Journals >Opto-Electronic Engineering
Contents
2014
Volume: 41 Issue 6
16 Article(s)
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Research Article
A Modeling and Calibration Method of Portable Vision Metrology
TAN Wenbin, LI Xingfei, LIU Chao, and ZHU Jia
A mathematical model and calibration method is proposed for column two-dimensional portable vision metrology. The analysis of the measuring principle and system components is given. The overall mathematical model in line with measuring principle is established based on the exercise of independent positioning and cameraA mathematical model and calibration method is proposed for column two-dimensional portable vision metrology. The analysis of the measuring principle and system components is given. The overall mathematical model in line with measuring principle is established based on the exercise of independent positioning and camera imaging model. In the process of calibration, firstly, the calibration of geometric errors such as the positioning error is completed. Then, the image of round hole is evenly distributed in the image plane of the camera by moving the camera. At last, the calibration of camera imaging model parameters is achieved using nonlinear least squares fitting method, according to the target workbench position, pixel coordinates and the amount of the corresponding moving mechanism moves. Results show that the average error of measurement is 1.8 μm by modeling and calibration. The modeling and calibration method of portable vision metrology can effectively improve the system accuracy..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 1 (2014)
High Accurate Flash Synchronization for Wheel-set Image Acquisition
WU Kaihua, CAI Xin, ZHU Xiaofeng, and ZHOU Weixiang
On the background of the image of online detection of rail transport wheel-set parameters, a kind of high accurate synchronization flash image acquisition method was proposed in order to solve the problem of short exposure time and lack of exposure when the vehicle wheel-set moving fast. The exposure and flash time seqOn the background of the image of online detection of rail transport wheel-set parameters, a kind of high accurate synchronization flash image acquisition method was proposed in order to solve the problem of short exposure time and lack of exposure when the vehicle wheel-set moving fast. The exposure and flash time sequence was designed in synchronous timing, using high-intensity flash light to ensure luminous flux. Trigger signal was processed by optical coupler and MCU. And with high-precision delay control module, the exposure and flash moments could be controlled. Asynchronous image acquisition was designed and realized so that a clear image can be acquired accurately when the wheel-set arrives at the position set in advance. The influencing factors of the synchronization error were analyzed. According to the results of experiment, when the speed is less than 80 km/h, the synchronization error of the system would be less than 25 μs and the motion blurred would be less than 1 mm..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 7 (2014)
Digital Measurement for Cylinder Head Combustion Chamber Volume of Automobile Engine
QI Mingdong, TANG Tao, WU Zhuoqi, and XI Juntong
In order to solve the difficulties and problems such as low accuracy and low efficiency in current measure of cylinder head combustion chamber volume by titration method, a new method based on liner scanner three-dimensional measuring system was proposed. The volume of cylinder head combustion chamber can be measured rIn order to solve the difficulties and problems such as low accuracy and low efficiency in current measure of cylinder head combustion chamber volume by titration method, a new method based on liner scanner three-dimensional measuring system was proposed. The volume of cylinder head combustion chamber can be measured rapidly and precisely with the proposed method. Besides, the method has been applied in actual engineering. In this article, the measuring principle and process were introduced, and the key method was expounded for getting cylinder head combustion chamber volume through a series of filtering and volume compute procedures, including point cloud filtering, hole fixing, surface reconstruction, extraction of effective point cloud and volume compute, etc. Lastly, based on the prototyping platform, the method has been verified..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 13 (2014)
Machine Vision Detection Method of Pattern Fabric Flaws
WANG Mingjing, BAI Ruilin, HE Wei, and JI Feng
In order to achieve real-time detection of pattern fabric defects in the process of weaving, a machine vision-based rapid real-time detection method is proposed. In off-time case, through the distance matching function of flawless image and the analysis of extreme weight to obtain the periods of pattern fabric accurateIn order to achieve real-time detection of pattern fabric defects in the process of weaving, a machine vision-based rapid real-time detection method is proposed. In off-time case, through the distance matching function of flawless image and the analysis of extreme weight to obtain the periods of pattern fabric accurately, extract the standard element, establish a sequence of the element, extract features and construct a fuzzy classifier. In real-time case, extract features of every image block based on the sequence established in off-time case and then classify the blocks. Construct the accurate classifier if flaw might exist. Experiments shows that, the method put forward in this paper can realize real-time detection for most class of fabrics in different patterns with only one-time learning from the flawless images. The method has a high instantaneity that an average time of detection is about 200 ms and a low fallout ratio that the accuracy rate is above 99%..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 19 (2014)
Development of an Optical Sampler for Online Beam Diagnosis of High Energy Lasers
WANG Fei, CHEN Shaowu, FENG Guobin, TAO Mengmeng, and YE Xisheng
To fulfill the requirements of the high energy laser beam online sampling diagnosis, an optical sampler based on circular reflector is developed. The optical sampler is circularly shaped, expending the beam circularly, which enables more than half of the detectors to receive the sampling beam. The reflecting surface isTo fulfill the requirements of the high energy laser beam online sampling diagnosis, an optical sampler based on circular reflector is developed. The optical sampler is circularly shaped, expending the beam circularly, which enables more than half of the detectors to receive the sampling beam. The reflecting surface is arc-shaped, expending the beam perpendicularly, which simplifies the alignment, while increasing the attenuation factor. Appropriate variation ranges of certain parameters are specified through numerical simulation, satisfying the requests of the coupling aperture angle between the detector and the reflected laser beam. Experiments show that this optical sampler can be used in the online diagnosis of high energy lasers with large beam profiles..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 27 (2014)
Temperature Influence in the TDLAS Detection of Escaping Ammonia
ZHANG Zengfu, ZOU Debao, CHEN Wenliang, ZHAO Huijuan, and XU Kexin
Tunable Diode Laser Absorption Spectroscopy (TDLAS) provides a reliable means of on-line detection technology for sampling style escaping ammonia. Since the temperature had great effects on the 2f signal in the field environment, the results must be modified. When the temperature changed from 25 ℃ to 250 ℃, the concentTunable Diode Laser Absorption Spectroscopy (TDLAS) provides a reliable means of on-line detection technology for sampling style escaping ammonia. Since the temperature had great effects on the 2f signal in the field environment, the results must be modified. When the temperature changed from 25 ℃ to 250 ℃, the concentrations of 100 × 10-6 NH3 were detected in the Herriott cell and the 2f signals spectrogram were obtained. The results show that the 2f signal intensity decreases and the curve smooth with the temperature rising. When the pressure changed from 20kPa to 100kPa, the results show that the 2f signal intensity decreases and the curve smooth with the pressure rising. According to the above results, the experience formula of temperature correction was raised. The formula reliability was evaluated through the correction of the 50 × 10-6 concentration NH3 in different temperatures, and the error correction was within 5.1%, which greatly improved the precision of the detection. The results show that the system is suitable for online sampling style monitoring in high temperature environment..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 32 (2014)
Selective Band Subsets Anomaly Detection Based on Spectral Unmixing for Hyperspectral Imagery
CHENG Baozhi
The current anomaly detection algorithms are shortage to solving anomaly detection problem because hyperspectral imagery has a higher order features and complicated background information distribution characteristics. By analyzing the spectral features and the spatial features, and exploiting spectral unmixing and subsThe current anomaly detection algorithms are shortage to solving anomaly detection problem because hyperspectral imagery has a higher order features and complicated background information distribution characteristics. By analyzing the spectral features and the spatial features, and exploiting spectral unmixing and subspace divided methods, based on statistical learning theory, an algorithm of anomaly detection of hyperspectral imagery selectivity band subsets is proposed based on spectral unmixing(UNBS-KRX). At first, hyperspectral imagery reduce the background interference and prominent anomaly target information by using spectral unmixing methods, which extract endmembers spectral, that is great influence on background information distribution of hyperspectral imagery. Then, the algorithm divides the whole bands space to a few subspaces. The size of the subspace is different, and non-Gaussian measurement criterion is used to extract the characteristic bands in each subspace. The bands are rich in anomaly target information. At last, as an anomaly detection operator, the kernel RX completes anomaly target detection. The real hyperspectral data sets are used in the experiments, and the result shows the UNBS-KRX is effective and reasonable, and has an execllent detection performance..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 38 (2014)
Regularization Image Restoration Algorithm for Diffractive Optic Imaging Spectrometer
ZENG Wenming, CHEN Yuheng, and SHEN Weimin
In order to eliminate the interference of out-of-focus optical images in in-focus image formed within a diffractive optic imaging spectrometer, a regularization method is proposed that can be applied to restore its spectral image. Through introduction of a stable functional and addition of some priori or assumed conditIn order to eliminate the interference of out-of-focus optical images in in-focus image formed within a diffractive optic imaging spectrometer, a regularization method is proposed that can be applied to restore its spectral image. Through introduction of a stable functional and addition of some priori or assumed conditions, the inverse filter function is regularized so as to reduce the perturbance in image restoration process from the systematic noise and transfer the recovering process into the problem to solve a well-posed equation. By adjusting and choosing appropriate regularization parameter, our restored spectral images are the best and are evaluated with their Mean Square Error (MSE) and absolute error distribution. Computer simulation experiment shows that regularization algorithm is effective for restoring the spectral images formed with diffractive optic imaging spectrometer and suppressing its noise’s influence on the restored images..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 45 (2014)
Pointing Error Modification Method for Three-axis Optoelectronic Tracking System
ZHANG Yudie, LIU Wansheng, LUO Yihan, and ZHONG Daijun
In order to modify the pointing error of three-axis optoelectronic tracking systems, a new method based on the optical-mechanical structure of three-axis systems was proposed. Firstly, related equations which show the impaction of axis errors to the pointing error of spatial target were analyzed based on the rotation tIn order to modify the pointing error of three-axis optoelectronic tracking systems, a new method based on the optical-mechanical structure of three-axis systems was proposed. Firstly, related equations which show the impaction of axis errors to the pointing error of spatial target were analyzed based on the rotation transform theory of quaternion. Then, a new modification model of three-axis optoelectronic tracking system was obtained thought all the different equations. Experimental results show that the method can reduce the pointing error effectively, and the exterior-error modified capability of this method is higher than spherical-function modification model. At the same time, the method would have a certain reference guide to estimate the pointing precision during assemblage and debugging..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 51 (2014)
Target Tracking Algorithm Based on Kalman Filter and Optimization Mean Shift
HAN Tao, WU Heng, ZHANG Hulong, HOU Haixiao, ZOU Qiang, and ZHANG Xingguo
Background change, shape change and target covering will cause target tracking failure. Real-time and accuracy in target tracking must be considered. First, the Mean Shift algorithm is presented, and then the Mean Shift algorithm iterative weight is modified with main information more prominent, secondary information sBackground change, shape change and target covering will cause target tracking failure. Real-time and accuracy in target tracking must be considered. First, the Mean Shift algorithm is presented, and then the Mean Shift algorithm iterative weight is modified with main information more prominent, secondary information suppressed, avoiding the tedious root, and improving the real-time and effectiveness of target tracking. The target template updating algorithm is presented to solve change of background and target shape change. Then a Kalman filter in the horizontal position and the vertical position is established to solve the problem of target tracking completely covered. Simulation results show that target tracking algorithm on the condition of target template update has higher tracking accuracy, higher real-time property and at the same time is more robust than the traditional Mean Shift tracking algorithm..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 56 (2014)
Thermal Property of Large Aperture Light Primary Mirror
HE Yan, WANG Jihong, and PENG Qi
To analyze the influence of temperature on the large aperture light weight mirror reflecting surface, a three-dimensional model has been established based on a large aperture light weight mirror. The steady-state and transient thermal characteristic is studied by taking the advantage of Finite Element Method (FEM) softTo analyze the influence of temperature on the large aperture light weight mirror reflecting surface, a three-dimensional model has been established based on a large aperture light weight mirror. The steady-state and transient thermal characteristic is studied by taking the advantage of Finite Element Method (FEM) software patran/nastran. The uniform temperature distribution, axial temperature difference, radial temperature difference and the changing ambient temperature have been analyzed. The analysis shows that in the case of axial temperature difference, radial temperature difference and the changing ambient temperature, the mirror surface suffers serious thermal aberration, and the PV value and RMS value increase linearly with the temperature gradient. The influence from uniform temperature is slight, at the temperature of ±3 ℃, the PV value and RMS value are respectively 27.6 nm and 6.5 nm with defocus aberration removed..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 63 (2014)
The Variable Speed Motion Model in Aspheric Surface Equal-remove Rate Grind-polishing Process
ZHANG Chuan, CHEN Yaolong, CHEN Xiaoyan, and WANG Ping
Based on CCOS and Preston assumption, a grind-polishing technique for rotational symmetry aspheric surface polishing process is proposed. In order to achieve equal-remove rate, a variable speed motion model is established based on keeping the contact pressure between grinding tool and workpiece as a constant. By this tBased on CCOS and Preston assumption, a grind-polishing technique for rotational symmetry aspheric surface polishing process is proposed. In order to achieve equal-remove rate, a variable speed motion model is established based on keeping the contact pressure between grinding tool and workpiece as a constant. By this theoretical principle, the functions of rotate speed and feed speed for every processing position have been inferred. To solve these functions, the rotation speed of workpiece and feed speed of grind-polish wheel in different working position should be gotten. CNC equipment would execute processing accurately. The results of experiment prove that the motion control model could ensure precision of grinding process, so that, the difficulty of polishing process has been reduced and whole processing efficiency has been improved..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 70 (2014)
Influence of Adhesives on Dynamics Characteristic of Opto-mechanical Structure
WU Zhihui, WANG Dongping, ZHOU Liansheng, NI Mingyang, and LI Xianling
Adhesives are widely used in opto-mechanical structure, and its influence on dynamics characteristic of opto-mechanical structure can’t be ignored. This paper researches the dynamics characteristic of lens sets with adhesives by Finite Element Model (FEM) analysis method. Three kinds of FEM, which are ignoring adhesiveAdhesives are widely used in opto-mechanical structure, and its influence on dynamics characteristic of opto-mechanical structure can’t be ignored. This paper researches the dynamics characteristic of lens sets with adhesives by Finite Element Model (FEM) analysis method. Three kinds of FEM, which are ignoring adhesives, node connection in bonded face and gluing in bonded face, are established respectively, and then modal analysis simulation of two kinds of lens sets with different adhesives is made. In order to validate the FEM, modal test of lens sets is taken to acquire the first-order modal frequency and modal shape. Comparison of simulation and test results indicates that error of ignoring adhesives model is large, whereas errors of the first-order modal frequency of node connection in bonded face model and bonded in gluing face model are both less than 5%, and modal shapes are consistent. It is indicated that node connection in bonded face model and gluing in bonded face model are effective. Further analysis of the influence of material property of adhesives on modal frequency of lens set is made, and the effect of Young’s modulus is obvious, but Poisson’s ration and density are insignificant. It supplies helpful guidance to choose opto-mechanical adhesives..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 75 (2014)
Processing Experiments of Digital in-line Holographic Video
WANG Fengpeng, DENG Shigui, ZHANG Xuanzhou, WANG Xingquan, and ZENG Xiangzhi
In dynamic digital holography, due to different objects at different distances recorded, and constantly changing, the reconstructed image was not always in a clear state. A continuous dynamic observation method based on digital in-line holographic video was proposed. The dynamic tracking focus and video processing algoIn dynamic digital holography, due to different objects at different distances recorded, and constantly changing, the reconstructed image was not always in a clear state. A continuous dynamic observation method based on digital in-line holographic video was proposed. The dynamic tracking focus and video processing algorithms were studied. The center of the measured object in the reconstructed image was used as the center of focusing window in the reconstructing for next frame of holographic video. The focusing window always follows the moving target all the time. Thus ensuring each frame of reconstructed video was in focused accurately, so that the observed target in the video was always in a clear state. In order to improve the processing speed of digital holographic video, the focused distance on a frame was used as the search center of reconstructed distance to avoid repeated operation when dealing with different holograms. Experimental results show that the proposed digital holographic video imaging technology can achieve the moving objects in three-dimensional space of continuous dynamic observation..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 81 (2014)
Computer Generated Hologram of Gyrator Transform and Its New Type Encoding Method
LIN Rui
The Computer Generated Hologram of Gyrator Transform (GT-CGH) is proposed based on the numerical algorithm of gyrator transform (GT) and the theory of Computer Generated Hologram (CGH). The Lohmann coding method is applied to produce the GT-CGHs at different transform angles. Their digital reconstructions are also realThe Computer Generated Hologram of Gyrator Transform (GT-CGH) is proposed based on the numerical algorithm of gyrator transform (GT) and the theory of Computer Generated Hologram (CGH). The Lohmann coding method is applied to produce the GT-CGHs at different transform angles. Their digital reconstructions are also realized respectively. The rules of reconstructions are consistent with the GT hologram reported in the relevant paper, which shows that it is feasible to create the GT-CGH. A novel encoding method, encoding by equivalent area of trapezium, is proposed for the CGH. This method can be effective to increase the phase quantization order in a single sampling unit.The simulation experiments of the creation and digital reconstruction are performed on CGH of Fourier Transform (FT-CGH) with the new encoding method. The results show that the reconstruction of the off-axis CGH at the 0th order diffraction can be realized by the application of new method. By using the new method, the production and the digital reconstruction of GT-CGH are also realized. The experimental results above all demonstrate the feasibility and validity of the proposed new type encoding method for the CGH..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 6, 87 (2014)
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