TY - GEN A1 - Homberg, Ulrike A1 - Baum, Daniel A1 - Wiebel, Alexander A1 - Prohaska, Steffen A1 - Hege, Hans-Christian T1 - Definition, Extraction, and Validation of Pore Structures in Porous Materials N2 - An intuitive and sparse representation of the void space of porous materials supports the efficient analysis and visualization of interesting qualitative and quantitative parameters of such materials. We introduce definitions of the elements of this void space, here called pore space, based on its distance function, and present methods to extract these elements using the extremal structures of the distance function. The presented methods are implemented by an image processing pipeline that determines pore centers, pore paths and pore constrictions. These pore space elements build a graph that represents the topology of the pore space in a compact way. The representations we derive from μCT image data of realistic soil specimens enable the computation of many statistical parameters and, thus, provide a basis for further visual analysis and application-specific developments. We introduced parts of our pipeline in previous work. In this chapter, we present additional details and compare our results with the analytic computation of the pore space elements for a sphere packing in order to show the correctness of our graph computation. T3 - ZIB-Report - 13-56 Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-42510 SN - 1438-0064 ER - TY - JOUR A1 - Baum, Daniel A1 - Lindow, Norbert A1 - Hege, Hans-Christian A1 - Lepper, Verena A1 - Siopi, Tzulia A1 - Kutz, Frank A1 - Mahlow, Kristin A1 - Mahnke, Heinz-Eberhard T1 - Revealing hidden text in rolled and folded papyri JF - Applied Physics A N2 - Ancient Egyptian papyri are often folded, rolled up or kept as small packages, sometimes even sealed. Physically unrolling or unfolding these packages might severely damage them. We demonstrate a way to get access to the hidden script without physical unfolding by employing computed tomography and mathematical algorithms for virtual unrolling and unfolding. Our algorithmic approaches are combined with manual interaction. This provides the necessary flexibility to enable the unfolding of even complicated and partly damaged papyrus packages. In addition, it allows us to cope with challenges posed by the structure of ancient papyrus, which is rather irregular, compared to other writing substrates like metallic foils or parchment. Unfolding of packages is done in two stages. In the first stage, we virtually invert the physical folding process step by step until the partially unfolded package is topologically equivalent to a scroll or a papyrus sheet folded only along one fold line. To minimize distortions at this stage, we apply the method of moving least squares. In the second stage, the papyrus is simply flattened, which requires the definition of a medial surface. We have applied our software framework to several papyri. In this work, we present the results of applying our approaches to mockup papyri that were either rolled or folded along perpendicular fold lines. In the case of the folded papyrus, our approach represents the first attempt to address the unfolding of such complicated folds. Y1 - 2017 U6 - https://doi.org/10.1007/s00339-017-0808-6 VL - 123 IS - 3 SP - 171 ER - TY - JOUR A1 - Kozlíková, Barbora A1 - Krone, Michael A1 - Falk, Martin A1 - Lindow, Norbert A1 - Baaden, Marc A1 - Baum, Daniel A1 - Viola, Ivan A1 - Parulek, Julius A1 - Hege, Hans-Christian T1 - Visualization of Biomolecular Structures: State of the Art Revisited JF - Computer Graphics Forum N2 - Structural properties of molecules are of primary concern in many fields. This report provides a comprehensive overview on techniques that have been developed in the fields of molecular graphics and visualization with a focus on applications in structural biology. The field heavily relies on computerized geometric and visual representations of three-dimensional, complex, large and time-varying molecular structures. The report presents a taxonomy that demonstrates which areas of molecular visualization have already been extensively investigated and where the field is currently heading. It discusses visualizations for molecular structures, strategies for efficient display regarding image quality and frame rate, covers different aspects of level of detail and reviews visualizations illustrating the dynamic aspects of molecular simulation data. The survey concludes with an outlook on promising and important research topics to foster further success in the development of tools that help to reveal molecular secrets. Y1 - 2016 U6 - https://doi.org/10.1111/cgf.13072 VL - 36 IS - 8 SP - 178 EP - 204 ER - TY - JOUR A1 - Krone, Michael A1 - Kozlíková, Barbora A1 - Lindow, Norbert A1 - Baaden, Marc A1 - Baum, Daniel A1 - Parulek, Julius A1 - Hege, Hans-Christian A1 - Viola, Ivan T1 - Visual Analysis of Biomolecular Cavities: State of the Art JF - Computer Graphics Forum N2 - In this report we review and structure the branch of molecular visualization that is concerned with the visual analysis of cavities in macromolecular protein structures. First the necessary background, the domain terminology, and the goals of analytical reasoning are introduced. Based on a comprehensive collection of relevant research works, we present a novel classification for cavity detection approaches and structure them into four distinct classes: grid-based, Voronoi-based, surface-based, and probe-based methods. The subclasses are then formed by their combinations. We match these approaches with corresponding visualization technologies starting with direct 3D visualization, followed with non-spatial visualization techniques that for example abstract the interactions between structures into a relational graph, straighten the cavity of interest to see its profile in one view, or aggregate the time sequence into a single contour plot. We also discuss the current state of methods for the visual analysis of cavities in dynamic data such as molecular dynamics simulations. Finally, we give an overview of the most common tools that are actively developed and used in the structural biology and biochemistry research. Our report is concluded by an outlook on future challenges in the field. Y1 - 2016 U6 - https://doi.org/10.1111/cgf.12928 SN - 1467-8659 VL - 35 IS - 3 SP - 527 EP - 551 ER - TY - CHAP A1 - Ritter, Zully A1 - Prohaska, Steffen A1 - Brand, R. A1 - Friedmann, A. A1 - Hege, Hans-Christian A1 - Goebbels, Jürgen A1 - Felsenberg, Dieter T1 - Osteocytes number and volume in osteoporotic and in healthy bone biopsies analysed using Synchrotron CT: a pilot study T2 - Proc. ISB 2011 Y1 - 2011 ER - TY - JOUR A1 - Oberleithner, Kilian A1 - Sieber, Moritz A1 - Nayeri, Christian A1 - Paschereit, Christian A1 - Petz, Christoph A1 - Hege, Hans-Christian A1 - Noack, Bernd A1 - J. Wygnanski, Israel T1 - Three-dimensional Coherent Structures of the Swirling Jet Undergoing Vortex breakdown: Stability Analysis and Empirical Mode Construction JF - J. Fluid Mech. Y1 - 2011 U6 - https://doi.org/10.1017/jfm.2011.141 VL - 679 SP - 383 EP - 414 ER - TY - GEN A1 - Günther, David A1 - Reininghaus, Jan A1 - Prohaska, Steffen A1 - Weinkauf, Tino A1 - Hege, Hans-Christian ED - Peikert, Ronny ED - Hauser, Helwig ED - Carr, Hamish T1 - Efficient Computation of a Hierarchy of Discrete 3D Gradient Vector Fields T2 - Topological Methods in Data Analysis and Visualization II Y1 - 2012 U6 - https://doi.org/10.1007/978-3-642-23175-9_2 SP - 15 EP - 29 PB - Springer ER - TY - CHAP A1 - Kuß, Anja A1 - Prohaska, Steffen A1 - Meyer, Björn A1 - Rybak, Jürgen A1 - Hege, Hans-Christian T1 - Ontology-Based Visualization of Hierarchical Neuroanatomical Structures T2 - Proceedings of the Eurographics Workshop on Visual Computing for Biomedicine VCBM 2008 Y1 - 2008 SP - 177 EP - 184 ER - TY - CHAP A1 - Goubergrits, Leonid A1 - Pöthke, Jens A1 - Petz, Christoph A1 - Hege, Hans-Christian A1 - Spuler, Andreas A1 - Kertzscher, Ulrich T1 - 3D Bildgebung von zerebralen Aneurysmen T2 - Bildverarbeitung für die Medizin Y1 - 2008 U6 - https://doi.org/10.1007/978-3-540-78640-5_31 SP - 153 EP - 157 ER - TY - CHAP A1 - Petz, Christoph A1 - Prohaska, Steffen A1 - Goubergrits, Leonid A1 - Kertzscher, Ulrich A1 - Hege, Hans-Christian T1 - Near-Wall Flow Visualization in Flattened Surface Neighborhoods T2 - Proc. Simulation and Visualization 2008 Y1 - 2008 UR - http://www.simvis.org/Tagung2008/sv-proceedings.html SP - 93 EP - 105 CY - Magdeburg, Germany ER -