The essence of character recognition is a comparison between the unknown character and a set of reference patterns. Usually, these reference patterns are all possible characters themselves, the whole alphabet in the case of letter characters. Obviously, N analog measurements are highly redundant, since only K = log2N binary decisions are enough to identify one out of N characters. Therefore, we devised K reference patterns accordingly. These patterns, called principal components, are found by digital image processing, but used in an optical analog computer. We will explain the concept of principal components, and we will describe experiments with several optical character recognition systems, based on this concept.
© 1979 Optical Society of America
Original Manuscript: November 29, 1978
Published: August 15, 1979
B. Braunecker, R. Hauck, and A. W. Lohmann, "Optical character recognition based on nonredundant correlation measurements," Appl. Opt. 18, 2746-2753 (1979)