The development of phase diversity

Phase diversity is one kind of advanced wavefront sensing technique. The optical system involved is relatively simple. It makes use of the methods of optimization and image processing, which can jointly estimate the phase aberration and image with the focused and the additional defocused image of the same extended object. The method of phase diversity has been used in cophasing the segmented telescopes and recovering high quality image. The performance of the method is not yet perfect because its computations have been perceived as being too burdensome, and the range of wavefront detected is no more than one wave. There are still many problems to be discussed and studied for the application in the future.