Journals >Opto-Electronic Engineering
Contents
2011
Volume: 38 Issue 4
26 Article(s)
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Research Article
An Improved Colorimetric Temperature Measurement Method
XU Bao-chang, and ZHANG Ding-yuan
To improve the accuracy of temperature measurement using CCD image, for the selection of the wavelength impacts the result of the temperature measurement greatly, an improved colorimetric temperature measurement method is proposed, which is independent of the spectroscopic characteristics and the representative wavelenTo improve the accuracy of temperature measurement using CCD image, for the selection of the wavelength impacts the result of the temperature measurement greatly, an improved colorimetric temperature measurement method is proposed, which is independent of the spectroscopic characteristics and the representative wavelengths of the CCD. Using the relationship between color and temperature, three solutions of temperature are obtained, and the temperature value based on the correlation of those temperatures is optimized. Then the optimum temperature is obtained. The improved method not only avoids the measurement errors caused by the wavelength selection, but also makes the calculated values closer to the true value. The experimental results show that, compared with the traditional method, the measurement error of the improved colorimetric temperature measurement method is decreased by 1.16%, and the accuracy and practicality of colorimetric temperature measurement are improved..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 1 (2011)
A Method for Correcting the 2D Calibration Target
LIU Xiao-li, YIN Yong-kai, HE Dong, and PENG Xiang
A novel method for correcting the 2D calibration target is proposed. Firstly, we captured multiple images of the inaccurate calibration target from multi-views and located the coordinates of those circle landmarks in these images. Secondly, homonymous landmarks in different images could be detected by a scheme for a spA novel method for correcting the 2D calibration target is proposed. Firstly, we captured multiple images of the inaccurate calibration target from multi-views and located the coordinates of those circle landmarks in these images. Secondly, homonymous landmarks in different images could be detected by a scheme for a special topology relation. Thirdly, we could accurately reconstruct the 3D coordinates of landmarks with a scale constraint using bundle adjustment strategy. Finally, the scale was computed from an accurate distance between any two landmarks. Then we could obtain the true coordinates of landmarks, which multiplied by the scale. The experimental results validated that our method has the advantages of high-precision, low-cost and easy-implementation, which can be widely applied in vision measurement and system calibration..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 7 (2011)
Methane Concentration Sensor Based on Orthogonal Polarized Light
YANG Wei-hong, LIU Ke-ming, XU Guang-ming, and REN Lan-zhu
Basic principle of methane concentration sensor system was introduced. Methane concentration detection model of difference absorption structure based on orthogonal polarized light was presented. Mathematical model of methane concentration sensor was established. System structure of the sensor was designed and structureBasic principle of methane concentration sensor system was introduced. Methane concentration detection model of difference absorption structure based on orthogonal polarized light was presented. Mathematical model of methane concentration sensor was established. System structure of the sensor was designed and structure of optical path and gas chamber of the sensor was designed. Experimental research on the sensor was carried out. Using the polarizer, the sensor system transformed two difference wavelength monochromatic lights into orthogonal polarized lights, and then made the two orthogonal polarized lights pass the detection gas chamber simultaneously. Finally, the two monochromatic lights were separated by Wollaston prism, and light intensity signal of the two monochromatic lights was collected respectively by photodetectors. The experimental results show that the sensitivity and resolution of the sensor system were improved by using this method. The sensor has good linearity, stability, and strong anti-interference ability. This method has good detection effects..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 12 (2011)
Software Design and Realization for the Pose Relay Measurement System Using Multi-cameras
CHAO Zhi-chao, JIANG Guang-wen, FU Si-hua, and JIN Yan
Traditional videometric approach could not be used to measure the pose deformation of objects in a large viewing field or between intervisible objects in the large structures. Pose Relay Measurement System Using Multi-cameras (PRMSUMC) could be used to overcome the difficulties encountered in applying traditional videoTraditional videometric approach could not be used to measure the pose deformation of objects in a large viewing field or between intervisible objects in the large structures. Pose Relay Measurement System Using Multi-cameras (PRMSUMC) could be used to overcome the difficulties encountered in applying traditional videometric to deformation measurement between non-intervisible objects. First, basic principle of PRMSUMC was discussed. Then, functional module as well as flow chart of the software design was proposed based on the structure of the system’ hardware. Finally, Client software and host software were designed and developed according to the classic Client/Server architecture in Visual C++ platform. A large number of experiments conducted both outdoors and indoors and real ship measurements show that the software system is designed stably and reliably, and it is convenient to use as well as good extendibility..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 17 (2011)
Analysis of Crosstalk between Radial Tilt Error and Tracking Error in Tracking Servo of Blue-ray Disc
ZHANG Jing-jing, WANG Yu-xing, and FENG Shi-meng
Based on diffraction theory and groove and land model with elliptical pits blue-ray disc, the energy distribution on exit pupil was investigated and tracking error signal was obtained by Differential Push Pull (DPP) method when focus spot scanning through the blue-ray disc. Furthermore, the influence of traditional squBased on diffraction theory and groove and land model with elliptical pits blue-ray disc, the energy distribution on exit pupil was investigated and tracking error signal was obtained by Differential Push Pull (DPP) method when focus spot scanning through the blue-ray disc. Furthermore, the influence of traditional square pits and elliptical pits disc radial tilt on tracking error signal was compared. Result shows that ultra-high density disc for 50 GB blue-ray disc is very sensitive to radial tilt. In order to make sure that the disk is read correctly, the allowable radial tilt angle should be less than 0.15o..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 25 (2011)
An Active Disturbance Rejection Controller in the Servo System of an Air-borne Opto-electronic Tracking Platform
ZHOU Tao, and ZHU Jing-cheng
The friction nonlinearity in the servo system of an air-borne opto-electronic tracking platform causes creeping phenomena in the lower velocity and increases the steady error of the servo system. It is difficult for the routine PID controller to satisfy performance specifications of the high precision servo system of tThe friction nonlinearity in the servo system of an air-borne opto-electronic tracking platform causes creeping phenomena in the lower velocity and increases the steady error of the servo system. It is difficult for the routine PID controller to satisfy performance specifications of the high precision servo system of the opto-electronic tracking platform. An Active Disturbance Rejection Controller (ADRC) with a new control function of the second-order discrete system is studied. The new ADRC is used as the position-loop controller in the servo system of the air-borne opto-electronic tracking platform. The experimental results show that the position tracking error of the servo system is less than ±(4.1×10-3)° and the velocity tracking error is less than ±0.024°/s after 0.5 second when the servo system tracks the sine input signal whose amplitude is 0.5° and frequency is 0.159 Hz. They demonstrate that the ADRC increases the position and the velocity tracking precision of the servo system through effective compensating the friction nonlinearity..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 31 (2011)
Coordinates-decoupling of Multidimensional Precision Optical Adjusting Frame
LUO Yong
In optical alignment, because quantizing and compensating of the coupling relation keeps a problem, the coordinates coupling is usually ignored, resulting in adjusting error in accurate optical adjusting. Through modeling and simulation, the coupling relation of each adjusting freedom of a multidimensional precision opIn optical alignment, because quantizing and compensating of the coupling relation keeps a problem, the coordinates coupling is usually ignored, resulting in adjusting error in accurate optical adjusting. Through modeling and simulation, the coupling relation of each adjusting freedom of a multidimensional precision optical adjusting frame is analyzed in detail. Through decomposed transformation of each adjusting freedom, the coupling relation between each adjusting freedom is compensated and corrected. Test result shows that: by using this method, the error between expected optical adjusting value and actual mechanical adjusting value can be reduced effectively, and more accurate optical adjusting is achieved..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 37 (2011)
Radius/Center Constraint Fuzzy C-spherical Shell Clustering Algorithm
LI Mao-kuan, JIANG Tao, and GUAN Jian
A radius/center constraint Fuzzy C-Spherical Shell clustering (FCSS) algorithm is presented for the circle detection problem in digital image processing and computer vision. FCSS substitutes spherical shells for points as the prototype based on conformal geometric algebra, and the inner product of patterns and sphericaA radius/center constraint Fuzzy C-Spherical Shell clustering (FCSS) algorithm is presented for the circle detection problem in digital image processing and computer vision. FCSS substitutes spherical shells for points as the prototype based on conformal geometric algebra, and the inner product of patterns and spherical shells in conformal space is equal to the distance from the patterns to spherical shells. Meanwhile, FCSS represents the membership between the patterns and its spherical shells by the introduction of fuzzy membership. Then the objective function for radius/center constraint FCSS clustering analysis is expressed, and a unified solution to minimize this constraint objective function is deduced. Experimental results of both artificial data and real image have proved that the clustering algorithm can cluster the spherical shell type data and detect circles in image effectively..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 41 (2011)
More Precise Determination of Band Gap via Optical Spectra Using Natural Way
LIU Chang-shi
Based on Tauc relation produced by energy conservation, one model with three parameters is developed to determinate band gap, Eg, by optical spectroscopy more precisely and reliably. Band gap, the index n stand for the nature and useful diagnostic A of material appear as parameter in this natural method. Thus, when nonBased on Tauc relation produced by energy conservation, one model with three parameters is developed to determinate band gap, Eg, by optical spectroscopy more precisely and reliably. Band gap, the index n stand for the nature and useful diagnostic A of material appear as parameter in this natural method. Thus, when non-linear fitting in the direction of least-square is finished, these key label Eg, n and A can be obtained accurately and reliably. Application results of model described above demonstrate that this method is most accurate, easiest and fast for energy band gap determination. Hence, this work makes the prediction of band gap and index of materials nature of materials more precise and reliable..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 48 (2011)
Effect of Spectral Pretreatment on Near Infrared Spectroscopy for Rapid Detection of Wine Alcohol
ZHOU Yang, DAI Shu-guang, LU Jin, LIU Tie-bing, and SHI Yang
A study of the Near Infrared Spectroscopy of rice wine is studied, with the purpose to discuss the impact of spectral pretreatment methods on wine alcohol rapid quantitative model, and to compare and analyze the effects of Partial Least Squares quantitative model of spectroscopy after the five traditional methods whichA study of the Near Infrared Spectroscopy of rice wine is studied, with the purpose to discuss the impact of spectral pretreatment methods on wine alcohol rapid quantitative model, and to compare and analyze the effects of Partial Least Squares quantitative model of spectroscopy after the five traditional methods which include smoothing, first derivative, second derivative, multiplicative scatter correction and standard normal transform and the three new methods which contain wavelet transform, Fourier transform and orthogonal signal correction. The results indicates that the cross-validated R=0.998 and RMSECV=0.135 7 after the orthogonal signal correction is superior to the other pretreatment methods. Therefore, pretreatment with the noise reduction performance is superior to pretreatment with the sharpening performance which illustrate that the random noise of the spectrum is a major influence factor on model accuracy. The results provide an effective pretreatment method for establishing a stable near infrared spectroscopy fast quantitative model for alcohol content of rice wine, and it also offers a reference for rice wine quality online fast detection..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 54 (2011)
Extraction and Analysis of Targets’ Imaging Features in Astronomical Opto-electronic Image Sequences
HUANG Zong-fu, HAN Jian-tao, and CHEN Zeng-ping
In the image sequences obtained by astronomical opto-electronic observation system with large field of view on terrestrial surface, the image characteristics of space targets and large amount of stars are similar. Most targets appear weak and small. The valid reliable recognition of targets must be based on the tiny diIn the image sequences obtained by astronomical opto-electronic observation system with large field of view on terrestrial surface, the image characteristics of space targets and large amount of stars are similar. Most targets appear weak and small. The valid reliable recognition of targets must be based on the tiny difference of features between them. Firstly, according to the view of space domain and time domain, the imaging features of targets are classified as static features and dynamic features, and the methods of calculating corresponding feature values are proposed in detail. Then combined with large quantity of real-measured data, the imaging features of space targets and stars are deeply analyzed with the feature-extraction result, especially the contrast of features between them are particularly described. The imaging feature extraction and analysis of space targets and stars provide many decision proofs to eliminate false space targets, and they help to realize the detection and recognition of space targets with very low false alarm rate..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 59 (2011)
Design and Research of the Sun Sensor Based on the Technology of the Optical Fiber
LI Dan, ZHOU Wang, and LI Ye
Based on the technology of optical fiber, an analog sun sensor was designed. It consists of three parts: the optical head, optic-electronic sensor and the measurement and calculation of sun angle. The optical design of the sun sensor adopts two pairs of optical fiber and a central optical fiber, and then obtains the reBased on the technology of optical fiber, an analog sun sensor was designed. It consists of three parts: the optical head, optic-electronic sensor and the measurement and calculation of sun angle. The optical design of the sun sensor adopts two pairs of optical fiber and a central optical fiber, and then obtains the relative angular relationship between the sun and the spacecraft's own coordinate system by calculating the difference value of importing light of each pair of optical fiber. The optical structure can suit multi-fields of view, including both small and large. It can increase the accuracy of the positioning system. Optical fiber was used as a leader, which connected the optic-electronic sensor inside the spacecraft. Keeping the sensor deep inside the spacecraft will protect the sensor from being damaged by high-energy particle in space. Circuit and signal processing were briefly described, and compensation of the error was analyzed. Preliminary test has shown that the system accuracy can reach ±0.15 degrees. This sun sensor is particularly applicable to attitude control system of spacecraft and solar tracking system on ground..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 66 (2011)
Transmission Properties of Subwavelength Period Hole Arrays
SUN Mei, XU De-gang, and YAO Jian-quan
The samples of subwavelength hole arrays in metallic films are designed in order to verify the important role of periodicity in enhanced transmission of light. The samples were fabricated by Electron Beam Lithography (EBL), Focused Ion Beam (FIB) and Reactive Ion Etching (RIE) system. The comparison of optical transmisThe samples of subwavelength hole arrays in metallic films are designed in order to verify the important role of periodicity in enhanced transmission of light. The samples were fabricated by Electron Beam Lithography (EBL), Focused Ion Beam (FIB) and Reactive Ion Etching (RIE) system. The comparison of optical transmission for the square and hexagon hole arrays shows that the SPPs play the important role in enhanced transmission. We further study the transmission through periodic H-shaped arrays in metallic thin films. The position of transmission peak shifts to the short wavelength by about 140 nm when the line width of H-shaped structure is increased from 120 nm to 200 nm. Our experiment and theory confirm again that the SPPs are the dominant element of the enhanced transmission. The simulation by using Transfer Matrix Method (TMM) reproduces quite well the obtained transmission spectrum..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 72 (2011)
Property and Sensor Performance of Photonic Crystal Surface Wave with Prism Coupling
QIAN Lin-bo, ZHOU Jun, JIN Li, LIN Hao, and GAO Yong-feng
One-dimensional photonic crystal with prism coupling is constructed, and its transmission property and structure are simulated by transmission matrix. Result show: there is a surface wave on the prism coupling photonic crystal. Moreover, the angle site, reflectivity and Full Width at Half Maximum (FWHM) in the reflecteOne-dimensional photonic crystal with prism coupling is constructed, and its transmission property and structure are simulated by transmission matrix. Result show: there is a surface wave on the prism coupling photonic crystal. Moreover, the angle site, reflectivity and Full Width at Half Maximum (FWHM) in the reflected spectrum of the surface wave will change when the refractive index and thickness of medium change. Besides, this surface wave is very sensitive to the property of the outmost layer. These properties are useful for designing high accuracy sensor..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 77 (2011)
Optical Thin Films Design Using Digital Filters Method
WANG Xu, FENG Zhi-rong, HU Zong-hua, CHEN Xiu-li, and WANG Quan-hui
Design method for the optical thin film with digital filters method is given. The optical thin films purpose spectra transfer function is obtained by utilizing the digital filters design software. Turning the math form of optical thin film transfer matrix to the lattice digital filters, the recursive relationship betweDesign method for the optical thin film with digital filters method is given. The optical thin films purpose spectra transfer function is obtained by utilizing the digital filters design software. Turning the math form of optical thin film transfer matrix to the lattice digital filters, the recursive relationship between the coefficients of the transfer function is got from the purpose transfer function. The film’s refractive index of each layer fit for the purpose spectra is designed with layer-peeling method by the recursive relationship. Two examples of four layers anti-reflective and eight layers reflective films design with equal optical thickness are given by this method..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 82 (2011)
Multi-focus Image Fusion Using Dual-tree Contourlet and Compressed Sensing
JIN Wei, FU Ran-di, YE Ming, and LI Jin-xiang
In order to expand the capability of Compressed Sensing (CS), a fusion method for multi-focus image using Dual-tree Contourlet (DT-Contourlet) and CS is proposed. First, the source images are decomposed using DT-Contourlet for extracting multiscale and direction information while overcoming the limitation of traditionaIn order to expand the capability of Compressed Sensing (CS), a fusion method for multi-focus image using Dual-tree Contourlet (DT-Contourlet) and CS is proposed. First, the source images are decomposed using DT-Contourlet for extracting multiscale and direction information while overcoming the limitation of traditional contourlet which is lack of shift invariance. Then, in DT-Contourlet domain, the decomposition coefficients are treated as containing two components, i.e., dense and sparse components. The dense components are fused using selection method by introducing neighborhood gradient as clarity index to indicate the characteristics of defocus. The sparse components are fused under the framework of CS via fussing a few linear measurements by solving the problem of L1 norm minimization which is based on a two-step iterative shrinkage/threshold reconstruction algorithm. The experiments demonstrate that the convergence rate of reconstruction is faster than that of orthogonal matching pursuit. Meanwhile, the proposed method provides more satisfactory fusion results in terms of visual quality and quantitative criterion..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 87 (2011)
Raw-echo-based Channel Balancing Algorithm for SAR-GMTI
QIAN Jiang, Lü Xiao-lei, LI Liang-hai, YANG Min, and XING Meng-dao
The channel mismatch problem was investigated in multi-aperture Synthetic Aperture Radar (SAR). A channel balancing technique based on the two-stage filters in the different raw data domains was presented. The amplitude and phase filter in the range Doppler domain corresponds to the antenna beam pattern difference, andThe channel mismatch problem was investigated in multi-aperture Synthetic Aperture Radar (SAR). A channel balancing technique based on the two-stage filters in the different raw data domains was presented. The amplitude and phase filter in the range Doppler domain corresponds to the antenna beam pattern difference, and the filter in the range frequency azimuth time domain corresponds to the frequency response difference. In the first stage filtering process, we constructed an adaptive filter in the region with higher coherence, and a non-adaptive one in the noise dominated region to remove the deterministic difference between channels. In the second stage filtering process, the noise was removed and only the target signatures were left. The feasibility of the channel balancing algorithm carried out in the raw data domain is demonstrated with the measured airborne data..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 95 (2011)
Realization of Fast-high-quality Image Rotation Using Block Division
LI Bing, WANG Yun-kuan, HUANG Wei, WU Shao-hong, and LIU Hai-long
A novel algorithm called block division for fast image rotation with accuracy guarantee was proposed. In our algorithm, we only rotate a small region of rotated image and get entire rotated image by simple coordinate transformations. For convenient hardware implementation, we propose Dart model to store the informationA novel algorithm called block division for fast image rotation with accuracy guarantee was proposed. In our algorithm, we only rotate a small region of rotated image and get entire rotated image by simple coordinate transformations. For convenient hardware implementation, we propose Dart model to store the information of affine transformations in advance, and combine this model with the technology of block division to eliminate float calculation. Tests shows that the proposed algorithm can realize high-accuracy and high-speed image rotation..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 103 (2011)
A Fast Image Enlargement Method Based on Curvature-driven Quasi-bilinear Interpolation
LU Jin-zheng, ZHANG Qi-heng, XU Zhi-yong, and PENG Zhen-ming
To satisfy fast image zooming requirement with preserving edge-sharpness, a quasi-bilinear algorithm based on profile curvature of brightness surface is introduced. Firstly, in view of inherent low-pass property of bilinear, an amendatory formula is established via including pixel variation. Then, for obtaining the domTo satisfy fast image zooming requirement with preserving edge-sharpness, a quasi-bilinear algorithm based on profile curvature of brightness surface is introduced. Firstly, in view of inherent low-pass property of bilinear, an amendatory formula is established via including pixel variation. Then, for obtaining the dominant direction of neighboring pixels, image coordinate and its brightness are treated as surface when gray value being simulated as altitude of earth surface. Lastly, magnitudes of curvatures of specified direction is regarded as adjustment reference of structures type of image, such as edge or texture. Therefore, weights of direction of a pair of two pixels average can be adaptively evaluated according to several thresholds of curvatures. Experiment results of synthetic data demonstrate that, compared with other similar techniques, Power Signal to Noise Ratio (PSNR) gain of image twice-interpolated is 7.8 dB, and improvement of Structural Similarity (SSIM) is 0.1. Especially, arithmetic type of proposed algorithm is simple, and its complexity is relatively low, thus it is convenient to real-time application over fixed platform..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 108 (2011)
Region of Interest Extraction Algorithm of Color Image Based on Visual Perception Information
LI Shuang, LIU Wei, XU Wei-dong, LI Li-hua, KE Er-ting, WU Li, and Bin ZHENG
A Region of Interest (ROI) extraction algorithm of color image is proposed, which is based on the classical seeded region growing method guided by eye-tracking perception information. Based on the analysis of subjects’ eye-tracking data, the proposed algorithm can generate the interesting points automatically, whose neA Region of Interest (ROI) extraction algorithm of color image is proposed, which is based on the classical seeded region growing method guided by eye-tracking perception information. Based on the analysis of subjects’ eye-tracking data, the proposed algorithm can generate the interesting points automatically, whose neighborhood information is then used to obtain a series of initial ROIs by color homogeneity criterion in specific color space. The final ROI is picked up from the initial ROIs according to the viewer’s attentive degree. The proposed algorithm is tested in RGB, HSV and L*a*b color space. Experimental results show that the proposed algorithm using in RGB and HSV color space can accord human’s subjective perception, and have certain application value..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 115 (2011)
Solution of Nozzle Radiative Transfer Based on the Hybrid Finite Volume/Finite Element Method
JIN Wei, and Lü Xiang-yin
For the radiative transfer problem in irregular three-dimensional non-gray absorbing media, the hybrid finite volume/finite element method was adopted to solve it. The calculating process of the hybrid method was deduced in orthogonal coordinates. Combining the theory of vector and matrix, the finite element equation gFor the radiative transfer problem in irregular three-dimensional non-gray absorbing media, the hybrid finite volume/finite element method was adopted to solve it. The calculating process of the hybrid method was deduced in orthogonal coordinates. Combining the theory of vector and matrix, the finite element equation general composition method coupling boundary condition was given. The radiative transfer of the attitude thruster nozzle expending segment and its interior absorbing media were regarded as the object to be solved. The spectral radiative luminance and 3~5 μm band radiative heat flux at the nozzle exiting section were obtained by adopting the method. Compared with the calculating results of the finite volume method, while the discrete value of the space or the angle is increased, the same point source spectral radiative luminance obtained by the two methods will get more and more closely. It is shown that the radiative transfer in irregular three-dimensional non-gray absorbing media can be solved by the hybrid finite volume/finite element method accurately..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 124 (2011)
A New Modulation Scheme of Free-space Optical Communication
LENG Jiao-feng, HAO Shi-qi, WANG Yong, LI Jin-ming, and Lü Xu-guang
A new modulation scheme called Dual-Duration-Multi-Pulse Position Modulation (DDMPPM) is proposed for free-space optical communication systems by resolving the problems which exist in Pulse Position Modulation (PPM) and Differential Pulse Position Modulation (DPPM). After introducing symbol structure, information transA new modulation scheme called Dual-Duration-Multi-Pulse Position Modulation (DDMPPM) is proposed for free-space optical communication systems by resolving the problems which exist in Pulse Position Modulation (PPM) and Differential Pulse Position Modulation (DPPM). After introducing symbol structure, information transmission rate, bandwidth requirement and average transmission power are studied. Meanwhile, the packet error rate is analyzed based on weak turbulence channel mode. After compared with On-off Keying (OOK), PPM, MPPM, PWM and DPPM, the theoretical and simulation results show that the Packet error rate of DDMPPM, which corresponds to MPPM, is higher than that of PPM and DPPM, but obviously less than OOK and PWM. DDMPPM has no problem such as overflow and underflow in the buffer by fixing the symbol length, and has built-in symbol synchronization. Hence, DDMPPM is superior in free space optics communication systems..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 130 (2011)
A Driving Circuit Design for High Frame Rate EMCCD
WANG Ming-fu, YANG Shi-hong, WU Qin-zhang, and XIA Mo
In order to meets the high frame rate and high sensitivity needs of wavefront sensor in adaptive optics systems, an external driving circuit for E2V’s high frame rate and low-light EMCCD chip CCD60 was designed. This system used FPGA to generate the primary control logics and all of timing signals, and used pin driver In order to meets the high frame rate and high sensitivity needs of wavefront sensor in adaptive optics systems, an external driving circuit for E2V’s high frame rate and low-light EMCCD chip CCD60 was designed. This system used FPGA to generate the primary control logics and all of timing signals, and used pin driver EL7156 to generate the special driving signals of CCD60 from FPGA’s TTL logical signals. High voltage sine driving signal was used to drive high-voltage gain gate, which was generated by Direct Digital Synthesizer (DDS) and amplified by a novel high-voltage amplifier module. The range of designed high voltage sine driving signal can be real-timely adjusted and worked very well when generating electron gain. The design of the driving circuit has been successfully applied in CCD60 high frame rate and low-light imaging system..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 135 (2011)
Method of Dove Lens Assembling and Adjustment Based on Optical Alignment Machining
ZHANG Xue-min, WEI Ru-yi, HOU Xiao-hua, DUAN Jia-you, and LI Hua
In order to ensure the parallelism between the optical axis of dove prism and its rotation axis, a method based on the reversing image theory of Dove prism and the optical alignment machining was described. This method takes advantage of the optical property that the direction of the output beam changes with the rotatiIn order to ensure the parallelism between the optical axis of dove prism and its rotation axis, a method based on the reversing image theory of Dove prism and the optical alignment machining was described. This method takes advantage of the optical property that the direction of the output beam changes with the rotation axis diversion of Dove prism to determine the optical axis of Dove prism, and ensures the parallelism between the rotation axis of cylinder with the optical axis of Dove prism by using metal-turning. Two methods which are used to determine the optical axis of Dove prism was proposed. These two methods can ensure the parallelism between the reflecting surface axis of dove prism and its rotating axis, and the accuracy of axis determining is better than 0.01 mm..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 141 (2011)
An Applied Method for Reading Recognition of Index-instrument
TAO Bing-jie, HAN Jia-le, and LI En
As to the identification and calibration of index-instrument, a novel method for reading recognition based on digital image processing is proposed. Firstly, preprocessing operation on images is done, including image segmentation, image filtering, image dilation and thinning etc, and a method of improved adaptive medianAs to the identification and calibration of index-instrument, a novel method for reading recognition based on digital image processing is proposed. Firstly, preprocessing operation on images is done, including image segmentation, image filtering, image dilation and thinning etc, and a method of improved adaptive median filter is adopted to improve the image. Then, characteristic information of image is extracted with the improved dual thresholds Hough transformation, and the pointer reading is got using the linear relationship between scale and angle of instrument dial revolutionary. And as to the situation that pointer coincides with the whole tick, late correction has been done. The experiment results show that the algorithm is very valid for the pointer angle recognition, and has higher precision and real time. It has strong practical application value..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 4, 145 (2011)
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