Fuzzy pyramid scheme for distorted object recognition

Abstract

This paper considers the problem of distorted object recognition using the fuzzy pyramid approach developed by the authors. [Liu, Tan, Srinivasan, Ong and Xie, Pattern Recognition 27(5), 741-756 (1994)]. A distorted object is one that has undergone some kind of deformation in shape. Due to its nature, this recognition problem is considerably more difficult compared with that of conventional invariant object recognition. We first characterize the distortion of an object in terms of linear and nonlinear transformations along the two coordinate axes and provide a classification scheme for typical distortions. The fuzzy pyramid recognition system described earlier is then modified and applied to different classes of distorted objects. The key concepts are fuzzy entropy, which results in a significant reduction in feature dimension, and supervised learning, which is used to form object templates efficiently. To evaluate its performance, the system is applied to the practical problems of map recognition and character recognition. The effectiveness of the method is clearly demonstrated by the high recognition rate in these applications. Copyright © 1996 Pattern Recognition Society. Published by Elsevier Science Ltd.