Compact portable optical correlator with binary ferroelectric SLMs and optimum filters for disjoint noise applied to varying illumination conditions

Henrik Sjoeberg; Lech Wosinski; Bertrand Noharet

doi:10.1117/12.270363

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27 March 1997 Compact portable optical correlator with binary ferroelectric SLMs and optimum filters for disjoint noise applied to varying illumination conditions

Henrik Sjoeberg, Lech Wosinski, Bertrand Noharet

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Proceedings Volume 3073, Optical Pattern Recognition VIII; (1997) https://doi.org/10.1117/12.270363
Event: AeroSense '97, 1997, Orlando, FL, United States

Abstract

A compact optical correlator based on binary liquid crystal spatial light modulators has been built. The correlator has a 21 X 28 cm² footprint and can process 256 X 256 pixel images at a maximum frame rate of 220 Hz. The system is insensitive to transportation and can be used both in VLC and JTC configuration. It can process live images from an external camera as well as images from computer memory. Variations of illumination conditions can change the graylevels and perceptible details of a target considerably. When this is the case, classical filters like phase only and optimal trade-off fail to detect the target. An improvement of the results can be achieved by using the optimum generalized filter. In most cases, the contour of the target remains more or less the same even if the graylevels are fluctuating. We show that by edge-enhancing and binarizing the input images used together with the optimum generalized filter we can achieve comparable results as compared to using grayscale images.

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Henrik Sjoeberg, Lech Wosinski, and Bertrand Noharet "Compact portable optical correlator with binary ferroelectric SLMs and optimum filters for disjoint noise applied to varying illumination conditions", Proc. SPIE 3073, Optical Pattern Recognition VIII, (27 March 1997); https://doi.org/10.1117/12.270363

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