• Progressive compression of large evolutionary volumic meshes: geometry and properties.

    Scientific field: Informatique et science de l'information

    Research division: Mécatronique et numérique

    Strategic priority:

    2017-R11-08

    Location: Lyon

    Supervisor: Sébastien SCHNEIDER

    Apply: Sebastien.schneider@ifpen.fr

    The 3D mesh objects for dynamic volume simulations have increasing sizes making them complex to store, manipulate and visualize. These digital objects reach the target sizes of billions of cells. They are increasingly used in the context of web applications, collaborative platforms; they therefore need to be efficiently transmitted over the network, and processed on devices with computing power and resolutions of various strength. Thus, compression of these contents becomes a critical scientific challenge with several objectives such as the efficient storage of such data, an interactive time transmission on the network, a progressive display of the content adapted to the devices, or yet a random and quick access. Their compression in progressive mode allows access without decompressing the entire stored binary file, at some part of the mesh at different levels of resolution. In other words, this mode means to obtain a single binary file, encoding the entire mesh, either lossless compressed or with an allowable loss of information (reducing the initial numerical accuracy of the file) with a low compression rate (less than 10). This is the equivalent of lossless or lossy modes of the JPEG 2000 image compression standard.
    The aim of this thesis is to propose a new compression method for volumic meshes able to compress both the geometry and the associated properties, while allowing a progressive decompression adapted to the display devices. Geometry of the mesh can be structured (a set of hexahedral cells with an implied topology) or unstructured (mixture of different cell types: tetrahedron, hexahedron, prism, pyramid, etc.) and can evolve in time (3D + t). Today there is very few work on the progressive compression of sequences of volumic meshes, including properties. Also, we propose to focus this thesis on the volumic mesh compression composed of hexahedrons or tetrahedrons, corresponding to most cases in geosciences and in combustion, and predominantly treated in the literature. The thesis will build on recent work on compression of volumic mesh, surface mesh with attributes, as well as the skills of the MediaCoding I3S team in terms of compression. It will be the continuation of an internship (during the summer of 2014) and a post-doctoral work on the same theme, initiated at IFP Energies nouvelles in January 2015 in collaboration with I3S.

    Keywords: signal processing, wavelet, mesh, compression

    Academic supervisor Professor, Marc ANTONINI , I3S UMR 7271
    Doctoral School ED084 EDSTIC/Ecole Doctorale des Sciences et Technologies de l’Information et de la Communication, http://edstic.unice.fr/
    IFPEN Supervisor PHD, SCHNEIDER Sébastien, research engineer in Computer Science. Sebastien.schneider@ifpen.fr 
    Ph.D. location IFP Energies nouvelles, Lyon, France 
    Duration and start date 3 years, starting preferably on march 1, 2017 
    Employer IFP Energies nouvelles, Lyon, France 
    Academic requirements University Master degree in computer and information sciences 
    Language requirements Fluency in French or English, willingness to learn French 
    Other requirements Good knowledge of scientific programming in object languages (C++ or Java)














    For more information or to submit an application, see theses.ifpen.fr or contact the IFPEN supervisor.