Model based extraction of articulated objects in image sequences for gait analysis

This paper describes an approach to the extraction of articulated objects which will be used for gait analysis. In most medical applications markers are used to determine trajectories of different body parts. This approach works without any markers. Monotony operators which compute the displacement vector field are used to initialize a contour based tracking algorithm called active rays-for several body parts which are important for gait analysis. The contours of different parts of the human body are extracted and tracked. These parts are approached by simple 3D geometric objects (blocks), which 3D position and motion are estimated for the each image of the image sequence. Then, the trajectories of the moving parts represented by the 3D blocks can be determined and used for classification of different gait disorders.