A Time-Sequenced Rotation Invariant Optical Correlator For Multiple Target Recognition

Thomas R. Walsh; Jack E. Cravatt; Brian A. Kast; Michael K. Giles

doi:10.1117/12.960443

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30 August 1989 A Time-Sequenced Rotation Invariant Optical Correlator For Multiple Target Recognition

Thomas R. Walsh, Jack E. Cravatt, Brian A. Kast, Michael K. Giles

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Proceedings Volume 1098, Aerospace Pattern Recognition; (1989) https://doi.org/10.1117/12.960443
Event: SPIE 1989 Technical Symposium on Aerospace Sensing, 1989, Orlando, FL, United States

Abstract

A hybrid computer-controlled optical correlator has been developed, assembled, and evaluated for use as a rotation invariant multiple target recognition system. The system consists of an optical correlator with magneto-optic spatial light modulators (MOSLMs) at the input and filter planes and a vidicon at the correlation plane. A COMPAQ 386 (IBM compatible) personal computer with a frame grabber board is used to acquire, binarize and load binary amplitude-only video images to the input MOSLM, to write sequential stored Hartley binary phase-only filters to the filter MOSLM, and to sample and statistically analyze correlation plane data in order to locate and recognize objects of interest in the input scene. The sequential correlations and output data samples are obtained at near video rates (15 per second, limited by the peak detection algorithm and the asynchronous video interface), allowing multiple targets at any in-plane rotation in a given input image to be located and classified in less than 5 seconds. The results of a computer simulation and experiments indicate that this system can correctly identify objects within its target class more than 95% of the time, even in the presence of severe clutter and high noise densities (noise toggles 10% of all binary pixels).

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Thomas R. Walsh, Jack E. Cravatt, Brian A. Kast, and Michael K. Giles "A Time-Sequenced Rotation Invariant Optical Correlator For Multiple Target Recognition", Proc. SPIE 1098, Aerospace Pattern Recognition, (30 August 1989); https://doi.org/10.1117/12.960443

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