Determination of the identity, position and orientation of the topmost object in a pile

Abstract

In this paper, we first propose schemes for segmenting out the visible part of the topmost object from a pile of planar and curved objects. We then describe our work on using B-splines for the characterization of the topmost object surface when it is curved; the B-splines are used for deriving operators that yield the Gaussian and mean curvatures. This is followed by a description of our identification strategies which depend upon whether the topmost object is judged to be planar or curved. The identification strategy for planar objects revolves around the EGI representation of their visible surfaces and is a function of whether the number of visible planar surfaces is one, two, three, or more. In case the number of sufficiently visible planar surfaces is less than or equal to two, we have incorporated surface boundary information with angular relation between adjoining surfaces to improve the identification process. For curved objects, the identification strategy depends upon the signs of the Gaussian and the mean curvatures and the EGI. While these identification strategies are not guaranteed to work in every case, we expect them to be practically useful for a wide range of industrial objects. © 1986.