Patent ID: 8218178

Claim:
An image processing apparatus comprising: a determinant image management unit that manages identification information assigned to a paper document in association with protecting information specifying whether or not an action to process the paper document is allowable and a first edge image composed of edge components of the image of an paper document; a reader that reads an image of the paper document containing the identification information in response to the action to process the paper document assigned with the identification information; an extraction unit that extracts the identification information from the image of the paper document read by the reader; an acquisition unit that acquires from the determinant image management unit the protecting information and the first edge image corresponding to the identification information extracted by the extraction unit; a first determination unit that determines whether or not the action to process the paper document is allowable based on the protecting information acquired by the acquisition unit; a second determination unit that calculates, based on a differential image between a second edge image composed of edge components of the image of the paper document read by the reader and the first edge image acquired by the acquisition unit, a number of pixels in a defective part of the second edge image relative to the first edge image, and determines whether or not the paper document is spoofed based on whether or not the calculated number of pixels exceeds a threshold value having been set previously in association with the action to process the paper document; a third determination unit that determines that a processing in response to the action to process the paper document is allowable when the first determination unit determines that the action to process the paper document is allowable and the second determination unit determines that the paper document is not spoofed; and a processor that performs a processing according to the action to process the image read from the paper document by the reader if the third determination unit determines that the processing is allowable.