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Proceedings Paper

Image enhancement for astronomical scenes
Author(s): Jacob Lucas; Brandoch Calef; Keith Knox
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Paper Abstract

Telescope images of astronomical objects and man-made satellites are frequently characterized by high dynamic range and low SNR. We consider the problem of how to enhance these images, with the aim of making them visually useful rather than radiometrically accurate. Standard contrast and histogram adjustment tends to strongly amplify noise in dark regions of the image. Sophisticated techniques have been developed to address this problem in the context of natural scenes. However, these techniques often misbehave when confronted with low-SNR scenes that are also mostly empty space. We compare two classes of algorithms: contrast-limited adaptive histogram equalization, which achieves spatial localization via a tiling of the image, and gradient-domain techniques, which perform localized contrast adjustment by non-linearly remapping the gradient of the image in a content-dependent manner. We extend these to include a priori knowledge of SNR and the processing (e.g. deconvolution) that was applied in the preparation of the image. The methods will be illustrated with images of satellites from a ground-based telescope.

Paper Details

Date Published: 26 September 2013
PDF: 8 pages
Proc. SPIE 8856, Applications of Digital Image Processing XXXVI, 885603 (26 September 2013); doi: 10.1117/12.2025191
Show Author Affiliations
Jacob Lucas, The Boeing Co. (United States)
Brandoch Calef, The Boeing Co. (United States)
Keith Knox, Air Force Research Lab. (United States)


Published in SPIE Proceedings Vol. 8856:
Applications of Digital Image Processing XXXVI
Andrew G. Tescher, Editor(s)

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