| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain an appropriate gain setting value of amplification means in analog signal processing means in a short time. <P>SOLUTION: By controlling a whole device with an analog signal processing section 17, a CPU of an image reading apparatus exposures a white reference plate by an LED light source, and reads the white reference plate by using a CCD that converts light reflected by the white reference plate to an image signal, and outputs it every main scanning line. The CPU controls a register section 37 in the analog signal processing section 17 and a gain switching circuit 38, and subsequently switches a gain setting value of an amplification circuit 33 in one main scanning line. On the basis of a digital image signal obtained by the switching, a gain table in an image processing section positioned at a rear step of the analog signal processing section 17 calculates an appropriate gain setting value of the amplification circuit 33. <P>COPYRIGHT: (C)2013,JPO&INPIT |
