Iterative least-squares estimation requires accurate reflectance models t o retrieve geometrical parameters of 3-D objects f r o m a n image projection. W e investigate the use of separating the diffuse (body) reflection f r o m the specular (surface) reflection, where the latter as responsible f o r image hzghlights. The performance of several models has been analysed by comparing local hagher-order derivatives of the least-squares error function. Experiments show that the (smooth) diffuse

more »

... onent yields the best convergence properties, while the (sharp) specular component can be utilized to improve noise insensitivity.