| 摘要 |
<p>1,045,040. Automatic character reading. FARRINGTON ELECTRONICS Inc. March 15, 1965 [March 25, 1964], No. 10850/65. Heading G4R. In automatic reading apparatus the character is scanned in a vertical raster and black and white signals of each scan being compared with the black signal of the previous scan so that a stroke crossing several scans is followed from scan to scan. The image of the character is dissected by a slotted disc and signals produced by a photo-cell 543, Fig. 1 (not shown), are clipped. The video signals are delayed at 544 for example by being recorded on a magnetic drum and read again at another point. The delay is slightly less than one scan and the signals are stretched so as to overlap a similar signal in the next scan. In comparator 545 the delayed signal is gated with the video signal of the present scan and an output indicates that the same stroke or " stream " crosses both scans. The video signal is also applied to a stream counter 548 which counts the black strokes encountered in each scan. When new strokes are detected they are numbered and recorded in trigger matrix 549, along with old strokes, according to the sequence in which they appear. This information passes to a pattern control matrix 551 which controls the switch circuitry in stream switch unit 547 to route into appropriate channels the numbered streams as they re-appear in each successive scan. Signals from these circuits, which together form stream routing unit 546 pass to detector 522 producing at 553 and 555 signals indicating the presence of certain shape elements. These features are associated with the streams in which they occur and are designated as occurring in the upper or lower half of the character. The output signals are applied in appropriate combinations to And gates in recognition circuit 556 to obtain an indication of the character recognized. The elements extracted and used for recognition are as follows. A long vertical line which is detected by integrating the black signal in any scan. Two long vertical lines obtained in the same way. An upper split is indicated when a single stream detected in the upper half in one scan becomes two streams in the next. An upper join is indicated when two streams detected in the upper part of the character in one scan becomes a single stream in the next. A lower split and a lower join are as above, but occurring in streams in the lower half of the character. For the purpose of combining split and join signals with positive signals a circuit is provided which determines which of the four possible streams is the uppermost. The next feature is an upper horizontal. The presence of a horizontal is detected by measuring the height of a stream in successive scans. If a horizontal is detected in any stream this indication is combined/with an indication of whether or not that stream is uppermost. The last feature is a split after join which is obtained by combining a join signal with a split indication occurring any time afterwards.</p> |
