| 摘要 |
<p>1,032,902. Automatic character reading. INTERNATIONAL BUSINESS MACHINES CORPORATION. Jan. 4, 1965 [Jan. 30, 1964], No. 267/65. Heading G4R. In a character-reading apparatus the character is scanned and video signals are derived from each portion and applied to a clipping circuit, the level of which is adjusted in accordance with the video signals obtained from adjacent portions in the same scan and adjacent portions in the previous scan. The character is scanned in a series of vertical lines, each consisting of a number of horizontal strokes. The video signals are applied to a delay line the output taps of which are connected to a summation circuit. The centre tap is connected to a threshold circuit comprising transistor 30 and the output of the summation circuit, representing the portions above and below the centre, portion is applied to transistor 32 to obtain a clipping voltage which is passed via resistor 40 to the emitter of transistor 30. The output of transistor 30 passes to a onescan delay 52 via a consolidation circuit 47 (as described in ), in which each group of three horizontal strokes is designated " black " or " white." The signals relating to the three areas of the previous scan adjacent the central portion are taken via differently weighted resistors 55-57 to a summing circuit. The weighting is such that the area in the previous scan immediately adjacent the area of which the signal is being clipped has the greatest effect. An adjustable portion of the signal obtained is also applied to the emitter of transistor 30 via resistor 44. The two signals one from the current scan and one from the previous scan are combined in resistors 40, 44 to give the clipping level.</p> |
