| 摘要 |
<p>PURPOSE:To extract the character, which is entered in a window part, as a binary video signal, by controlling the amplification degree by an AGC so that the level of a photoelectric conversion signal obtained from the window part to that obtained from a region other than the window part. CONSTITUTION:A letter 10 is carried on a carrying path 20 in the C direction in a cnstant speed, and a scanning part 40 is controlled by a control part 50 so that the scanning part starts operating when the leading edge of the letter 10 reaches a detection point P. The letter 10 has the address entry side irradiated by a light source 30 at the detection point P, and the scattering light of the letter 10 is condensed to the scanning part 40 and is sent to a photoelectric conversion signal processing part 60. In this circuit 60, a gate pulse is generated in a gate pulse generating circuit 63 by the signal detected by a window detecting part 70. The level of the photoelectric conversion signal is made euqal to that, which is obtained from a region other than a window part, in an AGC circuit 61 by a gate circuit 26. The output of the circuit 61 is made binary by a binary circuit 64 and is discriminated by a discriminating part 80.</p> |
