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Proceedings Paper

Joint transform correlator using photorefractie Bi12SiO20 crystal with improved discrimination
Author(s): Santiago Vallmitjana; Colin M. Cartwright; Arturo Carnicer; N. J. Cook; Ignacio Prades Juvells; W. Allan Gillespie
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Paper 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.

Paper Details

Date Published: 23 August 1996
PDF: 8 pages
Proc. SPIE 2774, Design and Engineering of Optical Systems, (23 August 1996); doi: 10.1117/12.246724
Show Author Affiliations
Santiago Vallmitjana, Univ. de Barcelona (Spain)
Colin M. Cartwright, Univ. of Abertay Dundee (United Kingdom)
Arturo Carnicer, Univ. de Barcelona (Spain)
N. J. Cook, Univ. of Abertay Dundee (United Kingdom)
Ignacio Prades Juvells, Univ. de Barcelona (Spain)
W. Allan Gillespie, Univ. of Abertay Dundee (United Kingdom)

Published in SPIE Proceedings Vol. 2774:
Design and Engineering of Optical Systems
Joseph J. M. Braat, Editor(s)

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