title: A DOG filter model of the occurrence of Mach bands on spatial contrast discontinuities.
abstract: The present work proposes a unified model to explain two previously reported properties of the Mach band illusion. The first is the frequently referenced fact that Mach bands are prominently visible at ramps, but practically vanish at intensity steps. The second property, less studied, on the other hand may also be related to the first. It concerns the fact that the width of the illusory Mach bands appears to be a function of the slope of the ramp itself. The model proposed here combines the difference of Gaussians (DOG) model of lateral inhibition in receptive fields with the models of feature detection, based on a holistic approach. The sharpness of discontinuity (SOD) concept for Mach band stimulus has been defined and is related to the slope of the ramp. It is suggested that calculation of SOD leads to an adaptive change in inhibitory surround, a notion that has the support of physiological experiments too.
authors.affiliation: CDAC, Kolkata, Plot- E2/1, Block - GP, Sector - V, Salt Lake City, Kolkata, 700091, India.
authors.forename: Debasis
authors.initials: D
authors.lastname: Mazumdar
authors.affiliation: CDAC, Kolkata, Plot- E2/1, Block - GP, Sector - V, Salt Lake City, Kolkata, 700091, India.
authors.forename: Soma
authors.initials: S
authors.lastname: Mitra
authors.affiliation: Center for Soft Computing Research and Machine Intelligence Unit, Indian Statistical Institute, 203 B T Road, Kolkata, 108, India. kuntalghos@gmail.com.
authors.forename: Kuntal
authors.initials: K
authors.lastname: Ghosh
authors.affiliation: CDAC, Kolkata, Plot- E2/1, Block - GP, Sector - V, Salt Lake City, Kolkata, 700091, India.
authors.forename: Kamales
authors.initials: K
authors.lastname: Bhaumik
mesh_terms: D007088:Illusions / Q000502:physiology*; D008959:Models, Neurological; D016011:Normal Distribution
keywords: Adaptive surround; Contrast; Fourier analysis; Lateral inhibition; Mach band