| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an image reading apparatus which utilizes a dynamic range of an A/D conversion circuit at maximum efficiency without generating output saturation. <P>SOLUTION: An image reading apparatus includes a light source, image reading means, a reference white plate, and light amount adjusting means. The light amount adjusting means includes: a peak value detection part 331 and a peak position detection part 332 that turn on the light source and detect a peak value and a peak position from an output value of main scanning direction all pixels, obtained by reading and outputting the reference white plate by the image reading means; a black level corresponding value detection part 334 that turns off the light source and detects an output value of the peak position (black level corresponding value), obtained by reading and outputting the reference white plate by the image reading means; and a light amount adjusted value calculation part 335 that calculates a parameter so as to match the peak value to a target value by using the peak value and the black level corresponding value, and changes a preset first light amount adjusted value to a second light amount adjusted value obtained by applying the parameter to the first light amount adjusted value. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
