| 摘要 |
PROBLEM TO BE SOLVED: To judge size of an original by simple structure and in a short time. SOLUTION: Whether or not difference (x-y) between a mean value x of image data at a closing state of a cover and a mean value y of the image data at a closed state of the cover in each sensing area is equal to or less than a predetermined threshold th1 is judged (168). When the difference (x-y) is equal to or less than the threshold th1 here, it is judged that the original is laid on the sensing area and "1" is set in a status register of the sensing area (170), on the other hand, when the difference (x-y) is larger than the threshold th1, "0" is set in the status register of the sensing area (172). Then, presence/absence and the size of the original are judged based on values (values indicating whether or not the original is laid) of the status register set for each sensing area. COPYRIGHT: (C)2006,JPO&NCIPI
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