In this paper we address two problems crucial to motion analysis: the detection of moving objects and their localisation. Statistical and level set approaches are adopted in formulating these problems. For the change detection problem, the inter-frame dierence is modelled by a mixture of two zero-mean Laplacian distributions. At rst, statistical tests using criteria with negligible error probability are used for labelling as changed or unchanged as many sites as possible. All the connected components of the labelled sites are used thereafter as region seeds, which give the initial level sets for which velocity elds for label propagation are provided. We introduce a new multi-label fast marching algorithm for expanding competitive regions. The solution of the localisation problem is based on the map of changed pixels previously extracted. The boundary of the moving object is determined by a level set algorithm, which is initialised by two curves evolving in converging opposite directions. The sites of curve contact determine the position of the object boundary. Experimental results using real video sequences are presented, illustrating the eciency of the proposed approach.

@Article{ST01,
  author       = "Sifakis, Eftychios and Tziritas, Georgios",
  title        = "Moving object localization using a multi-label fast marching algorithm",
  journal      = "Signal Processing: Image Communication",
  number       = "10",
  volume       = "16",
  pages        = "963--976",
  year         = "2001",
  url          = "http://graphics.cs.wisc.edu/Papers/2001/ST01"
}