Patent ID: 7755804

Claim:
An image reading apparatus for reading an image with respect to a plurality of colors, comprising: a reference member; an image reading device including a plurality of light receiving elements, the image reading device reading the reference member to obtain white level information for the respective colors, the white level information for each of the colors being a set of data of a quantity obtained by the light receiving elements, the read image being corrected based on at least the white level information; a ratio calculator which calculates a ratio among the white level information of the respective colors; an abnormal-data determiner which determines that a first specific piece of data in the white level information of any particular color is abnormal data, at least one of the following two cases: (i) where the first specific piece of data in the white level information is different from a second specific piece of data in the white level information of the same color which second specific piece of data is in a predetermined relationship with the first specific data, by an amount not smaller than a predetermined threshold; and (ii) where the first specific data is outside a predetermined range; and a data corrector which obtains correction data which is obtained by multiplying, by the ratio, corresponding data which corresponds to the abnormal data according to a predefined principle and included in the white level information of at least one color which is determined not to include the abnormal data, and which replaces the abnormal data with the correction data.