Patent ID: 7277596

Claim:
An image input apparatus, comprising: a show-through elimination part configured to perform show-through elimination on image data read from a front face of an original and image data read from a back face of the original; and an image compression part configured to compress and convert, into codes, the image data of the front face and the back face from which image data show-through is eliminated, said show-through elimination part configured to use the image data of the back face when performing the show-through elimination on the image data of the front face and to use the image data of the front face when performing the show-through elimination on the image data of the back face, wherein, when pixel concentration of the front face is equal to or less than a first threshold value and pixel concentration of the back face in the same position is equal to or more than a second threshold value, the show-through elimination part determines that the pixel concentration of the front face is show-through pixel, and when the pixel concentration of the back face is equal to or less than the first threshold value and the pixel concentration of the front face in the same position is equal to or more than the second threshold value, the show-through elimination part determines that the pixel concentration of the back face is show-through pixel.