Patent ID: 8373900

Claim:
An image reading apparatus comprising: a first reading unit configured to read a first surface of a sheet, and output image data of the read first surface; a second reading unit configured to read a second surface of the sheet, and output image data of the read second surface; an MTF correction filter coefficient determination unit configured to detect, on the basis of output image data of a chart sheet from said first and second reading units, an MTF value for each of a plurality of areas to which reading areas of said first and second reading units are respectively divided, determine a reference MTF value based on the MTF value for each of the plurality of areas of said first and second reading units, and determine an MTF correction filter coefficient for each of the plurality of areas of said first and second reading units based on (a) the MTF value of the corresponding area of the plurality of areas of said first and second reading units and (b) the reference MTF value; and an MTF correction unit configured to perform MTF correction on output image data of a sheet of an original from said first and second reading units, based on the MTF correction filter coefficient for each of the plurality of areas of said first and second reading units.