of system stability is below 0.5μm. The method of collimation and measurement improves measurement efficiency and measurement precision is 4 times high than the requirement, it ensures credibility of code-bar grade rod measurement. The measurement system has been used in the stripes error inspection of code-bar grade rod successfully.Keywords：Code-bar grade rod;Vision collimation;interferometry;Image detection- 43
- |
- 6
- |
- 0
Published：2020-08-12 -
The selection and overall algorithm of definition algorithm in image measuring apparatus for micro parts
Abstract：Miniature parts are applied more broadly as instruments and equipments are getting more miniature. Imaging measuring methods used in miniature parts have become an important technology which is developing competitively at home and abroad. The methods are able to solve the limitation of routine measurements. This paper is based on image measuring methods and the image measuring apparatus for micro parts. There are many algorithms which are employed to appraise definition nowadays; however, different algorithms may get different results in different measuring systems and there is not a well-rounded algorithm to tell user how to make choice. So it is not easy to select a certain algorithm according to the characteristic of the appointed apparatus. The aim of his paper is to present an algorithm to deal with the selection of definition and the process in this paper shows typical ways of orientation for Telecentric systems. The procession of the experiment can be mainly divided into three parts. Firstly, the Telecentric image measuring system is used to grab image at different working distances; and the distance between the camera and the benchmark is recorded by a laser interferometer with double frequency. Secondly, the correlative algorithms including Brenner function, Tenengrad function, Gradient square function and the four modifier formula, entropy function are employed to appraise definition in this paper. Finally, the principal component analysis and the factor analysis are employed to analyze the data so as to work out the algorithm which is suitable for the apparatus from the above 8 algorithms and to work out the overall merit algorithm for definition. As a result, the suitable definition algorithm is worked out to be Tenengrad function and the overall merit algorithm for definition is presented. The synthesis evaluating model of definition has also been built in this paper. The data mining algorithm submitted in this paper is able to make choice in different evaluations when aiming at the exclusive requirement and to decrease the amount of the operands which will be used in next programs. The innovation of this paper is that it presents a whole new algorithm to deal with the selection of definition algorithm and a whole new algorithm to overall merit the definition algorithms. The experiment shows that the image grabbing system which using Telecentric systems would capture the most clear picture form series of pictures by using the algorithms.Keywords：Miniature parts;Visual measurement;Definition;principal component analysis;Factor analysis- 57
- |
- 7
- |
- 8
Published：2020-08-12 -
A Novel Perceptual Image Hash Algorithm
Abstract：We propose a perceptual image hashing scheme aimed at content authentication. Robust feature is first extracted by secret key, and we generate an image hash from the feature. To enhance security of Hash, the secret key is created by image optical feature. Experimental results show that the proposed scheme is robust against JPEG compression, filtering, noise and some else managements, but fragile against tamper.- 32
- |
- 6
- |
- 1
Published：2020-08-12 -
Research of imaging system used in the moving target tracking based on area CCD
Abstract：A kind of imaging system used in the moving target tracking was designed, and it used area CCD ICX415AL as sensor. This system carried out optical joining together with two slices of the area CCD, and made them complete share surface. So, this can make angle of visual field increase one time under guaranteeing the constant condition of goal resolution capacity, and solve the requirement of the big visual field of searching goal. First, the structure and the specification of area CCD ICX415AL sensor are introduced in this paper, then the circuits of working clock and power driver for the sensor are proposed. The noises of the video signal (KTC noise and 1/f noise) are filtered by using the correlated double sampling (CDS) technique, and the signal-to-noise ratio of the system is also enhanced. For get good imaging quality, radiation scale must be done after design. According to the scale experiment data given in the paper, the radiation dynamic range and the best working point of the system have been determined. Entire system adopts the Field Programmable Gate Array ( FPGA ) as key controller, and hardware is designed by the software which is based on the modularization design method from top to bottom. The development efficiency has been enhanced.Keywords：moving target tracking;area CCD;driving clock;CDS;FPGA- 34
- |
- 6
- |
- 15
Published：2020-08-12
Article
Loading...
0