Silicon models of lateral inhibition

The neurological process known as lateral inhibition (LI) has long been acknowledged as a critical operation for the preprocessing many types of sensory stimuli. In the mammalian retina, LI is utilized to enhance visual images by performing differential amplification on the pixels from which the image is composed. In this study, LI is implemented using VLSI-based models. These models consist of small two-dimensional arrays of generalized sensory pixels, each of which inhibits, and in turn is inhibited by, each of its immediate neighbors. Two custom CMOS array prototypes circuits have been designed, fabricated, and characterized. Test results indicate that both circuits are able to impart contrast to arbitrary two-dimensional geometric images in a flexible yet stable manner, and do so immediately and simultaneously. These arrays thus offer a level of performance not attainable by software methods, making this method well suited for machine vision systems that utilize parallel architectures.