Phase retrieval implies extraction of a wavefront θ(f) at one spatial plane based on the intensity p(x) in a conjugate plane. For example, θ(f) might be the phase distortion at the entrance pupil of an imaging system when a distant point source is imaged through a turbulent atmosphere; p(x) is the real, non-negative point spread function measured in the image plane. In this paper we describe the mathematics of the technique and show computer simulations.
Robert A. Gonsalves,
"Wavefront Sensing By Phase Retrieval", Proc. SPIE 0207, Applications of Digital Image Processing III, (28 December 1979); doi: 10.1117/12.958223; https://doi.org/10.1117/12.958223