| 摘要 |
PURPOSE:To properly trace and store a white level of a picture signal of all picture elements even if a character or the like is written on a read original by dividing the picture signal from the CCD into n-set of periods having a preset time division width and tracing/storing a peak value in the unit of periods. CONSTITUTION:In receiving a picture signal by one line from a CCD1, it is divided into n-set of periods having a preset time division width by an n-channel analog demultiplexer 9 and the peak value of the picture signal at each period is stored and traced in peak hold circuits 10-1-10-n. Succeedingly, the n-set of peak values are extracted and combined by the n-channel analog demultiplexer 11 sequentially to trace and store the while level of the picture signal at each period. Even if a character or the like is written on an original, the white level of the picture signal of all the picture elements is traced and stored properly.
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