| 摘要 |
PROBLEM TO BE SOLVED: To generate density irregularity at a part of starting transition to the part of image information from a base part at the end part of an original by preparing the density histogram of each pixel each time of reading a scanning line and correcting the gradation of a read image based on a previously set value. SOLUTION: A histogram preparing circuit 60 prepares the density histogram from image data from a scanner part 1. At the time of judging that the frequency of a pixel value at a black peak position is smaller than a prescribed black peak detecting threshold, a default value at the black peak position is inputted to a reference value calculating part 63 to calculate the black reference value based on the default value at the black peak position to store in a reference value register 64. When a white reference value is also stored in the register 64, a range correcting circuit 65 corrects the read image based on the white reference value and the black reference value. With respect to the original of the same degree of the density, etc., of image information of a base or an original, density irregularity is minimized by using the default value corresponding to an actual original. |
