| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a system which compares a read image obtained by reading a sheet with an inspection image to inspect an output with an image formed thereon, while detecting periodic defects with high accuracy.SOLUTION: A degree of flatness indicating gray level change for each pixel is calculated for a master image. A difference image is acquired by calculating a differential value between the master image and the read image. The acquired difference image is frequency-analyzed in terms of the change in differential value depending on a position on an image, to determine periodic defects depending on the image position, in the read image. On the basis of the degree of flatness, it is determined that periodic defects occur mainly in an area having slow gray level change for each pixel.</p> |
