FREE CURVE RECOGNITION PROCESSING METHOD

PURPOSE: To reduce a burden on an operator by finding a core line from contour vectors extracted from a binary image, selecting an contour section and making it into a core line, and judging how many core lines there are and finding the angle between two core lines among the core lines when there are plural core lines. CONSTITUTION: When 0 deg. < angle α < 180 deg., the refraction point P of the contour section 8 closest to a point B from a contour section on the onward-directional side of a straight line AB is found, the intersections D and E of a straight line which passes the point P and is perpendicular to the straight line PB, and the straight line AB and straight line BC are found, and based on the straight lines DB and BE, a spline curve is found. When α=0 deg. or α=180 deg., spline curve interpolation is not performed. When 180 deg.