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Proceedings Paper

The optical synthetic aperture image restoration based on the improved maximum-likelihood algorithm
Author(s): Zexun Geng; Qing Xu; Baoming Zhang; Zhihui Gong
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Paper Abstract

Optical synthetic aperture imaging (OSAI) can be envisaged in the future for improving the image resolution from high altitude orbits. Several future projects are based on optical synthetic aperture for science or earth observation. Comparing with equivalent monolithic telescopes, however, the partly filled aperture of OSAI induces the attenuation of the modulation transfer function of the system. Consequently, images acquired by OSAI instrument have to be post-processed to restore ones equivalent in resolution to that of a single filled aperture. The maximum-likelihood (ML) algorithm proposed by Benvenuto performed better than traditional Wiener filter did, but it didn't work stably and the point spread function (PSF), was assumed to be known and unchanged in iterative restoration. In fact, the PSF is unknown in most cases, and its estimation was expected to be updated alternatively in optimization. Facing these limitations of this method, an improved ML (IML) reconstruction algorithm was proposed in this paper, which incorporated PSF estimation by means of parameter identification into ML, and updated the PSF successively during iteration. Accordingly, the IML algorithm converged stably and reached better results. Experiment results showed that the proposed algorithm performed much better than ML did in peak signal to noise ratio, mean square error and the average contrast evaluation indexes.

Paper Details

Date Published: 24 September 2012
PDF: 10 pages
Proc. SPIE 8451, Software and Cyberinfrastructure for Astronomy II, 845139 (24 September 2012); doi: 10.1117/12.925301
Show Author Affiliations
Zexun Geng, Zhengzhou Institute of Surveying and Mapping (China)
Qing Xu, Zhengzhou Institute of Surveying and Mapping (China)
Baoming Zhang, Zhengzhou Institute of Surveying and Mapping (China)
Zhihui Gong, Zhengzhou Institute of Surveying and Mapping (China)

Published in SPIE Proceedings Vol. 8451:
Software and Cyberinfrastructure for Astronomy II
Nicole M. Radziwill; Gianluca Chiozzi, Editor(s)

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