Accurate Calibration of Multiple Pan-Tilt Cameras for Live Broadcasts

We aim to realize new image expressions-3D position analysis and computer graphics (CG) synthesis-by using multiple pan-tilt cameras for live broadcasts. For this purpose, a camera calibration technique is needed that is accurate over a wide space such as a stadium and has high operability. We thus propose a method to accurately calibrate multiple pan-tilt cameras that can be used in live broadcasts. This method enables cameras to be accurately calibrated over a wide space by using multiple calibration patterns and a system to be efficient prepared at a filming location. After the preparation, accurate camera parameters can be obtained in real time using the pan-tilt angles acquired from angle sensors in the camera platform. We showed the effectiveness of the proposed method through CG simulation and experiments using a real system. In addition, we developed a 3D ball tracking system that uses our calibration method.