Adaptive Two-Dimensional Neighborhood Sensitivity Control By A One-Dimensional Process
Oliver A. Hilsenrath, Yehoshua Y. Josh Zeevi · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1988
The adaptive characteristics of the retina, which operates over an extremely wide range of light intensities, exceed by far the performance of serially accessed sensors such as vidicons or C.C.D.'s. The latter, operating over the entire optical field (or sampled grid) as a single neighborhood, are easily cut off by small areas of high intensity, resulting in the well known effect of "obscured images". Implementation of the biological solution of two-dimensional neighborhood processing, in which sensitivity at a given point is determined by the surrounding (receptive) field, would be the best solution. This approach requires, however, a new generation of still unavailable detector arrays with random access, neighborhood processing and local sensitivity feedback. The approach proposed in this paper is devised for sequentially accessed detectors/detector-arrays with one-dimensional processing, in which a Peano-Hilbert-like scan-path acquires visual data, thereby preserving a compact two-dimensional neighborhood relation. Neighborhood suppression is controlled by the expected value of a one-dimensional string, mapped onto the relevant two-dimensional neighborhood and subtracted, in turn, from the intensity of the delayed central element of the confined data string.