DYNAMIC CODING OF VISUAL INFORMATION

This paper introduces a novel approach to visual data compression. The approach, named dynamic coding, consists of an effective competition between several representation models used for describing data portion s, The image data is represented as the union of several regions each approximated by a representation model locally appropriate, The dynami c coding concept leads to attractive features such as genericness, fle xibility, and openness and is therefore particularly suited to a multi media environment in which many types of applications are involved. Dy namic coding is a general proposal to visual data compression and many variations on the same theme may be designed. They differ by the part icular procedure by which the data is segmented into objects and the l ocal representation model selected, As an illustrative example, a vide o compression scheme based on the principles of dynamic coding is pres ented, This compression algorithm performs a joint optimization of the segmentation (restricted to a so-called generalized quadtree partitio n) together with the representation models associated with each data s egment. Four representation models are competing namely, fractal, moti on compensation, text and graphics, and background modes, Optimality i s defined with respect to a rate-distortion tradeoff and the optimizat ion procedure leads to a multicriterion segmentation.