Real-time motion tracking using a single camera.

Any rigid body in motion has six degrees of freedom. To track a moving rigid body one needs only to track any three non-colinear points of the body under motion. However, if one is allowed to observe the rigid body only through a single camera, the problem is a little harder. It can be shown that the observation of four coplanar points in space is necessary and sufficient to guarantee uniqueness of motion. We have developed a new, simple analytical technique to solve for the parameters of motion by tracking, on the image plane, four points whose relative positon in 3-D is known. In this paper, we will discuss the principles of operation of such a system and describe some of the implementation aspects of our system. We will compare it to other motion tracking systems in use and outline some of the advantages of this system and its potential uses.