POLYNOMIAL TEXTURE MAPPING AND 3D REPRESENTATIONS

The results of a multi-image photographic technique are compared with those obtained by close-range scanning of the same object by a 3D colour laser scanner. The 3D representation achieved by the polynomial texture map (PTM) is compared with the extraction of normals from the same image set by photometric stereo. It is shown that the median of each of the X,Y,Z distributions of normal components for a large number of 3-light combinations is a good estimator of the true normal at each point. Using an incised Egyptian stone tablet, normals derived from these two techniques are compared with those generated by a 3D laser scanner. It is shown that the photometric stereo method produces the highest quality rendering of the surface.