ON SHAPE FROM SHADING

We present a new method for the recovery of a bivariate function H(x,y) that describes a 'nice', almost everywhere differentiable height profile from shading information. The given shading data is assumed to be a result of diffuse, Lambertian reflection of light from the surface. This implies that, if the scene is uniformly illuminated from above, the shading yields information on the cosine of the angle between the vertical and the surface normal at each point. The new shape-from-shading method that we discuss is based on a recursive way of determining equal-height or level contours of the surface starting at a given level curve.