| 摘要 |
PURPOSE:To eliminate the effect to be exerted on a picture signal processing due to the difference of background density, by providing an original absence/ presence detector before the reading position of an original and controlling the release means of the peak value of the picture signal with a detected output, in the paper carrying path of the original. CONSTITUTION:The original 1 carried sequentially from the plurality of originals 1' is illuminated with a fluorescent light 4 and the reflected light is applied to an image sensor 6. The output of the image sensor 6 is applied to a peak value detection circuit 8 and a comparator 11. The detected peak value is stored in a peak value holding circuit 9. The paper carrying path of the original is provided with the original presence/absence sensors 14a, 14b and the detected output (a) is applied to a control circuit 13 at the edge of the original 1. An output (b) of the control circuit 13 closes a switch 9d of the peak hold circuit 9 and discharges a peak value holding capacitor 9c. The comparator 11 binary-codes the picture signal by using this peak value and the result is stored in a storage circuit 12. Thus, the picture signal processing depending on the density of the original is attained. |
