Region adaptive correction method for radial distortion of fish-eye image

2012 ◽  
Author(s):  
Ki Sun Song ◽  
Young Seok Han ◽  
Moon Gi Kang
Keyword(s):  
Correction Method ◽  
Radial Distortion ◽  
Adaptive Correction ◽  
Fish Eye

CCD Nonuniformity Adaptive Correction Method Based on Empirical Mode Decomposition

2010 ◽  
Vol 30 (7) ◽  
pp. 2012-2016
Author(s):  
李静 Li Jing ◽  
王军政 Wang Junzheng ◽  
汪首坤 Wang Shoukun ◽  
沈伟 Shen Wei
Keyword(s):  
Empirical Mode Decomposition ◽  
Correction Method ◽  
Mode Decomposition ◽  
Adaptive Correction

Radial Distortion Correction of Fish-Eye Lens Using Straight Lines

2013 ◽  
Vol 432 ◽  
pp. 364-367
Author(s):  
Jong Eun Ha
Keyword(s):  
Distortion Correction ◽  
Eye Lens ◽  
Wide Field ◽  
Lens Model ◽  
Radial Distortion ◽  
Straight Line ◽  
Wide Field Of View ◽  
Planar Pattern ◽  
Straight Lines ◽  
Fish Eye

Fish-eye lens is used in various applications because it can give wide field of view. But, it deviates from the conventional pin-hole camera assumption. It has large radial distortion compared to the conventional lens. In this paper, we present an algorithm for radial distortion correction of fish-eye lens using the property of straight line. First, we estimate the center of radial distortion using the algorithm of Hartely and Kang [4]. We adopt fish-eye lens model of Devernay and Faugeras [5] and estimate the parameter thorough searching. We use planar pattern with chessboard and generate undistorted points by given parameter value. We evaluate the correctness of the parameter by checking the distance of a point to the fitted line. In experiments, we compare proposed algorithm with Wang et al. [6]. Proposed algorithm gives more stable result with less distortion error.

scholarly journals Measurement of the PMSM Shaft Position with An Absolute Encoder

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1229
Author(s):  
Tomasz Rudnicki
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Permanent Magnet Synchronous Motor ◽  
Correction Method ◽  
Synchronous Motor ◽  
Motor Speed ◽  
Motor Shaft ◽  
Adaptive Correction ◽  
Absolute Encoder ◽  
Motor Operation

The most critical aspect of assessing a permanent magnet synchronous motor is the problem of correctly measuring the position of the synchronous motor shaft. The purpose of this article was to show the effects of employing an absolute encoder to control a synchronous motor with permanent magnets while encountering disturbances. This problem is often overlooked, but it appears from time to time. The correct measurement of the shaft position eliminates improper motor operation characterized by jerking. The article showed that despite momentary erroneous readings of the shaft’s position, it was still possible to control the permanent magnet synchronous motor (PMSM). This also allows for correct measurement of the motor speed. This paper originally proposed an adaptive correction method for a rotary encoder.

scholarly journals Deep Learning Assisted Zonal Adaptive Aberration Correction

2021 ◽  
Vol 8 ◽  
Author(s):  
Biwei Zhang ◽  
Jiazhu Zhu ◽  
Ke Si ◽  
Wei Gong
Keyword(s):  
Deep Learning ◽  
Adaptive Optics ◽  
Degrees Of Freedom ◽  
Correction Method ◽  
Tissue Imaging ◽  
Optical Aberrations ◽  
Volume Imaging ◽  
Adaptive Correction ◽  
Average Mean Square Error ◽  
Deep Tissue Imaging

Deep learning (DL) has been recently applied to adaptive optics (AO) to correct optical aberrations rapidly in biomedical imaging. Here we propose a DL assisted zonal adaptive correction method to perform corrections of high degrees of freedom while maintaining the fast speed. With a trained DL neural network, the pattern on the correction device which is divided into multiple zone phase elements can be directly inferred from the aberration distorted point-spread function image in this method. The inference can be completed in 12.6 ms with the average mean square error 0.88 when 224 zones are used. The results show a good performance on aberrations of different complexities. Since no extra device is required, this method has potentials in deep tissue imaging and large volume imaging.

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