| 摘要 |
PURPOSE:To attain a device usable for a processing circuit with longer access time, by slowing down a clock of a photoelectric converting element than the timing of conventional original reading, in obtaining the correction coefficient based on optical information from a uniform reflecting plane. CONSTITUTION:When a transfer control signal is outputted, the original is read. Switches S2-S5 are switched to contact (b) position. That is, the shading correction coefficient stored in a high speed buffer memory 20 in advance is given to a D/A converter 13 in synchronizing with a clock phi1 of original reading. The coefficient is converted into an analog value at the converter 13 and outputted as VY from a sample hold circuit 12. The content of a storage circuit 18 is stored in the memory 20 in advance. Processing of operations VX, VY is done at an operation processing circuit 14 together with the original reading signal VX and the result is outputted as a signal VO after correction. |
