Two-Dimensional Shape Recognition Using Redundant Hashing

Ishwar K. Sethi; Nagarajan Ramesh

doi:10.1117/12.969760

1 March 1990 Two-Dimensional Shape Recognition Using Redundant Hashing

Ishwar K. Sethi, Nagarajan Ramesh

Proceedings Volume 1192, Intelligent Robots and Computer Vision VIII: Algorithms and Techniques; (1990) https://doi.org/10.1117/12.969760
Event: 1989 Symposium on Visual Communications, Image Processing, and Intelligent Robotics Systems, 1989, Philadelphia, PA, United States

Abstract

In addition to invariance with respect to certain geometric transformations, there are two other key requirements for any shape recognition system. It should be flexible enough to adopt to a variety of sets of shapes with minimal training; and it should be capable of performing even in presence of occlusion. This paper describes one such shape recognition system that is currently under development. The system is based on the redundant hashing scheme of Kohonen for recognizing and correcting misspelt words. The current version of the system is meant for 2-D shapes; however, the same approach is applicable to 3-D shape recognition. In the present implementation for 2-D shapes, a polygonal approximation of the given shape is encoded in the form of a string. The encoded string is then used to generate a very small set of shape hypotheses through the use of redundant hashing. The best hypothesis from the set of competing hypotheses is selected by a very simple matching scheme followed by a verification phase based on rotation transformation. The experiments thus far indicate that the system is capable of recognizing shapes in presence of occlusion with about 5% error. The system has significant ability to adopt to new sets of shapes; it does not require any training except the building of hash index table and the corresponding shape dictionary.

Citation Download Citation

Ishwar K. Sethi and Nagarajan Ramesh "Two-Dimensional Shape Recognition Using Redundant Hashing", Proc. SPIE 1192, Intelligent Robots and Computer Vision VIII: Algorithms and Techniques, (1 March 1990); https://doi.org/10.1117/12.969760

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