GB1175391A - Improvements in or relating to Character Reading Apparatus - Google Patents

Abstract

1,175,391. Character recognition. COGNITRONICS CORP. 27 Jan., 1967 [27 Jan., 1966], No. 4278/67. Heading G4R. Character data from a remote scanner is coded, transmitted to a central station having character recognition means and there decoded. A plurality of horizontal scans are made along a whole line of characters on a document 14, Fig. 2, by means of an optical reading head 18, by rotating drum 12, then advancing screw 16. The head output is digitized in amplifier 19 and gated into flip-flop 30 by clock pulses from disc 26. The clock pulses are also counted in an 8- stage binary counter 34 which is gated to buffer register 40 and reset under control of a 5-bit shift register 32 fed by flip-flop 30, in such a way that successive counts represent the number of bits between successive transitions between white and black (both directions). A given count can occupy one or more four-bit groups, counter 34 being able to develop and register 40 being able to receive up to two such groups at a time, a bit 42, 44 following each group specifying if the count has ended. The code 00001 is forced into the register 40 when register 32 holds all blacks. Termination of counts is controlled by occurrence of black or white alternately in stage 38 of register 32, the alternation occurring on count termination (so alternate counts will be terminated on black and white respectively) except that after a termination resulting from detecting a black in stage 38, the alternation does not occur if the register 32 contains any white and the next count is terminated by the next black outside the register 32 reaching stage 38, rather than on the next white. Whenever register 40 receives 5 or 10 bits, they are transferred to buffer 46 for transmission over telephone lines 48 to a central station. If the buffer 46 becomes full, the counter &c. is suspended for one revolution of drum 12. The central station receives the counts from a plurality of units as in Fig. 2 and deals with them on a time-division-multiplex basis. The counts are written into a buffer section of a magnetic drum in the central station, counts relating to blank spaces between lines of characters &c. being written over. By means of a counter, the counts from a line of characters are decoded to reconstitute the character patterns which are recorded in another section of the magnetic drum in a linear format corresponding to a plurality of vertical scans of the characters taken in turn. In this order, the data is read out to character recognition circuitry. Unrecognizable characters are so indicated on a cathode ray tube display so a human can enter the correct characters on a keyboard. A black bit is forced into the register 32 at the beginning and end of each horizontal scan. The end bit enables a check on transmission to be made at the central station, the reconstituted bits being counted and what should be the last being tested to see if it is black.