Image-reading device and method for performing a white-shading correction

摘要

An image-reading device (1) is provided. The image-reading device (1) comprises a photoelectric converting element (25) reading a first image from a subject copy (D), a reference-white member (12) functioning as a reference white used in a white-shading correction, reading means (4) for reading a second image from a constant range on a surface of the reference-white member (12) by using the photoelectric converting element (25), averaging means (44; 22) for dividing image data of the second image into a plurality of blocks in a sub-scanning direction so that each of the blocks includes a plurality of lines and obtaining average values of image data of the lines in the blocks respectively, peak-value determining means (45, 46; 22) for obtaining a peak value of the average values, and white-shading correcting means (43; 22) for performing the white-shading correction to image data of the first image by using the peak value as white-shading data. IMAGE