| 摘要 |
PURPOSE:To similiarly correct record density by detecting the reading characteristic of an image sensor by reading the densities of two reference density plates and providing variably a threshold that identifies the record density according to the reading characteristic. CONSTITUTION:Two densities with different values of two density plates are read by an image sensor 12 and a reader 18. According to the result of the reading, the reading characteristic of the image sensor 12 is detected at a reading characteristic detection circuit 19. And based upon the detected result of this reading characteristic, the threshold that identifies the record density of an original picture image is set variably. Therefore, the correction of the record density including half tone is similiarly executed through all density area even with the secular change of an optical system, such as the image sensor 12 etc.
|
