Despite the existence of various biometric techniques, like fingerprints, iris scan, as well as hand geometry, the most efficient and more widely-used one is face recognition. This is because it is inexpensive, non-intrusive and natural. Therefore, researchers have developed dozens of face recognition techniques over the last few years. These techniques can generally be divided into three categories, based on the face data processing methodology. There are methods that use the entire face as input data for the proposed recognition system, methods that do not consider the whole face, but only some features or areas of the face and methods that use global and local face characteristics simultaneously. In this paper, we present an overview of some well-known methods in each of these categories. First, we expose the benefits of, as well as the challenges to the use of face recognition as a biometric tool. Then, we present a detailed survey of the well-known methods by expressing each method's principle. After that, a comparison between the three categories of face recognition techniques is provided. Furthermore, the databases used in face recognition are mentioned, and some results of the applications of these methods on face recognition databases are presented. Finally, we highlight some new promising research directions that have recently appeared.

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Digital watermarking for 3D meshes is a means to copyright protection. In this paper, we propose a robust watermarking algorithm for 3D Meshes. We work on multiresolution, triangular and semi regular meshes having various sizes. Our algorithm is able to insert high amount of information in the field of multiresolution. For this reason, we apply a uniform scalling then a wavelet transform to the host mesh. Embedding step consist on modifying wavelet coefficients vector according to the bit to be inserted. These techniques do not generate a quality degradation of the mesh despite the important capacity adopted. Tests applied to various attacks have shown the robustness of our algorithm against rotation, translation, uniform scaling, Noise addition, smoothing, simplification and coordinate quantization. A comparison with literature revealed that we have a remarkable improvement over the published results.