US Patent 7609419 Image scanning apparatus and method

An image scanning apparatus and method are provided in which shading data of the image scanning apparatus is acquired when manufacturing the image scanning apparatus, which is when a white reference or the shading data is cleanest. An original document is scanned using the shading data acquired when manufacturing the image scanning apparatus and shading data of non-contaminated regions of a white reference or shading reference, thereby eliminating distortion such as white lines in an image caused by pollutants stuck to the shading reference or the white reference and improving the performance of the image scanning apparatus. The apparatus and method includes acquiring the shading data when manufacturing the image scanning apparatus and storing the shading data in a memory, and comparing the shading data acquired when manufacturing the image scanning apparatus with shading data acquired when using the image scanning apparatus and, based on the result of the comparison, processing the image of the original document.