GB1293128A - Code reading system - Google Patents

Abstract

1293128 Sensing records; character recognition SCANNER Inc 20 April 1970 [21 April 1969] 18788/70 Headings G4M and G4R Records.-Labels attached to merchandise have coded characters recorded on them, each character comprising transverse code lines in selected ones of three positions in adjacent tracks (which may be concentric) and the total number of lines in each character being the same. The code lines may be linked by lines parallel to the tracks to produce a character which is humanly legible, as shown in Fig. 4, where each character is in a 4/6 code and has one pair of code lines which are aligned in the two tracks. Fig. 6 (not shown) illustrates a similar arrangement using a 3/6 code. Sensing.-An image of the circular tracks is centred with respect to an optical axis and is rotated with respect to a pair of photo-detectors by an image converter tube and optical system as described in Specification 1,219,251. Circuit, Fig. 5.-Outputs from the two sensing channels 87, 88 are supplied to a clock generator 90 supplying pulses for shifting the sensed data into registers 101, 102 and for advancing a divide by 3 counter 103. When this counter provides an output, gate 121 checks that an output is simultaneously obtained from gate 120 signifying that the character just sensed had an odd number of coinciding code lines (gate 114 and toggle flip-flop) and at least one single code line (gate 116 and bi-stable 117). When the gap 47, Fig. 4, following a character is detected at 111, generator 95 produces a character pulse CP provided gate 121 and hence gate 122 have not produced an invalid character output to set error detector 130 and reset bi-stable 135. The character pulse CP enables a decimal decoder 105 and a Y10 check circuit 123 so that if a valid output is obtained from decoder 105, the output of BCD converter 106 is passed to a recirculating delay line store 108. If error detector is set during the sensing of a label, it opens the recirculating path of store 108 to erase the data stored. When detector 131 detects a long gap at the end of the data, the contents of store 108 are transferred to an output magnetic disc or tape, printer or punching apparatus. The sensing operation is automatically repeated if an error was detected, and a counter 138 may be provided to allow output transfer of data only after a given number of error-free sensing operations have been performed. A similar but simplified circuit is used for codes of the Fig. 6 type.