MACH BANDS - HOW MANY MODELS ARE POSSIBLE - RECENT EXPERIMENTAL FINDINGS AND MODELING ATTEMPTS

Mach bands are illusory bright and dark bands seen where a luminance p lateau meets a ramp, as in half-shadows or penumbras. A tremendous amo unt of work has been devoted to studying the psychophysics and the pot ential underlying neural circuitry concerning this phenomenon. A numbe r of theoretical models also have been proposed, originating in the se minal studies of Mach himself. The present article reviews the main ex perimental findings after 1965 and the main recent theories of early v ision that have attempted to account for the effect. It is shown that the different theories share working principles and can be grouped int o three classes: (a) feature-based; (b) rule-based; and (c) filling-in . In order to evaluate individual proposals, it is necessary to consid er them in the larger picture of visual science and to determine how t hey contribute to the understanding of vision in general. Copyright (C ) 1996 Elsevier Science Ltd.