| 摘要 |
PURPOSE:To keep the quality of a received picture constant and to facilitate the processing of the received picture at a reception side by prescanning a photograph original at a high speed and converting the density areas of the brightest part and the darkest part on an obtained original into any normalized desired output density areas so as to electrically transfer when the photograph original is electrically transferred. CONSTITUTION:At the time of prescanning, prescanning is executed where the gain of a normalizing circuit 7 is 1/8, for instance, and a shift is zero V. A voltage read-out at every picture element is AD-converted. Upon the completion of prescanning, the read-out voltage VWT of the brightest part and that VBK of the darkest part are found. Upon the completion of prescanning the finally detected VWT and VBK are normalized in concert with a CPU 6 and the normalizing circuit 7 so that they can be expanded in the entire area of the processing range of an ADC 5. After the operation enters a reading scan, normalized density area data is inputted to the ADC 5. The brightest part voltage VREF and the darkest voltage zero V are converted into FF and OO, respectively, and they are transferred to the CPU 6 and processed therein.
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