Purchase this article with an account.
Frederick A. A. Kingdom, Reza Kasrai; Colour contrast can facilitate perceived 3D shape-from-shading. Journal of Vision 2002;2(7):111. doi: 10.1167/2.7.111.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
It has been suggested that one of the purposes of colour vision is to help disambiguate material and illumination changes in naturals scenes, since whereas an intensity change might be due to either a change in material or a change in illumination, a colour change is invariably due to a change in material. Here we demonstrate a compelling phenomenon that can be explained by just such a role for colour vision. A plaid made from two otherwise identical orthogonal sine-wave luminance gratings appears corrugated in depth when colour contrast is added to one of the gratings. The perceived depth corrugation follows the pure luminance grating. A plausible explanation is that the mixed colour-plus-luminance grating is interpreted as a material surface and the pure luminance grating as shading. We measured the perceived depth of the corrugation for various amounts of added colour contrast by adjusting the amplitude of a textured disparity grating to match the corrugation, and found a monotonic relationship between colour contrast and perceived depth. We also report estimates of the degree to which the illusory depth in the plaid is paralleled by a perceptual ‘flattening’ of the luminance contrast in the coloured grating, as measured using a matching technique. We conclude that colour vision can play an important role in helping to decompose the visual scene into its illumination and material laye rs, or ‘intrinsic images’.
This PDF is available to Subscribers Only