IMAGE READING DEVICE, IMAGE PROCESSING DEVICE AND IMAGE PROCESSING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an image reading device that can detect accurately an image document size at low costs and with high convenience for a user, and an image reading method of the same.SOLUTION: The image reading device, when reading an image of a document placed on a document stand, performs the following process: acquiring a length of an edge of the document on the basis of image data acquired by reading the document while moving reading means for optically reading an image the document using moving means for moving the reading means; then extracting a plurality of candidate sizes to be estimated as the size of the document on the basis of the acquired length of the edge of the document and sizes of a plurality of regular documents memorized in a memory; further analyzing the image data with respect to a region to be specified based on a difference of the plurality of extracted candidate sizes to be estimated as the size of the document so as to determine whether a document exists in the region; and determining the size of the regular document placed on the document stand on the basis of the plurality of extracted candidate sizes to be estimated as the size of the document and the result of the determination.