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Analysis of correlation algorithms for Shack-Hartmann wavefront sensors
Author(s): Zhaojun Xiong; Shanqiu Chen; Lizhi Dong; Ping Yang; Bing Xu; Wang Zhao; Xin Yu; Kangjian Yang; Xun Wang; Xing He
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Paper Abstract

Shack-Hartmann wavefront sensors calculate the position of focal spot in each sub-aperture from intensity distributions, the noises of the detector itself would have a certain impact on the detecting accuracy and would lead to inaccurate wavefront detections using conventional centroiding method. It has been demonstrated that the correlation algorithms with template matching is able to improve the accuracy. In this paper, several correlation algorithms such as absolute difference function, absolute difference function-squared, square difference function, cross-correlation function and normalized cross-correlation are compared at different signal-to-noise ratios. To further improve the accuracy, interpolation algorithms including equiangular line fitting, parabola interpolation, gauss interpolation and least square method are brought in, which turns out that least square method could minimize the detecting error. Besides, simulations within single aperture and full aperture both illustrate that cross-correlation function is most robust but needs more calculations, so is least square method. Moreover, although absolute difference function would be inaccurate at low signal-to-noise ratios, it still can obtain high detecting accuracy at high signal-to-noise ratios and it minimizes the calculations.

Paper Details

Date Published: 11 January 2019
PDF: 8 pages
Proc. SPIE 10837, 9th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, 108370P (11 January 2019); doi: 10.1117/12.2507015
Show Author Affiliations
Zhaojun Xiong, Institute of Optics and Electronics (China)
Univ. of Chinese Academy of Sciences (China)
Shanqiu Chen, Institute of Optics and Electronics (China)
Lizhi Dong, Institute of Optics and Electronics (China)
Ping Yang, Institute of Optics and Electronics (China)
Bing Xu, Institute of Optics and Electronics (China)
Wang Zhao, Institute of Optics and Electronics (China)
Univ. of Chinese Academy of Sciences (China)
Xin Yu, Institute of Optics and Electronics (China)
Univ. of Chinese Academy of Sciences (China)
Kangjian Yang, Institute of Optics and Electronics (China)
Univ. of Chinese Academy of Sciences (China)
Xun Wang, Institute of Optics and Electronics (China)
Univ. of Chinese Academy of Sciences (China)
Xing He, Institute of Optics and Electronics (China)


Published in SPIE Proceedings Vol. 10837:
9th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes
Xiaoliang Ma; Bin Fan; Yongjian Wan; Adrian Russell; Xiangang Luo, Editor(s)

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