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Proceedings Paper

Multiframe averaging and homomorphic filtering for clarification of dark and shadowed video scenes
Author(s): Samuel Grady Burgiss; Steven G. Goodridge
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Paper Abstract

In order to clarify detail of objects in shadows, we present a combination of frame averaging and homomorphic filtering. Multi-frame averaging allows exploitation of temporal redundancy in video to reduce noise present in dark scenes. One common method to enhance images suffering from low contrast is gain. Gain has the side effect of saturating brighter areas of the scene. Homomorphic filtering allows the effects of differing illumination conditions to be equalized across a scene. This is accomplished by applying a spatial high-pass filter to the natural log of pixel values. By following frame averaging with homomorphic filtering, details obscured by shadows may be clarified without losing important foreground information. Noise reduction through frame averaging greatly improves the results of homomorphic filtering, which usually amplifies Gaussian white noise.

Paper Details

Date Published: 21 February 2001
PDF: 9 pages
Proc. SPIE 4232, Enabling Technologies for Law Enforcement and Security, (21 February 2001); doi: 10.1117/12.417566
Show Author Affiliations
Samuel Grady Burgiss, Signalscape, Inc. (United States)
Steven G. Goodridge, Signalscape, Inc. (United States)

Published in SPIE Proceedings Vol. 4232:
Enabling Technologies for Law Enforcement and Security
Simon K. Bramble; Lenny I. Rudin; Simon K. Bramble; Edward M. Carapezza; Lenny I. Rudin, Editor(s)

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