Journals >Optics and Precision Engineering
Contents
2008
Volume: 16 Issue 7
30 Article(s)
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Research Article
Study on resolving power of varied line-space grating
LIU Zheng-kun, TAN Xin, XU Xiang-dong, HONG Yi-lin, and FU Shao-jun
On the basis of Fraunhofer diffraction theory,the diffraction patterns of a Varied Line-space(VLS) grating were obtained for incidence beam in parallel and uniform.The intensities of the diffraction spots changing with diffraction angles were figured out and pictured,when the diameter of incident spots were 5 mm and 10On the basis of Fraunhofer diffraction theory,the diffraction patterns of a Varied Line-space(VLS) grating were obtained for incidence beam in parallel and uniform.The intensities of the diffraction spots changing with diffraction angles were figured out and pictured,when the diameter of incident spots were 5 mm and 10 mm to the same VLS grating,and 10 mm to different VLS gratings.The result was validated by the experimentation for the sensor's resolving power when the diameter of incident spot was different to the same VLS grating.The result reveals that the diameter of incident spot is very important to the sensor's resolving power for the diffraction pattern of VLS grating..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1153 (2008)
Detection of weak ultrasonic signal using optical heterodyne interferometry
LI Xing-fei, WANG Chi, XIANG Hong-biao, and ZHANG Guo-xiong
In order to detect weak ultrasonic signal,a high-sensitivity optical heterodyne interferometer was developed.A linearly polarized laser with good coherence was used as light source to improve interference intensity,and a diaphragm was employed to eliminate the optic noises and the influences of feedback lights on the lIn order to detect weak ultrasonic signal,a high-sensitivity optical heterodyne interferometer was developed.A linearly polarized laser with good coherence was used as light source to improve interference intensity,and a diaphragm was employed to eliminate the optic noises and the influences of feedback lights on the light path.Then,the system was easily adjusted by using the 1 st order light as reference light.Experimental results indicate that the measured vibration signal frequency and amplitude are 62.38 kHz and 76.4 mV respectively,when a square wave is adopted to excite the ultrasonic probe with 62.42 kHz central frequency and 74 V amplitude,which shows proposed system can satisfy the detection requirement of weak ultrasonic signal..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1158 (2008)
Characterization of crystalline silicon solar cells by electrical parameters
ZHOU Chun-lan, WANG Wen-jing, LI Hai-ling, ZHAO Lei, and DIAO Hong-wei
In order to analyze the possible defects effecting on efficiency of three types of industrial silicon solar cells:P-type of cast-multicrystalline silicon,Edge-defined Film-fed Growth(EFG) and single silicon solar cells,several important cell parameters,such as the curve of spectral response(External Quantum Efficiency,In order to analyze the possible defects effecting on efficiency of three types of industrial silicon solar cells:P-type of cast-multicrystalline silicon,Edge-defined Film-fed Growth(EFG) and single silicon solar cells,several important cell parameters,such as the curve of spectral response(External Quantum Efficiency,EQE),mapping of short-circuit current,ideality factors of diodes,saturation currents I0 and the parasitic resistances RS and RSH,were characterized and analyzed.After analyzing EQE curve with and without bias white light during EQE measurement,the mapping of defect induced shunt current in solar cells and electrical parameters of solar cells were respectively measured by Light Beam Induced Current(LBIC) and dark and illuminated current-voltage(I-V) measurements.Then,based on diode equivalent model of solar cell,the simulation of measured I-V curve was used to obtain some important parameters of solar cells.From these results,it shows that the main defects effecting on salar cell parameters are the grain boundaries,dislocation and impurity in bulk silicon for cast-multicrysalline silicon and EFG solar cells,but born-oxygen defect pairs for single silicon solar cell.Because of the variable type of minor carrier recombination centers in raw material,the final conversion efficiencies of cast-multicrystalline silicon,EFG and single silicon solar cells are 10.5%,11.7% and 15.7%,respectively..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1163 (2008)
Novel optimization method for wavefront coding system
LEI Guang-zhi, ZHANG Xin, ZHANG Jian-ping, YANG Hao-ming... and ZHANG Xin|Show fewer author(s)
In order to bring forth a new method to design Wovefront Coding(WFC) system with commercial lens design software,a new merit function formed by the traditional imaging quality factor,Strehl Ratio(SR) and Encircled Energy(EE),was proposed to describe the "insensibility to defocus".A triplet system using WFC teIn order to bring forth a new method to design Wovefront Coding(WFC) system with commercial lens design software,a new merit function formed by the traditional imaging quality factor,Strehl Ratio(SR) and Encircled Energy(EE),was proposed to describe the "insensibility to defocus".A triplet system using WFC technology was designed by the new merit function.The new system extends the depth of focus more 10 times than that of the original system.The results show that the WFC system designed by proposed optimal method can be achieved in design software CODE Ⅴ and zemax and can come to a better trade-off between "insensibility to defocus" and "restorability"..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1171 (2008)
Relationship between aerosol fine particle and visibility
LI Xue-bin, DONG Chun-wen, XU Qing-shan, and WEI He-li
The effect of aerosol fine particle(PM2.5) on the visibility was discussed,and the relationship between PM2.5 and visibility was established theoretically.The relative PM2.5/PM10 and extinction coefficient were analyzed with changing of particle distributions based on Mie scattering theory.By comparison of measured datThe effect of aerosol fine particle(PM2.5) on the visibility was discussed,and the relationship between PM2.5 and visibility was established theoretically.The relative PM2.5/PM10 and extinction coefficient were analyzed with changing of particle distributions based on Mie scattering theory.By comparison of measured data and calculated values,experimental results indicate that the pollution of PM2.5 is the main factor that results in visibility dropping,and the error of calculated value is less than 30%,which is significant for dealing with pollution of PM2.5 and improving atmospheric visibility..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1177 (2008)
Optimal design of pose and position fine tuning apparatus for secondary mirror in large optical telescope
XU Gang, YANG Shi-mo, and GONG Yu-bing
The performance requirements of pose and position fine tuning apparatus for secondary mirror in large optical telescope were analyzed.Based on Gough-Stewart manipulators,two design criteria for the optimal design of pose and position fine tuning apparatus were brought out,one is transmission precision performance and tThe performance requirements of pose and position fine tuning apparatus for secondary mirror in large optical telescope were analyzed.Based on Gough-Stewart manipulators,two design criteria for the optimal design of pose and position fine tuning apparatus were brought out,one is transmission precision performance and the other is stiffness performance.Two angular-dimensioned parameters and three nondimensionalized linear-dimensioned parameters as design parameters were selected to analyse the effect of each parameter on performances.Then,two global conditioning indexes were brought out,one is movement precision performance index and the other is stiffness performance index.Based on requirement for pose and position adjustments,a general workspace was adopted to replace the reachable workspace.In the guideline of unified objective method,a unified objective function and a mathematical model were established for solving a constrained single objective optimization problem,and an improved genetic algorithm was used to obtain the Pareto optimal solution within the definite areas selected.Experimental results indicate that the performance is optimal when the ratio of base radius to platform radius is 1.095.Compared with the optimal performance when the ratio of base radius to platform radius is less than 1,transmission precision performance index increases by 0.7% and stiffness performance index reduces by 4.0%..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1181 (2008)
Initial alignment of antenna for laser communication system between aircraft and ground station
ZHAO Xin, WANG Shi-feng, TONG Shou-feng, HAN Cheng, and JIANG Hui-lin
In order to solve initial alignment of antenna for laser communication system between an aircraft and a ground station,the composition and algorithm theory of an antenna alignment system were demonstrated in detail,and the experimental data were analyzed.The parameters of position and attitude of communication terminalIn order to solve initial alignment of antenna for laser communication system between an aircraft and a ground station,the composition and algorithm theory of an antenna alignment system were demonstrated in detail,and the experimental data were analyzed.The parameters of position and attitude of communication terminals were obtained using GPS,INS and etc,the azimuth and elevation essential to antenna alignment of two terminals were obtained by coordinate conversion.By doing an experiment between two pots of 12.5 km distances,the data of initial alignment of antenna were given,and the initial alignment of antenna was completed.Experiment shows the area of uncertainty is 35 mrad,which will be the foundation of antenna scanning..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1190 (2008)
Novel measuring method for refractive index of micro-quantity liquid
XING Man-nan, BAI Ran, and PU Xiao-yun
On the basis of imaging principle of a coaxial spherical surface optical system,a new measuring method using glass capillary for the the refractive index of micro-quantity liquid was introduced.The refractive index was obtained through measuring the focal position of a capillary filled with the liquid by a reading micrOn the basis of imaging principle of a coaxial spherical surface optical system,a new measuring method using glass capillary for the the refractive index of micro-quantity liquid was introduced.The refractive index was obtained through measuring the focal position of a capillary filled with the liquid by a reading microscope,and doing a calculation with an analytic formula.The refractive indexes of four liquid mediums,water,ethanol,ethylene glycol and glycerin were measured,the required sample was less than 0.002 ml,the precisions of obtained refractive indexes were better than 0.000 3 for water and ethanol,and 0.000 7 for ethylene glycol and glycerin.The results show that the new measuring method can be characterized by a micro-quantity sample,and has advantages in simple equipment,easy operation and high measurement accuracy.It is adapted to measure the refractive index of transparent or translucent micro-quantity liquid sample..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1196 (2008)
Extrapolation method to extend dynamic range of Shack-Hartmann wave-front sensor
LI Hua-qiang, SONG He-lun, RAO Chang-hui, and RAO Xue-jun
A software-based method called extrapolation method was presented to overcome the trade-off between the sensitivity and the dynamic range of displacement of Shack-Hartmann Wave-front Sensor(HS).Firstly,a beginning focal-spot of a random sub-aperture(A) was obtained,and the focal-spots of the neighbor sub-apertures(B) oA software-based method called extrapolation method was presented to overcome the trade-off between the sensitivity and the dynamic range of displacement of Shack-Hartmann Wave-front Sensor(HS).Firstly,a beginning focal-spot of a random sub-aperture(A) was obtained,and the focal-spots of the neighbor sub-apertures(B) on A were found through the extrapolation method.By taking a focal-spot of B as the beginning point,the focal-spots of the neighbor sub-apertures on B could be obtained.In the same way,the other focal-spots could also be obtained.In order to demonstrate the feasibility and practicability of the extrapolation method,an experiment was carried out.The results show that the extrapolation method can restore the wave-front while the aberration of the incident wave-front is about twice that of dynamic range of HS,which can satisfy measurement requirements for the large dynamic range and high sensitivity of HS..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1203 (2008)
Fiber-optic fluorescence measuring system suitable for pesticides in soil
WANG Zhong-dong, YAN Tie, and WANG Bao-hui
In order to realize on-line measurement for pesticide residua in soil,a fiber-optic fluorescent measuring system was put forward.The foundational principle of organic molecules emitting fluorescence and the feasibility of measuring pesticides by fluorescence method were analyzed.Then,a fiber-optic fluorescent measuringIn order to realize on-line measurement for pesticide residua in soil,a fiber-optic fluorescent measuring system was put forward.The foundational principle of organic molecules emitting fluorescence and the feasibility of measuring pesticides by fluorescence method were analyzed.Then,a fiber-optic fluorescent measuring system was established based on the techniques of fiber-optic sensing and fluorescence analysis.In the system,a pulsed xenon lamp was used as an excitation lamp source and a self-made cone-shape fiber-optic probe was used for detecting the fluorescence,a small-sized flat field grating spectrometer for dispersing fluorescence and a high-speed datum-collecting module for collecting and converting the fluorescent signals.The fluorescence spectrum of the pesticide could be obtained with only one exposure of the system.In this way,the fluorescence experiments on carbaryl of different concentrations in soil were carried out and the working curve and the minimum detecting limit of the system were examined.Experimental results show the system can get high-resolution fluorescence spectra with a linear relationship between the fluorescence intensity and the concentration in the range of 0.005～0.1 mg/kg.For the Limits of Detection(LOD) of 0.005 mg/kg and the Relative Standard Deviation(RSD) of ≤3 %,the system can surely meet the needs of detecting pesticides in soil..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1208 (2008)
Novel process for fabrication of RF MEMS switch with high mechanical reliability
HU Guang-wei, LIU Ze-wen, HOU Zhi-hao, and LI Zhi-jian
In order to improve the mechanical reliability and lifetime of a series contact Radio Frequency Microelectro-mechanical System(RF MEMS) switch with dielectric bridge,the fabrication process was studied.The switch structure was analyzed,the results illustrated that the mechanical reliability of the switch was debased wiIn order to improve the mechanical reliability and lifetime of a series contact Radio Frequency Microelectro-mechanical System(RF MEMS) switch with dielectric bridge,the fabrication process was studied.The switch structure was analyzed,the results illustrated that the mechanical reliability of the switch was debased with regular process because of the stress concentration of the bridge film.After that,an isotropic undercutting process for forming the upper control electrodes and contact bar under the bridge was proposed to obtain plane bridge film.Finally,the whole process of the switch was presented.Compared with the regular process,the proposed method can avoid the problem of stress concentration,and can improve the mechanical reliability of the switch.As a result,the yield rate of the switch increases from 10% up to 95%,the lifetime is improved from 1 000 cycles up to 2.5×107 cycles.In addition,under the actuation voltage of 23.3 V,the insertion loss is less than 0.55 dB@DC-10 GHz,and the isolation is more than 53.2 dB@DC-10 GHz.These results show that proposed process can satisfy the modern wireless communication system requirements of yield rate,lifetime and microwave performance..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1213 (2008)
Speed test and control for ultrasonic motor working in vacuum
LU Dan, ZHENG Wei, and ZHAO Chun-Sheng
A system using a Single Chip Micyoco(SCM) to test and control the speed of ultrasonic motor was studied.Based on the relation between the ultrasonic motor's speed and its driving frequency,the speed of ultrasonic motor working in vacuum is controlled by fuzzy PI control strategy.The test results prove that the ultrA system using a Single Chip Micyoco(SCM) to test and control the speed of ultrasonic motor was studied.Based on the relation between the ultrasonic motor's speed and its driving frequency,the speed of ultrasonic motor working in vacuum is controlled by fuzzy PI control strategy.The test results prove that the ultrasonic motor using the system can work steadily in design speed in vacuum(the highest vacuum degree can be up to 0.003 Pa),and the speed deviation doesn't exceed 1 r/min.It can satisfy the requirement for measuring and controlling the speed of ultrasonic motor working in vacuum..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1218 (2008)
SCM-based nanomechanical property measurement system of AFM
YAN Yong-da, FEI Wei-dong, HU Zhen-jiang, CHENG Xiang-jie... and DONG Shen|Show fewer author(s)
In order to obtain the force depth curve directly and change the loading time,keeping load time and unloading time arbitrarily in the nanomechanical property measurement by Atomic Force Microscope(AFM),an AFM system was modified.A Single Chip Micyoco(SCM)-based input/output module was developed in the present study.ConIn order to obtain the force depth curve directly and change the loading time,keeping load time and unloading time arbitrarily in the nanomechanical property measurement by Atomic Force Microscope(AFM),an AFM system was modified.A Single Chip Micyoco(SCM)-based input/output module was developed in the present study.Connected this module to the control system of AFM,a novel AFM-based nanomechanical property measurement system was formed with the signal output precision of 0.15 mV,signal input precision of 0.3 mV,and the moving accuracy of the stage of 1.53 nm.The normal load of measurement system could be changed continuously to get the in-situ force-depth curve according to the corresponding arithmetic.The out rate of the D/A output port could be varied by the SCM controller,so that the rate of loading,unloading and keeping period could be changed also.Integrated with a two-dimensional precision stage,the array indentation tests were carried out with a larger scale.The nanoindentation test results on polycarbonate and polydimethylsiloxane show that the nanomechanical property parameters of samples can be obtained with high accuracy and high speed based on this system.Samples like PDMS,micro beam and so on can also be investigated under the pure elastic deformation..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1223 (2008)
On-line monitoring micro-size drilling based on rough set fuzzy control
YANG Zhao-jun, LI Xue, and CHEN Shu-fen
For online monitoring micro-size drilling,a fuzzy control method based on rough set was developed to improve original control method on too many fuzzy rule numbers and complicated calculations for a high-dimensional input fuzzy system.With processing data on line by a created fuzzy system for a spindle motor's 3-phFor online monitoring micro-size drilling,a fuzzy control method based on rough set was developed to improve original control method on too many fuzzy rule numbers and complicated calculations for a high-dimensional input fuzzy system.With processing data on line by a created fuzzy system for a spindle motor's 3-phase current signal on the Matlab platform,the connotative wear state information of micro-size drill was obtained for on-line monitoring micro-size drilling process.The results show that the breakage of micro-size drill will be effectively avoided when the monitoring threshold value is 76.7.This method has important significance for reducing the cost of manufacture and improving the productivity..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1230 (2008)
Multiple sensor fusion in large scale measurement
ZHANG Fu-min, QU Xing-hua, and YE Sheng-hua
In order to realize the geometric measurement of large scale workpiece,a measuring net for multiple measurement stations was established.With the aim of the information fusion of multiple measurement station,a relevant multi-sensor information fusion method was researched.The spatial data of multiple measurement statioIn order to realize the geometric measurement of large scale workpiece,a measuring net for multiple measurement stations was established.With the aim of the information fusion of multiple measurement station,a relevant multi-sensor information fusion method was researched.The spatial data of multiple measurement stations were registrated based on singular value decomposition to unify as global coordinate system.Then,the measuring model of each measurement station was established to get its covariance matrix and Jacobian matrix,so the weight matrix was obtained by the optimum fusion criterion of matrix weighting linearity minimum variance for fusing effectively measured data of multiple measurement station.A simulation experiment was carried out and the average measuring results were given as follow,the measurement errors of total station,theodolite and laser tracker are 0.745 1 mm,0.044 9 mm and 0.032 7 mm,respectively,and the fusion measurement error is 0.012 8 mm.Finally,the fusion method was applied to measure a net in tunnel component.The validity of fusion criterion for precision is proved by theory,simulation and practical experiments,and the fusion precision is superior to each partial precision..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1236 (2008)
Application of laser scanning confocal microscope in micro-electro-mechanical system
ZENG Yi-bo, JIANG Shu-sen, HUANG Cai-hong, ZHANG Yu-long, and ZHANG Yan
An application of Laser Scanning Confocal Microscope (LSCM) in micro-structure analysis was discussed in order to enhance the analyzing and measuring levels of micro structure.LSCM could be used to measure large angle because of its high resolution and adjustable light intensity,and could analyze the micro structure byAn application of Laser Scanning Confocal Microscope (LSCM) in micro-structure analysis was discussed in order to enhance the analyzing and measuring levels of micro structure.LSCM could be used to measure large angle because of its high resolution and adjustable light intensity,and could analyze the micro structure by combining with picture disposal system qualitatively and quantitatively,also its full-automatic sample stand could automatically scan along X axis and Y axis to realize a picture mosaic.The experimental results indicate that the maximum slope angle measured by LSCM reaches at least 50°,and the clear three dimensional profile is obtained in the profile analysis of cantilever.Meanwhile,the deformation accurately measured by two dimensional quantitative analysis is 3.145 μm,and the field area is 384 μm×288 μm in mosaic function equipped with LSCM in 100× objective,which can solve the problem that the watched object's total shape in single frame micrographic image can not be obtained under high microscopic enlargement times.Experimental results show that the LSCM can make up for measuring functional deficiency of other profile analytic equipment and can improve the testing level of MEMS..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1241 (2008)
Transmission properties of adhesive single-layer bandpass FSS
MENG Zhi-jun, HUANG Jun, WU Zhe, and LV Ming-yun
By taking slot arrays as illustrative examples,the compound structures of Frequency-Selective-Surface(FSS) and dielectric slab were investigated based on modal matching method and experimentation.The frequency responses of FSS structures by different compounding approaches were analyzed,including the influence of polyiBy taking slot arrays as illustrative examples,the compound structures of Frequency-Selective-Surface(FSS) and dielectric slab were investigated based on modal matching method and experimentation.The frequency responses of FSS structures by different compounding approaches were analyzed,including the influence of polyimide base film and adhesive coating with different thicknesses on resonant frequency.The results show that the influence of base film and adhesive coating in FSS structures can not be neglected,for they have a close relationship with the compounding approach and dielectric thickness.The compound structure should contain adhesive coating to eliminate the effect of air gap.When dielectric constants of base film and adhesive coating are less than or close to that of the slab only,the slab is over 10 times thicker than those of base film and adhesive coating,the influence of base film and adhesive coating on the transmission properties of properly compound structures would be the minimum.The comparison of measurement and computation of frequency response of FSS structures loaded with dielectric slab of a series thickness on one side shows that the flaw of adhesion will change the transmission properties of FSS structures.All factors mentioned above should be considered in FSS design..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1247 (2008)
Constant temperature thermal vacuum sensor based on micro-hotplate
ZHANG Feng-tian, TANG Zhen-an, YU Jun, and WANG Jia-qi
To study the characteristics of Micro-hotplate(MHP)based vaccum sensor at constant temperature working mode,the influences of working temperature and dimensions on the working characteristics of MHP-based thermal vacuum sensor at constant temperature was analyzed based on the thermal analysis of MHP.An MHP-based thermaTo study the characteristics of Micro-hotplate(MHP)based vaccum sensor at constant temperature working mode,the influences of working temperature and dimensions on the working characteristics of MHP-based thermal vacuum sensor at constant temperature was analyzed based on the thermal analysis of MHP.An MHP-based thermal vacuum sensor was designed in the supporting beams of 65 μm long and 21 μm wide,and the gas gap below micro-hotplate of 0.5 μm.The micro sensor was fabricated successfully with surface micromachining technology.The testing results show that the fabricated vacuum sensor is sensitive in pressure range of 2～105 Pa and the sensor response characteristics are consistent with the theoretical calculated results..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1253 (2008)
Novel pre-stressed six-component force sensor and its position and orientation error analysis
HOU Yu-lei, KANG Kai-jia, ZENG Da-xing, YAO Jian-tao... and ZHAO Yong-sheng|Show fewer author(s)
In order to obtain the six-component force sensor with excellent comprehensive performance,a novel pre-stressed six-component force sensor based on Stewart platform was presented,and its position and orientation error was analyzed.Compared with the traditional Stewart platform-based six-component force sensor,the strucIn order to obtain the six-component force sensor with excellent comprehensive performance,a novel pre-stressed six-component force sensor based on Stewart platform was presented,and its position and orientation error was analyzed.Compared with the traditional Stewart platform-based six-component force sensor,the structure feature of proposed pre-stressed six-component force sensor was described.Then,the mathematical model of the position and orientation error was established using the influence coefficient method and vector method,the position and orientation error sensitivity indices were defined and the influence conditions of different error factors on the sensor's position and orientation error were analyzed by plotting histograms of error sensitivity.Finally,a sensor prototype was fabricated and the calibration experimentation was carried out.The experimental results indicate that the force measurement precision of the prototype is within 1%,which shows the research is useful for the design and calibration experimentation of the six-component force sensor..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1258 (2008)
Real-time adaptive inverse control based on neural networks for piezoceramic actuator
DANG Xuan-ju
In order to improve the actuator precision,a method for eliminating nonlinear and no-smooth hysteresis characteristic of piezoceramic actuator was proposed.An inner product-based dynamic neural network nonlinear and no-smooth hysteresis inverse model for piezoceramic was established,in which the feedback error learningIn order to improve the actuator precision,a method for eliminating nonlinear and no-smooth hysteresis characteristic of piezoceramic actuator was proposed.An inner product-based dynamic neural network nonlinear and no-smooth hysteresis inverse model for piezoceramic was established,in which the feedback error learning method was used to avoid obtaining Jacobian information of piezoceramic by positive model.On dSPACE system platform,a neural networks adaptive inverse control was realized combined with a PID control.In order to satisfy the requirement of real time control,the program was designed by a high efficiency and fast C-MEX S function.The experimental results indicate that the precision of the proposed adaptive inverse control based on neural networks is 0.13 μm and PID control precision is 0.32 μm.It is shown that the proposed control method can remove effectively the hysteresis characteristic of piezoceramic and has higher control precision..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1266 (2008)
Optimal design of PGF compression encoder based on xDM standard
HU Xin-hua, DENG Yuan-yong, and WANG Xian-ping
A Progressive Graphic File(PGF) compression encoder based on xDM standard was presented for the real-time image compression of a solar image.The PGF compression algorithm with advantages of natural image compression and compression speed was analyzed and customized.According to the interfaces required by xDM standard,aA Progressive Graphic File(PGF) compression encoder based on xDM standard was presented for the real-time image compression of a solar image.The PGF compression algorithm with advantages of natural image compression and compression speed was analyzed and customized.According to the interfaces required by xDM standard,a PGF compression encoder was designed.Aiming at the features of the DaVinci hardware architecture,the PGF compression encoder was optimized on many aspects such as software design,C language program and linear assembly language program.Finally,a real-time online test was carried out for the performance parameters on compression ratio,compression time and SNR of the PGF compression encoder.The experimental result shows that the speed of the optimized PGF compression encoder is 18.7 times that of original one,which can fully meet the design requirements of the real-time image processing system of a solar telescope..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1273 (2008)
Motion estimation algorithm of serial star images based on adaptive window selection PIV technique
CHEN Wei-zhen, CHEN Biao, ZHANG Chun-hua, and SONG Ru-gang
A motion estimation algorithm of serial star images based on adaptive window selection PIV technique is proposed.The algorithm chooses the analysis window of maximum energy by an adaptive method.Then,the global motion parameters can be estimated through the cross-correlation of two analysis windows.The experimental resA motion estimation algorithm of serial star images based on adaptive window selection PIV technique is proposed.The algorithm chooses the analysis window of maximum energy by an adaptive method.Then,the global motion parameters can be estimated through the cross-correlation of two analysis windows.The experimental results show that the presented algorithm improves the precision of parameter estimation,and overcomes the influence introduced by stars moving in or moving out of the analysis window.The algorithm reduces the estimation error to less than 0.01 pixel and can estimate the global motion parameters with high accuracy and high speed.It provides a good way for solving star image matching..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1279 (2008)
Monte Carlo simulation of Fourier-domain OCT in multi-layered media
LI Gang, ZHENG Yu, LIN Ling, and LIU Jing-jing
According to the theory of first-order Born approximation,a Fourier Domain Optical Coherence Tomography(FDOCT) model of single scattering infinite narrow beam is established,and the reason why it is hard to obtain the exact solution of integrated scattering equation is analyzed.The Monte Carlo simulation results indicaAccording to the theory of first-order Born approximation,a Fourier Domain Optical Coherence Tomography(FDOCT) model of single scattering infinite narrow beam is established,and the reason why it is hard to obtain the exact solution of integrated scattering equation is analyzed.The Monte Carlo simulation results indicate that two kinds of photon are different in spatial distributions.The multiple backscattering photons can be rejected and more single backscattering photons can be received by adjusting the detection area.Then,the advantage of FDOCT is confirmed by analyzing the differences between Time Domain OCT(TDOCT) and FDOCT.The simulation results provide an important reference for experiments.The gray level distortion of complex bio-tissue image resulting from energy attenuation can be approximately compensated by changing the model's structure..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1285 (2008)
Improved HSBH algorithm against SPA
ZHANG Jian, YU Xiao-yang, HUANG Hai-xia, and FAN Shen-shen
In order to improve the robust of image information hiding method and to increase the hiding capacity,a High Significant Bit Hiding(HSBH) algorithm against SPA(Sample Pair Analysis) analysis is proposed.The idea and the principle of SPA are introduced,and the HSBH algorithm is analyzed,results show that the HSBH drawbaIn order to improve the robust of image information hiding method and to increase the hiding capacity,a High Significant Bit Hiding(HSBH) algorithm against SPA(Sample Pair Analysis) analysis is proposed.The idea and the principle of SPA are introduced,and the HSBH algorithm is analyzed,results show that the HSBH drawback can not resist the SPA attack.So an improved HSBH algorithm is presented.The experimental results indicate that,considering the SPA idea,the correct rate of detection is nearly 95% when the embedding rate is more than 3%.And no matter how much message is embedded by the improved algorithm,SPA steganalysis will get a very small estimation value and form an incorrect judgment to hide information,so that the information can be hidden securely..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1295 (2008)
An anti-disturbing method for extracting light-knife center
XIANG Chang-bo, YIN Chuan-li, and SONG Jian-zhong
In the light-sectioning method,it is difficult to accurately extract light-knife center contour due to those influences such as sun light,surface texture information and the low reflection of measured object,So an effective solution to eliminate those influences is presented.By controlling the laser,two consecutive imaIn the light-sectioning method,it is difficult to accurately extract light-knife center contour due to those influences such as sun light,surface texture information and the low reflection of measured object,So an effective solution to eliminate those influences is presented.By controlling the laser,two consecutive images in which only one image contains laser information are acquired.Then,the background motion compensation is processed to make the two images have slightly difference only in the laser location,thereby the laser trace is emerged after image subtraction.Finally,a complete light-knife center contour is obtained through refinement and repair for data.The experimental results show that proposed method is effective to eliminate the influences mentioned above and it is adapted for measuring 3D shape of the mobile objects in a measuring locale..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1303 (2008)
3D datum mosaic method of multi-view and large scale based on optical coding
CHEN Gang, and YAO Ying-xue
A multi-view 3D datum mosaic method is presented by measuring optical coded points in an overlapped area in two partial measurement units with a stereo vision sensor.The method obtains the stereo vision sensor's location and attitude transform matrixes R and T by minimizing the linear least square criterion,and achA multi-view 3D datum mosaic method is presented by measuring optical coded points in an overlapped area in two partial measurement units with a stereo vision sensor.The method obtains the stereo vision sensor's location and attitude transform matrixes R and T by minimizing the linear least square criterion,and achieves the mosaic of measurement results through transforming the latter measurement results into the coordinate system of the former measurement process.When 12 coded points is adopted,the average errors in 1.2 m×1 m×0.4 m range at X,Y and Z directions are 0.08 mm,-0.07 mm and-0.02 mm respectively.The experimental results show that is a higher mosaic precision.Moreover,this method doesn't need to stick any target points on the object,which makes no-contact measurement come true..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1309 (2008)
Embedded block wavelet coding method based on block bit-length
WANG Ren-long, HAO Yan-ling, and LIU Ying
An embedded block wavelet coding method based on block bit-length is put forward for resolving the problem of occupying a large amount of memory in coding process for a wavelet coder.The memory occupancy can be reduced and coding efficiency can be improved through four measurements in the coding process.The four measurAn embedded block wavelet coding method based on block bit-length is put forward for resolving the problem of occupying a large amount of memory in coding process for a wavelet coder.The memory occupancy can be reduced and coding efficiency can be improved through four measurements in the coding process.The four measurements mentioned above are:(1) LLn sub-band is separately coded;(2) Block bit-length chart in terms of bit-length defined by the author is established;(3) The space of memory is saved by employing bit-length chart instead of fining lists and ranking processes;(4) The key blocks are searched by constructing bit-length chart to overcome the repeat scan and to improve the coding speed.The software experimental results show that for a piece of 512 pixel×512 pixel×8 bit image,occuping memory space by proposed method is 1/27 that of SPECK,the performance of radar image derived from hardware test can satisfiy the international standard.Meanwhile,proposed method can keep the high quality of PSNR and can be implemented through hardware easily..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1315 (2008)
A compression algorithm of remote sensing image based on ROI for ocean surveillance satellite
SUI Yu-ping, HE Xin, and WEI Zhong-hui
According to the characteristics of the remote sensing images for ocean surveillance satellite,an adaptive near-lossless compression algorithm based on ROI(Regions of Interest) is proposed.After maximum lifting of morphological Harr wavelet,the objects are detected by threshold method and connectivity analysis of eightAccording to the characteristics of the remote sensing images for ocean surveillance satellite,an adaptive near-lossless compression algorithm based on ROI(Regions of Interest) is proposed.After maximum lifting of morphological Harr wavelet,the objects are detected by threshold method and connectivity analysis of eight adjacent regions.The ROI of high-frequency sub-bands is depicted by the intersection of enclosing rectangle and an annulus in the lowest-resolution and gained by mosaic magnification in other resolution levels.In high-frequency sub-bands,Rice lossless entropy encoder is used for ROI,and bit plane encoder for background region,while DPCM and Rice for low-frequency sub-band.The experimental results show that the algorithm can segmentalize the ROI effectively without any visible segmentation trace.The PSNR(Peak Signal Noise Ratio) of proposed algorithm is 2～5 dB higher than that of JPEG2000 at low and middle bit rate,and both are higher than 45 dB at high bit rate.The algorithm has the advantages of low complexity,higher adaptive ability and independent datum packet and is easy to be implemented in hardware.Moreover,the algorithm can adapt to near-lossless compression for ocean surveillance satellite image..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1323 (2008)
Video camera rotation compensation algorithm based on feature matching of sequence image frames
WANG Hui-feng, LIU Shang-qian, WANG Da-bao, and NIU Jian-jun
In order to eliminate the measurement error caused by video camera rotation during its moving along the axis,a high precision video camera moving estimation algorithm based on the feature point matching of sequence image frames and the least-square estimatimation is presented.In the algorithm,the strong correlation of In order to eliminate the measurement error caused by video camera rotation during its moving along the axis,a high precision video camera moving estimation algorithm based on the feature point matching of sequence image frames and the least-square estimatimation is presented.In the algorithm,the strong correlation of sequence image frames is used to analyze the moving parameters of two continuous image frames.Then,the feature points of sequence image frames are detected by Harris operator and matched by template,and the moving parameters of the video camera are obtained with the least-square algorithm.Finally,the obtained moving parameters are used to compensate the video camera rotation precisely.The experimental results show that the rotation angle error of the video camera is less than 5% when the rotation angle of inter-frame is less than 10°,but more than 20% when it is more than 14°.Because the rotation angle of inter-frame is less than 5° in practical application,the algorithm eliminates the influence of video camera rotation on measurement precision,compensates its measurement error,and improves the measurement precision,which meets the requirement of practical application..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1330 (2008)
Imaging and analyzing subsurface morphologies of jade objects with optical coherence tomography
ZENG Nan, HE Yong-hong, and MA Hui
An application of optical coherence tomography to jade measurement was described.An optical coherence tomography(OCT) system applied in jade imaging and measurement was implemented with scanning speed of 1 frame/s,depth resolution of 15 μm and penetration depth of 3mm.The experimental results and theoretical analysis oAn application of optical coherence tomography to jade measurement was described.An optical coherence tomography(OCT) system applied in jade imaging and measurement was implemented with scanning speed of 1 frame/s,depth resolution of 15 μm and penetration depth of 3mm.The experimental results and theoretical analysis of jade imaging and measurement based on OCT method were demonstrated.By analyzing the optical backscattering data based on the variation with depth and the distribution in tomography plane,the transparency of jade could be characterized qualitatively;meanwhile,OCT imaging could be used to observe and provide some discrimination information of the impregnation and calcification of ancient jade materials.The experimental results give an available microstructure information,confirm the feasibility of OCT method in evaluating transmission features of jades,and show a potential of OCT in analyzing subsurface morphologies of archaic jades..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 7, 1335 (2008)
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