Investigation of Directional Filter on Kube-Pentland’s 3D Surface Reflectance Model using Photometric Stereo

This paper uses theory, simulation and laboratory experiment to investigate the directional filter on Kube and Pentland’s linear reflectance model which presents the image directionality as a product of the illuminant direction and surface directionality. As a result, a surface rotation is not equivalent to an image rotation if the illuminant is not rotated. It can be seen that the directional filter characteristics of an image are described by the term of cosine function. The non-linear and shadowing effects neglected by the model are also investigated. Finally surface orientations estimated from this model using photometric stereo are examined, and experimental results verify the theoretical predictions.