An improved algorithm for the shape from shading problem.

Abstract

Recently developed techniques for estimating surface shape from shading information suffer from the following drawback. Surface slpoes are estimated without ensuring that those slopes correspond to a valid surface. In this paper, an existing iterative algorithm is improved by projecting the surface slope estimates on to a valid set of surface slopes at each iteration. Specifically , we require the second partial derivative of the surface do not depend on the order in which differentiation is performed. The result is a more stable shape from shading algorithm with the reduction in sensitivity to modelling errors and incomplete boundary conditions. Experimental results are presented for simulated and real images.