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Proceedings Paper

Can broad-band image restoration rival speckle restoration?
Author(s): Donald Fraser; Andrew J. Lambert; M. Reza Sayyah Jahromi; David Clyde; Nikila Donaldson
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Paper Abstract

The restoration of images formed through atmospheric turbulence is usually attempted through operating on a sequence of speckle images. The reason is that high spatial frequencies in each speckle image are effectively retained though reduced in magnitude and distorted in phase. However, speckle imaging requires that the light is quasi-monochromatic. An alternative possibility, discussed here, is to capture a sequence of images through a broadband filter, correct for any local warping due to position-dependent tip-tilt effects, and average over a large number of images. In this preliminary investigation, we simulate several optical transfer functions to compare the signal levels in each case. The investigation followed encouraging results that we obtained recently using a blind-deconvolution approach. The advantages of such a method are that narrow-band filtering is not required, simplifying the equipment and allowing more photons for each short exposure image, while the method lends itself to restoration over fields of view wider than the isoplanatic patch without the need to mosaic. The preliminary conclusions are that, so long as the ratio of the telescope objective diameter, D, to Fried parameter, r0, is less than about 5, the method may be a simple alternative to speckle imaging.

Paper Details

Date Published: 23 December 2002
PDF: 8 pages
Proc. SPIE 4792, Image Reconstruction from Incomplete Data II, (23 December 2002); doi: 10.1117/12.451788
Show Author Affiliations
Donald Fraser, Univ. of New South Wales (Australia)
Andrew J. Lambert, Univ. of New South Wales (Australia)
M. Reza Sayyah Jahromi, Univ. of New South Wales (Australia)
David Clyde, Univ. of New South Wales (Australia)
Nikila Donaldson, Univ. of New South Wales (Australia)

Published in SPIE Proceedings Vol. 4792:
Image Reconstruction from Incomplete Data II
Philip J. Bones; Michael A. Fiddy; Rick P. Millane, Editor(s)

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