Extracting Illuminant Direction from Visual Information for Perceiving Shape from Shading

Abstract

To reconstruct shape from shading, the illuminant direction is important. Many researchers have reported that human visual systems extract the illuminant direction from visual information for perceiving shape from shading. Pentland (1982) proposed that only the luminance distribution was needed to extract the illuminant direction from visual information. Besides, Berbaum et al. (1984) proposed that shape perception of other objects along with the surface luminance distributions was needed. However, Berbaum et al. (1984) pointed out that these two models haven’t been separately investigated in previous researches. In this research, we investigated how the human visual system extracts the illuminant direction from visual information for perceiving shape from shading to test the validities of the models. For the purpose, we manipulated independently binocular disparity to specify shape perception and luminance distribution of the stimulus. The results implied that both Pentland and Berbaum model were valid and that human visual system extracts the illuminant directions from the two systems and chose one of them depending on the stimulus situation for perceiving shape from shading, although there were individual differences.