Real-time optical intensity correlation using photorefractive BSO

Real-time optical intensity correlation using a photorefractive BSO crystal and a liquid crystal television is implemented. The underlying physics basis is considered, some specific techniques to improve the operation are proposed, and several optical pattern recognition tasks are achieved.<br/><br/>Photorefractive BSO is used as the holographic recording medium in the real-time intensity correlator. To improve the dynamic holographic recording, a moving grating technique is adopted. The nonlinear effects of moving gratings at large fringe modulation are experimentally investigated, and are compared with numerical predictions.<br/><br/>Optical bias is adopted to overcome the difficulty of a large drop in the optimum fringe velocity with moving gratings. The effects of optical bias on the optimum fringe velocity and on the diffraction efficiency are studied.<br/><br/>To overcome the inherent drawback of low discrimination of intensity correlation in optical pattern recognition, real-time edge-enhanced intensity correlation is achieved by means of nonlinear holographic recording in BSO.<br/><br/>Real-time colour object recognition is achieved by using a commercially available and inexpensive colour liquid crystal television in the intensity correlator. Multi-class object recognition is achieved with a synthetic discriminant function filter displayed by the Epson liquid crystal display in the real-time intensity correlator. The phase and intensity modulation properties of the Epson liquid crystal display are studied.<br/><br/>A further research topic which uses the Epson liquid crystal display to realize a newly designed spatial filter, the quantized amplitude-compensated matched filter, is proposed. The performance merits of the filter are investigated by means of computer simulations.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral Thesis

Grantor dc:publisher.institution

University of Abertay Dundee

Year dc:date.issued

1995

Author dc:creator

• Wang, Zhaoqi

Advisors dc:contributor.advisor

• Cartwright, Colin
• Gillespie, Allan

Language dc:language

eng

Identifier

oai:rke.abertay.ac.uk:studenttheses/f1330975-bc23-4532-ac7b-8aeb9cad8c81

OAI identifier oai:identifier

oai:rke.abertay.ac.uk:studenttheses/f1330975-bc23-4532-ac7b-8aeb9cad8c81