Patent ID: 6657748
Filing Date: 2003-12-02
Classification: H04N

Abstract:
An image reading apparatus comprising:an illumination unit adapted to irradiate light of a plurality of colors which includes at least first and second colors on an object; a photoelectric conversion unit adapted to receive light from said object and convert the received light into electric signals; an optical unit adapted to guide the light from said illumination unit to said photoelectric conversion unit via said object; and a moving unit adapted to relatively and reciprocally move a part or all of said object, said illumination unit, said optical unit, and said photoelectric conversion unit to obtain scan image information; wherein, a reference member having a uniform reflection density is used as said object to acquire shading data used for generating shading correction data to correct reading unevenness due to variation in characteristics of said illumination unit, said optical unit, and said photoelectric conversion unit, said photoelectric conversion unit reads the light from said reference member irradiated by the light of the first color by said illumination unit while moving in a forward direction by said moving unit to acquire shading data for the first color, and said photoelectric conversion unit reads the light from said reference member irradiated by the light of the second color by said illumination unit while moving in a backward direction by said moving unit to acquire shading data for the second color.