Precise online camera calibration in a robot navigating vision system

This paper proposes a camera calibration method with the aid of a robot, which is navigated by a vision system after all cameras in the system are calibrated. It can be carried out easily not only in the laboratory, but also in the working area. All that is needed in the calibration procedure is a stick with a ball on one end, with the other end of the stick mounted on the robot hand. The calibration program guides the robot to move to appropriate positions, while at the same time the ball is accurately recognized in camera images. Without knowing any initial specifics about the camera, all intrinsic and extrinsic parameters are well calibrated in the robot base coordinate frame. In order to obtain high accuracy, the lens radial distortion is also modelled.