Paper
21 February 2001 Multiframe averaging and homomorphic filtering for clarification of dark and shadowed video scenes
Samuel Grady Burgiss Jr., Steven G. Goodridge
Author Affiliations +
Proceedings Volume 4232, Enabling Technologies for Law Enforcement and Security; (2001) https://doi.org/10.1117/12.417566
Event: Enabling Technologies for Law Enforcement, 2000, Boston, MA, United States
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.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Samuel Grady Burgiss Jr. and Steven G. Goodridge "Multiframe averaging and homomorphic filtering for clarification of dark and shadowed video scenes", Proc. SPIE 4232, Enabling Technologies for Law Enforcement and Security, (21 February 2001); https://doi.org/10.1117/12.417566
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Cited by 3 scholarly publications.
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KEYWORDS
Video

Image filtering

Image processing

Video processing

Image enhancement

Reflectivity

Light sources and illumination

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