Joint transform correlator using photorefractie Bi12SiO20 crystal with improved discrimination

Santiago Vallmitjana; Colin M. Cartwright; Arturo Carnicer; N. J. Cook; Ignacio Prades Juvells; W. Allan Gillespie

doi:10.1117/12.246724

23 August 1996 Joint transform correlator using photorefractie Bi₁₂SiO₂₀ crystal with improved discrimination

Santiago Vallmitjana, Colin M. Cartwright, Arturo Carnicer, N. J. Cook, Ignacio Prades Juvells, W. Allan Gillespie

Proceedings Volume 2774, Design and Engineering of Optical Systems; (1996) https://doi.org/10.1117/12.246724
Event: Optical Instrumentation and Systems Design, 1996, Glasgow, United Kingdom

Abstract

An experimental realization of optical correlation for pattern recognition by using phase only filters as a reference in a real-time joint transform correlation is presented. The correlator operates with a liquid crystal television as the input and a photorefractive crystal at the recording plane. The use of photorefractive materials such as Bi₁₂SiO₂₀ as a dynamic holographic medium is becoming an interesting alternative to current liquid crystal based modulators in real-time optical image processing. In order to improve the performance of detection, the phase-only filter has been taken into account. Usually, this filter is used in the frequency domain, although it can be employed in the object space, becoming the reference in a joint transform correlator. As this filter requires negative values, holographic codification methods are required to encode it. Experimental results are presented and compared with those obtained with the classical matched filter.

Citation Download Citation

Santiago Vallmitjana, Colin M. Cartwright, Arturo Carnicer, N. J. Cook, Ignacio Prades Juvells, and W. Allan Gillespie "Joint transform correlator using photorefractie Bi₁₂SiO₂₀ crystal with improved discrimination", Proc. SPIE 2774, Design and Engineering of Optical Systems, (23 August 1996); https://doi.org/10.1117/12.246724

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