| 摘要 |
<p>PURPOSE:To ensure accurate binary coding of a photoelectric converted signal of an OCR with no complicated constitution, by binary coding a temperature compensated signal through a binary coding circuit and with a proper slice level. CONSTITUTION:An effect of the irregularity of sensitivity is eliminated by a shading compensating circuit 12 for the picture element signal supplied from a photoelectric converting part 11. Then the picture element signal is fed to a level detecting circuit 13 to deliver a mean value signal. At the same time, the shading compensated picture element signal is fed to a difference detecting circuit 14, and the smaller value of difference is delivered as a difference signal to which the polarity is decided on the basis of the value of the picture element signal to be binary coded. The shading compensated picture element at a position to be binary coded undergoes a compensation of density through a density compensating circuit 15 and based on the mean value signal, the difference signal and the picture element signal corresponding to the same position of a line sensor of prescan which is delivered from a shift memory 16.</p> |
