Image reading apparatus provided with correction for shadings in image data

Claim 1

An image reading apparatus, comprising: reading means for photoelectrically reading an image and generating image data representing the image; a reference portion for use in correcting a shading in the image data generated by said reading means; first memory means for storing image data generated from said reading means when said reading means reads said reference portion; second memory means having a plurality of addresses, said second memory means being for storing first and second sets of corrected image data, said first and second sets respectively comprising first corrected image data and second corrected image data are respectively associated with the same address data, said first set of corrected image data being data which have been corrected taking into account correction of shading in the image data only, said second set of corrected image data being data which have been corrected taking into account correction not only of shading in the image data but also of a characteristic of visual observation, and the first or second corrected image data being read out in accordance with said address data which is supplied to said second memory means; and read out means for supplying to said second memory means, in combination, as the address data, image data generated from said reading means when said reading means reads an original document and the image data stored in said first memory means, and for reading out corrected image data of either said first or said second set of corrected image data from said second memory means.