Determining motion of nonrigid objects by active tubes

Abstract

Analysis of motion of nonrigid objects in image sequences is an important and difficult problem in computer vision. This paper presents a model named active tubes for this purpose. It analyzes the temporal context in a spatio-temporal solid using an energy minimizing model like the snakes model of M. Kass, A. Witkin and D. Terzopoulos (1988). Active tubes constitute accumulations of snakes along the time axis using the temporal context. An input image sequence should be handled as a single image solid. In spatio-temporal solids, a locus of the moving object constitutes a 3D region. This removes the problem of feature correspondence. The problem of extracting and tracking the motion of objects in an image sequence can be replaced by the problem of segmenting the spatio-temporal solid. >