The phantom illumination illusion

Abstract

A novel brightness illusion in planar patterns is reported. The illusion occurs, for example, when surfaces with a luminance ramp shaded from black to white are positioned on a black homogeneous background, so that each white end of the surfaces faces a single point of the plane of the pattern. The illusion consists of the enhancement of the brightness of the background in a relatively wide area around the white ends of the surfaces. A parametric study was conducted in which participants were asked to rate the difference in brightness between the parts of the background inside and outside a virtual circle formed by disks with different luminance ramps. The results show that mean ratings of brightness depended on the luminance of the background, the luminance range of ramps, and the kind of ramp. Discussion of these results with reference to other brightness illusions (assimilation, neon color spreading, anomalous surfaces, visual phantoms, grating induction, and the glare effect) shows that t hephantom illumination illusion derives from processes producing the perception of ambient illumination.

Luminance Profiles of Luminance Gradients Affect the Feeling of Dazzling

“…Luminance gradients also affect the brightness of adjacent regions. For example, the recently discovered phantom illumination illusion is an illusion in which the brightness of a black homogeneous background is enhanced by some configurations of objects with luminance gradients (Zavagno 2005;Zavagno and Daneyko 2008). Brightness contrast is also enhanced by luminance gradients (Agostini and Galmonte 1997a, 1997b, 2002.…”

What can pictorial artifacts teach us about light and lightness?1

“…Luminance ramps are peculiar visual features (Correani, Scott‐Samuel, & Leonards, 2006), important in constructing shape from shading, in the perception of both luminosity (Zavagno & Caputo, 2001, 2005) and illumination (Zavagno, 2005; Zavagno & Daneyko, 2008b). It appears to us that they cannot be ignored if one wants to model lightness in a 3D world.…”

“…We think that a certain amount of research still needs to be carried out before we truly understand how the visual system uses luminance ramps to generate a variety of perceptual outcomes, such as: luminosity (Zavagno & Caputo, 2001, 2005), white phantoms (Sakurai & Gyoba, 1985), black phantoms and darkness enhancements (Gyoba, 1983; Zavagno, 1999), illumination effects (Zavagno, 2005; Zavagno & Daneyko, 2008b), and shape from shading combined with lightness (Arend & Goldstein, 1988). In addition, there is the new problem posed by luminance pseudo ramps, which are capable of generating brightness effects similar to those determined by actual luminance ramps.…”

Local Computation of Lightness on Articulated Surrounds

“…We call this view the ‘image decomposition hypothesis’. In this view, the variations in the retinal luminance are attributed to different causal layers and thus the perception of illumination greatly affects lightness computation (Anderson & Winawer, 2005, 2008; Lotto & Purves, 1999; Schirillo, 1999a, 1999b; Soranzo & Agostini, 2006a, 2006b; Zavagno, 2005). According to this view, articulating the surround as in Figure 1b facilitates the inference that the two surrounds are in different illuminations (Lotto & Purves, 1999; Schirillo, 1999a, 1999b; Soranzo & Agostini, 2006a, 2006b) and promotes the perception that low illumination (such as shadow) is cast over the dark articulated surround.…”