A unified theory of brightness contrast and assimilation incorporating oriented multiscale spatial filtering and contrast normalization

Abstract

Brightness induction includes both contrast and assimilations effects. Brightness contrast occurs when the brightness of a test region shifts away from the brightness of adjacent regions. Brightness assimilation refers to the opposite situation in which the brightness of the test region shifts toward that of the surrounding regions. Interestingly, in the White effect [Perception 8 (1979) 413] the direction of the induced brightness change does not correlate with the amount of black or white border in contact with the gray test patch. This has led some investigators to reject spatial filtering explanations not only for the White effect but for brightness perception in general. Instead, these investigators have offered explanations based on a variety of junction analyses and/or perceptual organization schemes. Here, these approaches are challenged with a critical set of new psychophysical measurements that determined the magnitude of the White effect, the shifted White effect [Perception 10 (1981) 215] and the checkerboard illusion [R.L. DeValois, K.K. DeValois, Spatial Vision, Oxford University Press, NY, 1988] as a function of inducing pattern spatial frequency and test patch height. The oriented difference-of-Gaussians (ODOG) computational model of Blakeslee and McCourt [Vision Res. 39 (1999) 4361] parsimoniously accounts for the psychophysical data, and illustrates that mechanisms based on junction analysis or perceptual inference are not required to explain them. According to the ODOG model, brightness induction results from linear spatial filtering with an incomplete basis set (the finite array of spatial filters in the human visual system). In addition, orientation selectivity of the filters and contrast normalization across orientation channels are critical for explaining some brightness effects, such as the White effect.

No Functional Magnetic Resonance Imaging Evidence for Brightness and Color Filling-In In Early Human Visual Cortex

“…Yet, we find powerful edge responses that are almost identical for disk and surround modulations. Given the psychophysical evidence that edges play a key role in color and brightness perception (Reid and Shapley, 1988;Brenner and Cornelissen, 1991;Rudd and Arrington, 2001;Bindman and Chubb, 2004a,b;Hong and Shevell, 2004a,b;Rudd and Zemach, 2004;Shapiro et al, 2004), our results could be interpreted as evidence that surface filling-in is unnecessary and that edge responses alone, or in combination with local luminance, determine surface brightness (Blakeslee and McCourt, 1999;Dakin and Bex, 2003;Blakeslee and McCourt, 2004;Shapiro et al, 2004).…”

The effect of eccentricity and the adapting level on the café wall illusion

“…Weighting across spatial frequency is a power function with a slope of 0.1, which was proposed by Blakeslee and McCourt (2004) on the basis of the suprathreshold con- trast sensitivity measurement of Georgeson and Sullivan (1975). This function was chosen because the café wall illusion is a suprathreshold phenomenon.…”

Organização espacial na percepção visual de luminosidade

“…Entre estes, por exemplo, a análise da iluminação, da profundidade espacial, da transparência e do agrupamento entre os estímulos (Bell & Badcock, 2008;Blakeslee & McCourt, 2004;Blakeslee, Reetz & McCourt, 2009;Buckley, Frisby & Freeman, 1994;Kingdom, Blakeslee & McCourt, 1997; Knill & Kersten,1991;Paradiso, 2000;Perna & Morrone, 2007;Purves, Shimpi & Lotto, 1999; Schirillo & Shevell, 1997;Wishart, Frisby & Buckley, 1997).…”