Abstract
The presence of specular highlights can give rise to a perception of gloss that propagates across the surface. Under binocular viewing, the disparity of a specular highlight is dependent upon the sign and magnitude of surface curvature. Observers are somewhat sensitive to highlight disparity in perceiving surface gloss (e.g. Blake and Buelthoff (1990); Wendt et al., 2008, 2010). However, a comprehensive description of the relationship between the perceived sign and magnitude of surface curvature, the sign and magnitude of highlight disparity and the perceived gloss of a surface is missing. We asked observers to judge the glossiness of convex and concave surfaces. On each trial, the scene consisted of two partial spheres that protruded from a flat surface; one was rendered to be convex and one to be concave, relative to the observer. Surface shape was defined by both visual (shading, disparity) and haptic cues. A single specular highlight was present on one of the two objects. The highlight disparity varied in magnitude and sign from trial to trial. Subjects made gloss judgments using a continuous scale. Our results confirm that observers are sensitive to the magnitude of highlight disparity with smaller highlight disparities (relative to the surface disparity) reducing gloss perception. However, we find that observers are less sensitive to the sign of disparity than suggested by Blake and Buelthoff (1990).
ESRC studentship for ISK.