Journals >Optics and Precision Engineering
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2008
Volume: 16 Issue 8
33 Article(s)
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Research Article
Material removal efficiency in ion beam figuring for optical component
JIAO Chang-jun, XIE Xu-hui, LI Sheng-yi, and ZHOU Lin
The removal efficiency and the relative removal efficiency between two different materials and three performance factors,normal removal rate,volume removal rate and sputtering yield,were analyzed in ion beam figuring process.With the Sigmund sputtering theory,the relation models between three factors and processing parThe removal efficiency and the relative removal efficiency between two different materials and three performance factors,normal removal rate,volume removal rate and sputtering yield,were analyzed in ion beam figuring process.With the Sigmund sputtering theory,the relation models between three factors and processing parameters,such as ion energy,ion flux and ion incident angle,were established.The experiments with samples of zerodur,SiO2 and K4 glass were carried out to analyze these relations and to verify the theoretical models,which indicates that the removal efficiency increases with the ion current linearly and shows an approximate proportion to the square root of the ion energy.It also increases with incident angle and climbs the summit at about 60～80°.The relative removal efficiency is independent of ion flux,but has a little effect from beam energy,which can be ignored.However,the effect of angle on the relative removal efficiency is rather obvious..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1343 (2008)
Numerical analysis of Yb/Er co-doped double cladding fiber amplifier
ZHAO Chong-guang, NING Yong-qiang, LIU Yang, WANG Ji, and WANG Li-jun
To optimize the fiber amplifier,an Yb/Er co-doped double cladding fiber amplifier pumped at 980 nm was analyzed numerically.The gain of the amplifier with different signal powers was analyzed and the distribution of population inversion,pump power and signal power along the axis direction of the fiber were calculated aTo optimize the fiber amplifier,an Yb/Er co-doped double cladding fiber amplifier pumped at 980 nm was analyzed numerically.The gain of the amplifier with different signal powers was analyzed and the distribution of population inversion,pump power and signal power along the axis direction of the fiber were calculated at stable state.According to the numerical results,a fiber amplifier with 10 m Yb/Er co-doped double cladding and launched maximum pump power of 6 W was set up.Proposed amplifier shows the maximum output power of 1.9 W and slope efficiency of 23.4% on conditions of the initial signal power of 0.5 W..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1349 (2008)
Dynamic exposure model of laser direct writing in Cartesian coordinate
ZHANG Shan, TAN Jiu-bin, WANG Lei, and JIN Zhan-lei
A new dynamic exposure model was proposed to predict the laser direct writing quality in Cartesian coordinate exactly.By considering the effect of photoresist absorbing beam energy,the Gaussian distribution of writing beam and the dynamic exposure process,numerical simulation results indicate that when the incident lasA new dynamic exposure model was proposed to predict the laser direct writing quality in Cartesian coordinate exactly.By considering the effect of photoresist absorbing beam energy,the Gaussian distribution of writing beam and the dynamic exposure process,numerical simulation results indicate that when the incident laser beam is shape of constant Gauss,the results obtained by proposed model agree well with that by Dill model under equivalent conditions.The model makes up the shortcomings of the traditional models and can be taken as an appropriate solution to the dynamic exposure process.Based on the model,the influences of the direct writing power and velocity on the profile of writing line are also analyzed,which can be considered as an effect analysis method for optimizing the parameters of laser direct writing..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1354 (2008)
Optical system design for MEMS based digital sun sensor
WEI Xin-guo, JIANG Jie, WEN Zhi-ming, ZHANG Guang-jun, and FAN Qiao-yun
A reasonable optical system for Micro-electro-mechanical System(MEMS) based on digital sun sensor was designed.Based on scalar diffraction theory,the imaging model of the optical system for the sun sensor with a structure of circular aperture was developed.A computer simulation was carried out to obtain the parameters A reasonable optical system for Micro-electro-mechanical System(MEMS) based on digital sun sensor was designed.Based on scalar diffraction theory,the imaging model of the optical system for the sun sensor with a structure of circular aperture was developed.A computer simulation was carried out to obtain the parameters of optical system in the distance of 4 mm,aperture of 50 μm and the space between holes of 700 μm.The ground experiment was carried out for this optical system with a sun simulator,and the results show that the optical system is designed well and can meet the requirements of miniaturization and high accuracy of a sun sensor..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1361 (2008)
Suppressing stray light for 4J32 alloy by electrochemistry
JIANG Wei, ZHANG Yun-Kun, ZHANG Zhong-yu, and REN Ming-Wen
In order to realize stray light suppressing for 4J32 alloy in fine optical system,the stray light suppressing coatings were prepared on 4J32 alloy from a conventional anodisation-plating bath containing Ce and dual salt additive.The bath formula and rational process parameters were investigated using a orthogonal test.In order to realize stray light suppressing for 4J32 alloy in fine optical system,the stray light suppressing coatings were prepared on 4J32 alloy from a conventional anodisation-plating bath containing Ce and dual salt additive.The bath formula and rational process parameters were investigated using a orthogonal test.By testing the influences of concentrations of K2Cr2O7,MnSO4and(NH4)2SO4 in electrolyte solution,galvanic voltage,operating temperature and anodizing time on the anodizing films of 4J32 alloys,the optimal process conditions were gained as follows:20 g/L K2Cr2O7,20 g/L MnSO4,20 g/L(NH4)2SO4,15 g/L Ce and dual salt additive,temperature of 25 ℃,last time of 20 min and voltage of 30 V.A black stray light suppressing film was obtained with the process.The results of reflection testing,thick testing and shock testing show that 4J32 stray light suppressing coating has a low-reflecting ratio(1.5%),a few dimension change(<0.8 μm) and good adhesion to substrate,and it is suitable to suppress the stray light in fine optic system..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1367 (2008)
Novel fiber-typed variable optical attenuator
LI Zhi-quan, TIAN Xiu-xian, and WANG Hui-bo
A novel variable optical attenuator was developed and a detecting device was designed for testing its coupling characteristics.Based on coupling theory,the relations between the attenuation and the changing parameters were analyzed and the wavelength minim-loss was discussed.The experimental results indicate that the aA novel variable optical attenuator was developed and a detecting device was designed for testing its coupling characteristics.Based on coupling theory,the relations between the attenuation and the changing parameters were analyzed and the wavelength minim-loss was discussed.The experimental results indicate that the attenuation can change sharply and approach to 30 dB through adjusting the lateral displacement u of two tapered fibers,the attenuation can change slightly and reach 37 dB by adjusting the longitudinal coupling length L of two tapered fibers.And this variable optical attenuator can obtain the wavelength minim-loss less than 0.2 dB.By this new design structure,the light signal can be weakened or controlled ideally.The reliability and singleness can be guaranteed using its wavelength minim-loss characteristic when the gas concentration measurement and identity are carried out..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1371 (2008)
Analysis and optimal design of illuminator for leadfess tin solder joint inspection
LU Sheng-lin, and ZHANG Xian-min
In order to improve the performance of Automatic Optical Inspection(AOI) system,an illuminator for leadless tin solder joint inspection was studied.The structure of the illuminator was introduced,which is composed of the LED arrays with three colors and different radiation angles.Then,the radiance model of the illuminaIn order to improve the performance of Automatic Optical Inspection(AOI) system,an illuminator for leadless tin solder joint inspection was studied.The structure of the illuminator was introduced,which is composed of the LED arrays with three colors and different radiation angles.Then,the radiance model of the illuminator and the irradiance model of the solder joint were developed.Finally,the dimensions of the illuminator were optimized based on the irradiance model.The simulation and experimental results verify the validity of proposed illuminator for leadless solder joint inspection,and show it can enlarge the feature distances from different classes.The maximum feature distance of different solder joints illuminated by the proposed illuminator is 11.88 times of that illuminated by the hemisphere illuminator.The simulation and experimental results verify the validity of the design..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1377 (2008)
Null corrector for Φ1.2 m F/1.5 paraboloidal mirror
CHEN Qiang, YUAN Jia-hu, WU Fan, GAO Ping-qi, and WU Gao-feng
A null corrector was designed to compensate 0.087 mm surface departure from the best fitting sphere for a Φ1.2 m F/1.5 paraboloidal mirror and to realize the surface error less than 0.033λ(RMS).The structure design,error analysis,manufacturing,certification and final application of the corrector were introduced in detaA null corrector was designed to compensate 0.087 mm surface departure from the best fitting sphere for a Φ1.2 m F/1.5 paraboloidal mirror and to realize the surface error less than 0.033λ(RMS).The structure design,error analysis,manufacturing,certification and final application of the corrector were introduced in detail.The certification by Computer-Generated Hologram(CGH) in advance shows that the shape and conic errors produced by corrector are 0.012λ(RMS)and 0.006 4%,and the final null testing results give that the surface and conic errors of primary mirror are 0.027λ(RMS)and 0.030 6%,which is consistent with the tolerance analysis well.The results indicate that the design,tolerance analysis and the quality of the corrector are rational and reliable,and it can lay a solid foundation for the null test of larger primary mirror..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1384 (2008)
Simulation design of saddle-shaped parallel tracking platform
LIU Feng, WANG Xiang-jun, XU Wei, and ZHANG Zhao-cai
In order to improve the simulation design velocity of parallel device,a simulation design method combining the Matlab simulation code with the ADAMS simulation analysis was presented for the saddle-shaped parallel tracking platform.By compiling the Matlab simulation code to optimize the saddle-shaped parallel tracking In order to improve the simulation design velocity of parallel device,a simulation design method combining the Matlab simulation code with the ADAMS simulation analysis was presented for the saddle-shaped parallel tracking platform.By compiling the Matlab simulation code to optimize the saddle-shaped parallel tracking platform and by using the optimum design size to realize the 3D reconstruction,the 3D model was analyzed in the ADAMS environment and the saddle-shaped parallel tracking platform experiment sample was manufactured by using the simulation result.The correctness of the simulation results were proved by compiling the data monitor module to monitor the velocity of experimental sample drive poles and comparing the monitor results and the simulation results.The results show that this simulation design method can solve the problem of repeated 3D reconstruction and the simulation design period is half that of the current method..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1389 (2008)
Fabrication of a flexible three-dimensional neural microelectrode array
SUN Xiao-na, ZHOU Hong-bo, LI Gang, ZHU Zhuang-hui... and REN Qiu-shi|Show fewer author(s)
A fabricating method for the flexible 3D protruding Microelectrode Arrays(MEAs) for neural applications was proposed.This method used a photosensitive polyimide(Durimide 7510) as substrate and an anisotropically etched Si as mold to fabricate a flexible pyramid-shaped microelectrode array by combining a micro-molding tA fabricating method for the flexible 3D protruding Microelectrode Arrays(MEAs) for neural applications was proposed.This method used a photosensitive polyimide(Durimide 7510) as substrate and an anisotropically etched Si as mold to fabricate a flexible pyramid-shaped microelectrode array by combining a micro-molding technique,a metallic patterning and an electrochemical-based sacrificial layer technique.An evaluation for 3D protruding electrode was also performed by simulation,SEM and resistance test,and the 3D flexible polyimid-based microelectrode with 4 × 4 array of electrode sites was fabricated using the proposed method,in which each individual electrode site has base area of 60 μm×60 μm and the height of 37 μm in pyramid shaped tip.Compared with conventional planar microelectrodes in the same base area,the electrode impedance of 3D pyramid-shaped microelectrode decreases by 63%.The results show that the pyramid-shaped electrode configuration allows electrode sites to be close to target neurons.On the other hand,the pyramid-shaped configuration can reduce electrode impedance and increase charge injection,which is helpful to neural stimulation..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1396 (2008)
Study and improvement on ablation system in mass spectrograph
LU Hui-qing, WANG Bao-guang, CHAO Zhong-yuan, and LI Ya-biao
In order to improve the ablation precision,efficiency and the automation of Laser Ablation System(LAS) in Mass Spectrograph(MS),the intelligentization of laser ablation system was studied in MS by taking inert gas isotope-MS as an experimental subject.A two-dimensional sample worktable was redesigned,the automation of In order to improve the ablation precision,efficiency and the automation of Laser Ablation System(LAS) in Mass Spectrograph(MS),the intelligentization of laser ablation system was studied in MS by taking inert gas isotope-MS as an experimental subject.A two-dimensional sample worktable was redesigned,the automation of graphite furnace injection system was also given.A series of control subroutines were designed to calibrate the vision system.After calibration,the laser ablation system is very accurate,the maximal repeatability error of auto-focus is 0.005 mm.The experimental results show that new system has a higher stability and work efficiency..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1403 (2008)
Establishment of mean line in surface metrology by B-spline filter
XU Jing-bo, YUAN Yi-bao, and LIU Bo
According to Z-transform representations of discrete B-spline functions,the fitting and decomposing of the signal in B-spline space can be implemented with FIR filters and IIR filters.With combination of theory above and variational calculus,the B-spline filter was constructed to determine the mean line in surface rougAccording to Z-transform representations of discrete B-spline functions,the fitting and decomposing of the signal in B-spline space can be implemented with FIR filters and IIR filters.With combination of theory above and variational calculus,the B-spline filter was constructed to determine the mean line in surface roughness measurement.A zero phase shift filtering was used in the B-spline filter to obtain the difference equations.The experiment in surface profile of a workpiece validates this method.The B-spline filter also shows the characteristic of zero phase shift and its computing efficiency is three times higher than that of Gaussian filtering mean line..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1411 (2008)
Borosilicate glass film bending by CO2 CW-laser
WU Dong-jiang, NIU Fang-yong, LIU Shuang, MA Guang-yi... and WANG Xu-yue|Show fewer author(s)
An experiment of borosilicate glass film bending by CO2 CW-laser was presented,and the laser power density threshold was determined for glass specimen with thickness of 150 μm.The effects of process parameters(laser power,scanning velocity,number of scannings) and work piece geometry(specimen width) on the bending anglAn experiment of borosilicate glass film bending by CO2 CW-laser was presented,and the laser power density threshold was determined for glass specimen with thickness of 150 μm.The effects of process parameters(laser power,scanning velocity,number of scannings) and work piece geometry(specimen width) on the bending angle were investigated,then the experimental phenomenon was analyzed.The extent scopes of the laser power and scanning velocity were generalized for the bending progress,meanwhile,several groups of processing parameters were obtained.The experimental result indicates that the borosilicate glass film could be bent to an angle up to 24°using CO2 CW-laser..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1416 (2008)
Evaluation of spatial straightness errors based on multi-target optimization
YUE Wu-ling, and WU Yong
In order to realize accurate and fast evaluation for spatial straightness,its mathematical model and Successive Quadratic Programming(SQP) algorithm were investigated.Based on the condition of minimum zone method,a nonlinear programming model was established for spatial straightness error evaluation.This nonlinear modeIn order to realize accurate and fast evaluation for spatial straightness,its mathematical model and Successive Quadratic Programming(SQP) algorithm were investigated.Based on the condition of minimum zone method,a nonlinear programming model was established for spatial straightness error evaluation.This nonlinear model was further proved to be a multi-target optimization problem in essence,and could be transformed into a single-target optimization problem.A unified and efficient SQP algorithm was proposed to solve the model.As the nonlinear programming model is convex and SQP algorithm can retain such nonlinear information,the algorithm has very loose requirements for initial parameters and shows its stable,reliable and highly efficient in optimization.Several experiments of spatial straightness error evaluation were carried out,the results can meet the requirements for convex programming's global optimization very well,the precision is 10-3 mm and consumed time is about 0.4 s,which has proved the above mentioned conclusion..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1423 (2008)
Design and analysis of underground pipeline detecting system based on PSD
SHEN Lin-yong, LI Ya-min, ZHANG Ya-nan, and QIAN Jin-wu
With combination of a Position Sensitive Device(PSD) and other components,a kind of detecting system in interpostion was developed for detecting underground pipeline.The system detected the orientaion data at different measuring sites to obtain the orientations of underground pipeline by walking along the pipeline,whicWith combination of a Position Sensitive Device(PSD) and other components,a kind of detecting system in interpostion was developed for detecting underground pipeline.The system detected the orientaion data at different measuring sites to obtain the orientations of underground pipeline by walking along the pipeline,which could be used in those pipeline with inter diameter of 80～130 mm and bend diameter of 50～1 000 m ignoring the burying depth,the concentration of pipeline and other environments.The analyzing results of experiment show the relative error of the detecting method is 7.45% in horizontal orientation and 1.07% in vertical orientation..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1429 (2008)
Study on adaptive capacity of stewart platform
CHEN Hong-li, ZHAI Lin-pei, and XIAO Zhan-quan
It is necessary for processing the ground tests from different types of aerial cameras to design a stewart platform with load adaptive capacity.Considering the range of cameras' weight and the electrical-mechanical structure of designed stewart platform,the relationship between the load(aerial camera) and the potenIt is necessary for processing the ground tests from different types of aerial cameras to design a stewart platform with load adaptive capacity.Considering the range of cameras' weight and the electrical-mechanical structure of designed stewart platform,the relationship between the load(aerial camera) and the potentiometer(position feedback device) signal amplitude was studied.A measuring method for the inertia moment of the load automatically was presented using numerical calculation method.The method is simple and does not need to add any device to most digital control systems.The simulation experimental results show that R2 is 0.997 3,RMS is 0.171 6 by 4th degree polynomial,while R2 is 0.999 6,RMS is 0.063 78 by 5th degree polynomial.It comes out that the precision of 5th degree polynomial is coincident with the stewart platform..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1436 (2008)
Phase transformations of grinding monocrystalline silicon wafer surfaces
ZHANG Yin-xia, GAO Wei, KANG Ren-ke, and GUO Dong-ming
In order to understand the material removal mechanism during wafer rotation grinding,the phase transformations on the ground silicon wafer surface were investigated by Raman microspectroscopy.The results existing the amorphous silicon(α-Si),Si-Ⅲ phase,Si-Ⅳ phase and Si-Ⅻ phase on the semi-fine and fine ground wafer surIn order to understand the material removal mechanism during wafer rotation grinding,the phase transformations on the ground silicon wafer surface were investigated by Raman microspectroscopy.The results existing the amorphous silicon(α-Si),Si-Ⅲ phase,Si-Ⅳ phase and Si-Ⅻ phase on the semi-fine and fine ground wafer surfaces indicate that the Si-Ⅰ phase has been transformed into ductile metal phase(Si-II phase) during grinding,and the Si-Ⅱ phase is ductile and easily be removed by ductile mode.There is no obvious polycrystalline silicon on the rough ground wafer surface,but very small amounts of α-Si is observed,these materials are removed by brittle mode.From rough grinding to fine grinding,the material removal mode changes from micro-fracture mode to ductile mode gradually.During the transition from rough grinding to semi-fine grinding,the ductile mode removal degree increases with the increasing phase transformation degree;the transition from semi-fine grinding to fine grinding,the ductile mode removal degree increases with the decreasing phase transformation degree..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1440 (2008)
Single axis attitude control and energy storage system with two flywheels
BAI Yue, WU Yi-hui, and HAN Bang-cheng
A single axis Integrated Power and Attitude Control System(IPACS) with double flywheels,including its working principle and configuration,were given to simulate the charge,discharge and the attitude control process during the full sun and the eclipse.The simulation analysis results show that single axis IPACS with doubA single axis Integrated Power and Attitude Control System(IPACS) with double flywheels,including its working principle and configuration,were given to simulate the charge,discharge and the attitude control process during the full sun and the eclipse.The simulation analysis results show that single axis IPACS with double flywheels is feasible.The impact of the system parameter on the control precision was discussed,then the parameter optimization approach was offered.A experimental equipment of single axis attitude control and energy storage system was founded and the experiments on 20 000 r/min speed show that the system can be used to store and release energy while adjusting the attitudes of a platform or a satellite.The angle of the platform can be controlled within 1.5° and 1.2′,respectively,when the bus DC voltage is 24 V and the fluctuating is less than 1.8%.After eliminating unbalance affection,such as the difference in motors,the scheme using flywheels to perform the energy storage and attitude control in the satellite is effective..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1446 (2008)
SVM generalization error estimation for facial feature selection
Li Wei-hong, Gong Wei-guo, Yang Li-ping, and Gu Xiao-hua
To investigate the validity of Support Vector Machine(SVM) generalization error bounds as the feature selection criterion,a novel framework of facial feature selection based on Filter and Wrapper approaches was proposed.By taking a Wavelet Transformation(WT) and Kernel Principal Component Analysis(KPCA) as a Filter appTo investigate the validity of Support Vector Machine(SVM) generalization error bounds as the feature selection criterion,a novel framework of facial feature selection based on Filter and Wrapper approaches was proposed.By taking a Wavelet Transformation(WT) and Kernel Principal Component Analysis(KPCA) as a Filter approach,the Vapnik-Chervonenkis(VC) Leave-one-Out(LOO) error bound was minimized.Then,the span bound of support vector was regarded as the feature selection criterion of Wrapper approach.Finally,Recursive Feature Elimination(RFE) search strategy was used for searching optimum facial subset.The experiments on UMIST face database were executed by the proposed method.The experimental results indicate that the facial feature dimensions can be reduced to 80 and 70,respectively,while both of the classification accuracies remain over 94%,so the proposed feature selection criterion and search strategy are effective for facial feature selection..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1452 (2008)
Illumination compensation based on multi-level wavelet decomposition for face recognition
GONG Wei-guo, YANG Li-ping, GU Xiao-hua, and LI Wei-hong
The appearance of face will vary dramatically when the illumination changes,which makes face recognition even more challengeable.In this paper,an illumination compensation method by means of multi-level wavelet decomposition and spline interpolation is proposed to reduce the effect of illumination variation on face recThe appearance of face will vary dramatically when the illumination changes,which makes face recognition even more challengeable.In this paper,an illumination compensation method by means of multi-level wavelet decomposition and spline interpolation is proposed to reduce the effect of illumination variation on face recognition.The light variation in an image can be modeled as additive noise and multiplicative noise.The additive noise,called background,can be estimated and eliminated by multi-level wavelet decomposition followed by spline interpolation;the multiplicative one,called gain,can be done in the similar way in the logarithm domain.Experimental results on Yale B face database show that the proposed method achieves 2%～11% recognition rate,higher than that of the others.It can effectively adjust the facial images under varying illumination conditions,as well as improve the recognition rate and robustness of face recognition..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1459 (2008)
Random sampling subspace locality preserving projection for face recognition
YANG Li-ping, GONG Wei-guo, LI Wei-hong, and GU Xiao-hua
A Random Sampling Subspace Locality Preserving Projection(RSSLPP) method is proposed to improve the recognition performance of a single Locality Preserving Projection(LPP).At the training stage,based on random sampling of the principle component subspace of training set,the multiple discrepant and complementary LPP subA Random Sampling Subspace Locality Preserving Projection(RSSLPP) method is proposed to improve the recognition performance of a single Locality Preserving Projection(LPP).At the training stage,based on random sampling of the principle component subspace of training set,the multiple discrepant and complementary LPP subspaces are generated by LPP method.At the recognition stage,test sample is successively projected into each random sampling principle component subspace,then the nearest neighbor classifier is used for classification and recognition.Finally,majority voting criterion is used to fuse the recognition result of each LPP subspace.The experimental results on FERET subset illustrate that the performance of RSSLPP method is superior to those of Eigenface,Fisherface,LPP and discriminant LPP(DLPP).The recognition accuracy of RSSLPP is over 10% higher than that of LPP.The RSSLPP method can effectively combine the complementary information of each LPP subspace and can improve face recognition accuracy..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1465 (2008)
Facial expression recognition based on supervised kernel local linear embedding
HUANG Hong, LI Jian-wei, and FENG Hai-liang
A novel supervised kernel local linear embedding(SKLLE) method is introduced to facial expression recognition,which maps face images to a high dimensional kernel space through nonlinear kernel mapping,then fuses prior class-label information and nonlinear facial expression submanifold of real face images to extract disA novel supervised kernel local linear embedding(SKLLE) method is introduced to facial expression recognition,which maps face images to a high dimensional kernel space through nonlinear kernel mapping,then fuses prior class-label information and nonlinear facial expression submanifold of real face images to extract discriminative features for expression classification.SKLLE can not only gain a perfect approximation of facial expression manifold,and enhance local within-class relations,but also can do well on the new samples.The experimental results on JAFFE database show that the proposed method can achieve the highest recognition rate(100%) using only 2D embedding feature vectors,which improves face expression classification performance effectively..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1471 (2008)
Research of track recognition method for multiple targets
LIU Yan-jun, WANG Yong-xin, HE Xin, and WEI Zhong-hui
In order to realize the position measurements of multiple targets on the ground,a project of track recognition for multiple targets is established,and the recognition method in pixel coordinates for large area optical electronic measurement sets is researched.An evaluation function based on target motion,such as the diIn order to realize the position measurements of multiple targets on the ground,a project of track recognition for multiple targets is established,and the recognition method in pixel coordinates for large area optical electronic measurement sets is researched.An evaluation function based on target motion,such as the direction,speed and the acceleration is established.According to the correlation degree between point and track decided by the evaluation function,the track recognitions for multiple targets are accomplished.By considering the losses of some points in some frames,the lost points are replenished by the track data with Kalman filter to ensure the track continuance during the course of recognition.The experimental results show that this method can recognize 50 tracks,which meets the requirements for position measurements of multiple targets..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1478 (2008)
Image encryption algorithm based on new two-dimensional map for rectangular image
REN Hong-e, SHANG Zhen-wei, and ZHANG Jian
A new encryption algorithm was proposed to apply to both square and rectangular image encryptions.A new two-dimensional map based on image segmentation was applied to the location scrambling,and a spread function containing chaos map to the gray scrambling,so that an image encryption algorithm combined with both positiA new encryption algorithm was proposed to apply to both square and rectangular image encryptions.A new two-dimensional map based on image segmentation was applied to the location scrambling,and a spread function containing chaos map to the gray scrambling,so that an image encryption algorithm combined with both position and gray scramblings was obtained.The experimental simulation shows that this algorithm can achieve good image encryption for any size of square and rectangular images with a large key space(1015～1030).Proposed algorithm also has advantages in withstanding statistical and known plaintext attack,which basically satisfies the requirements of validity and safety for image encryption..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1483 (2008)
Optical implementation of Mallat algorithm
HAN Liang, TIAN Feng-chun, XU Xin, and LI Li
To expand optical wavelet transform method into the digital signal processing domain,the optical implementation method of discrete wavelet transform algorithm(Mallat algorithm) for optical 4f system is proposed.Because amplitude-only Spatial Light Modulator(SLM) can only implement non-negative real function and CCD canTo expand optical wavelet transform method into the digital signal processing domain,the optical implementation method of discrete wavelet transform algorithm(Mallat algorithm) for optical 4f system is proposed.Because amplitude-only Spatial Light Modulator(SLM) can only implement non-negative real function and CCD can only record light intensity,a design method for optical wavelet filters used in optical 4f system is presented.According to the sampling spacing,the two-dimension wavelet filters are constructed with one-dimension coefficients of wavelet filter in terms of tensor product method.Then the frequency domain wavelet filters in the form of non-negative real function are constructed with splitting,Fourier transform and normalization.Finally,the corresponding optical wavelet transform post-processing method is given.With this kind of optical wavelet filter and its corresponding post-processing method,the wavelet decomposition is implemented by optical 4f system,and wavelet reconstruction by numerical computation in Mallat algorithm.The simulation experimental results show that the input images can be reconstructed theoretically by proposed method with high precision,the average reconstructed PSNR is 54.27 dB,even under the condition of introducing the optical device quantization error.Also,the input images with good quality can be reconstructed by optical experiment in actual optical 4f system.The simulation analysis and optical experimental results verify proposed method..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1490 (2008)
Control system for cell injection device based on TMS320DM642 and S3C2410
YU Bao-jun, YANG Zhi-gang, and ZHOU Guang-lu
In order to improve the low efficiency and the low velocity of common cell injection device in manual operation machine at present,a cell injection device based on DSP and ARM was presented.An image processing subsystem based on TMS320DM642 was used to accomplish image sampling and processing,and the results were storeIn order to improve the low efficiency and the low velocity of common cell injection device in manual operation machine at present,a cell injection device based on DSP and ARM was presented.An image processing subsystem based on TMS320DM642 was used to accomplish image sampling and processing,and the results were stored to a special RAM.The control subsystem based on S3C2410 was designed to have man-machine conversation and control macro-micro dual-drive table,and the HPI interface of TMS320DM642 was utilitied to transfer data between DSP and ARM.The experimental results indicate that the positioning precision of the system is 1 μm,which improves the motion precision of the system,and obtains the velocity of image processing of 11 frame/s..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1500 (2008)
Automatic focusing technique based on illumination optimum
SUN Ming-lei, ZONG Guang-hua, and BI Shu-sheng
The effect of illumination intensity on automatic focusing in the microscopic vision research field is discussed.An automatic illumination control system is developed to provide experimental conditions for illumination research on microscopic vision.The fast Fourier transform(FFT) is used to analyze spectra of image seThe effect of illumination intensity on automatic focusing in the microscopic vision research field is discussed.An automatic illumination control system is developed to provide experimental conditions for illumination research on microscopic vision.The fast Fourier transform(FFT) is used to analyze spectra of image sequences at defocus and image sequences under different illumination intensities,which proves that illumination intensity conditions impact significantly on the high-frequency energy of images.A evaluating function for the high-frequency energy of images is proposed.The experimental results show that illumination intensity has a great impact on focusing curves,and higher accuracy of 0.857 μm can be achieved after illumination optimization,which shows that illumination opitimization can improve automatic focusing accuracy..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1508 (2008)
influence of surface irregularity of on-axis TMA mirror on wave-front error
ZHONG Xing, JIN Guang, WANG Dong, and YAN Yong
By taking an actual on-axis Three Mirror Anastigmatic(TMA) system with a Φ600 mm primary mirror for example,the influences of the surface irregularities of primary mirror,secondary mirror and tertiary mirror on Gaussian focus wave-front error were analyzed,and the mathematic expressions of the influences were fitted.CiBy taking an actual on-axis Three Mirror Anastigmatic(TMA) system with a Φ600 mm primary mirror for example,the influences of the surface irregularities of primary mirror,secondary mirror and tertiary mirror on Gaussian focus wave-front error were analyzed,and the mathematic expressions of the influences were fitted.Circle field fixed Zernike polynomial was used as an optic-mechanic interface to analyze the environment influence on primary mirror and system performance degeneration.Finally,by taking the result as reference,the supporting structure of primary mirror was improved.Based on the Marechal criterion and environment endurance,the manufacturing accuracy of primary mirror is deduced,which shows that it should be higher than λ/36.5..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1516 (2008)
Relationship between swath width of space borne optical sensor and orbital elements
ZHANG Gui-xiang, JIN Guang, and Qu Hong-song
By taking Sun Synchronous Orbit(SS-O) for example,the relationship between swath width and orbital elements(especially the orbital altitude) was discussed,and a SS-O design method for satisfying the swath width requirement of space borne optical sensor was also given.The theory of non-spherical earth perturbation and tBy taking Sun Synchronous Orbit(SS-O) for example,the relationship between swath width and orbital elements(especially the orbital altitude) was discussed,and a SS-O design method for satisfying the swath width requirement of space borne optical sensor was also given.The theory of non-spherical earth perturbation and the definition of SS-O were discussed.Then,the relationship among nodal period,fundamental interval and orbital altitude was educed by deriving the definitions of fictitious node.Finally,the restriction conditions of orbit altitude satisfying swath width requirement based on the discussion above were given.The definition of fictitious node very helpful to comprehend the theory on SS-O was first put forward.Furthermore,the mathematical relationship between SS-O nodal period and orbital semimajor axis was deduce,which has been available for SS-O design..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1522 (2008)
Switch algorithm for quick small satellite attitude maneuver
XU Kai, JIN Guang, CHEN Juan, and CHEN Chang-qing
By taking aim at the application of Single Gimbal Control Moment Gyroscope(SGCMG) to quick small satellites,a switch control algorithm was presented to control the maneuver of small satellite.The small satellite with rigid bodies was used as a model,and the switch control for toques of small satellite with SGCMG was adBy taking aim at the application of Single Gimbal Control Moment Gyroscope(SGCMG) to quick small satellites,a switch control algorithm was presented to control the maneuver of small satellite.The small satellite with rigid bodies was used as a model,and the switch control for toques of small satellite with SGCMG was adjusted to avoid saturation singularity.SGCMG was controlled by pseudo-inverse steer law with zero-motion.The simulations show that the small satellite is capable of large angle maneuver with rotation of 45° at 14 s and average rate of 3.2 °/s.It proves that this switch algorithm can meet requirement for quick small satellite..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1528 (2008)
Design of new type spaceborne lightweighted primary mirror support
YAN Yong, JIA Ji-qiang, and JIN Guang
In order to satisfy the development requirement of spaceborne telescope primary mirror,a design of lightweighted primary mirror sub-assembly structure was presented.The influences of the material thermal math,lightweight pattern and the optimal support structures were considered during the mechanical/thermal design proIn order to satisfy the development requirement of spaceborne telescope primary mirror,a design of lightweighted primary mirror sub-assembly structure was presented.The influences of the material thermal math,lightweight pattern and the optimal support structures were considered during the mechanical/thermal design process.A high resolution Cassegrain optical payload with Φ650 mm primary mirror was designed,in which its specially support system could keep both high rigidity of structure and fine stability of thermal dimension.By considering the telescope manufacture and work station,the reasonable and optimal structure of the primary mirror sub-assembly was taken finally,analyzed results show its PV is less than λ/10,which can satisfy the requirement for the high resolution satellite primary mirror design..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1533 (2008)
Satellite attitude control simulation test bed based on VSCMG
DAI Lu, JIN Guang, and CHEN Tao
A new kind of triaxial air bearing test bed based on Variable-Speed Control Moment Gyro(VSCMG) was described for satellite attitude determination and control system simulation.A triaxial air-bearing platform newly developed was used as the test bed and a cluster of four variable speed control moment gyros was constructA new kind of triaxial air bearing test bed based on Variable-Speed Control Moment Gyro(VSCMG) was described for satellite attitude determination and control system simulation.A triaxial air-bearing platform newly developed was used as the test bed and a cluster of four variable speed control moment gyros was constructed in pyramid mounting arrangement as a main actuator in the simulation system.Also the system used the six gas thrusters to assist VSCMGs to avoid singularity.The attitude determination system was introduced,which consists of three fiber optical gyros,a horizon sensor and a magnetometer.The main parameters of all parts were given to illustrate that the platform can be used in the simulation and validation of many algorithms for modern agile small satellite,which can provide reference for other facilities in this research field..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1546 (2008)
Design and optimization of lightweight outer baffle for space camera
JIA Xue-zhi, JIN Guang, and ZHANG Lei
The structure of the outer baffle designed for a space camera was investigated.In order to achieve the minimum weight,the carbon fibre composite and TC4 were chosen as the main material,and the finite element optimization method was used for the design of the outer baffle.According to the dimension of baffle,the inequaThe structure of the outer baffle designed for a space camera was investigated.In order to achieve the minimum weight,the carbon fibre composite and TC4 were chosen as the main material,and the finite element optimization method was used for the design of the outer baffle.According to the dimension of baffle,the inequalities relating to baffle's mode and camera parameters were given in this work,the thicknesses of the outer baffle and diaphragm could be determined.The optimization results show a reduction of weight from 7.2 kg to 4.4 kg,which is lighter 38.9% than that of original one.Moreover,the modes of the outer baffle change a little,while the impulsion in the launch progress is reduced.Finally,the static and dynamic analysis was afforded by finite element method,and the results satisfy the requirement of design in production..
Optics and Precision Engineering
- Publication Date: Sep. 21, 2021
- Vol. 16, Issue 8, 1560 (2008)
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