Ask HN: Where to start with computer vision for sumo robot competition?

I'm going to create autonomous robot for sumo robot competition. Main goal of the robot is to stay within the circular playing field while pushing the other robot out. Cameras will be the only input of the robot.

I have completely zero knowledge about computer vision and about processing data from camera.

Could you please point me to some materials explaining how to process video data so robot will be able to find out its position within the playing field? Also how to recognize other objects and their movement?