| 摘要 |
<P>PROBLEM TO BE SOLVED: To amplify the output power value of a photoelectric conversion element appropriately, even when the amount of light is instable. <P>SOLUTION: Each time one line in the main scan direction is read, determination is made of a magnitude correlation between main reference image data which was read beforehand from a main white color reference material disposed on the outside of a manuscript readable region and having a prescribed width in a sub-scan direction and a length equal to one line in the main scan direction and sub-reference image data which is read from a spot corresponding to a position in the one line equivalent sub-scan direction on a sub-white color reference material disposed at right angles to the main white color reference material and having a prescribed width in the main scan direction and having a length equal to all lines in the main scan direction. While the sub-reference image data corresponding to the one line is larger than the main reference image data, gain necessary to amplify the output power value of a photoelectric conversion element is subtracted by a prescribed correction value before the one line is read again and a magnitude correlation is decided on. While this process is repeated, when the sub-reference image data becomes equal to or smaller than the main reference image data, the next one line is read. <P>COPYRIGHT: (C)2012,JPO&INPIT |
