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Cascade Kalman filter for gravity anomaly distortion correction based on second order potential model

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Journal of Southeast University(English Edition) 2008年第4期24卷 482-486页

作者：赵立业李宏生周百令李坤宇东南大学仪器科学与工程学院南京210096

Using a gravity anomaly covariance function based on the second-order Ganssian Markov gravity anomaly potential model, the state equation of a gravity anomaly signal is obtained in marine gravimetry. Combined with the system state equation and the measurement equation, a new method of the cascade Kalman filter is proposed and applied to the correction of gravity anomaly distortion. In the signal processing procedure, an inverse Kalman filter is used to restore the gravity anomaly signal and high frequency noises first. Then an adaptive Kalman filter, which uses the gravity anomaly state equation as the system equation, is set to estimate the actual gravity anomaly data. Emulations and experiments indicate that both the cascade Kalman filter method and the single inverse Kalman filter method are effective in alleviating the distortion of the gravity anomaly signal, but the performance of the cascade Kalman filter method is better than that of the single inverse Kalman filter method.

关键词： gravimeter gravity anomaly cascade Kalman filter inverse Kalman filter distortion correction

Lens distortion correction based on one chessboard pattern image

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Frontiers of Optoelectronics 2015年第3期8卷 319-328页

作者： Yubin WU Shixiong JIANG Zhenkun XU Song ZHU Danhua CAO School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 China

This paper proposes a detection method of chessboard comer to correct camera distortions -including radial distortion, decentering distortion and prism distor- tion. This proposed method could achieve high comer detection rate. Then we used iterative procedure to optimize distortion parameter to minimize distortion residual. In this method, first, non-distortion points are evaluated by four points near image center; secondly, Levenberg-Marquardt nonlinear optimization algorithm was adopted to calculate distortion parameters, and then to correct image by these parameters; thirdly, we calculated comer points on the corrected image, and repeated previous two steps until distortion parameters converge. Results showed the proposed method by iterative procedure can make the impact of slight distortion around image center negligible and the average of distortion residual of one line is almost 0.3 pixels.

关键词： computer vision camera distortion distortion correction comer detection

Straight line feature based image distortion correction

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Engineering Sciences 2008年第2期6卷 83-86,96页

作者： Zhang Haofeng Zhao Chunxia Lu Jianfeng Tang Zhenmin Yang Jingyu Dept. of Computer Science Nanjing Univ. of Sci. ＆ Tech. Nanjing Jiangsu 210094 China

An image distortion correction method is proposed, which uses the straight line features. Many parallel lines of different direction from different images were extracted, and then were used to optimize the distortion parameters by nonlinear least square. The thought of step by step was added when the optimization method working. 3D world coordination is not need to know, and the method is easy to implement. The experiment result shows its high accuracy.

关键词： distortion correction straight line feature nonlinear least square multi-step optimization

Researches on Image distortion correction Method Based on Image Magnification

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Researches on Image Distortion Correction Method Based on Im...

On Filter distortion correction for Laser Probe

2012 International Conference on Advances in Materials Science and Engineering(AMSE 2012)

作者： Xiaoying Jiang Jianliang Xu Xiaofen Fang Xinxing Zhang Yinling Peng Kunli Fang School of Mechanical Engineering Quzhou University School of Mechanical and Electrical Engineering Quzhou College of Technology

A new method to correct a distorted image is proposed in this paper, which is based on the relationship between image magnification and distortion ***, the image magnification is ***, the image distorted coefficient can be obtained with simple linear ***, experiments are carried out, and the correction results obtained by the collinear points-based method are compared with the method proposed in this *** results show that both provide good correction *** the same time, the accuracy of the new proposed method is *** proposed method takes the advantages of simple algorithm, few known conditions and fast computing *** new method has great significance in engineering metrology and complex condition.

关键词： distortion correction distortion coefficient Magnification Line-fitting

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On Filter Distortion Correction for Laser Probe

Ray tracing particle image velocimetry-Challenges in the application to a packed bed

2011 Chinese Control and Decision Conference（CCDC）

作者： Hu Ying is with the Automation Research Center,Dalian Maritime University,Dalian 116026,China.Yang Yun-xiang is with the Automation Research Center,Dalian Maritime University,Dalian 116026,China

As to improve the environmental adaptability of laser probe,filter is installed on the *** the measurement accuracy will be depressed by the distortion of image brought by the *** this paper,the effect of filter to imaging feature is discussed in detail *** the distortion model is established through theoretical and experimental ***,the distortion model is added into the probe calibration model and the distortion is corrected at probe calibration *** the experiment of object scanning and registration,it is conclude that the model is effective and it can ensure the measurement accuracy of laser probe.

关键词： Laser probe Filter distortion correction

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Particuology 2024年第1期84卷 194-208页

作者： Christin Velten Mirko Ebert Christian Lessig Katharina Zahringer Lehrstuhl für Strömungsmechanik und Strömungstechnik Otto-von-Guericke-Universität Magdeburg39106MagdeburgGermany Institut für Simulation und Graphik Otto-von-Guericke-Universität Magdeburg39106MagdeburgGermany

Ray tracing Particle Image Velocimetry(RT-PIV)is an optical technique for high resolution velocity measurements in challenging optical systems,such as transparent packed beds,that uses ray tracing to correct for distortions introduced by transparent geometries in the light *** ray tracing based correction is a post processing step applied to the raw PIV particle images before classical PIV *** this study,RT-PIV is performed in the top layer of a body centred cubic(bcc)sphere packing with gaseous flow,where optical access is obtained by the use of transparent N-BK7 glass balls with a diameter of d=40 ***-PIV introduces new experimental and numerical challenges,for example a limited field of view,illumination difficulties,a very large required depth of field and high sensitivity to geometric parameters used in the ray tracing *** challenges and their implications are the main scope and discussed in the present ***,the validation of the ray tracing reconstruction step is presented and examples for the obtained corrected vector fields in a packed bed are *** results show the strength of the method in reconstructing velocity fields behind transparent spheres that would not have been accessible by optical measurement techniques without the ray tracing correction.

关键词： Ray tracing particle image velocimetry(RT-PIV) Transparent spherical particles Packed bed distortion correction Gas flow

correction Optimization of Lens Radial distortion with Bending Measurement Function

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天津大学学报：英文版 2016年第4期22卷 374-379页

作者：张敏吴凡路金龙旭李国宁韩双丽张宇 Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Precision Measuring Technology and Instruments Tianjin University Tianjin 300072 China

In this paper, a distortion correction method with reduced complexity is proposed. With the singleparameter division model, the initial approximation of distortion parameters and the distortion center can be calibrated. Based on the distance from the image center to the fitting lines of the extracted curves, a bending measurement function with a weighted factor is proposed to optimize the initial value. Simulation and experiments verify the proposed method.

关键词： arc fitting camera calibration distortion correction division model field angle

A corrected method of distorted printed circuit board image

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Chinese Physics B 2011年第1期20卷 366-370页

作者：乔闹生叶玉堂黄永林 School of Optoelectronic Information University of Electronic Science and Technology of China School of Physics and Electronics Hunan University of Arts and Science

This paper proposes a corrected method of distorted image based on adaptive control. First, the adaptive control relationship of pixel point positions between distorted image and its corrected image is given by using polynomial fitting, thus control point pairs between the distorted image and its corrected image are found. Secondly, the value of both image distortion centre and polynomial coefficient is obtained with least square method, thus the relationship of each control point pairs is deduced. In the course of distortion image processing, the gray value of the corrected image is changed into integer with bilinear interpolation. Finally, the experiments are performed to correct two distorted printed circuit board images. The results are perfect and the mean square errors of residual error are tiny.

关键词： distortion correction adaptive control printed circuit board image mean square errorof residual error

Spatial weight matrix in dimensionality reduction reconstruction for microelectromechanical system-based photoacoustic microscopy

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Visual Computing for Industry,Biomedicine,and Art 2020年第1期3卷 247-256页

作者： Yuanzheng Ma Chang Lu Kedi Xiong Wuyu Zhang Sihua Yang MOE Key Laboratory of Laser Life Science&Institute of Laser Life Science College of BiophotonicsSouth China Normal UniversityGuangzhou 510631China Guangdong Provincial Key Laboratory of Laser Life Science College of BiophotonicsSouth China Normal UniversityGuangzhou 510631China

A micro-electromechanical system(MEMS)scanning mirror accelerates the raster scanning of optical-resolution photoacoustic microscopy(OR-PAM).However,the nonlinear tilt angular-voltage characteristic of a MEMS mirror introduces distortion into the maximum back-projection ***,the size of the airy disk,ultrasonic sensor properties,and thermal effects decrease the ***,in this study,we proposed a spatial weight matrix(SWM)with a dimensionality reduction for image *** three-layer SWM contains the invariable information of the system,which includes a spatial dependent distortion correction and 3D *** employed an ordinal-valued Markov random field and the Harris Stephen algorithm,as well as a modified delay-and-sum method during a time *** results from the experiments and a quantitative analysis demonstrate that images can be effectively reconstructed using an SWM;this is also true for severely distorted *** index of the mutual information between the reference images and registered images was 70.33 times higher than the initial index,on ***,the peak signal-to-noise ratio was increased by 17.08%after 3D *** accomplishment offers a practical approach to image reconstruction and a promising method to achieve a real-time distortion correction for MEMS-based OR-PAM.

关键词： Photoacoustic microscopy Spatial weight matrix Dimensionality reduction distortion correction Mutual information