Tracking and modeling people from video sequences has become an increasingl
y important research topic, with applications including animation, surveill
ance, and sports medicine. In this paper, we propose a model-based 3-D appr
oach to recovering both body shape and motion. It takes advantage of a soph
isticated animation model to achieve both robustness and realism. Stereo se
quences of people in motion serve as input to our system. From these, we ex
tract a 2 1/2-D description of the scene and, optionally, silhouette edges.
We propose an integrated framework to ft the model and to track the person
's motion. The environment does not have to be engineered. We recover not o
nly the motion but also a full animation model closely resembling the subje
ct. We present results of our system on real sequences and we show the gene
ric model adjusting to the person and following various kinds of motion. (C
) 2001 Academic Press.