Nonisoplanatic imaging by phase diversity

Phase diversity allows one to use multiple images with known phase changes such as defocus to learn the optical characteristics of an imaging medium and to estimate the unknown object. It is shown that the method can be extended to the case in which the optical system is nonisoplanatic; thus it can recover both the extended object and the angle-dependent, aberrating phase of the medium. The technique is a timely extension of the conventional phase-diversity concept and could be used to solve the isoplanatic patch problem of adaptive optics, to determine a spatially varying point-spread function in image restoration, and to image through a single-fiber optic.