Non-classical receptive field inhibition and its relation to orientation-contrast pop-out and line and contour saliency ─ a computational approach

N Petkov, M A Westenberg (Institute of Mathematics and Computing Science, University of Groningen, Postbus 800, 9700 AV Groningen, Netherlands; email: petkov@cs.rug.nl; website: http://www.cs.rug.nl/~petkov )

Non-classical receptive field (non-CRF) inhibition has been suggested as the possible origin of various perceptual effects, such as overestimation of an acute angle between two lines [Blakemore et al., 1970 Nature 228 37-39] and orientation-contrast pop-out [Knierim and van Essen, 1992 J. Neurophysiology 67 961-980] [Nothdurft et al, 1999 Visual Neuroscience 16 15-34]. Computational models of two types of cell that incorporate non-CRF inhibition, which are based on Gabor energy filters extended by surround suppression of two kinds, isotropic and anisotropic, were intrtoduced in [Petkov and Westenberg, 2003 Biological Cybernetics 88 236-246].  We apply these computational models to the images used to demonstrate the referred perceptual effects. The results of these computer simulations confirm the rightness of the hypothesis for a possible functional role of non-CRF inhibition in the referred and further effects, such as reduced saliency of lines and contours embedded in gratings [Galli and Zama, 1931 Zeitschrift für Psychologie 31 308-348] [Kanizsa, 1979 Organization in Vision, Essays on Gestalt Perception (New York: Praeger)] and reduced saliency of contours surrounded by textures.  We made the algorithms and images available on internet [http://www.cs.rug.nl/~imaging] for use by other researchers. A demonstration will be given on site.