Optical signal dependent noise reduction by variable spatial thresholding of the fourier transform

摘要

Spatially variable nonlinear optical thresholding in the Fourier plane reduces signal-dependent noise, such as scalar multiplicative noise. Coherent artifact noise reduction by a factor of four is attained using deamplifying photorefractive two-beam coupling. A variable light transmittance threshold across a spatially thresholded light modulating element such as a photorefractive crystal is utilized for this purpose.