| 摘要 |
PROBLEM TO BE SOLVED: To provide an image reader capable of reading an image with a high picture quality without influence even when dust or dirt is stuck on a read line. SOLUTION: A signal level for each of pixels comprising image data provided by reading a white reference board at an initial read position is compared with a threshold level and when there is the pixel of low signal level, a signal level for each of pixels comprising the image data provided by reading the white reference board is compared with the threshold level after changing the read position. When there is the pixel of low signal level, similar operation is performed after changing the read position into other position and finally, image data at the read position, where all the signal levels for each of pixels comprising the image data provided by reading the white reference board are higher than the threshold level, are acquired as shading correction data.
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