A novel photometric stereo method with nonisotropic point light sources

This paper presents a photometric stereo method with nonisotropic point light sources. Subject to the non-uniform lighting conditions produced by the nonisotropic point sources, each incident light ray should be precisely determined so as to realize an accurate calculation of surface normal. In the proposed method, radiance model of the light source is firstly introduced to the classical photometric stereo framework. By considering the distance and angular attenuations of incident light rays, a precise description for the lighting field can be established. Based on the initial 3D reconstruction result, an iterative process is introduced to optimize the primary light model parameters with respect to the unknown distance factor. The experimental setup is quite simple, which only consists of some LEDs and one camera. And the experimental results show that, with the proposed method, accuracy of the reconstructed surface normal can be greatly improved in comparison with some conventional light models.