| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an image reading apparatus and a program for detecting a color shift in different achromatic regions with high accuracy. <P>SOLUTION: An image reading apparatus detects a boundary region (in the middle of a change from black to white or from white to black) between achromatic regions on the basis of image data B,G and R. When the detected boundary region is within the predetermined number of pixels, a difference in concentration between the achromatic regions on both sides of the boundary region is equal to or greater than a predetermined value, and a difference in maximum pixel value and minimum pixel value of the image data B, G and R corresponding to pixels existing in the boundary region is equal to or greater than a predetermined threshold ThC (step 224B), the apparatus outputs a color shift occurrence signal indicating the occurrence of a color shift (steps 224F and 224K). <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
