Study on Axis Calibration Method of the Coordinate Measurement System Based on Binocular Vision

For a coordinate measurement system based on binocular vision, system calibration is an important factor for measurement accuracy. In this paper we present a flexible calibration method for the axis calibration of rotation stage which is installed in front of the binocular vision system to increase the system measurement range. By putting a standard ball in front of the binocular vision system, a sequence of pictures is taken by the two cameras with a few different rotation angles of the rotation stage. With the method of space intersection of two straight lines, the reference points (the ball centers at each rotation angles) for axis calibration are figured out. The trail of standard ball is a circle. Since all ball centers of rotation are on a plane perpendicular to the axis, the center of circle is on the axis of rotation stage. The rotation axis of stage is then calibrated according to the calibration model.