Determining surface curvature with photometric stereo

A method is described to compute dense representations of the intrinsic curvature at each point on a visible surface, based on photometric stereo. The idea of photometric stereo is to use the intensity values recorded from multiple images obtained from the same viewpoint but under different conditions of illumination. Previously, photometric stereo has been used to obtain local estimates of surface orientation. Here, an extension to photometric stereo is described in which the spatial derivatives of the intensity values are used to determine the principal curvatures and associated directions, at each point on a visible surface. The result shows that it is possible to obtain reliable local estimates of intrinsic surface curvature. The method is demonstrated using images of two pottery vases, one of which is used for calibration purposes