Phase retrieval from Fresnel zone intensity measurements by use of Gaussian filtering

The reconstruction of a complex-valued object from intensity measurements in the Fresnel zone region is considered. The reconstruction is based on the phase-retrieval method from Fresnel zone intensity data obtained by modulation of the object with a known Gaussian function and with its shifted functions along the horizontal and the vertical directions in rectangular coordinates. Two types of reconstruction system are presented. In the two systems a Gaussian amplitude filter and a Gaussian illuminating beam are used as the known Gaussian functions. Computer-simulated examples in two dimensions illustrate the performance of the reconstruction in these systems. (C) 1998 Optical Society of America