Authors
Fredric Solomon, Katsushi Ikeuchi
Carnegie Mellon University
Portals
Abstract
Two important aspects of part inspection are the measurement of surface shape and surface roughness. We propose a noncontact method of measuing surface shape and surface roughness. The method, which we call \"four light photometric stereo\" , uses four lights which sequentially illuminate the object under inspection, and a video camera for taking images of the object. Conceptually, the problem we are solving has three parts: shape extraction, pixel segmentation and roughness extraction. The shape information is produced directly by the three light and four light photometric stereo methods. After we have shape information, we can apply statistical segmentation techniques to determine which pixels are specular and which re non-specular. Then, we can use the specular pixels and shape information, in conjugation with a simplified Torrance-Sparrow reflectance model to determine the surface roughness The method has successfully been applied to a number of synthetic and real objects.