Off-the-shelf vision for a robotic ball catcher

We present a system for catching a flying ball with a robot arm using off-the-shelf components (PC based system) for visual tracking. The ball is observed by a large baseline stereo camera, comparing each image to a slowly adapting reference image. We track and predict the target position using an extended Kalman filter, also taking into account the air drag. The calibration is achieved by simply performing a few throws and observing their trajectories, as well as moving the robot to some predefined positions.