| 摘要 |
PURPOSE:To read specially thin ruled lines without destroying a thick part such as a character by darkening by adding a differentiated video signal obtained by differentiating the video signal to the video signal, amplifying and outputting. CONSTITUTION:A photoelectric transducer (CCD) 1 scans an original and converts the variable densities into an electrical signal. A differentiation circuit 2 consists of a resistance RX and a capacitor CX and forms the differentiated video signal obtained by differentiating the video signal read from the original by the photoelectric transducer 1. An amplifier circuit 3 functions as an analog emphasis circuit for adding the video signal read by the photoelectric transducer 1 and the differentiated video signal formed by the differentiation circuit 2 and amplifying. An A/D converter 4 converts the analog emphasized and amplified video signal by the amplifier circuit 3 into a digital signal and outputs.
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