Elaboration d'une technique de tatouage video basée sur la perturbation des vecteurs de mouvements

The recent development of digital multimedia allows to obtain a perfect copy of an original source, which leads the providers to deal with the hacking of multimedia contents. The digital protection of the original media has became a major research issue in the image processing area. The first contribution exposed in this thesis is a novel system of video scrambling which permits to use the motion vectors for the protection of a digital video. Then, we propose an invisible solution of protection for the digital video contents, built on a local disturbance of the motion vectors. We show in chapter one a solution of video scrambling, based on the disturbance of the motion vectors of a video stream, compressed using the well known MPEG4 codec. Then, we pursue on a novel watermarking algorithm in the uncompressed domain, based on the local disturbance of the motion vectors. This algorithm is mainly based on a defined reference grid applied in the insertion rules. In chapter two, we expose the principles of watermarking, but also an outline of the main techniques used in video watermarking. Then, in chapter three, we present our watermarking algorithm, and the drawbacks of motion vectors disturbance. In chapter four, we explore the invisibility of our approach, in relation with the several issues raised in the previous chapter. Accordingly, we present a state of the art on the human visual system, and the main quality metrics applied in video. From this, we show how we developed our specific algorithms, which allow to minimize the visual impact of the watermarking procedure. At last, we conclude in chapter five on our approaches, and present the possible evolutions and improvements of our algorithms.