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The Improvement of the Correlation Method for Shack-Hartmann Wavefront Sensors using Multi-Resolution Method

다중 해상도 중심점 탐색법을 이용한 샥-하트만 센서용 상관관계법의 속도 개선

  • Yoo, Jae-Eun (Department of Mechanical Engineering, KAIST and Image Information Research Center) ;
  • Youn, Sung-Kie (Department of Mechanical Engineering, KAIST and Image Information Research Center)
  • 유재은 (한국과학기술원 기계공학과, 영상정보특화연구센터) ;
  • 윤성기 (한국과학기술원 기계공학과, 영상정보특화연구센터)
  • Published : 2008.02.29

Abstract

Shack-Hartmann sensors are widely employed as a wavefront measuring device in various applications. Adaptive optics is one of the major applications. Since an adaptive optics system should be operated in real-time, high-speed wavefront sensing is essential. In high-speed operation, integration time of an image detector is very short. In this case, noises such as readout noise and photon noise greatly influence the accuracy of wavefront sensing. Therefore a fast and noise-insensitive centroid finding algorithm is required for the real-time wavefront sensing. In this paper, the multi-resolution correlation method is proposed. By employing multi-resolution images, this method greatly reduces the computation time when compared to the fast Fourier transform (FFT) correlation method. The verification is performed through the computational simulation. In this paper, the center of mass method, correlation method and multi-resolution correlation method are employed to compare the measurement accuracy of the centroid finding algorithms. The accuracy of a Shack-Hartmann wavefront sensor using the proposed algorithm is proved to be comparable to that of the conventional correlation method.

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