Differential algorithm for the determination of shape from shading using a point light source

摘要

This paper presents a linear algorithm for recovering shape information of Lambertian surfaces from the shading information inherent in a single 2D image. The local orientation of a planar Lambertian surface patch is determined from a single video image when both camera and a light source are near to the surface. A simple linear relationship is derived between the ratios of the measured image intensities and their first partial derivatives and the components of the surface normal vector. An advantage of the formulation is that the resulting equations are independent of the intensity strength of the illuminating source as well as the surface reflection coefficient (albedo). Results for noisy synthetic images as well as real images are presented.