| 摘要 |
PURPOSE:To generate a video signal excellent in quality without noise on paper and a blurred character by detecting a background level of a photoelectric converting signal obtained by a scanner having plural scanning channels as to an optical character reader and correcting other background level on the basis of the background level of a specific scanner or a scanning channel. CONSTITUTION:The grounding level at each scanning channel are outputted to a level variable section 70 through signal lines l6-l9. A photoelectric converting signal at each channel led through signal lines l2-l5 is delayed for a time corresponding to one or several scanning lines' time at four delay circuits 61-64 of a delay section 60, its delay photoelectric converting signal is outputted to a binary-coding section 80 through a signal line l10, and outputted to the level variable section 70 from signal lines l11-l13. The ground level led through the signal line l6 and the ground level led through the signal lines l7-l9 are compared by three level variable circuits 71-73 of the level variable section 70, the photoelectric converting signal level led through signal lines l11 and l12 is subject to change so as to uniform the level with the level of the photoelectric converting signal led finally through the signal line l10.
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