Abstract

An optoelectronic system is described that can segment a natural scene into regions of different texture characteristics, independent of the illumination levels in those regions. The system consists of a cascade of a thresholding hard-limiting spatial light modulator with controllable threshold, a bank of coherent spatial filters designed for specific textures, a square-law operation (coherent-to-incoherent conversion), a low-pass incoherent spatial filter, and a final thresholding-hard-limiting operation. The scheme works because thresholding at the local texture median produces a binary distribution that preserves considerable texture-related information and that has maximum energy per unit area in non-zero spatial frequencies. In addition, that energy per unit area is the same, independent of the specific texture, implying that only the distribution of spectral energy is different and that selective filtering can be used to discriminate in favor of a given texture and against others. The basic system and its underlying theory of operation will be discussed, and the results of numerical experiments will be presented.

© 1992 Optical Society of America