The technique of moving gratings in a photorefractive crystal is applied to the edge enhancement of objects and edge-enhanced optical correlation. The nonlinear dependence of the optimum fringe velocity on the fringe modulation and the variation of the enhancement of the diffraction efficiency with fringe modulation at a fixed fringe velocity appropriate to high fringe modulations are experimentally investigated. It is shown that the diffraction at high fringe modulations, which corresponds to the high-spatial-frequency components of the Fourier spectrum, is enhanced by a factor of approximately 3.7, whereas the diffraction at low fringe modulations is suppressed by a factor of 0.6. The proposed technique has the advantages of real-time enhancement, arbitrary selection of the spatial frequency to be enhanced, and improved stability of the output. Experimental results of the edge enhancement of objects and edge-enhanced correlation are presented.
© 1998 Optical Society of America
Zhaoqi Wang, Hui Zhang, Colin M. Cartwright, Meisong S. Ding, Nick J. Cook, and W. Allan Gillespie, "Edge Enhancement by Use of Moving Gratings in a Bismuth Silicon Oxide Crystal and its Application to Optical Correlation," Appl. Opt. 37, 4449-4456 (1998)