Phase retrieval in imaging

The phase problem (PP) in imaging is reviewed in this paper, i.e., retrieving the phase of the image field from the recorded image irradiance distribution. The PP in one spatial lateral dimension (perpendicular to the optic axis) is treated from analytical (uniqueness) and numerical points of view (algorithms). A heuristic discussion of the 2-D PP is given based on the approach by Bruck and Sodin.