[OPTICAL REVIEW Vol. 1, No. 1 (1994) 55-58]

Matched Spatial Filtering by Primitive Reference Patterns and Correlation Diagrams for Shape Invariant Pattern Recognition

Shun-ichi KAMEMARU and Mitsuaki KOBAYASHI

Department of Systems Engineering, Faculty of Engineering, Ibaraki University, 4-12-1, Naka-narusawa, Hitachi, 316 Japan

(Accepted July 22, 1994)

In this paper, twelve linear primitive reference patterns are proposed for synthesizing a matched spatial filter, known as a shape invariant filter, which can recognize all patterns with various shapes. Furthermore, reprocessed data, given by correlation between the input object of the system and the reference patterns “correlation diagrams” are introduced for processing peak signals in a digital system. By correlating the diagram from the input object with the standard diagrams, the 26 of the alphabet letters were recognized in the experiment. Moreover, feasibility of the rotational invariance of the filter was suggested by the computer simulation.

Key words : pattern recognition, matched spatial filter, hybrid system, reference pattern, primitive pattern, correlation diagram, shape invariant, rotation invariant