In the image brightness amendment device amendment the brightness of the scan image which is read

摘要

PROBLEM TO BE SOLVED: To provide an image luminance correcting device capable of preventing black lines and light shadows from occurring in an image that has been subjected to luminance correction. SOLUTION: A scanned image is divided into a plurality of blocks (step S4), the luminance value of a pixel with the highest luminance value among pixels included in each block is regarded as a background value of the each block (step S4), and luminance correction processing is applied to the scanned image on the basis of the background value of the each block (step S5 to S8). According to this, if the lighting of an image reading means is not uniform and even if the way of placing a book document on contact glass is not uniform (if the way of a page floating differs between the upper edge and the lower edge of the page), it is possible to prevent black lines and light shadows from occurring in the image that has been subjected to luminance correction, because a background value is detected within a local area to perform luminance correction compared with a case where the scanned image is subjected to luminance correction in a band-shape on the basis of a background value of a portion of the scanned image.