Photometric surface analysis in a tri-luminal environment

Methods for the analysis of images of the same scene taken under three different lighting conditions are illustrated. A technique that separates the effects of geometry and surface coloration/texture in this "tri-luminal" environment is developed and experimental results are shown. Exploiting this technique to isolate geometric information, two methods which extract differential geometric properties of surfaces (the sign of Gaussian curvature and its magnitude to within a multiplicative factor) directly from tri-luminal photometric data are derived and demonstrated.