Journals >Opto-Electronic Engineering
Contents
2011
Volume: 38 Issue 2
25 Article(s)
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Research Article
Analysis of Trapping Forces Combining Near-field Optical Tweezers with AFM Probe
LIU Bing-hui, YANG Li-jun, WANG Yang, and YUAN Ju-long
Recently, interest in nano-manipulation using the evanescent wave generated by near-field optical probes has been growing. The possibility of using the metallic tip of an atomic force microscope illuminated by evanescent wave from a fiber probe to create optical tweezers for selective manipulation of nano-particles is Recently, interest in nano-manipulation using the evanescent wave generated by near-field optical probes has been growing. The possibility of using the metallic tip of an atomic force microscope illuminated by evanescent wave from a fiber probe to create optical tweezers for selective manipulation of nano-particles is explored. A generalization of the conservation law for momentum using three-dimensional finite difference time domain method for rigorous calculations is applied to analyze near-field trapping forces. Calculations show that the scheme is able to trap smaller particle with lower laser intensity than that required by conventional near-field optical tweezers. The trapping potential is sensitively dependent on the distance between two probes and incident angle, as well as the incident polarization direction and wavelength. Based on the high manipulation efficiency and the high resolution of AFM system, the scheme allowing for effective and accurate manipulation of nano-particles opens a way for research on single nano-particle area..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 1 (2011)
Nonlinear Innovation Adaptive Kalman Filter Algorithm for Electro-optical Tracking
WANG Qiu-ping, ZUO Ling, and KANG Shun
In order to solve the problem of accuracy decline caused by the linearization error in nonlinear reduced state Kalman filter, a new nonlinear adaptive reduced state Kalman filter algorithm is provided by using UT transformation to calculate the covariance of the system state error and modify adaptively the system noiseIn order to solve the problem of accuracy decline caused by the linearization error in nonlinear reduced state Kalman filter, a new nonlinear adaptive reduced state Kalman filter algorithm is provided by using UT transformation to calculate the covariance of the system state error and modify adaptively the system noise covariance based on innovation, and the algorithm structure is summarized in detail. Then, the algorithm is applied in nonlinear measurement electro-optical tracking system and the performances of nonlinear adaptive reduced state Kalman filter were compared with unscented Kalman filter and nonlinear reduced state Kalman filter. The Matlab simulation results show that applying UT transformation and modifying adaptively the system noise covariance based on innovation in reduced state Kalman filter is valid, and the performance outperforms those of the unscented Kalman filter and nonlinear reduced state Kalman filter.技术。.
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 9 (2011)
Fish Motion Tracking Research Based on Video Algorithm
CHENG Shu-hong, CAI Jing, and HU Chun-hai
Aiming at the problem of water environment protection using fish motion tracing, the fish motion monitor research is proposed based on the video algorithm. It can obtain trajectory and velocity of the fish by means of segmentation and tracing of the fish motion video, which lie a theory foundation for the fish to partiAiming at the problem of water environment protection using fish motion tracing, the fish motion monitor research is proposed based on the video algorithm. It can obtain trajectory and velocity of the fish by means of segmentation and tracing of the fish motion video, which lie a theory foundation for the fish to participate in the environment pollution research (through the comparison of some parameters of the fish motion in different polluted environment, to carry out quantitative analysis of the water pollution degree). The algorithm uses marker multi-scale watershed method for fish motion segmentation, then tracks the fish motion video with the improved weighted-Hausdorff. Finally, in order to accommodate the shape change of the fish in the moving process, introduce the Euclid norm into multi-value images as the restriction to accomplish the update of the tracing model. The experiment shows that the proposed method presents the state of stable tracking, the position shift in the tracking of the successive 100 frame is within a pixel, and the tracing velocity difference is within 0.12 pixels, which can segment and track the fish motion object fleetly and precisely..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 14 (2011)
Spatiotemporal Interactive Multi-camera Object Tracking with Bayesian Inference
FAN Jing-jing, HU Bo, and FENG Wei
A novel algorithm is proposed to perform object tracking with multiple cameras in the Bayesian Inference framework. Firstly, Bayesian network is used to model the system of multiple static cameras’ tracking system. Then, the high-dimensional joint posterior of the state (object location) is propagated spatiotemporally.A novel algorithm is proposed to perform object tracking with multiple cameras in the Bayesian Inference framework. Firstly, Bayesian network is used to model the system of multiple static cameras’ tracking system. Then, the high-dimensional joint posterior of the state (object location) is propagated spatiotemporally. Finally, the estimation of the target location in each camera view is achieved by using an efficient message passing mechanism with sequential Monte Carlo Approximation (particle filter) of the joint posterior. Meanwhile, by taking full advantage of image data and position data from multiple cameras, the tracking algorithm is very robust to occlusion in some cameras of the system. Both qualitative and quantitative experiments have demonstrated the effectiveness and robustness of the proposed algorithm..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 19 (2011)
Detection Analysis and Fuzzy Recognition Investigation for Lightning Signal
XIANG Zhen, LIU Ming, LI Peng, ZHENG Yi, and FAN Jiang-bing
Simultaneous detection and location system of lightning optical and electrical signals based on DSP system were used to detect the optical and electrical signals simultaneously in Hangzhou, August, 2009. The detected data are analyzed statistically by time domain characteristics, and statistical results on initial timeSimultaneous detection and location system of lightning optical and electrical signals based on DSP system were used to detect the optical and electrical signals simultaneously in Hangzhou, August, 2009. The detected data are analyzed statistically by time domain characteristics, and statistical results on initial time difference, peak time difference, rise time difference and pulse widths difference between the optical and electrical signals are obtained. The results show that the lightning optical signal is always delayed from the electrical signal on onset and peak time, and the optical pulse rises more slowly to the peak and its pulse-width is broader. The four characteristics of in-cloud flash are all larger than that of Cloud-ground flash. At last, based on fuzzy mathematics, and the above four characteristics as the fuzzy recognition characteristics, fuzzy membership function is established, by which the pattern recognition of lightning is researched and the recognition rate achieves 95%..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 28 (2011)
Electric Target Based on Non-diffracting Beam and Error Analysis
CHEN Hui, and ZHAO Bin
A new electronic target based on the principle of the non-diffracting beam is proposed for guidance of shield machine. The spot center location of the incident laser of the total station in CCD fixed in the electronic target and the angle data of the total station are combined by constituting mapping database. The actuA new electronic target based on the principle of the non-diffracting beam is proposed for guidance of shield machine. The spot center location of the incident laser of the total station in CCD fixed in the electronic target and the angle data of the total station are combined by constituting mapping database. The actual attitude angles of the electronic target and the center of the head of shield machine are computed by mapping database and the angles of electronic gradienter. The errors of the total station and components of the electronic target in measuring process are analyzed. The errors of attitude angles and the center of the head of shield machine are derived. The result shows that the measuring precision of the head of shield machine by the electronic target could reach a millimeter-level, which could meet the requirement of the shield machine guidance precision..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 34 (2011)
Technology of Detecting Verdet Constant of Solute Separately and Its Applications
SHEN Xiao, and LIANG Zhong-cheng
The separate detecting system of detecting Verdet constant of solute is designed based on Faraday effect principle. The detection technology can eliminate the impact of the background rotation such as solvents and containers to achieve the purpose of detecting Verdet constant of solute separately. The system used signaThe separate detecting system of detecting Verdet constant of solute is designed based on Faraday effect principle. The detection technology can eliminate the impact of the background rotation such as solvents and containers to achieve the purpose of detecting Verdet constant of solute separately. The system used signal amplification processing technology based on a pair of optical paths to improve the system's detection sensitivity. Analyzed the detection accuracy and error of the system, the results shows that the detection accuracy is related to the accuracy with magnification of the division amplifier and Verdet constant of the reference material and sample material; and the relative error from the approximated calculation of small-angle is small. The technology of detecting the mixed solution concentration is researched under the relationship between the Verdet Constant and the concentration of the solute..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 41 (2011)
Pyroelectric Arrays with Relax-based Ferroelectric Single Crystals
SHAO Xiu-mei, MA Xue-liang, YU Yue-hua, and FANG Jia-xiong
PMN-PT single crystal is a novel pyroelectric material with superior performances. An 8×1 linear array was designed, and research on the key processes of device fabrication was carried out based on PMN-PT crystal. The responsivity of the 8×1 chip was about 280 V/W. At the same time, the 8×1 pyroelectric PMN-PT single crystal is a novel pyroelectric material with superior performances. An 8×1 linear array was designed, and research on the key processes of device fabrication was carried out based on PMN-PT crystal. The responsivity of the 8×1 chip was about 280 V/W. At the same time, the 8×1 pyroelectric chip was coupled with an 8×1 read-out circuit. The performance of the 8×1 FPA was studied. The pyroelectric signal of the FPA device can’t be measured because the read-out circuits respond to visible light. The design of read-out circuits needs to be improved. The results of the paper lay a foundation for the development of large-scale uncooled pyroelectric FPA based on novel ferroelectric single crystals..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 46 (2011)
An Image Adaptive Semi-fragile Watermarking Algorithm Based on Visual Perception
YANG Heng-fu, and SUN Guang
An image adaptive semi-fragile watermarking algorithm was proposed by considering the human visual perception. First, the bit depth to be embedded was determined by exploiting the luminance, and texture masking characteristics. Then, the watermark is embedded into the host image with adaptive least significant Bit subsAn image adaptive semi-fragile watermarking algorithm was proposed by considering the human visual perception. First, the bit depth to be embedded was determined by exploiting the luminance, and texture masking characteristics. Then, the watermark is embedded into the host image with adaptive least significant Bit substitution. The watermark strength is dependent on the host image features due to the use of the visual perception features. Finally, an optimal pixel adjustment process is used to further enhance the transparency. Experiment results show that the proposed algorithm is sensitive to malicious attacks while robust to incidental attacks, and can classify effectively the type of attacks encountered on the watermarked image. When compared with some existing semi-fragile watermarking methods, the proposed scheme achieves about 2.90 dB higher PSNR..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 51 (2011)
Salt and Pepper Noise Filter Based on GA-BP Algorithm Noise Detector
SONG Yin-mao, and LI Xiao-juan
Noise detection-based median filters have been widely adopted to reduce salt and pepper noise in images. However, since noise pixel is not detected accurately, it is likely to blur the fringe of image under the case of high noise density. An algorithm of salt and pepper noise filter is proposed that is based on GA-BP aNoise detection-based median filters have been widely adopted to reduce salt and pepper noise in images. However, since noise pixel is not detected accurately, it is likely to blur the fringe of image under the case of high noise density. An algorithm of salt and pepper noise filter is proposed that is based on GA-BP algorithm noise detector to remove the salt and pepper noise in images. The algorithm firstly detects noise pixel’s location in image by using optimized GA-based BP network. Then, it introduce edge-preserving function and PRP algorithm to solve the objective function of extreme value and realize the image denoising. Compared with the traditional algorithms, experimental results show that the proposed algorithm has an evident improvement, and good characters of generalization, robust and self-adaptive..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 59 (2011)
Automatic Matching Strategy Based on SIFT
ZENG Luan, ZHAI You, and TAN Jiu-bin
For the purpose of actualizing automatic image matching, a new Scale Invariant Feature Transform (SIFT) matching strategy is presented. Firstly, compared with the given basal ratio of Euclidean distance from the closest neighbor to the distance of the second closest of features, the coarse matching collection of SIFT iFor the purpose of actualizing automatic image matching, a new Scale Invariant Feature Transform (SIFT) matching strategy is presented. Firstly, compared with the given basal ratio of Euclidean distance from the closest neighbor to the distance of the second closest of features, the coarse matching collection of SIFT is obtained. Then, obtain the histogram of coarse matching corresponding points’ main direction angle differences and the histogram of minimum Euclidean distances. The precise matching is taken under the conditions that the main direction angle differences fall into the neighborhood of histogram’s peak value. And the minimum Euclidean distance is smaller than the corresponding distance of histogram’s main peak. Finally, obtain the histogram of precise matching corresponding points’ ratio. The false matching is eliminated under the conditions that the ratio of Euclidean distance from the closest neighbor to the distance of the second closest is smaller than the corresponding ratio of histogram’s main peak. The experimental results prove that the proposed method is stable and reliable even if the image has some view point, illumination, rotation and scale variation. The proposed method can select the matching threshold automatically without manual intervention..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 65 (2011)
An Adaptive Single Scale Retinex Scheme for Image Enhancement Based on Luminance
LIU Gao-ping, and ZHAO Meng
To deal with the ‘graying out’, ‘noise enlargement’ and ‘halo’ effects existing in classical Retinex image enhancement algorithms, an adaptive single scale Retinex scheme based on luminance is proposed. The edge information is incorporated into the Gaussian filter to restrain ‘halo’ and ‘noise enlargement’ effects, in To deal with the ‘graying out’, ‘noise enlargement’ and ‘halo’ effects existing in classical Retinex image enhancement algorithms, an adaptive single scale Retinex scheme based on luminance is proposed. The edge information is incorporated into the Gaussian filter to restrain ‘halo’ and ‘noise enlargement’ effects, in which the filtering is carried out with adjacent pixels possessing the same characteristics. The original luminance is added to the obtained reflectance to restrain ‘graying out’ and ‘noise enlargement’ effects. Compared with other algorithms, the simulation results indicate that the proposed adaptive single scale Retinex scheme based on luminance can acquire more details, less ‘halo’, less noise and better color fidelity..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 71 (2011)
Feature Matching Based on Balanced Probabilistic Model and Its Application
CHEN Ying, and AI Chun-lu
A new algorithm of feature matching is proposed after balancing analysis of adjacency matrix of the matching model in a probabilistic framework. A probabilistic model is established and solved using Random Walks with Restart(RWR). Then a balancing analysis to the adjacency matrix of RWR is taken, and an efficient methoA new algorithm of feature matching is proposed after balancing analysis of adjacency matrix of the matching model in a probabilistic framework. A probabilistic model is established and solved using Random Walks with Restart(RWR). Then a balancing analysis to the adjacency matrix of RWR is taken, and an efficient method for bidirectional balance is presented. The approach considers not only all the interaction of the two candidate feature point sets and the weight of each relevance, but also the balancing of all relevance weight. It improves the discriminative and accuracy performance of matching. The experimental results confirm that the method is robust to outliers and geometric deformation, accurate in terms of matching rate in various matching applications, and robust and practicable in the object location and the object recognition..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 78 (2011)
An Adaptive Autofocus Method Using No-reference Structural Sharpness
XIE Xiao-fu, ZHOU Jin, and WU Qin-zhang
An adaptive mountain-climb searching strategy based on No-Reference Structural Sharpness (NRSS) of single image is proposed for autofocus system. This new method utilizes the prior knowledge on defocusing amount provided by NRSS. If the imaging system is greatly defocused, a large step-size is used to approach the focuAn adaptive mountain-climb searching strategy based on No-Reference Structural Sharpness (NRSS) of single image is proposed for autofocus system. This new method utilizes the prior knowledge on defocusing amount provided by NRSS. If the imaging system is greatly defocused, a large step-size is used to approach the focusing position quickly; otherwise, a small step-size is used to locate the focusing position accurately. This method has the same focusing accuracy to mountain-climb strategy, and it greatly decreases the number of images and the number of decision makings that are required. The experimental results indicate that the proposed method improves the speed of autofocus about 50%..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 84 (2011)
Algorithm Research of Finger Vein Authentication
LIN Chun-yi, ZHOU Yu-jian, and CHEN Qing-wu
A full set of algorithms on image processing and recognition for finger vein authentication was proposed. A new image normalization algorithm was designed. During normalization, a Sobel operator incorporating the first meet tracing was used to detect finger edges, and then image correction with rotation was done after A full set of algorithms on image processing and recognition for finger vein authentication was proposed. A new image normalization algorithm was designed. During normalization, a Sobel operator incorporating the first meet tracing was used to detect finger edges, and then image correction with rotation was done after the finger edges were fitted under the least mean-square error principle. Based on maximum curvature models, finger vein was extracted by using four direction gradient operators. To decrease False Rejection Rate (FRR) and increase recognition rapid, after expanded, the image was segmented with three levels and compressed to become a more compact vein pattern including finger vein, background and vague parts. At last, a new matching algorithm with point to point between mask and test patterns was put forward. Our experiments verify that our methods outperform traditional ones on speed and effectiveness. Its recognition rate is up to 100%, with a finger set horizontally..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 90 (2011)
Iris Segmentation Based upon Linear Basis Function Model
WANG Kai, and QIAN Yun-tao
To improve accuracy of non-circular iris segmentation, an iris segmentation algorithm based on linear basis function model is proposed. The proposed algorithm regards iris segmentation problem as a machine learning problem which derives iris boundary curve from iris boundary points. First, boundary points are located bTo improve accuracy of non-circular iris segmentation, an iris segmentation algorithm based on linear basis function model is proposed. The proposed algorithm regards iris segmentation problem as a machine learning problem which derives iris boundary curve from iris boundary points. First, boundary points are located by coarse segmentation. Second, a linear basis function model is constructed to derive boundary curve from boundary points, thus the segmentation is complete. Compared with traditional iris segmentation algorithms, the proposed method locates non-circular iris with high accuracy, with the expense of a few more time. Experiment results on the dataset of CASIA-3.0 IRIS-Interval reveal that the accuracy of proposed method is 99.92%, and the time cost is 1ms more, which is capable for state-of-the-art iris recognition systems..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 97 (2011)
Discriminant Analysis Based on Maximum Margin Marginal Fisher
WANG Yong, and LU Gui-fu
In order to address Small Sample Size (3S) problem encountered by Marginal Fisher Analysis (MFA), based on the maximum margin criterion, a novel algorithm called Maximum Margin Marginal Fisher Analysis (MMMFA) is proposed for supervised linear dimensionality reduction. The difference between similarity matrix which chaIn order to address Small Sample Size (3S) problem encountered by Marginal Fisher Analysis (MFA), based on the maximum margin criterion, a novel algorithm called Maximum Margin Marginal Fisher Analysis (MMMFA) is proposed for supervised linear dimensionality reduction. The difference between similarity matrix which characterizes the interclass separability and similarity matrix which characterizes the intraclass compactness is adopted as discriminant criterion. In such a way, the small sample size problem occurred in MFA is avoided. The relations between MMMFA and conventional linear dimensionality reduction methods such as PCA, LDA and LPP are revealed. Theoretical analysis shows that PCA, LDA and LPP methods could be derived from the MMMFA method. Besides, an efficient and stable MMMFA/QR algorithm for implementing MMMFA is developed. The experimental results on ORL and YALE face database show that the performance of MMMFA method is superior to those of PCA, LDA, LPP and MFA..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 102 (2011)
Object-oriented Classification Method Based on Quotient Space Theory
LI Gang, and WAN You-chuan
Traditional classification methods only based on spectrum features of pixels are not suitable for high-resolution remote sensing image. A new object-oriented classification method is proposed based on quotient space granular theory, cloud model, fuzzy support vector machines and decision tree algorithm. Considering thaTraditional classification methods only based on spectrum features of pixels are not suitable for high-resolution remote sensing image. A new object-oriented classification method is proposed based on quotient space granular theory, cloud model, fuzzy support vector machines and decision tree algorithm. Considering that the two factors which determinate the accuracy of classification results are image segmentation and classification algorithm, we make some improvements and our work includes the following aspects. Firstly, an adaptive region growing method is proposed based on the Cloud Model. Secondly, a hierarchy-synthesis classification technique is proposed based on quotient space granular theory, fuzzy support vector machine and decision tree. A new algorithm is designed to calculate the fuzzy membership of sample. By combining FSVM with ISODATA, we not only improve the quality of training sample, but also make objects classified automatically. More importantly, the strategy of hierarchical classification makes different categories discriminated more effectively. By using synthesis theory of quotient space, we can get the final classification result from classification results of multi-granular quotient spaces. According to the experiment result, our method can not only improve the accuracy of classification result and satisfy human eye, but also make objects classified automatically..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 108 (2011)
A Extracting Scheme for Targets of Interest in High Resolution Remote Sensing Imagery
ZHOU Wei, GUAN Jian, and ZHANG Guo-hua
During the analysis and interpretation of remote sensing image, it can greatly relieve the processing system of the heavy computing burden to extract targets of interest rapidly and correctly. According to the attention mechanism of human, a detection algorithm for targets of interest based on visual attention mechanisDuring the analysis and interpretation of remote sensing image, it can greatly relieve the processing system of the heavy computing burden to extract targets of interest rapidly and correctly. According to the attention mechanism of human, a detection algorithm for targets of interest based on visual attention mechanism was proposed. Firstly a saliency map was computed by analyzing the spectral residual, and then salient target can be extracted without a priori knowledge by searching through the saliency map with a control mechanism of win-take-all competing and inhibition-of-return. A majority of salient regions were discarded by using the possible bound of size and shape for target of interest. Otherwise the focused regions were projected to the target feature subspace, and the difference in the projection coefficients can be used to determine whether the region is of interest or not. The proposed scheme is tested using an amount of high resolution remote sensing images, and the results show that it is effective..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 115 (2011)
Research of UAV Aerial Image Mosaic Based on SIFT
HE Jing, LI Yong-shu, LU Heng, and REN Zhi-ming
The matching effect of conventional methods is poor, sometimes even not matching due to the instability of Unmanned Aerial Vehicle (UAV) air gesture and the defects such as the existence of its tilted capture images, uneven exposure. SIFT algorithm has a good adaptability for image geometric distortion, resolution diffThe matching effect of conventional methods is poor, sometimes even not matching due to the instability of Unmanned Aerial Vehicle (UAV) air gesture and the defects such as the existence of its tilted capture images, uneven exposure. SIFT algorithm has a good adaptability for image geometric distortion, resolution differences and rotation, etc. The SIFT algorithm is introduced to extract the feature points of UAV images, and the least-squares algorithm is used to match the images precisely. Moreover, the block splicing method is proposed to reduce the error spread in the process of stitching. The experimental results show that SIFT image matching algorithm has a good adaptability in matching UAV images. The matching error can be eliminated effectively to introduce the least-squares algorithm in the matching process. What is more, the time and space complexity can be obviously reduced..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 122 (2011)
Design for Display Parameters of OLED Adaptive with Temperature
ZHANG Lei, WU Hua-xia, HU Jun-tao, FU Yong, and Lü Guo-qiang
Design for display parameters adaptive with temperature for the portable Active Matrix Organic Light Emitting Device (AMOLED) device is described. Belonging to active light-emitting device, the spectrum of material between pixels of OLED doesn’t perform the same way with temperature, which makes errors of display paramDesign for display parameters adaptive with temperature for the portable Active Matrix Organic Light Emitting Device (AMOLED) device is described. Belonging to active light-emitting device, the spectrum of material between pixels of OLED doesn’t perform the same way with temperature, which makes errors of display parameters as contrast, color coordinates, etc. The method makes temperature adaptive correction in signal passage. Feature points of ambient temperature as negative feedback input, values of display parameters accordingly as sampling points, a mathematical model of the relationship between display parameters and temperature is established by Least Squares Fitting (LSF) algorithm, which is then performed in software. Besides, the temperature scan threshold is put to solve the problem of conflict between user menu interrupt and temperature correction. In the end, the result of experiment shows the method is feasible..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 127 (2011)
Transient Temperature Field and Thermal Stress of High Power LED
ZHU Xu-ping, YU Gui-ying, DING Shu-shu, and HU Shu-hong
Thermal characterization of high-power Lighting Emitting Diode (LED) device was reported, utilizing finite element software ANSYS with thermal stress analysis based on the thermal stress theory, and the transient temperature and stress field were obtained. The thermal stress, displacement and shear stress distribution Thermal characterization of high-power Lighting Emitting Diode (LED) device was reported, utilizing finite element software ANSYS with thermal stress analysis based on the thermal stress theory, and the transient temperature and stress field were obtained. The thermal stress, displacement and shear stress distribution on the path which was parallel with X axis at the top of LED substrate were calculated. The simulation results indicated that the maximum von mises stress was at the corner of the thermal sink and die attach, and the maximum displacement was located at the edge between the lens and the thermal sink. The maximum shear stress was concentrated at the corner region. The numerical study that was carried out with LED base center to understand the temperature distribution by FEM technology was experimentally calibrated. Finally, variation of the maximum temperature and maximum thermal stress with thermal conductivity of various materials was considered. The results are of great importance to the high-power LED package..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 132 (2011)
The Study of a New-style Matrix Encoder
GENG Li-ming, CAO Guo-hua, WANG Wen-wen, and SHANG Chun-min
To satisfy the requirement of encoder miniaturization and high measuring accuracy, a new-style absolute matrix encoder which offered significant advantages over small reticling circles and high precision was presented in the paper, which carried out the design of new-style matrix encoding disc and coding circuit, exactTo satisfy the requirement of encoder miniaturization and high measuring accuracy, a new-style absolute matrix encoder which offered significant advantages over small reticling circles and high precision was presented in the paper, which carried out the design of new-style matrix encoding disc and coding circuit, exact encoding track calibration and the design of fractionizing circuit by studying the photoelectric encoder. The Matlab simulation results prove that the encoding and coding methods are feasible. The test showed that the cubage of encoder was super-small, its resolution can reach 24 bits, and its precision can reach 0.2″ by A/D converter. The feasibility of encoding and coding method was further proved..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 138 (2011)
The Development of a New Atmosphere Transmittance Meter
CHENG Shao-rong, WEI Quan-zhong, and Lü Jun
An atmosphere transmittance meter is developed. With transmitting a beam light and detecting it, the atmosphere extinction coefficient is obtained and various weather condition can be forecasted. Prototype machine is developed and field test is done. Experiment results demonstrate the correction of test principle and tAn atmosphere transmittance meter is developed. With transmitting a beam light and detecting it, the atmosphere extinction coefficient is obtained and various weather condition can be forecasted. Prototype machine is developed and field test is done. Experiment results demonstrate the correction of test principle and technique approach. The actual measure error of atmosphere transmittance meter is approximate 10%, which is close to that of product of VAISALA in Finland. Therefore, this transmittance could meet the demand of practical application..
Opto-Electronic Engineering
- Publication Date: Oct. 09, 2021
- Vol. 38, Issue 2, 144 (2011)
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