| 摘要 |
PURPOSE:To compensate a secular change of an optical device, by storing an electiric signal at every picture element through directly scanning the surface of a reflecting plate and utilizing this electric signal level as a slice level of a binary circuit. CONSTITUTION:An electric signal 10 level at every picture elements obtained by directly scanning the surface of a reflecting plate is detected by a level detection circuit 13 having plural number of detection levels. The obtained result is stored in a storing circuit 16. When a signal obtained by scanning an original is changed to binary code by a binary circuit 11, the corresponding stored contents of picture elements stored in the storing circuit 16 are utilized as a slice level Vs. |
