| 摘要 |
1,117,854. Pattern recognition. INTERNATIONAL BUSINESS MACHINES CORPORATION. 13 Feb., 1967 [14 March, 1966], No. 6710/67. Heading G4R. Apparatus for controlling the movement of a beam of radiation scanning around a pattern comprises means for defining a band of predetermined width extending across the pattern and for defining an area displaced from the band and on the periphery of the pattern, and means for determining when the beam has scanned across the band and area to indicate completion of a scan cycle. The photomultiplier 9 of a flying-spot scanner 5, 9 controls, via AND 47, attenuation 26, 27 of sine and cosine voltages being fed to Y and X integrators 29, 28 providing the vertical and horizontal deflection voltages for the scanner so that the outline of the character to be recognized is followed round. The maximum and minimum vertical deflection voltages during following round are stored at 33, 35 and in order to move to the next character the average of these voltages is compared 31 with the current vertical deflection voltage to control attenuation 26, 27 via AND 39 so that the beam follows an imaginary horizontal boundary to the next character. A voltage divider R11 to R14 specifies the upper and lower limits of a horizontal stop band (which should contain the scan path between characters) to comparators 67, 69 which also receive the vertical deflection voltage to indicate whether the beam is within the stop band at any given time. When the beam has been following round a character for a predetermined time, as indicated by an output at V derived from the photomultiplier 9 being present for this time, and the beam is not in the stop band, a latch 71 is set, thus causing the current vertical and horizontal deflection voltages to be stored at 63, 51, voltage dividers R7 to B10, R3 to R6 supplying predetermined fractions of the stored voltages to comparators 59, 61, 55, 57 to specify the limits of a stop box. The comparators compare these limits with the vertical and horizontal deflection voltages to specify whether the beam is within the stop box at any given time. Setting of the latch 71 enables a latch 81 to be set as soon as the beam is next in the stop band but not in the stop box, and this enables a latch 95 to be set as soon as the beam is next outside both stop band and stop box. Setting of latch 95 allows a latch 99 to be set as soon as the beam is next inside the stop box and this allows a latch 103 to be set as soon as the beam next leaves the stop box. Setting of latch 103 applies signal CCDO to the recognition system 13 to indicate completion of following round the character (e.g. to initiate a character recognition scan, the first scan being for normalization). |
