Stationary phase approximations in Fresnel-zone magnitude-only reconstructions

Abstract

An analytic approximation of an iterative method of image reconstruction from Fresnel-zone magnitude data is discussed. The method of stationary phase is used to estimate both the Fresnel-zone transform and the inverse Fresnel-zone transform. With this theory we can explain why fewer iterations are needed for good images to be obtained at locations in the Fresnel-zone region of an optical processor that are farther from the Fourier-transform plane.