3 results
Search Results
Now showing 1 - 3 of 3
Item Heightfield and spatially varying BRDF Reconstruction for Materials with Interreflections(The Eurographics Association and Blackwell Publishing Ltd, 2009) Ruiters, Roland; Klein, ReinhardPhoto-realistic reproduction of material appearance from images has widespread use in applications ranging from movies over advertising to virtual prototyping. A common approach to this task is to reconstruct the small scale geometry of the sample and to capture the reflectance properties using spatially varying BRDFs. For this, multi-view and photometric stereo reconstruction can be used, both of which are limited regarding the amount of either view or light directions and suffer from either low- or high-frequency artifacts, respectively. In this paper, we propose a new algorithm combining both techniques to recover heightfields and spatially varying BRDFs while at the same time overcoming the above mentioned drawbacks. Our main contribution is a novel objective function which allows for the reconstruction of a heightfield and high quality SVBRDF including view dependent effects. Thereby, our method also avoids both low and high frequency artifacts. Additionally, our algorithm takes inter-reflections into account allowing for the reconstruction of undisturbed representations of the underlying material. In our experiments, including synthetic and real-world data, we show that our approach is superior to state-of-the-art methods regarding reconstruction error as well as visual impression. Both the reconstructed geometry and the recovered SVBRDF are highly accurate, resulting in a faithful reproduction of the materials characteristic appearance, which is of paramount importance in the context of material rendering.Item Visualization Framework for the Integration and Exploration of Heterogeneous Geospatial Data(The Eurographics Association, 2009) Greß, Alexander; Klein, Reinhard; D. Ebert and J. KrügerThis paper presents an interactive visualization framework for heterogeneous geospatial data developed in context of an interdisciplinary research project that aims at the risk analysis of sea-dumped chemical weapons in the Baltic Sea. In the focus of the analysis are geophysical, hydrographical, geochemical, and biological data acquired on research cruises as well as data produced by toxic compound migration and bioaccumulation modeling. These different types of data to be visualized are represented as height fields, 2D vector maps, seismic profiles, and time-dependent scalar and vector fields. In general, these datasets are given at largely varying resolutions and geospatial extents, which makes their integration into one visualization especially challenging and requires efficient level-of-detail techniques. Furthermore, special care is taken on the appropriate integration and efficient 3D visualization of all different types of data at the same time. Several examples demonstrate the effectiveness of the resulting visualizations for collaborative analysis of the data.Item Completion and Reconstruction with Primitive Shapes(The Eurographics Association and Blackwell Publishing Ltd, 2009) Schnabel, Ruwen; Degener, Patrick; Klein, ReinhardWe consider the problem of reconstruction from incomplete point-clouds. To find a closed mesh the reconstruction is guided by a set of primitive shapes which has been detected on the input point-cloud (e.g. planes, cylinders etc.). With this guidance we not only continue the surrounding structure into the holes but also synthesize plausible edges and corners from the primitives intersections. To this end we give a surface energy functional that incorporates the primitive shapes in a guiding vector field. The discretized functional can be minimized with an efficient graph-cut algorithm. A novel greedy optimization strategy is proposed to minimize the functional under the constraint that surface parts corresponding to a given primitive must be connected. From the primitive shapes our method can also reconstruct an idealized model that is suitable for use in a CAD system.