| 摘要 |
PURPOSE:To always obtain stably a binary picture signal realizing a pseudo intermediate picture with good reproducibility by detecting a peak value of an analog picture signal and using it to change the level of a dither signal used for the comparison at a comparator. CONSTITUTION:The analog picture signal from an original or the like read by a CCD is inputted to a high frequency emphasis circuit 1, where the peak value of the analog picture signal is detected. A dither level outputted from a nonlinear DA converting circuit 2 following the peak value of the analog picture signal is inputted to a non-inverting terminal of the comparator 3, where it is compared with the analog picture signal inputted to an inverting terminal, and a binary picture signal is outputted. Since the dither level is changed while being corresponded to the peak value of the analog picture signal at the read of a picture element in such a way, the binary picture signal realizing directly the pseudo intermediate picture is obtained without requiring a complicated signal processing.
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