Geometrical distortions are the Achilles heel for many watermarking schemes. Most countermeasures proposed in the literature only address the problem of global affine transforms (e.g., rotation, scaling, and translation). In this paper, we propose an original blind watermarking algorithm robust to local geometrical distortions such as the deformations induced by Stirmark. Our method consists in adding a predefined additional information to the useful message bits at the insertion step. These additional bits are labeled as resynchronization bits or reference bits and they are modulated in the same way as the information bits. During the extraction step, the reference bits are used as anchor points to estimate and compensate for small local and global geometrical distortions. The deformations are approximated using a modified basic optical flow algorithm.

During the last decade, a significant effort has been put into designing watermarking algorithms. The watermarking community now needs some advanced attacks and fair benchmarks in order to compare the performances of different watermarking technologies. Moreover, attacks permit the weaknesses of an algorithm to be found and consequently trigger further research in order to overcome the problem. These ideas motivated the creation of the European Certimark project. After a short definition of dewatermarking, we present an original attack based on self similarities. This attack is then put to the test with three different publicly available watermarking tools. Finally, we discuss briefly the feasibility of a generic attack i.e. a dewatermarking attack which should succeed in removing whatever watermarks have been inserted by whatever watermarking tools.

In the past few years, much research on watermarking has been focused on improving robustness to attacks. The starting point of the present study is an R&D algorithm which was not optimised for still images, but offered a good trade-off in terms of capacity, visibility and robustness, and worked in a full blind manner. We have focused on adapting it to video and on optimising it to the world of embedded terminals, such as digital still cameras, digital television and wireless terminals, where the computing power and storage resources of a Pentium are not available. Results of our adaptations are shown in the form of execution times versus platform capabilities. This work is the result of a close collaboration between the Eurecom research institute and STMicroelectronics.

The aim of this demonstration is to present the ongoing performance of our research and development watermarking scheme software for owner and image authentication. The proposed illustrations cover a large panel of original images (in grey levels and colors), watermarks and attacks. Evaluation is performed according to ratio, visibility and robustness.

In this correspondence, a new circuit structure is proposed which basically supresses the possibility of hazards and critical races in asynchronous sequential machines. In contrast to many approaches which try to solve these problems by changing the form of the automaton model, we suggest a more general "hardware" solution. This configuration provides performance extremely close to that of classical circuits while allowing substantial reduction in circuit cost.

Because of dramatic reductions in cost of mini-computers, peripherals and logic modules, it is becoming evident that many problems confronting the computer system designer will be solved in the future by hybrid designs involving not only software but also specialized computers with architectures best suited to each application. Accordingly, hardware research must no longer be considered as a separate discipline by system programmers but as a tool in exactly the same way as languages. To illustrate this philosophy, a hardware laboratory has been set up at the University of Montreal. The primary interest of the founders was in designing and building small specialized computing systems.