Abstract

Quantitative geometric descriptions of the movements of persons are obtained by fitting the projection of a three-dimensional person model to consecutive frames of an image sequence. The kinematic of the person model is given by a homogeneous transformation tree and its body parts are modeled by right-elliptical cones. The values of a varying number of degrees of freedom (DOFs; body joints, position, and orientation of the person relative to the camera) can be determined according to the application and the kind of image sequence. The determination of the DOFs is understood as an estimation problem which is solved by an iterated extended Kalman filter (IEKF). For this purpose, the person model is augmented by a simple motion model of constant velocity for all DOFs which is used in the prediction step of the IEKF. In the update step, both region and edge information are used. Various experiments demonstrate the efficiency of our approach.

Abbreviations: modeling of personsAbbreviations: articulated motion estimationAbbreviations: Kalman filter