Determining Grasp Configurations using Photometric Stereo and the PRISM Binocular Stereo System

This paper describes a system which locates and grasps parts from a pile. The system uses photometric stereo and binocu lar stereo as vision input tools. Photometric stereo is used to make surface orientation measurements. With this informa tion the camera field is segmented into isolated regions of a continuous smooth surface. One of these regions is then selected as the target region. The attitude of the physical ob ject associated with the target region is determined by histo graming surface orientations over that region and comparing them with stored histograms obtained from prototypical objects. Range information, not available from photometric stereo, is obtained by the PRISM binocular stereo system. A collision-free grasp configuration is computed and executed using the attitude and range data.