METHOD AND APPARATUS FOR RECOGNIZING A QUADRILATERAL OBJECT CONTAINED IN AN INPUT BITMAP IMAGE

Described is an image processing system which is operative to automatically determine a quadrilateral object such as a character frame, page mark, or position correction mark only with a mouse click. A field is automatically specified by displaying a scanned image of a form including a black frame on a display, clicking within a character frame at the left end for each recognition field, and clicking within a character frame at the right end of the same field. In this case, a field position/size determination program scans the image in the vertical and horizontal directions from the two clicked points to detect the inner wall of the black frame, and produces a histogram by establishing rectangles between two character frames to automatically detect the number of character frames in the field and the thickness of the black line between the character frames. In addition, for a form with a page mark or position correction mark, what is the mark can be automatically detected from the surrounding is black, and the height of the mark only by clicking the inside of the mark with a mouse.