Lighting Direction Estimation in Perspective Shape from Shading by Genetic Algorithm

In oblique shape from shading (SfS), the lighting (illumination) direction is essential for recovering the 3D surface of a shaded image. On the other hand, fast marching methods (FMM) are SfS algorithms that use the mechanism of wave propagation to reconstruct the surface. In this paper, the estimation of lighting direction is addressed and we model it as an optimization problem. The idea is to minimize the inconsistency of wave propagation of FMM during the reconstruction. As the consistency of wave propagation is a multi-modal function, genetic algorithm (GA) is utilized to determine the lighting direction. Experimental results on four oblique SfSs with an unknown lighting direction are presented to demonstrate the performance of the proposed algorithm.