Spécialité: Vision Pour La Robotique Acknowledgements First of All, I Would like to Thank

The automatic 3d modeling of an environment using images is still an active topic in Computer Vision. Standard methods have three steps: moving a camera in the environment to take an image sequence, reconstructing the geometry of the environment, and applying a dense stereo method to obtain a surface model of the environment. In the second step, interest points are detected and matched in images, then camera poses and a sparse cloud of 3d points corresponding to the interest points are simultaneously estimated. In the third step, all pixels of images are used to reconstruct a surface of the environment, e.g. by estimating a dense cloud of 3d points. Here we propose to generate a surface directly from the sparse point cloud and its visibility information provided by the geometry reconstruction step. The advantages are low time and space complexities; this is useful e.g. for obtaining compact models of large and complete environments like a city. To do so, a surface reconstruction method by sculpting 3d Delaunay triangulation of the reconstructed points is proposed. The visibility information is used to classify the tetrahedra in free-space and matter. Then a surface is extracted thanks to a greedy method and a minority of Steiner points. The 2-manifold constraint is enforced on the surface to allow standard surface post-processing such as denoising, refinement by photo-consistency optimization ... This method is also extended to the incremental case: each time a new key-frame is selected in the input video, new 3d points and camera pose are estimated, then the reconstructed surface is updated. We study the time complexity in both cases (incremental or not). In experiments, a low-cost catadioptric camera is used to generate textured 3d models for complete environments including buildings, ground, vegetation ... A drawback of our methods is that thin scene components cannot be correctly reconstructed, e.g. tree branches and electric posts. Key-words: 2-Manifold Reconstruction, 3d Delaunay Triangulation, Steiner Vertices, Complexity Analysis, Sparse Point Cloud, Structure-from-Motion. vii te l-0 08 44 40 1, v er si on 1 15 J ul 2 01 3