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Proceedings Paper

Strehl ratio and image sharpness for adaptive optics
Author(s): Julian C. Christou; Kenneth J. Mighell; Russell B. Makidon
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Paper Abstract

The performance of an adaptive optics system is typically given in terms of the Strehl ratio of a point spread function (PSF) measured in the focal plane of the system. The Strehl ratio measures the normalized peak intensity of the PSF compared to that of an ideal PSF, i.e. aberration-free, through the system. One advantage of this metric is that it has been shown to be proportional to the rms wavefront error via the Marechel approximation. Thus, Strehl ratio measurements are used to determine the performance of the system. Measurement of the Strehl ratio is frequently problematic in the presence of noise as can be the peak determination for critically sampled data. We have looked at alternative metrics, in particular the S1 sharpness metric. This metric measures the compactness of the PSF by the normalized sum of the squared image intensity and therefore relates to the intensity variance of the image. Using simulated AO PSFs, we show that there is a unique relationship between S1 and the Strehl ratio and we can therefore relate it back to the rms wavefront error.

Paper Details

Date Published: 28 June 2006
PDF: 12 pages
Proc. SPIE 6272, Advances in Adaptive Optics II, 62721Y (28 June 2006); doi: 10.1117/12.670430
Show Author Affiliations
Julian C. Christou, Ctr. for Adaptive Optics, Univ. of California, Santa Cruz (United States)
Kenneth J. Mighell, National Optical Astronomy Observatories (United States)
Russell B. Makidon, Space Telescope Science Institute (United States)

Published in SPIE Proceedings Vol. 6272:
Advances in Adaptive Optics II
Brent L. Ellerbroek; Domenico Bonaccini Calia, Editor(s)

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