Patent ID: 8675267

Claim:
An image reading apparatus comprising: a conversion unit configured to convert first image information into second image information by using a predetermined color conversion factor group, wherein the first image information represents color levels in a first color space, and the second image information represents color levels in a second color space which is different from the first color space; and a setting unit configured to: obtain the second image information of at least two color samples for correcting color level differences of a light source, wherein the obtained second information of the color samples comprises at least two color levels converted by the conversion unit from the first image information of the color samples, and wherein the first image information of the color samples is generated by reading light irradiated from the light source and reflected from the color samples, select a corrected color conversion factor group corresponding to the obtained second image information of the color samples, from among a plurality of previously stored color conversion factor groups, using a correspondence relationship between the plurality of previously stored color conversion factor groups and a combination of the at least two color levels comprising the obtained second image information of the color samples, wherein the correspondence relationship is predetermined by differences in the at least two color levels exhibited by different categories of light sources that may be used as the light source when light reflected from the color samples is read using the different categories of light sources, and set the conversion unit to use the selected corrected color conversion factor group instead of the predetermined color conversion factor group.