Patent US 3,967,241

In a pattern recognition system of the type in which an input pattern is read, and stored in a two-dimensional memory, and after the features of the input pattern are extracted, they are compared with the standard patterns in storage in such a way that the degrees of similarity of the input pattern to the standard patterns are obtained so as to establish one-to-one correspondence between the input pattern and one of the standard patterns in storage that has the maximum degree of similarity, a part of the input pattern is enlarged when the degrees of similarity of the input pattern to two of the standard patterns are in excess of a predetermined level, so that the features of the enlarged part of the input pattern information may be extracted so as to establish one-to-one correspondence between the input pattern and one of said two standard patterns. Additionally, a reject signal is provided when the input pattern has a greater-than-predetermined similarity to three or more standard patterns.