Recovery of 3-D shape using hybrid reflectance model

A 3-D shape recovery algorithm, which is based on the hybrid reflectance model and M ring shaped lights for specular surfaces, is presented. We derive a radiance L_r as a function of slant angle θ_n of a surface point in polar coordinate. Then, by using the input intensity images and the radiance function, the M slant angle at each point are obtained. The final slant angle is determined as a weighted sum of the M slant angles. Finally, the surface gradient, which is obtained from the slant angle and its contours, is integrated to the depth map. Examples are provided using both synthetic and real data