Paper
11 January 2019 Analysis of correlation algorithms for Shack-Hartmann wavefront sensors
Author Affiliations +
Proceedings Volume 10837, 9th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes; 108370P (2019) https://doi.org/10.1117/12.2507015
Event: Ninth International Symposium on Advanced Optical Manufacturing and Testing Technologies (AOMATT2018), 2018, Chengdu, China
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.
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Zhaojun Xiong, Shanqiu Chen, Lizhi Dong, Ping Yang, Bing Xu, Wang Zhao, Xin Yu, Kangjian Yang, Xun Wang, and Xing He "Analysis of correlation algorithms for Shack-Hartmann wavefront sensors", Proc. SPIE 10837, 9th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, 108370P (11 January 2019); https://doi.org/10.1117/12.2507015
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KEYWORDS
Signal to noise ratio

Wavefront sensors

Detection and tracking algorithms

Image sensors

Spatial light modulators

Interference (communication)

Computer simulations

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