AN INTEGRATED CORTICAL LAYER FOR ORIENTATION ENHANCEMENT

This paper presents a set of two analog chips performing the following chain of operations: phototransduction of an image projected on the f irst chip, edge enhancement by high-pass filtering, current-to-pulse f requency conversion of the filtered image, and pulse coded transmissio n of the filtered image to the second chip which generates a ''project ive held'' whose shape and size are widely programmable through few bi as lines, The end result of the processing chain is an image with enha nced edges along a programmable orientation, The design of this system draws from the knowledge gathered by neurobiologists about the first steps of visual perception: retinal image processing and coding follow ed by ''simple cells'' processing in the visual cortex, The focus of t he paper is on the cortical layer chip since information about the ret ina is available elsewhere [12], The system's main advantages are real time operation and ease of module interconnection for true parallel p rocessing.