Image processing apparatus and image processing method

An image processing method executed by an image processing apparatus including an image photographing unit, and a control unit, wherein

• the method comprises:
• a document image acquiring step of acquiring a document image including at least an image of a document photographed by the image photographing unit;
• a contour extracting step of extracting a contour of the document from the document image acquired at the document image acquiring step, the extracting the contour being performed based on luminance;
• a distortion position detecting step of detecting a contour straight line located at a location where a distance between the contour extracted at the contour extracting step and a center point of a rectangle having the minimum area surrounding the contour is shortest, the contour straight line being detected as a distortion position in the document, the contour straight line being located on the contour;
• and
• a corrected image generating step of performing a geometric correction on the document image to extend the contour to a correction reference line determined from the distortion position detected at the distortion position detecting step, and generating a corrected image having the distortion in the document image corrected,
• wherein the steps are executed by the control unit.