Modelling and Tracking Articulated Motion from Multiple Camera Views

This paper describes a scheme for modelling and tracking the motion of articulated bodies using a number of video cameras. The aim is to obtain complete and accurate information on the three-dimensional location and motion of the bodies over time. Applications include medicine, sports analysis and motion capture for animation. Feature extraction is avoided by placing markers at the joints of the body so that model selection, marker-to-measured-point association, occlusion and the choice of tracking filter are the important issues. While the scheme is general for any number of cameras, emphasis is placed on systems with a small number of cameras where occlusions are a major problem. The system is an amalgamation of new ideas and existing techniques drawn from a variety of disciplines such as machine vision, geometric algebra and radar tracking theory, which have been extended and developed for the marked joints/multiple camera problem. The proposed schemes for modelling and tracking would be easily adapted to markerless motion capture. The paper concludes with examples of the system successfully tracking limb motion using three cameras.