Generative-model-based tracking by cluster analysis of image differences

The EM algorithm is used to track moving objects as clusters of pixels significantly different from the corresponding pixels in a reference image. The underlying cluster model is Gaussian in image space, but not in grey-level difference distribution. The generative model is used to derive criteria for the elimination and merging of clusters, while simple heuristics are used for the initialisation and splitting of clusters. The system is competitive with other tracking algorithms based on image differencing.