Redundant image representations in security applications

To be efficient, data protection algorithms should generally exploit the properties of the media information in the transform domain. In this paper, we will advocate the use of nonlinear image approximations using highly redundant dictionaries, for security algorithms. We show that a flexible image representation based on a multidimensional and geometry-based coding scheme, has precious attributes for security information embedding. Redundant expansions provide very good approximation properties, as well as an increased resiliency to coding noise and a simple stream structure enables easy manipulations. This paper describes simple examples of image scrambling and watermarking applications, based on a matching pursuit image coder. It illustrates the very interesting potential of redundant decompositions for data protection and security applications.