GB1472927A - Character recognition - Google Patents

Abstract

1472927 Character recognition systems SHARP KK 1 May 1974 19114/74 Heading G4R A character to be recognized is scanned by a column of sensors PT which is moved across the character field. Signals are derived representing the presence or absence of portions of a character (black) in horizontal zones α-# in each of a number of successive vertical slices of the field, as viewed during successive horizontal positions of the sensors. The signals occurring during particular vertical zones WP and WPa-WPd, each comprising at least two slices, are decoded to identify the character. The characters are in stylized form, e.g. embossed on a card, and are scanned by a column of phototransistors. The outputs of the columns feed ashift register connected to gates defining the zones α-#. For example the presence of black in any of the top three stages causes an output #, and the presence of black in each of the next three an output 8 at respective gates. These outputs pass to a diode matrix which develops one or more of signals A<SP>1</SP>-F<SP>1</SP>, each dependent upon the presence or absence of some-of the outputs α-# (Fig. 6, not shown). Signals A<SP>1</SP>-F<SP>1</SP> pass to logic circuitry (Figs. 7 and 8, not shown), which is also fed with timing signals corresponding to the zones WP and WPa-WPd. Provided that, in the respective zones, the relevant signals occur during a certain number of adjacent vertical slices of the field corresponding signals a-h are generated. For example, if signal F<SP>1</SP> is present during two adjacent slices during zone WPb signal h is generated. A further signal i is generated in respect of zones WPc and WPd. Signals a-i correspond to the waveforms indicated in Fig. 3, each waveform representing the black/white state of the horizontal zones α-# for vertical slices in the vertical zones indicated. The signals pass to a recognition unit which identifies the characters. For example, numeral 2 is identified if signals d, e and h are present and f and i absent, the state of a, b, c and g being immaterial. When the card has been scanned in one direction it is then scanned in the reverse direction. If the characters identified during the two scans are not identical an error signal is generated.