Journals >Optics and Precision Engineering
Contents
2010
Volume: 18 Issue 8
30 Article(s)
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Research Article
Application of principal component analysis to selection of characteristic wavelengths with total light scattering
TANG Hong, ZHENG Wen-bin, and LI Xian-xia
To select the characteristic wavelengths which contain important information about particle sizes and refractive indexes in a total light scattering particle sizing method,a wavelength selection method was proposed by performing the Principal Component Analysis(PCA) for the extinction spectra, the first-order differentTo select the characteristic wavelengths which contain important information about particle sizes and refractive indexes in a total light scattering particle sizing method,a wavelength selection method was proposed by performing the Principal Component Analysis(PCA) for the extinction spectra, the first-order differential extinction spectra and the second-order differential extinction spectra of monomodal R-R particle system in visible and visible-infrared regions. This method firstly used the principal component transform to dispose the first-order differential extinction spectra, and then regarded the contribution rate of the principal component to the first-order differential extinction spectra at each wavelength as the mainly criterion to select the characteristic wavelengths. Meanwhile, the boundary wavelengths in the spectral region were also selected as the characteristic wavelengths. The numerical simulations on the monomodal and biomodal R-R distributions were performed, and the experimental data of reference materials were also validated.Experimental results show that the inversion errors of reference materials based on the PCA selection method are less than 3%. It is concluded that the selection method has advantages of convenient computation and easy realization, and can ensure to the extinction values of selected characteristic wavelengths to show the most valuable information about the particle size distribution..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1691 (2010)
Development of vacuum application solar simulation Xe flash-lamp array
REN Jian-yue, SU Ke-qiang, WANG Bing, CHEN Chang-zheng, and ZHANG Jun
In order to do the thermal balance tests for some type space-cameras and to overcome the shortcomings of traditional solar simulators in complicated structure, high costs and low light efficiencies, a simulated solar Xe flash-lamp array placed in a vacuum tank was developed. The theoretical principles of the simulated In order to do the thermal balance tests for some type space-cameras and to overcome the shortcomings of traditional solar simulators in complicated structure, high costs and low light efficiencies, a simulated solar Xe flash-lamp array placed in a vacuum tank was developed. The theoretical principles of the simulated solar lamp array were analyzed, then it pointed out that its irradiance should be set to 635.2～905.4 W/m2 and its efficiency of optical system is 0.144 4. The heat conduction ability of the liquid nitrogen cooling system in the vacuum tank was analyzed, and the results indicate that the temperature of cooling system in the vacuum tank ΔT is 2.074 1 K and lower than a super cooling temperature of 4 K, which means that the liquid nitrogen cooling system can export the heat of solar simulated lamp array out from the vacuum tank. The thermal design of the simulated lamp was analyzed and discussed, results show that the temperatures of optical integrator and mirror are all around 200 ℃ , and the temperatures of cathode and negative electrodes of the lamp are around 92 ℃, which meets their normal working conditions for a long time. Finally, the technological specifications of the simulated solar lamp were tested, it is shown that its radiation intensities are 600～1 000 W/m2, and the inuniformity and unsteadiness of radiation are less than ±5％ and ±5％/h, respectively. Those data are well coincident with the design targets.
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1699 (2010)
Optical fiber attenuated total reflection sensor for on-line measurement of biomass concentration
ZHAO Ming-fu, ZHONG Nian-bing, LUO Bin-bin, HU Xin-yu, and ZHONG Lian-chao
With the aim to measure the biomass concentration in the biodegradation of organic waste gas for a trickling biofilter, an optical fiber Attenuated Total Reflection(ATR) sensor for measuring the biomass concentration was designed and the composition principle, structural parameters, optical path analysis and the theoreWith the aim to measure the biomass concentration in the biodegradation of organic waste gas for a trickling biofilter, an optical fiber Attenuated Total Reflection(ATR) sensor for measuring the biomass concentration was designed and the composition principle, structural parameters, optical path analysis and the theoretical explanation of the sensor were also discussed.A new method to measure the biomass concentration was proposed based on the principles that the evanescent wave is scattered and absorbed by the bacterial suspension when the beams enter into the interface between the optically denser medium-Si crystal and the optically less dense-bacterial suspension, and the receiving bacterial power of the light is changed by the bacterial suspension. Under a temperature of 25℃, the biomass concentration was measured by a visible light source. Experimental results indicate that the mean relative error by proposed method is 2.217%, which can satisfy the on-line measurement requirements of the biomass concentration. The design principle and method of the sensor is significance and can be used in reagent preparation, alcohol production, biochemistry, etc..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1707 (2010)
Post processing for magnetorheological finishing of optical mirrors
SONG Ci, DAI Yi-fan, PENG Xiao-qiang, and SHI Feng
The topological structure and coordinate transformation of Magnetorheological Finishing (MRF) machine tool KDMRF-1000 were analyzed and its kinematics was calculated,then the post processing algorithm model of MRF for an optical lens was established. According to the characteristic of four-axis linkage machine tool, thThe topological structure and coordinate transformation of Magnetorheological Finishing (MRF) machine tool KDMRF-1000 were analyzed and its kinematics was calculated,then the post processing algorithm model of MRF for an optical lens was established. According to the characteristic of four-axis linkage machine tool, the model was treatmented approximately. By taking the post processing of a spherical lens as an example, a post processing algorithm that can be used for a raster tool path was deduced and the errors imported by this approximate treatment were analyzed. By simulating the effect of the algorithm on the spherical lenses with different apertures and relative apertures, the polishing range of this algorithm was achieved. Furthermore, a spherical part (K9, 200 mm in diameter, f=640 mm) was polished by MRF, experimental results show that obtained errors are less than 65 nm PV and 9 nm RMS in excluding the edge effect. This experiment proves the veracity of post processing algorithm and the feasibility of four-axis linkage approximate treatment. The work done in this paper has an important purpose for polishing the optical lenses with different apertures and shapes..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1715 (2010)
Photoelectric measuring system with large field for cloud position determination
WANG Hao-jing, WANG Jian-li, WANG Ming-hao, YIN Yu-mei, and ZHANG Yan-hui
In order to improve the service and observing efficiencies of space target surveillance equipment, a photoelectric measuring system was designed to determine the positions and distributions of clouds and to decrease the false alarm rate and damage possibility due to severe weather. This system employed a large field opIn order to improve the service and observing efficiencies of space target surveillance equipment, a photoelectric measuring system was designed to determine the positions and distributions of clouds and to decrease the false alarm rate and damage possibility due to severe weather. This system employed a large field optical design and took a set of flat ellipsoid catadioptric lens as its core.By using an uncooled infrared focal plane array detector, it could collect sky images in all day long.A computer with a color card was used to perform pseudo-color and bracket removal operations and to get a pseudo-color image which could distinguish clean, haze, cloud and their transitions.Furthermore, the position information of the interesting points could be obtained based on the pre-established function between position information in the sky and pixels in the image. Experimental results demonstrate that this measurement system can collect cloud images in the sky above elevation 20°,and can offer a processed image every 5 s. The positioning accuracy of the system is 1°,which can achieve the position determination with large field for the cloud distributions and can improve service efficiency..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1722 (2010)
Test of parallax parameters for optoelectronic sights in small arms
YU Qiu-shui, AN Zhi-yong, YANG Rui-ning, LIANG Shuang, and SONG Jing-yi
According to the research of traditional parallax measuring techniques, a parameter test method based on the auto-focus technology was proposed, and the principle of auto-focus and its composition block diagram were introduced. Then, in consideration of the specific requirements of small arms for sight performance, a pAccording to the research of traditional parallax measuring techniques, a parameter test method based on the auto-focus technology was proposed, and the principle of auto-focus and its composition block diagram were introduced. Then, in consideration of the specific requirements of small arms for sight performance, a parallax test system was designed combined with the auto-focus technology and the auto-focus processes before or after the measuring sight placed in the test system were described in detail. Furthermore, the parallax parameters were obtained according to the difference of diopter. Five experiments were performed on the requirements of the actual optical system, and the obtained parallax parameters were analyzed. Results show that the measurement accuracy of parallax parameters is 0.029 6 m-1, which achieves the technical specification less than 0.1 m-1 and guarantees the measuring accuracy..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1732 (2010)
Application of miniature optical encoders to angular rate identification of motors
LI Lin, LI Ming, and AI Hua
A signal processing method for encoders based on stationary Kalman filter technology is implemented to satisfy the requirements of angular rate prediction of a servo control system. Firstly, the typical structure of a motor system and the composition of an optical encoder for measuring noises are analyzed, and the paraA signal processing method for encoders based on stationary Kalman filter technology is implemented to satisfy the requirements of angular rate prediction of a servo control system. Firstly, the typical structure of a motor system and the composition of an optical encoder for measuring noises are analyzed, and the parametric mathematical model of the motor system and optical encoder is built for stationary Kalman filter design. Then, the uniform parametric design results of stationary Kalman filter are presented by using the model.Under the Matlab/Simulink environment, the simulation model of the motor system, optical encoder and Kalman filter is completed and the universality and filtering effect of parametric stationary Kalman filter are predicted by different parameters. Finally, an experimental platform is built to verify the simulation conclusion, and the filtering performance is measured. The simulation and experiment results show that the parametric stationary Kalman filter is universalizable for motor systems and the adaptive stationary Kalman filter can estimate the angular-rates by using optical encoders.Obtained data indicate that the standard deviation is 0.021 (°)/s and the maximum error can be controlled under 0.06 (°)/s,which can satisfy the requirements of motor control systems for the angular-rate precision..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1738 (2010)
Fast Fourier transform analysis of single-detector polarization-sensitive optical coherence tomographic signals
CHEN Xiao-dong, WANG Yi, LI Hai-feng, LI Qiao, and YU Dao-yin
This paper focused on the relationship of the biological tissue character and the Fast Fourier Transform(FFT) of Polarization-sensitive Optical Coherence Tomography(PS-OCT) signals,and researched the influence of the birefringence,texture and the structure of tissues on the FFT of PS-OCT signals. After describing the sThis paper focused on the relationship of the biological tissue character and the Fast Fourier Transform(FFT) of Polarization-sensitive Optical Coherence Tomography(PS-OCT) signals,and researched the influence of the birefringence,texture and the structure of tissues on the FFT of PS-OCT signals. After describing the single-detector PS-OCT imaging theory in detail,it set up a three-layer tissue model. On the basis of the model,it simulated its single detector PS-OCT signals and analyzed the influence of different model parameters on the FFT of signals. By taking the bovine tendons and cartilages as samples,a A-scan experiment was carried out with the single detector PS-OCT system.Obtained FFT shows that the spectral shapes and relative frequencies change with the different tissue characters,such as birefringence,back scattering indexes and structures. The researches approve the ability of single-detector PS-OCT in detecting biological tissue characters..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1746 (2010)
Computer-aided alignment of off-axis three-mirror system by using Zernike coefficients
GONG Dun, TIAN Tie-yin, and WANG Hong
A computer-aided alignment method in combining with the interferometry was proposed to optimize the detection and alignment of an off-axis three-mirror system.By using a multi-fields ZYGO interferometer, a series of Zernike coefficients were obtained to express the incorrect parameters of the system, which were then trA computer-aided alignment method in combining with the interferometry was proposed to optimize the detection and alignment of an off-axis three-mirror system.By using a multi-fields ZYGO interferometer, a series of Zernike coefficients were obtained to express the incorrect parameters of the system, which were then transformed into geometric aberrations as the corrected objects based on the dependence of Zernike-coefficents on Seidel aberrations.Furthermore,an optical design software was used to derive the sensitivity matrix related to the incorrect parameters and to determine the incorrect parameter mostly sensitive to the redual aberration. Consequently, the adjusted result was brought into the software to verify the selection of incorrect parameters.Experimental results show that the RMS value of the system is lower than 0.04λ after iterations, which proves the effectiveness of the method in alignment guidance..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1754 (2010)
Fast alignment of Coude optical system in alt-alt two axis tracking turntable
QIAO Jian, GAO Yun-guo, HAN Guang-yu, and ZHAO Tian
In order to realize the fast and high accuracy alignment of Coude optical system in an alt-alt two axis tracking turntable, an auto-collimation alignment and testing system was built, which was composed of an auto-collimator with a flat reflector. The working principle and components of Coude optical system in the turnIn order to realize the fast and high accuracy alignment of Coude optical system in an alt-alt two axis tracking turntable, an auto-collimation alignment and testing system was built, which was composed of an auto-collimator with a flat reflector. The working principle and components of Coude optical system in the turntable were introduced, and its alignment and testing methods were proposed according to the principle of optical autocollimating. On the basis of the characteristics of Coude system,the principle of rectangular coordinate transformation was deduced and the fast alignment of Coude optical system was achieved with computer-aided alignment.The errors in Coude optical system with latitude and longitude axes rotated were measured. The results show that the wobble errors of Coude optical system aligned by this methods is 5.2″, which is superior to the system precision expected by laser launching system in 8″,and meets the requirements of technology index. This methods can be widely used in the alignment of Coude optical system with the two axes rotated , and has broad application prospects in practical engineering..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1760 (2010)
Error compensation and parameter identification of circular grating angle sensors
GAO Guan-bin, WANG Wen, LIN Keng, and CHEN Zi-chen
An error compensation and parameter identification method based on sine function and particle swarm optimization was presented to improve the measurement accuracy of circular grating angle sensors. The measurement errors of the sensors were calibrated discretely by a photoelectric autocollimator and a metal polyhedron.An error compensation and parameter identification method based on sine function and particle swarm optimization was presented to improve the measurement accuracy of circular grating angle sensors. The measurement errors of the sensors were calibrated discretely by a photoelectric autocollimator and a metal polyhedron. By analyzing the calibration data with the Fast Fourier Transform(FFT), it was found that the measurement errors of the sensors are composed mainly of the sinusoidal signals with different frequencies. Thus an error compensation model consisting of seven constants to be determined was presented based on sine functions.Furthermore,by taking these constants as the location coordinates of particles and the average error as the fitness function, one identification model based on particle swarm optimization was built to calculate the constants in the compensation model.Finally, the compensation method was used to compensate the errors of the sensors in an articulated arm coordinated measuring machine. The experimental results show that the average errors of the sensors are reduced about 398~1 102.5 times after compensation..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1766 (2010)
Design of compact Offner hyperspectral imaging system with Féry prism
CHENG Xin, HONG Yong-feng, ZHANG Bao, and XUE Qing-sheng
In order to decrease the volume and quality of an imaging system and to correct the smile of a spectral image, a novel Offner hyperspectral imaging system with Féry prisms is presented. In this system,a pairs of Féry curved surface prisms are located at two arms of the Offner relay configuration and the lightIn order to decrease the volume and quality of an imaging system and to correct the smile of a spectral image, a novel Offner hyperspectral imaging system with Féry prisms is presented. In this system,a pairs of Féry curved surface prisms are located at two arms of the Offner relay configuration and the light beam passes through the prisms twice to be dispersed. Therefore,the system shows a lighter and smaller structure as compared with conventional one when it gains a given dispersion value. To decrease the nonlinear dispersion of spectral channel in Visible-Near Infrared (VNIR), a couple of anti-dispersion flint Féry prisms are introducted into this system again. Then,two kinds of hyperspectral imaging systems applied to VNIR and Short-Wave Infrared (SWIR) channels are designed, respectively.The analytical results indicate the smiles and keystones of the two spectral imaging systems are less than 0.1 pixel and 0.045 pixel, respectively, and the nonlinearity is less than 0.1, which satisfies the requirements of airborne or spaceborne hyperspectral imagers..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1773 (2010)
Thermal deformation compensation of high-energy laser mirrors
FENG Zhi-qing, BAI Lan, ZHANG Zeng-bao, and LIN Guan-yu
A compensation system composed of a PZT,a pressure sensor,an annular force mechanism and a control circuit is developed to compensate the sphere error brought by thermal deformation of a laser mirror. Under the effect of two coaxial annular forces with different radii, the circular mirror produces parabolic deformationA compensation system composed of a PZT,a pressure sensor,an annular force mechanism and a control circuit is developed to compensate the sphere error brought by thermal deformation of a laser mirror. Under the effect of two coaxial annular forces with different radii, the circular mirror produces parabolic deformation in the inner region,which can compensate the sphere error brought by the thermal deformation of the mirror. The finite element method is used to analyze the mirror and the relation among the center displacement with energy absorbance and the force is derived. The experiments of force-deformation and energy absorbance-force-deformation are conducted for a flat mirror with the diameter of 100 mm and the thickness of 8 mm,in which a interferometer is used to monitor the surface deformation. Obtained results show that under different forces, the deformation of effective region always maintains a parabolic shape. Furthermore,the force-deformation curve is obtained,which shows that the centre displacement is over 3 μm under 225 N.Under different energy absorbances,the central displacement of the mirror varies with the force in linearity and the coefficient of force-centre displacement is 0.013 μm/N..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1781 (2010)
Manufacturing technology of PC optical resin metrological grating
Chen Yun, Wang Li-feng, and Li Yan-ru
To solve the problems that the glass base slices of metrological gratings can not suffer the bad environments such as strong vibration and big impact, a new type material,Polycarbonate(PC),was chosen to replace the glass to manufacture metrological gratings. The optical characteristics,light transmittance,heat tolerancTo solve the problems that the glass base slices of metrological gratings can not suffer the bad environments such as strong vibration and big impact, a new type material,Polycarbonate(PC),was chosen to replace the glass to manufacture metrological gratings. The optical characteristics,light transmittance,heat tolerance and the chemical resistance of the PC were analyzed and a cleanout method for the PC was given. On the basis of traditional manufacturing of gratings, a new manufacturing technology,namely,coating first and vacuum plating Cr afterwards,was developed. Finally,by taking the PC as a base slice,a PC optical resin metrological grating was produced in the vacuum degree of 1.2×10-3 Pa and evaporation distance of 150 mm, in which the film thickness was controlled by the quality of Cr. The PC metrological grating was observed in a 45× microscope.Results show that the edges of lines are vertical and no slips. The results indicate that the technology is feasible and technologic parameters are correct.It can provide an examination basis to develop precision measuring angle instruments..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1788 (2010)
Fabrication of metal micro hole array by using over-plating technology
HU Yang-yang, ZHU Di, and LI Han-song
The over-plating technology was introduced to fabricate micro hole arrays, for it is difficult to fabricate a micro hole array with the size less than 10 μm by traditional methods. A mathematical model was presented to simulate the over-plating process by Finite Element Method (FEM). Using the optimized parameters (bakThe over-plating technology was introduced to fabricate micro hole arrays, for it is difficult to fabricate a micro hole array with the size less than 10 μm by traditional methods. A mathematical model was presented to simulate the over-plating process by Finite Element Method (FEM). Using the optimized parameters (bake 120 ℃/60 min, exposure 3 000 mJ/cm2, and development 2 min),the AZ EXP 125nXT-10A resist structure in a diameter of 50 μm and a height of 50 μm was prepared, and then the over-plating technology was employed to shrink the micro hole. The experimental result shows that the simulation result is correct. Finally,a micro hole array in a diameter of 4 μm and a height of 70 μm was fabricated after over-plating 2 h. The result indicates that over-plating is a simple and low cost method to fabricate micro hole array, and it is suitable for batch production..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1793 (2010)
Design of online measuring device for surface profile of Wolter Type I mirror
CUI Tian-gang, WANG Yong-gang, MA Dong-mei, MA Wen-sheng, and CHEN Bo
As traditional interference-based measurements can not be suited to measure the surface profile of the Wolter Type I revolving aspheric mirror, a new method was proposed to measure this kind of mirror in this paper. On the basis of a Long Trace Profiler (LTP), a new measuring device was also established by introducing As traditional interference-based measurements can not be suited to measure the surface profile of the Wolter Type I revolving aspheric mirror, a new method was proposed to measure this kind of mirror in this paper. On the basis of a Long Trace Profiler (LTP), a new measuring device was also established by introducing a pentaprism into the scanning mechanism for ray turning. The working principles, structure parameters and data processing algorithms of the device were investigated, then a standard plane mirror was used as the reference to calibrate the device. Finally, a mirror sample was measured to verify the measuring device. Experimental results indicate that designed device can achieve the slope error of RMS 6.7 μrad , repeatability of 0.75 μrad and the height profiles of PV 0.24λ and RMS 0.07λ, which meets the design requirements basically..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1801 (2010)
Calibration and detection of compound eye model
WANG Ke-yi, ZHANG Hao, CAO Zhao-lou, GUO Fang... and YAN Pei-zheng|Show fewer author(s)
A new compound eye model with wider fields of view and higher agility was introduced to track the low-flying targets in a complex background. The struction and preparation of the compound eye model were described and its imaging channels were traced by Zamax to evaluated imaging characteristics.The calibration and deteA new compound eye model with wider fields of view and higher agility was introduced to track the low-flying targets in a complex background. The struction and preparation of the compound eye model were described and its imaging channels were traced by Zamax to evaluated imaging characteristics.The calibration and detection of the compound eye were introduced,then LM neural network calibration algorithm was trained to build the relationship between object points and corresponding image points. This calibration algorithm provides an accurate direction angle prediction from their corresponding image points, and it is easy to integrate into the system. Preliminary experimental results for neural network calibration were presented and evaluated, which shows that the residual errors between actual and measured direction angles are around 10-3~10-4 rad. In detection simulation experiments, several points were calculated and results show that the errors between actual and calculated coordinates of position are within 3%. This is a good result for the compound eye sensor that sacrifices the spatial resolution to improve the angle resolution..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1807 (2010)
Locking device for magnetic bearing flywheel and its optimization
LIU Qiang, FANG Jian-cheng, HAN Bang-cheng, and BAI Guo-chang
To remedy the defect of an one-off locking device which can not repeat locking or releasing for a magnetic bearing flywheel, a novel repeated locking device based on the motor, extension and shrinkage mechanism was proposed and the composition and working principles of the locking device were introduced. According to tTo remedy the defect of an one-off locking device which can not repeat locking or releasing for a magnetic bearing flywheel, a novel repeated locking device based on the motor, extension and shrinkage mechanism was proposed and the composition and working principles of the locking device were introduced. According to the deformation of carbon fiber, the locking process of locking device was divided into stages of bending and compressing, and its mechanical property was analyzed. The software of Multidisciplinary Design Optimization (iSIGHT) combined with the finite element analysis software (ANSYS) were applied to the optimization of carbon fibers. Then,by taking the structural strength, structural force and the resonance frequency as constraints, the carbon fiber was optimized by using the method of point-by-point comparing at macrocosm combined with the sequential quadratic programming method. The result indicates that the mass of carbon fiber reaches minimum by decreasing from 112 g to 46 g (is reduced by 59%) when the number of carbon fiber slices is 12. It is concluded that the method improves the reliability and efficiency of locking device designed, and has important significance in the optimization design of flywheel systems..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1814 (2010)
Flow behavior of resist in room-temperature micro-imprinting and its process optimization
WEI Zheng-ying, XIONG Xiao-dong, DU Jun, and DING Yu-cheng
To improve the replicating precision of resist in micro-imprinting, the POLYFLOW was used to simulate its flow behavior in room-temperature micro-imprinting based on the Fluid-Solid-Interaction(FSI) method.The effects of the initial thickness and residual thickness of the resist, the ratio of height to width and duty rTo improve the replicating precision of resist in micro-imprinting, the POLYFLOW was used to simulate its flow behavior in room-temperature micro-imprinting based on the Fluid-Solid-Interaction(FSI) method.The effects of the initial thickness and residual thickness of the resist, the ratio of height to width and duty ratio of the mold,and the imprinting velocity of the mold on the resist flow behavior in a cavity were analyzed systematically. A platform of visual experiments was established, and the process of micro-imprinting and the profile of resist in different technological conditions were observed. Comparing the experimental results to the simulation results, it is concluded that the filling rate can come up to 90% when the imprinting velocity is slower than 1 μm/s, the duty ratio is more than 0.375, and the ratio of height to width is less than 2. Obtained results show that the imprinting process condition and the structure of the mold have been optimized and the replicating precision can be improved by the optimized results..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1822 (2010)
Design of flexible support structure of reflector in space remote sensor
WANG Zhong-su, ZHAI Yan1, MEI Gui1, JIANG Fan, and CHENG Zhi-feng
To reduce the surface deformation of a remote sensor reflector in complex and execrable space environments, a flexible support structure was designed. By defining the thickness, width and radius as design variables, the flexible hinge in an oblong reflector subassembly was optimized. Then,the surface figure precision, To reduce the surface deformation of a remote sensor reflector in complex and execrable space environments, a flexible support structure was designed. By defining the thickness, width and radius as design variables, the flexible hinge in an oblong reflector subassembly was optimized. Then,the surface figure precision, structural strength and dynamic stiffness of the reflector subassembly in the thermal-structural coupling state were analyzed with finite element method. Simulation results show that the maximum PV value is decreased to 59.03 nm from 350.08 nm, the maximum RMS value is decreased to 9.11 nm from 102.67 nm and the thermal dimensional stability is ensured by proposed flexible structure. Finally, the thermal-structural simulation subassembly was subject to a mechanical test,and results indicate that the fundamental frequencies of the component in three directions are 264 Hz, 290 Hz and 320 Hz,respectively. Analysis and test results demonstrate that the flexible support structure is reasonable..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1833 (2010)
Comparison on linear and contact nonlinear analysis methods of pull-rod bent focusing mirror assembly
L Qing-tao, XUE Song, PENG Zhong-qi, ZHU Wan-qian, and FU Yuan
For analysis on pull-rod bent focusing mirror assemblies in engineering, the accurate results can be obtained by a contact nonlinear method rather than a linear analysis. As analysis of a nonlinear system by linear method shows a bigger error, this paper researches the causes of errors. A pull-rod bent focusing mirror For analysis on pull-rod bent focusing mirror assemblies in engineering, the accurate results can be obtained by a contact nonlinear method rather than a linear analysis. As analysis of a nonlinear system by linear method shows a bigger error, this paper researches the causes of errors. A pull-rod bent focusing mirror assembly is simulated by the finite element method, then the contact nonlinear analysis method is introduced to analyze the response of focusing mirror when its pull-rod is bended. In comparison of the nonlinear analysis results with detection results, it is pointed out that the errors between them on scope and radius are 4 μrad and 5 km when the bent vector height of focusing mirror is a constant, which can meet the requirements of engineering. Finally, the tested results of the bent focusing mirror from linear analysis, nonlinear analysis and detection are compared, which indicates that the nonlinear analysis is closer to a real system in engineering analysis and suits to simulate the real conditions at the scope of limited errors..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1842 (2010)
Restoration of broadband white light image using phase diversity technique
WU Yuan-hao, WANG Bin, ZHAO Jin-yu, MING Ming... and WANG Guo-qiang|Show fewer author(s)
The Phase Diversity (PD) technique used in wavefront detection was studied. The technique utilizes the PD between the two images on the focus and defocus to estimate the wavesfront phase aberration and to restore the degraded images. A white light imaging system was designed and a experimental platform which takes a brThe Phase Diversity (PD) technique used in wavefront detection was studied. The technique utilizes the PD between the two images on the focus and defocus to estimate the wavesfront phase aberration and to restore the degraded images. A white light imaging system was designed and a experimental platform which takes a broadband white light as a source was established, then the system above was used to simulate broadband white objects and wavefront phase aberrations in infinite distances. To grab the two images of different channels only by the same camera, a right angle trapezoid prism was designed to split the light beam into two channels, which eliminates the system deviation from different cameras and suppresses the effect of noises on the image restoration. After splitting, the denoising ability of the system for white Gaussian noise has reached 10%. Moreover the experiments also demonstrate that the resolution of the restored image has increased by 19% as compared with that of a original image. These results show that the proposed method is a good mean to restore degraded images in photoelectric image systems..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1849 (2010)
Design of a variable structure PI controller and its application in photoelectronic tracking systems
XIONG Ai, FAN Yong-kun, and WU Qin-zhang
With the aim to provide a high performance servo control for photoelectronic tracking systems, a simple Variable-structure PI controller(VSPI) is presented by combining the traditional PI controller theory and the variable-structure idea, then the principles of the controller are introduced and its design parameter selWith the aim to provide a high performance servo control for photoelectronic tracking systems, a simple Variable-structure PI controller(VSPI) is presented by combining the traditional PI controller theory and the variable-structure idea, then the principles of the controller are introduced and its design parameter selection is also discussed. Based on the structure of a photoelectronic tracking system , the servo control systems by using VSPI,Anti-windup PI controller(AMPI) and Integral Separation PI controller(ISPI) are simulated, respectively, and the experiments on positioning tracking and equivalent sine tracking are also carried out. The experimental result shows that the system with VSPI controller has no overshoot and its rise time, settling time and tracking precision are 0.378 s,0.488 s and 1.26″,respectively. Compared with the systems using other two algorithms, the system with VSIP can complete real time control and can offer better comprehensive performance, which completely satisfies the requirements of photoelectronic tracking systems for high precision and fast response..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1855 (2010)
Infrared adaptive correlation tracking of fusing distance information
CHEN Da-qing, HAN Jiu-qiang, and YU Zhi-jian
This paper mainly researches how to apply the distance information of millimeter wave radars to the object-tracking of infrared image sequences. In connection with the image sequences whose objects are gradually magnified, a template updating strategy in which the template updating cycle is confirmed by the distance beThis paper mainly researches how to apply the distance information of millimeter wave radars to the object-tracking of infrared image sequences. In connection with the image sequences whose objects are gradually magnified, a template updating strategy in which the template updating cycle is confirmed by the distance between target and missile is proposed after analyzing the effect of image magnification on the correlation characteristics. In combination of the timing updating, template buffer updating with the distance updating, an adaptive template updating algorithm for fusing distance information is presented. By taking a building as experimental target, the effectiveness of the method is verified. It demonstrates that the method is very suitable for the proposed image sequences. As compared with the traditional tracking methods,it has improved the tracking accuracy and tracking stability greatly and its tracking accurateness is more than 90% for different images..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1862 (2010)
Application of automatic image enhancing technique to road defect detection systems
ZHANG Da-qi, QU Shi-ru, and HE Li
In order to improve precision and adaptive capability of road defect detection system, an image enhancement technique for automatic road defect is investigated. To estimate the crossover points of gray transform, a new 3-D pattern formed with two local features of the neighborhood of each pixel and one global feature bIn order to improve precision and adaptive capability of road defect detection system, an image enhancement technique for automatic road defect is investigated. To estimate the crossover points of gray transform, a new 3-D pattern formed with two local features of the neighborhood of each pixel and one global feature based fuzzy measurement is constructed for pixel classification. In design of a fuzzy membership function with image enhancement ability, the Non-uniform Rational B-Splines(NURBS) is used to produce a double S shape fuzzy membership function as the gray transform function. The gray transform function can easily be united with the crossover points perfectly and its designable shape can offer capability of gray level centralization. Therefore, the method can obtain the road crack only by a few operations of iteration and enhancement. Experimental results testify that this adaptive technique can provide satisfactory enhancement effects and the detection accuracy of road crack region pixels reaches 95%. The proposed technique shows better reliability and precision for road defect detection systems..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1869 (2010)
Reduction of trailing for moving images in FPD by grayscale control
LIN Lin, QIAO Yan-feng, and SU Wan-xin
To reduce the trailing phenomena for moving images in a Flat Panel Display(FPD), a grayscale control algorithm which simulates Cathode Ray Tube(CRT) grayscale rendition process is proposed. Firstly, the basic concept of FPD is introduced and the current major technology of reducing trailing, Black Frame Insertion TechnTo reduce the trailing phenomena for moving images in a Flat Panel Display(FPD), a grayscale control algorithm which simulates Cathode Ray Tube(CRT) grayscale rendition process is proposed. Firstly, the basic concept of FPD is introduced and the current major technology of reducing trailing, Black Frame Insertion Technology, is explained.Then, the reasons of trailing phenomena from moving images are introduced and the work processes of human eyes when moving images are displayed on CRT and FPD are illuminated and the grayscale rendition of a pixel is obtained. Furthermore, based on algorithm derivation, the algorithm realization steps and compared experiment results of traditional and proposed FPD grayscale control algorithms are discussed. Finally, the main program implemented with Very-High-Speed Integrated Circuit Hardware Description Language(VHDL) is presented and the specific rendition process is described. Experimental results indicate that the image quality is evidently improved and the trailing phenomena have been reduced to nearly 90% when the moving images are displayed by the FPD.The result meets the eye reflection mechanism.Moreover,the algorithm has advantages in less operation and storagy space and is easy to be implemented by hardware..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1877 (2010)
Description of rotation invariant texture image with local Walsh spectrum
SUN Hui-xian, ZHANG Yu-hua, and LUO Fei-lu
In order to analyze the image texture effectively, the new rotation invariant and multiresolution texture descriptors are proposed based on Local Walsh Spectrum (LWS). Firstly, the Local Binary Sequence (LBS) of each pixel is obtained by comparing its gray-scale with neighboring points and the power spectrum of DiscretIn order to analyze the image texture effectively, the new rotation invariant and multiresolution texture descriptors are proposed based on Local Walsh Spectrum (LWS). Firstly, the Local Binary Sequence (LBS) of each pixel is obtained by comparing its gray-scale with neighboring points and the power spectrum of Discrete Walsh Transform (DWT) of the LBS is calculated. Then, the spectrum’s value in the power spectrum is expressed in characteristic histogram to describe the texture feature. Finally, based on the sequency characteristic of LBS, the Two-family Sequency LWS (TSLWS) is proposed to reveal the relationship between LWS and Local Binary Pattern (LBP).Because of the circular-shift-invariant of DWT power spectrum, the proposed texture descriptors show prior rotation invariance. Experimental results indicate that the texture classification precisions of LWS are better than those of the Gray Level Co-occurrence Matrix (GLCM) method and Gabor filter bank method. Furthermore,as compared with the LBP,the texture classification precision of the LWS is 3% higher than that of LBP in the same local neighborhood and the segmentation in inaccuracies of the LWS are 11% and 23% respectively less than those of LBP for two rotated mosaic texture images,which proves that the proposed method has better abilities of texture discrimination and rotation invariance.孙慧贤|Saber_sun@163.com.
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1886 (2010)
Improvement of performance for CMOS area image sensors by TDI algorithm in digital domain
QU Hong-song, ZHANG Ye, and JIN Guang
In order to provide a TDI function for CMOS area image sensors,the working principles of TDICCDs are researched and a TDI algorithm based on the digital domain is proposed,then,how to realize the algorithm by a FPGA is discussed. The algorithm can realize time delay integration on CMOS sensors without changing its deviIn order to provide a TDI function for CMOS area image sensors,the working principles of TDICCDs are researched and a TDI algorithm based on the digital domain is proposed,then,how to realize the algorithm by a FPGA is discussed. The algorithm can realize time delay integration on CMOS sensors without changing its device structure.The TDI algorithm for CMOS area image sensors in a digital domain is deduced through an example method.After optimization,the algorithm with optimized structure can save (m-1)(m-2)/2 memory space of image lines. Finally,on the basis of a remote sensing camera,the dependence of pixel resolution and row transfer time on frame rate is discussed and the frame rate requirements under the Ground Sample Distances(GSDs) and TDI stages are calculated by the numerical example method.Experiment results show that the 1 280×1 024 CMOS sensor with a frame rate more than 648 frame/s can meet the requirements of integration imaging for 1 m GSD of 96 TDI stages in an orbital altitude of 600 km..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1896 (2010)
Object detection based on geometric feature extracted by chord-tangent transformation
HE Lian, and ZHANG Qi-heng
A method to extract the geometric features of planar objects was proposed by using the Chord-tangent Transformation (CTT), then a 2D object was detected based on matching the geometric features obtained by the CTT. The theoretical basis of the CTT was introduced and how to realize the method was described. Meanwhile, tA method to extract the geometric features of planar objects was proposed by using the Chord-tangent Transformation (CTT), then a 2D object was detected based on matching the geometric features obtained by the CTT. The theoretical basis of the CTT was introduced and how to realize the method was described. Meanwhile, the errors and reliability of the method were analyzed and discussed. It was pointed out that the CTT can extract a kind of senior geometric feature from the information of edge points, and the extracted geometric feature not only has invariant characters for translation, rotation and scale, but also can obtain some important parameters such as rotation angles and movement levels. Therefore, this method solves many problems caused by the unsteadiness of gray features in complex environments and changing illumination. Moreover, it shows a robustness for the condition that there is distortion or damage in the object edges. Finally, an experiment was undertaken with some image sequences from various complex conditions, and the results show that the average accuracy of object detection is over 90%. Even if the distortion or damage of the object edges has been more than 40%, it also can offer a more accurate detection result. These results prove the effectiveness and accuracy of method..
Optics and Precision Engineering
- Publication Date: Sep. 19, 2021
- Vol. 18, Issue 8, 1904 (2010)
Universal modeling method and application for network intelligent sensors based on IEEE 1451
HUANG Guo-jian, LIU Gui-xiong, HONG Xiao-bin, and CHEN Tie-qun
A universal modeling method for network intelligent sensors based on IEEE 1451.0 standard is presented to improve the networking interoperability of intelligent sensors.The universal network intelligent sensor frameworks including static use-case model, dynamic behaviour models and system deployment model are describedA universal modeling method for network intelligent sensors based on IEEE 1451.0 standard is presented to improve the networking interoperability of intelligent sensors.The universal network intelligent sensor frameworks including static use-case model, dynamic behaviour models and system deployment model are described by using Unified Modeling Language(UML). Then, an insulator contamination status online monitoring sensor is rapidly constructed from these frameworks. Research results indicate that the UML-based modeling method could be used to effectively describe the simplified intelligent sensor model based on IEEE 1451 standards.The model shows well universal and expandable characteristics and can correlate different physical interfaces and realize network interoperability.Moreover, the development time for IEEE 1451-based network intelligent sensors has decreased over 60% as compared with those traditional methods..
Optics and Precision Engineering
- Publication Date: Sep. 26, 2021
- Vol. 18, Issue 8, 1914 (2010)
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