Patent ID: 7476847

Claim:
An image reading apparatus, comprising: not less than four light emission elements, each with an emission spectrum different from the others; an emission control unit adapted to controlling, at least one of emission cycle and emission intensity of the not less than four light emission elements, and causing the light emission elements, either whole or in part, to emit light, either for an identical or a differing cycle, within an accumulation cycle; a photoelectric conversion unit adapted to receiving light reflected from an original, which is obtained by emitting light from the not less than four light emission elements toward the original, according to the control of said emission control unit, and converting the reflected light into an electrical signal; and a reading unit adapted to reading image information from the original, in accordance with the electrical signal that is converted by said photoelectric conversion unit, wherein said photoelectric conversion unit receives light reflected from the original for each of a plurality of accumulation cycles in the main scanning direction; and said emission control unit causes the not less than four light emission elements, either whole or in part, to emit light, for each of the plurality of accumulation cycles in the main scanning direction, and causes a relative light emission quantity proportion of light emitted in at least one accumulation cycle to be approximated to one curve of three types of color-matching functions, wherein the number of accumulation cycles in the main scanning direction is not less than three, and less than the number of light emission elements.