Object wings - 2 1/2-D primitives for 3-D recognition

A set of 2 1/2-D primitives, called object wings, are introduced for representation and recognition of arbitrarily shaped 3-D objects. There are 34 simple wings. A simple wing is defined as a triple including a pair of surface patches separated by a contour segment. Simple wings can be grouped into composite wings through nonaccidental relationships such as cotermination, symmetry, parallelism, connectivity, colinearity, and curvilinearity. Both simple wings and composite wings, together with their spatial structures, can be used to construct internal models of real-world objects. The configurations of wings posses enough information to be of use for both indexing into models and determining instance pose. Wing definitions and techniques for their detection are presented. Representation in terms of the proposed wing primitives and recognition based on the wing representations are addressed. Experimental results are given to indicate that wing primitives can be stably extracted over a broad change of scale, and that reasonable representation can be constructed.