| 摘要 |
PROBLEM TO BE SOLVED: To provide an image reading apparatus which can reduces a horizontal stripe by improving black level detecting accuracy. SOLUTION: The image reading apparatus includes a color image sensor for optically reading an original to convert it into image data; a line period changing means for changing the line period of the color image sensor in a color mode and a white and black mode; a black level detecting range setting means for setting the black level detecting range of the main scanning direction and the sub-scanning direction of the color image sensor; a black reduced value calculating means for calculating the black level detected value in the black level detecting range of the main scanning direction and the sub-scanning direction, and calculating the black reduced value based on the calculated black level detected value; and a black level correcting means for reducing the black reduced value from the image data. COPYRIGHT: (C)2006,JPO&NCIPI
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