Patent Document ID: 4097847
Application ID: 05577151
Patent Flag: 1

Claim One:
1. Multi-font optical character recognition apparatus for converting character representative symbols located on a storage medium in the form of a two-dimensional field of brightness values into a digital code representative of said symbol, said apparatus including scanning means for optically scanning the storage medium to generate analog signals representative of the brightness values, contrast means for measuring the difference between the analog signals produced by the various brightness values, means for converting the analog signals into one bit digital data signals denoting either blackness for the symbol or whiteness for the background in dependence on the measurement of the contrast means, perimeter trace means for developing contour digital data representative of incremental movements between data points about the perimeter of the symbol, and recognition means for converting the contour data into a digital code representing the scanned symbol, wherein the improvement comprises a perimeter tracing means including: a character memory for storing the one bit digital data signals in predetermined arrays representing corresponding segmental areas of the scanned symbol, address means for addressing particular data bits in the character memory, a perimeter trace table memory for storing a search sequence for finding the perimeter of the character, and control means for causing the address means to follow the search sequence stored in the perimeter trace table so that the perimeter of the symbol stored in the character memory is searched for in a 5 .times. 5 array of a portion of the character memory according to the following sequence: row 2, col. 1; row 2, col. 2; row 2, col. 3; row 1, col. 2; row 1, col. 3; row 1, col. 4; row 2, col. 4; row 3, col. 4; row 2, col. 5; row 3, col. 5; row 4, col. 5; row 4, col. 4; row 4, col. 3; row 5, col. 4; row 5, col. 3; row 5, col. 2; row 4, col. 2; row 3, col. 2; row 4, col. 1; row 3, col. 1; row 2, col. 1; stopping in the search whenever a part of the perimeter is found, and beginning a new search with a shifted 5 .times. 5 array.