| 摘要 |
PURPOSE:To acquire the reproduction with adequate light and shade from the beginning, and at the same time, to obtain a clear reproduced picture even for an original with a dark ground by setting the gain of a picture signal amplifier before the start of reading corresponding to the color of the ground of the original to be read. CONSTITUTION:When read the original having a white ground or a dark ground, a color selecting switch is respectively set to the position of 'light' or 'dark'. Then, the preset data of a preset switch 8 is set to the numerical value 15 or to the numerical value 45. Here, when the ground is dark, an up/down counter 4 reads-in this numerical value 45, and initializes the terminals B1, B2...B5 of a D/A converter 2 at '45', and from this point of time, it scans and reads the original. The picture signal level of the dark ground is low, but the multiplying factor of the D/A converter 2 becomes larger by this initial value, and from the D/A converter 2, the output of almost the same degree as the case of white ground is obtained. As the result, even when the ground is dark, the picture is reproduced distinctly from the beginning.
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