An image processor includes a control unit, wherein the control unit includes an image obtaining unit that obtains an image including a document area corresponding to a document read by an image reader, an edge coordinate detecting unit that detects coordinate values of edge candidate pixels, a tilt calculating unit that calculates a tilt of the document area, or a tilt obtaining unit that obtains the tilt of the document area detected by a predetermined sensor, an edge end coordinate extracting unit that extracts a coordinate value of an edge end candidate pixel, a straight line calculating unit that calculates a straight line corresponding to the edge, and either one or both of a tilt correcting unit that corrects the tilt of the document area by rotating the document area, and an area clipping unit that clips the document area from the image.