Camera auto-calibration from articulated motion

This paper presents a novel auto-calibration method from unconstrained human body motion. It relies on the underlying biomechanical constraints associated with human bipedal locomotion. By analysing positions of key points during a sequence, our technique is able to detect frames where the human body adopts a particular posture which ensures the coplanarity of those key points and therefore allows a successful camera calibration. Our technique includes a 3D model adaptation phase which removes the requirement for a precise geometrical 3D description of those points. Our method is validated using a variety of human bipedal motions and camera configurations.