A prototype indexing approach to 2-D object description and recognition

This paper introduces an indexing approach to 2-D object description and recognition in the presence of rotation, translation, scale, and partial occlusion of objects. The scheme is based on the polygonal approximations of object boundaries. To obtain stable features to represent 2-D objects, three polygonal approximations are computed for the objects using different line fitting tolerances. Local structural features of objects are extracted, which consist of line and circular arc elements. The indexing entries computed based on the initial features are employed for fast access to the object-model database and generating hypotheses. A dynamic feature-matching method is designed to implement final-shape matching by evaluating and verifying the hypotheses. The system is tested with both manufactured workpieces and prototype-test-objects, and the experimental results are presented.