Image processing by nonlinear spatial frequency filtering

Abstract

The nonlinearities of liquids (CS2, CHCL3, CH3COCH3) and photorefractive materials (BSO, BGO, Fe:LiNbO3) are used to filter the Fourier spectrum of an object. Image processing techniques such as contrast inversion or contrast enhancement of amplitude object and phase object visualization are obtained with simple optical devices and low power CW laser.