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Proceedings Paper

Low-light level recognition using COTS optical correlator
Author(s): Alain Bergeron
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Paper Abstract

Optical correlation offers high speed processing capabilities of images mainly for filtering and pattern recognition applications. For a long time it has been kept in the laboratories at the state of prototype. The apparition of commercially available source of optical correlator opens the way to a wider spread of this technology. In real-time systems, illumination is an important issue, and has a strong impact on the final result of the correlation. In real-life applications, the level of illumination can vary depending of the environment, time of the day, etc. Two consequences result from the change of the illumination level, the first one is the reduction of the energy signature provided by the object, the second one is the relative augmentation of noise in the input scene. These two facts combined together can directly affect the value of the correlation peak. In off-line process these variations can be partly compensated by normalization of the input image. In live applications compensation has to be made in real-time. In this paper, results of live experiments performed with a COTS correlator are shown. The results indicate that live optical correlation can support a large amount of ambient light reduction in the input image provided that some kind of real-time feedback is provided to artificially increase the dynamical range of input gray level. The results shows that optical correlation, basically an integration operator, can identify object otherwise difficult to analyse conveniently by human being.

Paper Details

Date Published: 6 March 2002
PDF: 8 pages
Proc. SPIE 4734, Optical Pattern Recognition XIII, (6 March 2002); doi: 10.1117/12.458421
Show Author Affiliations
Alain Bergeron, National Optics Institute (Canada)

Published in SPIE Proceedings Vol. 4734:
Optical Pattern Recognition XIII
David P. Casasent; Tien-Hsin Chao, Editor(s)

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