Abstract

Performing optical processing operations directly on noncoherent objects offers obvious advantages. Two approaches, grating interferometers [W. Stoner, Appl. Opt. 16, 1451 (1977)] and two-pupil methods [A. W. Lohmann and W. T. Rhodes, Appl. Opt. 17, 1141 (1978)], have been proposed. We propose to employ the spatial coherence function generated by a spatially noncoherent distant object. A discrete record of this function already has been used in radioastronomy [P. Kellman, S. Leonard, and E. Barrett, Appl. Opt. 16, 1113 (1977)]. However, utilizing a wavefront folding interferometer it is possible to make a hologram of a distant noncoherent object by encoding the spatial coherence function. This hologram may be called a coherence hologram. In the reconstruction step the coherence hologram is illuminated by a plane uniform noncoherent source. The reconstruction is obtained by employing the same interferometric arrangement as that used to make the hologram. Furthermore, optical processing of such noncoherent objects can be accomplished by modifying in a special way the intensity distribution of the plane noncoherent source used in the reconstruction step. Examples of matched filtering, high-pass filtering, and low- pass filtering are discussed.

© 1986 Optical Society of America