Incoherent optical processing via spatially offset pupil masks.

Once it is appreciated that a lens imaging with spatially incoherent light may be interpreted as a spatial filter, it is natural to ask what freedom exists in lens design to implement an arbitrary filter function (or OTF, as it is known). Specifically, is it possible to implement OTFs for specialized data processing operations, such as radar pulse compression or deblurring radiographic images? The conventional answer to such questions is negative; the answer becomes affirmative if a hybrid approach is followed. This approach departs significantly from conventional optical processing, since it exploits the diffraction of light emanating from a spatially incoherent source. Two advantages follow: (1) resistance to noise and (2) relaxed requirements on input and output devices. It is the purpose of this paper to explain, demonstrate, and explore this new approach to optical processing, in which the essentially coherent operations lacked by incoherent optics are performed electronically.