Composite two-dimensional phase-restoration procedure

A four-step phase-restoration procedure that provides faithful reconstructions of images consisting of faint detail superimposed upon bright, broad backgrounds is presented. Such images tend to cause existing phase-retrieval algorithms considerable difficulty. The two middle steps consist of the simplest of our recently reported phaserestoration schemes and of Fienup’s algorithm. The first and crucial step is to subtract a fraction of the central lobe of the given intensity of the Fourier transform of the image. The image is then reconstructed in two parts, which are combined in the final step. Encouraging computational results are presented.