Abstract: In an image reading apparatus for reading from above the image of a document, which has some thickness like a book or a file and is laid on a document table with its reading surface facing upward, a histogram regarding the brightness distribution of the reading surface is generated based on the image data of the reading surface, and the mode brightness and the maximum brightness of the reading surface are calculated, and it is determined whether show-through exists on the reading surface depending on the difference between the mode brightness and maximum brightness for preventing false detection of the base brightness caused by show-through effect.

Abstract: An image reading device by which a plurality of images recorded and set in a prescribed posture on an original document are scanned by one scanning motion, changed in layout and then outputted in the changed order. The image reading apparatus includes an image reading means for reading an original document including a plurality of images and space, a distinguishing means for distinguishing the images from the space, a memory means for memorizing only the image data and an output means for outputting memorized image data in a different order.