High Density Shapes Using Photometric Stereo and Laser Range Sensor under Unknown Light-Source Direction

Much research is in progress on the acquisition of high-density three-dimensional shapes by acquiring and combining shape data and normal data. The method proposed in this paper estimates normals to object surfaces by employing the photometric stereo method and combines the estimation with the three-dimensional shape acquired by a laser range sensor. Although the photometric stereo method presumes that light-source directions for each image are known, the proposed method uses its light-source direction estimates. By linearizing the images as preprocessing, specular reflection and shadow effects within the image are removed and the precision for the light-source direction estimations is increased. Since the proposed method does not require the light-source directions to be known, it offers the advantage of broad applicability for measurement work.