GB1337368A - Character recognition device - Google Patents

Abstract

1337368 Character recognition systems INTERNATIONAL STANDARD ELECTRIC CORP 24 Feb 1972 [25 Feb 1971] 8548/72 Heading G4R A character recognition system includes a circuit providing a "decision" pulse which is applied to the recognition circuitry to maintain the correct timing even if the character is too badly mutilated to be recognized. As described OCR-A characters are scanned, the serial signals from the scanner passing to a shift register of capacity sufficient to hold all the data from the character field. Various of the cells are connected to gating logic, Fig. 4 (not shown), so that, in effect, a number of windows are swept over the character as the signals step through the register. When the "Black" character signals occupy at least some of the cells in a preset group of windows a "pattern" pulse is generated on a lead corresponding to the particular character being scanned. The pattern pulse leads are connected to respective counters forming part of the recognition circuitry, the counters being reset by a signal from the circuitry after a decision pulse has occurred. In order to make small gaps in the character insignificant only some of the cells of a window need be black to represent a character portion. For example, in the case of a vertical window 7 cells high and 1 cell wide a vertical portion of the character is considered to be present if 2 of the middle 3 cells are black and 1 of both the outer pairs of cells are black. The decision pulses are generated by a circuit, Fig. 5 (not shown), which receives as inputs all the pattern pulses and also black pulses from a selected one of the cells of the register. When a pattern pulse occurs a decision pulse is generated at a preset time thereafter, at which time the following character is being read in to the register. Receipt of a pattern pulse prevents the circuit responding to any subsequent pattern pulse arriving during a fixed period thereafter long enough to ensure that all the pattern pulses relating to the character being scanned have been generated. The circuit also generates a decision pulse when the start of the character is detected and when the inter-character space is detected. Thus a decision pulse is provided even if the character is too distorted to be recognized and no pattern pulses are generated, or if adjacent characters touch. Generation of any one of these decision pulses prevents the generation of either of the others.