| 摘要 |
<p>PURPOSE:To precisely convert the signal from a sensor, which reads a picture, to a binarized signal by not software processing but hardware by taking the color tone and the reflection factor of paper, the illuminance of illumination, etc., into consideration and excluding an influence due to the unevenness of the color tone of paper, the unevenness of illumination, or the like. CONSTITUTION:A linear differentiation circuit 51 which differentiates the image pickup signal obtained from a two-dimensional CCD through an image pickup processing circuit, a clock generating circuit 54 with quadratic differentiation which is provided with a quadratic differentiating circuit to differentiate the linear differential signal from the linear differentiation circuit 51 and outputs a taking-in signal of the timings of positive and negative peaks of displacement in the linear differential signal by the quadratic differential signal, a positive/ negative level floating slice circuit 53 which converts the linear differential signal to a binarized signal by the taking-in signal, and a J-K.F.F. (flip flop) circuit 55 are provided.</p> |
