Spatial organization affects lightness perception on articulated surrounds

Abstract

The articulation effect refers to a change in lightness contrast induced by adding small patches of different luminances to a uniform background surrounding a target in a lightness contrast display. This study investigated how local luminance signals are integrated to generate the articulation effect. We asked whether spatial organization due to perceptual grouping can influence the articulation effect even when the spatially averaged luminance of the surrounds is held constant. Grouping factors used were common-fate motion (Experiment 1), similarity of orientation (Experiment 2), and synchrony (Experiment 3). Results of all experiments consistently showed that the articulation effect was larger when the target was strongly grouped with the articulation patches. These findings provide converging evidence for the effects of spatial organization on the articulation effect. Moreover, they suggest that lightness computation underlying the articulation effect depends on a middle-level representation in which perceptual organization is at least partially established. The changes in lightness perception due to spatial organization could be accounted for by the double-anchoring theory of lightness (Bressan, 2006b).

Edge integration in achromatic color perception and the lightness-darkness asymmetry

“…The fact that the model's scaling calculations depend on figure-ground organization is another way in which the edge integration model differs from both retinex and anchoring theory. However, the model in its present form cannot account for several previously demonstrated effects of image segmentation on lightness (e.g., Agostini & Galmonte, 1999, 2002Agostini & Proffitt, 1993;Benary, 1924;Bressan, 2001;Bressan & Kramer, 2008;Gilchrist, 1977;Laurinen, Olzak, & Peromaa, 1997;Sawayama & Kimura, 2013). So further rules based on image segmentation will likely be needed to specify the way in which the visual system assigns weights to edges.…”

Double-anchoring theory of lightness vindicates the original anchoring theory

“…These have been compared to observed data in Bressan (2006aBressan ( , 2006bBressan ( , 2007aBressan ( , 2007b. Separate empirical tests and later findings consistent with the theory can be found, among others, in Bressan & Kramer (2008), Kramer & Bressan (2010), Pereverzeva & Murray (2009), Sawayama & Kimura (2013). The theory has also easily withstood two rounds of criticism (Bressan, 2007a(Bressan, , 2007b.…”