Classifying color transitions into shadow-geometry, illumination, highlight or material edges

We aim at using color information to classify the physical nature of a color edge: that is whether the transition is due to shadows, abrupt surface orientation changes, illumination, highlights or material changes. To achieve a physics-based edge classification, we propose a taxonomy of color invariant edges. The taxonomy is based upon the sensitivity of the various color edges with respect to different imaging dependencies i.e. shadows, object shape, shading (i.e. illumination intensity changes), highlights and material characteristics. From this taxonomy, the edge classifier is derived labeling color transitions into the following types: (1) shadow, geometry or shading edges, (2) highlight edges, (3) material edges. Experiments conducted with the edge classification technique on color and hyperspectral images show that the proposed method successfully discriminates the different edge types.