Image reconstruction from partial Fresnel zone information

An iterative algorithm for reconstructing an image from partial Fresnel zone information is described. With the standard 4-F canonical optical processor, processing is done midway between the two lenses in the Fourier transform plane. While others have studied iterative methods of reconstruction from partial Fourier plane information, we have investigated methods of reconstructing an object from partial information in the Fresnel region of an optical processor. Iterative algorithms for reconstructing an object from either the phase or magnitude of the Fresnel zone transform are described. In the case of reconstructing an image from Fresnel zone magnitude, we obtain good images in fewer iterations at locations which are further from the Fourier plane. Reconstructing an image from the Fresnel zone phase is fairly insensitive to this shift out of the Fourier plane.