Journals >Opto-Electronic Engineering
Contents
2008
Volume: 35 Issue 9
28 Article(s)
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Research Article
Fusion Tracking Method Based on Equivalent Sensor for Dissimilar Sensors
CEN Ming, LIU Xing-fa, and FU Cheng-yu
To improve calculation performance of centralized target tracking system which consists of multiple dissimilar sensors, a fusion tracking method based on equivalent sensor was presented. It was assumed in the method that all characteristics of a target could be observed by each local sensor, and characteristics which cTo improve calculation performance of centralized target tracking system which consists of multiple dissimilar sensors, a fusion tracking method based on equivalent sensor was presented. It was assumed in the method that all characteristics of a target could be observed by each local sensor, and characteristics which could not be observed actually were treated as outlier and reconfigured by using state estimate of the target from fusion center, and then measurements with different dimensions from dissimilar sensors were mapped to corresponding measurements of equivalent sensors on system observation space with same dimensions. Therefore, combined measurement filtering method could be adopted to overcome the shortcomings of current centralized fusion tracking method and reduce calculation costs. Experiment results show that tracking accuracy of the method presented is consistent with that of current method, but calculation cost is lower than that of the latter and hardly increases with the amount of sensors..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 1 (2008)
Detecting Infrared Dim and Small Target with High-order Cumulant Projection
SUN Li-hui, ZHOU Bing, YING Jia-ju, JIN A-li, and WANG Yong-zhong
In order to detect moving infrared dim and small target, a novel high-order cumulant projection algorithm was proposed. After background of infrared image sequence was suppressed, the normalized 3-order cumulant of temporal data was projected to 2-dimensions domain, and then target was detected by searching possible trIn order to detect moving infrared dim and small target, a novel high-order cumulant projection algorithm was proposed. After background of infrared image sequence was suppressed, the normalized 3-order cumulant of temporal data was projected to 2-dimensions domain, and then target was detected by searching possible track in 2-dimensions domain. The statistic distribution expressions of target and noise in 2-dimensions domain were established. Compared with concerned algorithms, calculation load of the new algorithm is lower than that of other algorithms and detection rate of the new algorithm increases quickly with Signal-to-Noise Ratio (SNR) improvement. A simulation experiment with actual infrared image sequences was done to prove the validity of the new algorithm, and the targets with SNR no less than 2 and speed in image equal to 2 frames/pixel were successfully detected..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 6 (2008)
New Moving Target Detection Algorithm
ZHANG Heng, LI Li-chun, and YU Qi-feng
For the important problem of moving target detection on a moving platform, an ego motion compensation algorithm is presented based on the Gabor feature descriptions. After compensating the camera ego motion, it is able to detect the relative moving targets to the camera efficiently. The interesting points are detected For the important problem of moving target detection on a moving platform, an ego motion compensation algorithm is presented based on the Gabor feature descriptions. After compensating the camera ego motion, it is able to detect the relative moving targets to the camera efficiently. The interesting points are detected by the scale-space theory firstly. Then the feature description for every interesting point is created according to its character scale and character angle. And the coarse matching results are obtained by cross-match. At last, the transform model is estimated by the Random Sample Consensus (RANSAC) algorithm. Experimental results show that the new method can effectively and accurately detect the moving targets on the moving platform..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 11 (2008)
Fast Track Initiation Approach for Passive Sensor System
CHEN Hui, XU Lin-hai, LI Chen, and ZHU Hong-yan
Aiming at the existing problems in the applications of traditional track initiation approaches for bearing-only target tracking, a fast track initiation approach for single passive sensor system is proposed. In this approach, the rule of screening out threatening target is set through analysis of the target motion charAiming at the existing problems in the applications of traditional track initiation approaches for bearing-only target tracking, a fast track initiation approach for single passive sensor system is proposed. In this approach, the rule of screening out threatening target is set through analysis of the target motion characteristics in polar coordinates. And the track initiation of threatening target is implemented in the shortest time based on a modified heuristic approach. Then, other target tracks are initialized based on a logic-based approach in polar coordinates. The cooperation of the two approaches makes track initiation more effective which provides a base for determining the threatening level of target in bearing-only target tracking system. The application of the proposed approach in a simulation and engineering system indicates its effectiveness and practicability..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 17 (2008)
Optimized Design of Active Support of Ultra Thin Mirror
NI Ying, HUANG Qi-tai, and YU Jing-chi
Ultra thin mirror has a large diameter-thickness rate, so it will be more deformable because of the change of work surroundings. In this paper, some analysis and computing simulation for active ultra thin mirror surface by using Finite Element Method (FEM) were introduced. An ultra thin mirror with a large ratio was siUltra thin mirror has a large diameter-thickness rate, so it will be more deformable because of the change of work surroundings. In this paper, some analysis and computing simulation for active ultra thin mirror surface by using Finite Element Method (FEM) were introduced. An ultra thin mirror with a large ratio was simulated by software "patran". The aberrations gotten with the Zernike polynomials several low-orders were used to simulate the surface error after ultra thin mirror fabrication and the deformation because of change of work surroundings. After getting the response function of single actuator, the optimum scheme of actuator array for an ultra thin active mirror with maximum corrective capability was achieved. At last, the optimal thickness of the mirror was determined..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 22 (2008)
Alignment Model of Moiré and its Application in Nanometer Lithography
ZHOU Shao-lin, CHEN Wang-fu, YANG Yong, TANG Xiao-ping, HU Song, MA Ping, YAN Wei, and ZHANG You-lin
In the application of nanometer lithography, two gratings with similar periods were chosen for alignment marks on the wafer and mask respectively. Then light was modulated by these two gratings when they traveled through two alignment marks, and some phenomenon such as diffraction and interference occurred so that reguIn the application of nanometer lithography, two gratings with similar periods were chosen for alignment marks on the wafer and mask respectively. Then light was modulated by these two gratings when they traveled through two alignment marks, and some phenomenon such as diffraction and interference occurred so that regular and periodic-distributed moiré patterns were formed in the process of alignment. Because the fringe with magnified period versus periods of two gratings has high sensitivity to represent relative movement of two gratings on wafer and mask, it has a good prospect in the application of alignment of lithography. Theoretical analysis and deduction of the regularity of approximate spatial distribution of moiré patterns resulting from superposition of two proximity gratings with close frequencies were performed in the viewpoint of Fourier Optics. Furthermore, a set of alignment marks which could double the sensitivity were designed. Approximate mathematical model of complex amplitude of interferometric fringes and the process of alignment of lithography were verified through simulation..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 27 (2008)
Novel Integrated Device of Optofluidic Variable-focus Microlens Array
LIANG Zhong-cheng, XU Ning, TU Xing-hua, CHEN Tao, and ZHAO Rui
A novel integrated device of optofluidic variable-focus microlens array is proposed to solve the problems of electrical focus-tuning and integration fabrication of microlens array. The basic structure of the array includes a core chip sandwiched between two glass covers. The core chip is made from electric conductor toA novel integrated device of optofluidic variable-focus microlens array is proposed to solve the problems of electrical focus-tuning and integration fabrication of microlens array. The basic structure of the array includes a core chip sandwiched between two glass covers. The core chip is made from electric conductor to simplify the device design and the fabrication technics. The lens materials consist of two kinds of immiscible liquids with different refractive index. The meniscus between two liquids is used as optical lenses. The focal distance is tuned by changing the curvature of this meniscus through the effect of electro-wetting..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 32 (2008)
Dynamic Measurement and Control of Radial-Hartmann Wave-front Test System
YANG Jun-tao, HE Yu-mei, and TANG Guo-mao
Radial-Hartmann wave-front Test System(RHTS)is a new measurement system for large-aperture optical system. It can be used for the measurement of the optical system without a large-flat mirror in the room. Currently, this system has some problems such as long time for measurement, large mount of image acquisition and thRadial-Hartmann wave-front Test System(RHTS)is a new measurement system for large-aperture optical system. It can be used for the measurement of the optical system without a large-flat mirror in the room. Currently, this system has some problems such as long time for measurement, large mount of image acquisition and the instability of the surrounding environment such as temperature and noise. During the course of the measurement for large-aperture optical system, based on the analysis of the control flow, a control method for dynamic measuring is put forward, a control circuit for the dynamic measuring is designed. And a fast dynamic measurement of the RHTS is achieved and the test time is decreased with a new method of data collection and calculation..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 36 (2008)
Design of Cavity Facet Reflectivity for 808 nm Semiconductor Lasers
DU Wei-hua, YANG Hong-wei, CHEN Guo-ying, CHEN Hong-tai, LI Ya-jing, and PENG Hai-tao
Material internal parameters, such as internal quantum efficiency, internal loss, transparent current density mode gain and so on, were obtained by P-I test for different cavity length 808nm semiconductor laser diodes. The relation between cavity facet reflectivity and power conversion efficiency was analyzed, and the Material internal parameters, such as internal quantum efficiency, internal loss, transparent current density mode gain and so on, were obtained by P-I test for different cavity length 808nm semiconductor laser diodes. The relation between cavity facet reflectivity and power conversion efficiency was analyzed, and the relation curves were acquired by the design of cavity facet reflectivity according to these internal parameters. Then, we did cavity facet coating experiments. Experimental results are well consisted with the theoretical prediction through comparison. The maximal power conversion efficiency can be achieved through the design of cavity facet reflectivity, and the semiconductor laser diodes can work in an optimal condition..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 41 (2008)
Analysis of the Ray Radiation Detection System for Nuclear Explosion
WU Jian-hui, YANG Kun-tao, and ZHANG Nan-yang-sheng
According to study of the characteristics of ray radiation from nuclear explosion, the detection system of nuclear explosion ray radiation based on high speed CMOS image sensor was analyzed in the theory and the structure. To meet the practical requirement, the high speed CMOS image sensor was used to make the photoeleAccording to study of the characteristics of ray radiation from nuclear explosion, the detection system of nuclear explosion ray radiation based on high speed CMOS image sensor was analyzed in the theory and the structure. To meet the practical requirement, the high speed CMOS image sensor was used to make the photoelectric sensor and the high speed image processing system about DSP was adopted to make the detection system. The detection principle of nuclear explosion was analyzed based on image processing and the measuring error caused by atmospheric transmission was calculated. The author devised the program of algorithm for image processing. The simulation experiment indicates that the system can detect some parameters accurately, like equivalent, angle of pitch and distance. Compared with the conventional method, it has relatively high accuracy as well as good stability and reliability. Besides, it is easier to operate. The experimental result indicates that performance of the system achieves the expected goals..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 45 (2008)
Application of Improved Genetic Algorithm in the Particle Sizing Technique
ZHANG Hu, DAI Jing-min, TANG Hong, and XIN Chun-suo
In the total light scattering particle sizing technique,a method based on the improved genetic algorithm is proposed to be applied to the inversion of particle size distribution. In the independent model, the improved genetic algorithm combined with simulated annealing algorithm overcomes the difficulties of determininIn the total light scattering particle sizing technique,a method based on the improved genetic algorithm is proposed to be applied to the inversion of particle size distribution. In the independent model, the improved genetic algorithm combined with simulated annealing algorithm overcomes the difficulties of determining the penalty coefficient of genetic algorithm based on the penalty function, which will cause the inversion result to be an infeasible solution. In the dependent model, the size distribution is well determined at only three wavelengths by the improved genetic algorithm. It is feasible to use the improved genetic algorithm to recover the particle size distribution in the total light scattering technique and the inversion results are steady and reliable, which avoids the defects that the simple genetic algorithm is easy premature and then the inversion result is easily trapped in a local solution..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 50 (2008)
Thickness Measurement of Ultra-thin Metallic Foil with Tandem Differential White Light Interferometry
DU Yan-li, and YAN Hui-min
White Light Interferometry (WLI), overcoming the disadvantage of the phase ambiguity in the narrow-band interferometry, allowed absolute position determination. A new tandem differential white light interference system for the thickness measurement of metallic foil was designed. In this work, the differential white ligWhite Light Interferometry (WLI), overcoming the disadvantage of the phase ambiguity in the narrow-band interferometry, allowed absolute position determination. A new tandem differential white light interference system for the thickness measurement of metallic foil was designed. In this work, the differential white light system consists of two Michelson Interferometers (MI) in tandem. Reflective surfaces measured were the corresponding surfaces of metallic foil. Therefore, the measured result is only related to the thickness but not to the position of metal foil. Theoretical analysis and preliminary experimental results show that the method has advantages of high accuracy, fast detection and anti-interference..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 55 (2008)
Detection of STN-LCD Defects Based on Image Registration
SHEN Hui-liang, ZHANG Hong-gang, and LI Zhi-neng
a method based on the technique of image registration is proposed for detecting the appearance defects of Super-twisted Nematic Liquid Crystal Display (STN-LCD). The standard template LCD image is first recovered from possible non-uniform illumination, and then the statistical information of each region is collected bya method based on the technique of image registration is proposed for detecting the appearance defects of Super-twisted Nematic Liquid Crystal Display (STN-LCD). The standard template LCD image is first recovered from possible non-uniform illumination, and then the statistical information of each region is collected by image thresholding and region labeling. The template and testing image are registered by control-point detection and affine transform. The defects including stroke-loss and pinhole of the LCD can then be detected by using region statistics such as mean and standard deviation of grayscales. To improve the accuracy of image registration, a special scheme of control-point selection and hybrid image interpolation is proposed. Experimental results show that the proposed method is robust and accurate, and can detect STN-LCD defects automatically. The proposed method is used for industrial applications, and offers advantages over the traditional manual inspection manner..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 60 (2008)
Numerical Calculation and Analysis on Plane Polarized Light Scattering by Spheral Particles
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This paper presented formula to calculate the scattering intensity and scattering coefficients of plane polarized light based on Mie theory. The results were calculated using link recursion algorithm. Intensive analysis on the simulation result of 1.06 μm laser was made. The scattering diagrams indicate a close link beThis paper presented formula to calculate the scattering intensity and scattering coefficients of plane polarized light based on Mie theory. The results were calculated using link recursion algorithm. Intensive analysis on the simulation result of 1.06 μm laser was made. The scattering diagrams indicate a close link between the scattering intensity distribution with angle and particle size. As the particle size increases, scattering intensity mainly focuses on the forward and backward directions, and the distribution angle decreases accordingly. The simulation results also indicate an extremum angle where the scattering intensity is the weakest. The extremum angle increases with the increase of particle size, approximating to 90° at last. The scattering intensity distribution with angle is related to wavelength. When they are in the same scale, the scattering intensity reaches its maximum. The scattering intensity has no relation to particle refractive index. The recursion algorithm used in the paper is simple and efficient. Because each step is independent with each other, there are no problems of instability or inconvergence. The minimal particle size is 10-4, and the maximum particle size is unlimited..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 66 (2008)
Research of Scattering Phase Function of Spheric Particle under Polarized State
ZHANG He-yong, REN De-ming, ZHAO Wei-jiang, QU Yan-chen, and SONG Bao-an
According to the definition of scattering phase function, we acquire the expression of single particle under polarized state. Three rules of orderliness are discovered as follows: 1) the smaller the particle radius is, the more symmetrical the distribution of extremum difference is.2) When scattering angle is in the raAccording to the definition of scattering phase function, we acquire the expression of single particle under polarized state. Three rules of orderliness are discovered as follows: 1) the smaller the particle radius is, the more symmetrical the distribution of extremum difference is.2) When scattering angle is in the range from 0 to 0.025 π, 0.997 π to π radian, the scattering phase function has no change on the whole. 3) When scattering angle is in the range from 0.025π to 0.997 π radian, the scattering phase function varies obviously. At the same time, distribution between single and multi- particle owing to the scattering angle and the polarized angle was compared. At last, we established the relationship of scattering phase function between polarized and unpolarized state according to the theory of light propagation in atmosphere, which offers a reference in the measurement of atmosphere return power and the research of approximate phase function..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 70 (2008)
Robot Extended Eye-in-hand Calibration Method Based on an Assistant Camera
WEI Zhen-zhong, GAO Ming, ZHOU Fu-qiang, and ZHANG Guang-jun
In order to solve the problem of calibrating the position and orientation of an object on the robot hand with respect to the camera, Extended-eye-in-hand calibration is proposed from traditional eye-in-hand calibration, which extends the robot hand-eye relationship to extended hand-eye relationship. An assistant cameraIn order to solve the problem of calibrating the position and orientation of an object on the robot hand with respect to the camera, Extended-eye-in-hand calibration is proposed from traditional eye-in-hand calibration, which extends the robot hand-eye relationship to extended hand-eye relationship. An assistant camera is introduced to accomplish robot extended-eye-in-hand calibration by using a planar calibration target and plenty of calibration points derived from the image feature of a rectangle on the robot extended hand. The results of the conducted real experiment illustrate the feasibility and validity of the method. The precision of the calibration depends on the precision of extended hand and the precision of the derived calibration points. In our experiment, the final Root Mean Square (RMS) is 0.113 mm..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 76 (2008)
Implementation of Augmented Reality Technology in Remote Reality
ZHU Qi-dan, ZHONG Xun-yu, and LU Jun
Remote Reality (RR) System was designed based on Mobile Robot, which was used for robot teleoperation assistance. In order to improve human-machine interaction, Augmented Reality (AR) was introduced to the remote reality system. According to the principle of 3D registration of AR, a vision-based registration method useRemote Reality (RR) System was designed based on Mobile Robot, which was used for robot teleoperation assistance. In order to improve human-machine interaction, Augmented Reality (AR) was introduced to the remote reality system. According to the principle of 3D registration of AR, a vision-based registration method used in hyperboloidal catadioptric omnidirectional imaging system was educed, which realized the registration of 3D virtual robot in omnidirectional image. Then Augmented Remote Reality (ARR) was used in the perspective interface unwrapped from circular omnidirectional image with a fast approximate algorithm. The experimental results show that the ARR improves visual effects and has annotation-based assistance information to enhance the capacity of human-machine interaction..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 81 (2008)
Theory Analysis of Fiber Grating Solitons Based on Electromagnetic Field Theory
LI Xiao-lu, JIANG Yue-song, and LI Fang
A theory analysis of fiber grating soliton was implemented using the matrix transfer function based on the principle of electromagnetic field and electromagnetic wave. The electromagnetic model of light wave of fiber grating soliton was established and described by the vector expression with complex amplitude. The CaylA theory analysis of fiber grating soliton was implemented using the matrix transfer function based on the principle of electromagnetic field and electromagnetic wave. The electromagnetic model of light wave of fiber grating soliton was established and described by the vector expression with complex amplitude. The Cayley-Hamilton theorem and Chebychev polynomial of the second kind were used to compute and prove the model. The reflectivity and transmissivity based on the matrix transfer function were emulated to get the analysis on characteristics of fiber long(short)-period grating and deep(light)- modulation grating, and the difference between the forward wave propagation and the backward wave propagation on initial grating has an impact on the electromagnetic wave of grating soliton on terminal grating. It is a common value to analyze the characteristic of nonlinear fiber grating and the diversified fabrication of fiber grating..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 86 (2008)
Parameter Design of Dynamic Target for Test Tracking Performance of Photoelectric Theodolite
WU Jin, ZHANG Bo, and SHEN Xiang-heng
The technical state of tracking test is determined through parameter of dynamic target. Tracking performance data is varied for different model of photoelectric theodolite. So the parameter design of dynamic target is different when test tracking performance of photoelectric theodolite is different. This paper describeThe technical state of tracking test is determined through parameter of dynamic target. Tracking performance data is varied for different model of photoelectric theodolite. So the parameter design of dynamic target is different when test tracking performance of photoelectric theodolite is different. This paper describes coordinate conversion between photoelectric theodolite and dynamic target, and gives the method for building simulation model to find optimal target parameter. And the method is proved to be fit to track performance data by testing some dynamic target with the simulation model..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 91 (2008)
Image Processing Technology for Signal of Light Screen Velocity Measuring System
HUANG Zhan-hua, WANG Dong, ZHAO Jie, and CAI Huai-yu
In the precision light screen velocity measuring system, a signal processing technology based on the arithmetic of image processing is put forward to eliminate the interference of random noise to opto-electronic detected signals, so the interval time of the object flying through the two light screens can be gained accuIn the precision light screen velocity measuring system, a signal processing technology based on the arithmetic of image processing is put forward to eliminate the interference of random noise to opto-electronic detected signals, so the interval time of the object flying through the two light screens can be gained accurately. It converted the counting of interval time into the counting of end position of the object in the image. At first, the image defects such as isolated point, burr etc. were eliminated to get the image which has only one seriate area, and then, the image area was divided by the average width to get the end position of the object. Each time when the object fly through the two light screens can be measured accurately by using the end position of the object in the image, and the interval time can be gained by subtracting the two time. The experiment show that the system can gain the interval time accurately by applying this processing technology, the speed data is stable and effective, and the system measurement precision can be up to 0.05%..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 95 (2008)
Aerial Image Mosaic Algorithm of MAV
HUANG Ying-dong, LI Jie, and FAN Ning-jun
Referring to the characteristics of the Micro Aerial Vehicle (MAV), a robust aerial image mosaic algorithm was presented. In this algorithm, phase correlation was used to estimate the overlapping area, in which Harris corner detector was used to extract feature points, and then a pseudo matching set was obtained. TheseReferring to the characteristics of the Micro Aerial Vehicle (MAV), a robust aerial image mosaic algorithm was presented. In this algorithm, phase correlation was used to estimate the overlapping area, in which Harris corner detector was used to extract feature points, and then a pseudo matching set was obtained. These pseudo matches were divided into inliers and outliers by using robust RANSAC algorithm. In the inliers sub-set, perspective transformation model was used to estimate the point transformation matrix between two images accurately. In the end, the image color of the overlapping band was smoothed with bilinear interpolation technique. Experimental results show that the image mosaic effect is wonderful..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 99 (2008)
Novel Algorithm for Image Retrieval Based on Chain Code
SUN Jun-ding
Based on the analysis of chain code in shape representation, two novel shape descriptors, named chain code distribution vector and chain code coherence vector, are introduced to express the spatial feature in the chain code. These two descriptors have the advantages of being invariant to the position, rotation and scalBased on the analysis of chain code in shape representation, two novel shape descriptors, named chain code distribution vector and chain code coherence vector, are introduced to express the spatial feature in the chain code. These two descriptors have the advantages of being invariant to the position, rotation and scaling of the image content and have nothing to do with the start point of the chain code. Combined with chain code histogram, two different matching methods are presented to measure the similarity of shape information. It is clear that both the statistical feature and the spatial feature of the chain code are considered in the new methods. Experiment results show that our methods give better performance than the traditional methods..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 105 (2008)
Estimation of Cardiac Motion Based on Non-rigid Motion Theory
SUN Zheng
An approach for analyzing 3D cardiac motion from X-ray coronary artery angiogram sequences based on non-rigid motion principles was presented. According to actual characteristics of cardiac motion which have been confirmed by medical observations, complex cardiac motion is decomposed into global rigid motion, global deAn approach for analyzing 3D cardiac motion from X-ray coronary artery angiogram sequences based on non-rigid motion principles was presented. According to actual characteristics of cardiac motion which have been confirmed by medical observations, complex cardiac motion is decomposed into global rigid motion, global deformation and local motion and deformation. Parameters of all components are estimated from global to local and coarse to fine to obtain quantitative description of cardiac dynamics. Experimental results demonstrate the feasibility and efficiency of the method..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 110 (2008)
Medical Ultrasound Image Denoising Based on Adaptive Morphological Despeckling Filter
DENG Yin-hui, WANG Yuan-yuan, and WANG Wei-qi
In view of speckle noise in medical ultrasound image, a denosing method based on adaptive morphological filter was proposed. Firstly, a set of structuring factors was constructed to detect different sudden changes of pixel values in images. Then a corresponding structuring element for morphological filtering was establIn view of speckle noise in medical ultrasound image, a denosing method based on adaptive morphological filter was proposed. Firstly, a set of structuring factors was constructed to detect different sudden changes of pixel values in images. Then a corresponding structuring element for morphological filtering was established for each structuring factor. Finally, the most possible structures of sudden changes in each pixel’s neighborhood were detected by using the set of structuring factors and a morphological filtering was performed to the pixel with the corresponding structuring element. The comparison experiment was carried out on simulated and real ultrasound images by using the proposed method, the speckle reducing anisotropic diffusion and different scale morphological filters, respectively. It is shown that the proposed method averagely improves the Signal-to-noise Ratio (SNR), Contrast-to-noise Ratio (CNR) and Figure of Merit (FOM) of ultrasound images by 15%, 37% and 69%. Therefore, the adaptive morphological despeckling filter may be an effective method to suppress speckle in ultrasound images..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 115 (2008)
Rapid Iris Localization Algorithm Based on Image Sampling
WANG Yun-xin, LIU Tie-gen, and JIANG Jun-feng
A rapid iris localization algorithm based on image sampling was proposed. One point in the pupil was firstly detected in the sampled image. With this point as the initial one, the coarse edge points were detected, and then the inner iris edge could be located by the exact edge points extracted by gradient operator in tA rapid iris localization algorithm based on image sampling was proposed. One point in the pupil was firstly detected in the sampled image. With this point as the initial one, the coarse edge points were detected, and then the inner iris edge could be located by the exact edge points extracted by gradient operator in the image with original resolution. The outer iris edge was located using Canny operator and Hough transform. Since the edges were extracted based on the sampled image, plenty of detailed boundaries such as iris texture were ignored, which reduced the outer disturbing boundaries and improved the real-time property of algorithm. The experiment results show that the algorithm achieves 99.47 % in accuracy and 0.162 s in speed. In comparison with other classical localization methods, the developed algorithm is much faster..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 122 (2008)
Face Recognition Based on Two Subspaces Linear Discriminant Analysis
ZHAO Ming-hua, LI Peng, and LIU Zhi-fang
Disadvantages of the several typical variants on Linear Discriminant Analysis (LDA) while dealing with the well-known small sample size problem in face recognition are revealed. A new discriminant analysis method named two subspaces LDA is proposed to deal with small sample size problem. Firstly, all the samples are prDisadvantages of the several typical variants on Linear Discriminant Analysis (LDA) while dealing with the well-known small sample size problem in face recognition are revealed. A new discriminant analysis method named two subspaces LDA is proposed to deal with small sample size problem. Firstly, all the samples are projected to the nonzero space of the total scatter matrix. Secondly, discriminant analysis is carried out in the zero subspace and nonzero subspace of the within-class scatter matrix respectively. Thirdly, the two kinds of discriminant features are fused to determine class of the samples. Experimental results show that the proposed algorithm is superior to other linear methods..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 127 (2008)
An Improved Iris Location Method
YUAN Wei-qi, and ZHANG Rui
On the basis of the original iris location method based on the structure feature, an improved method is proposed. To the iris’ outer boundary, we use the feature of the iris’ structure and mathematical means to verify whether the iris outer boundary points are correct, and calculate the correct ones if necessary. BecauOn the basis of the original iris location method based on the structure feature, an improved method is proposed. To the iris’ outer boundary, we use the feature of the iris’ structure and mathematical means to verify whether the iris outer boundary points are correct, and calculate the correct ones if necessary. Because of the disturbances of the eyelid and the eyelashes, the original iris location method based on the structure couldn’t locate the iris accurately, but the proposed method could effectively solve the problem. 1200 iris images (640×480 in size) comprising an iris image database are located in the experiment. The location accuracy of proposed algorithm reaches 99.08%, average time of location is only 0.8 s. The availability of proposed method is proved in the experiment..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 133 (2008)
Fragile Authentication Watermark Based on Singular Value Decomposition and Chaotic Mapping
YE Tian-yu, NIU Xin-xin, and YANG Yi-xian
An image fragile authentication watermark algorithm based on singular value decomposition and chaotic mapping was proposed, trying to apply chaotic mapping’s initial value sensitivity to tamper detection. Singular value decomposition was carried out on each image block, and authentication watermark was produced by usinAn image fragile authentication watermark algorithm based on singular value decomposition and chaotic mapping was proposed, trying to apply chaotic mapping’s initial value sensitivity to tamper detection. Singular value decomposition was carried out on each image block, and authentication watermark was produced by using Logistic chaotic mapping. Then Logistic chaotic mapping was used to design a mapping function defined on two separate blocks, and authentication watermark sequence was embedded into the corresponding mapping block’s LSB. The experimental results show that the algorithm is not only very sensitive to tamper, but also resists collage attack and distinguishes image content tamper from watermark tamper..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 35, Issue 9, 138 (2008)
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