| 摘要 |
PURPOSE: To extract a true boundary point without being affected by noise in an image by providing a boundary point extracting part for defining the position of a picture element on a scanning line as the boundary point from a white image area to a black image area. CONSTITUTION: This device is provided with a scanning line setting part 12 for setting the scanning line to a binary image and a cumulative histogram preparing part 13 for successively investigating the picture elements on the set scanning line of the binary image and preparing a cumulative histogram, to which a prescribed value is added each time a black picture element is detected, corresponding to the position of the picture element on the scanning line. Further, a boundary point extracting part 14 is provided to extract the point for moving the shape of this prepared cumulative histogram from flatness to monotonous increase and to define the position of the picture element on the scanning line corresponding to this point as the boundary point from the white pixel area to the back pixel area. Then, the boundary point between the area, in which black picture elements are dotted, and the white pixel area, the boundary point between the area in which white picture elements are dotted and the black pixel area of the boundary point between the areas, where the black and white picture elements are dotted, can be easily provided. |
