CALIBRATION MARKS AUTO-DETECTING MOTHOD IN CHECKERBOARD

摘要

A method for automatically extracting a cross point of a check board type is provided to robustly extract the cross point from a check board pattern by performing edge projection in a radius direction of a circle by a method capable of extracting the symmetry of a check board, and using at least one concentric circle. Edge information is projected to at least one concentric circle with respect to all points of an input image. If points of four maximum values are within a uniform range on at least one concentric circle to which the edge information is projected, the four points are extracted as cross point candidates. It is checked whether a brightness value is changed along directions of the extracted four cross point candidates. When the four cross points are crossed, the four cross points are added as candidate points. When a value of a cross rate which is established between candidate points, located on four points on a straight line and provided in projective geometry among the added candidate points is smaller than a uniform range, the candidate points are set up as cross points.