@misc{Westerhoff1999, type = {Master Thesis}, author = {Westerhoff, Natascha}, title = {Geometrische Methoden zur 3D-Segmentierung}, year = {1999}, language = {en} } @misc{Preis2012, type = {Master Thesis}, author = {Preis, Philipp}, title = {Sichtbarkeitsorientiertes Picking in Direct Volume Renderings mit Beleuchtungsmodellen}, year = {2012}, language = {en} } @masterthesis{Ruben2012, type = {Bachelor Thesis}, author = {Ruben, Karl}, title = {Kugelpackungen in arbitr{\"a}r geformten Volumina}, year = {2012}, language = {en} } @misc{Gensel2009, type = {Master Thesis}, author = {Gensel, Maria}, title = {Visualisierungsmethoden zur Verdeutlichung der r{\"a}umlichen Beziehungen zwischen linien- und fl{\"a}chenartigen Strukturen am Beispiel neurobiologischer Daten}, year = {2009}, language = {en} } @phdthesis{Sahner2009, author = {Sahner, Jan}, title = {Extraction of Vortex Structures in 3D Flow Fields}, year = {2009}, language = {en} } @misc{Wade2008, type = {Master Thesis}, author = {Wade, Moritz}, title = {Automatic Textbook-Like Layout of Biological Networks}, year = {2008}, language = {en} } @phdthesis{Weinkauf2008, author = {Weinkauf, Tino}, title = {Extraction of Topological Structures in 2D and 3D Vector Fields}, year = {2008}, language = {en} } @phdthesis{SchmidtEhrenberg2008, author = {Schmidt-Ehrenberg, Johannes}, title = {Analysis and Visualization of Molecular Conformations}, year = {2008}, language = {en} } @misc{Schuberth2011, type = {Master Thesis}, author = {Schuberth, Sebastian}, title = {High-Performance Tomographic Reconstruction using OpenCL}, year = {2011}, language = {en} } @misc{Brenner1996, type = {Master Thesis}, author = {Brenner, Thomas}, title = {Volume Rendering - Ein Projektionsansatz f{\"u}r den Cray T3D}, year = {1996}, language = {en} } @misc{Battke1996, type = {Master Thesis}, author = {Battke, Henrik}, title = {Entwicklung textur-basierter Verfahren zur Vektorfeldvisualisierung}, year = {1996}, language = {en} } @misc{Anders1996, type = {Master Thesis}, author = {Anders, Thomas}, title = {Effiziente Algorihmen zur Isofl{\"a}chengenerierung aus Volumendaten}, year = {1996}, language = {en} } @misc{Hoellerer1995, type = {Master Thesis}, author = {H{\"o}llerer, Tobias}, title = {Volume Rendering auf irregul{\"a}ren Gittern - Theorie und Implementierung}, year = {1995}, language = {en} } @book{OPUS4-4173, title = {Visualization and Mathematics}, journal = {Book Series}, editor = {Hege, Hans-Christian}, publisher = {Springer-Verlag}, year = {2010}, language = {en} } @book{OPUS4-4174, title = {VideoMath}, journal = {Video Series}, editor = {Hege, Hans-Christian}, publisher = {Springer-Verlag}, year = {2010}, language = {en} } @misc{OPUS4-4175, title = {Volume Graphics and Point-Based Graphics}, editor = {Hege, Hans-Christian and Machiraju, Raghu and Laidlaw, David}, year = {2010}, language = {en} } @book{OPUS4-4176, title = {EuroVis 2009}, editor = {Hege, Hans-Christian and Hotz, Ingrid and Munzner, Tamara}, publisher = {Blackwell Publishing}, year = {2009}, language = {en} } @book{OPUS4-4177, title = {Topology-based Methods in Visualization II}, journal = {Mathematics and Visualization}, editor = {Scheuermann, Gerik and Hege, Hans-Christian and Polthier, Konrad}, publisher = {Springer}, isbn = {978-3-540-88605-1}, year = {2009}, language = {en} } @book{OPUS4-4178, title = {Volume and Point-Based Graphics 2008}, editor = {Hege, Hans-Christian and Laidlaw, David and Pajarola, Renato and Staadt, Oliver}, publisher = {Eurographics Association}, isbn = {978-3-905674-12-5}, year = {2008}, language = {en} } @misc{WiebelMuellerGarthetal.2014, author = {Wiebel, Alexander and M{\"u}ller, Cornelius and Garth, Christoph and Kn{\"o}sche, Thomas}, title = {A System for Combined Visualization of EEG and Diffusion Tensor Imaging Tractography Data}, journal = {Visualization and Processing of Tensors and Higher-Order Descriptors for Multi-field Data}, editor = {Westin, Carl-Frederic and Burgeth, Bernhard and Vilanova, Anna}, publisher = {Springer}, pages = {325 -- 337}, year = {2014}, language = {en} } @misc{HombergBaumWiebeletal.2013, author = {Homberg, Ulrike and Baum, Daniel and Wiebel, Alexander and Prohaska, Steffen and Hege, Hans-Christian}, title = {Definition, Extraction, and Validation of Pore Structures in Porous Materials}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-42510}, year = {2013}, abstract = {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.}, language = {en} } @misc{DercksenHegeOberlaender2013, author = {Dercksen, Vincent J. and Hege, Hans-Christian and Oberlaender, Marcel}, title = {The Filament Editor: An Interactive Software Environment for Visualization, Proof-Editing and Analysis of 3D Neuron Morphology}, issn = {1438-0064}, doi = {10.1007/s12021-013-9213-2}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-43157}, year = {2013}, abstract = {Neuroanatomical analysis, such as classification of cell types, depends on reliable reconstruction of large numbers of complete 3D dendrite and axon morphologies. At present, the majority of neuron reconstructions are obtained from preparations in a single tissue slice in vitro, thus suffering from cut off dendrites and, more dramatically, cut off axons. In general, axons can innervate volumes of several cubic millimeters and may reach path lengths of tens of centimeters. Thus, their complete reconstruction requires in vivo labeling, histological sectioning and imaging of large fields of view. Unfortunately, anisotropic background conditions across such large tissue volumes, as well as faintly labeled thin neurites, result in incomplete or erroneous automated tracings and even lead experts to make annotation errors during manual reconstructions. Consequently, tracing reliability renders the major bottleneck for reconstructing complete 3D neuron morphologies. Here, we present a novel set of tools, integrated into a software environment named 'Filament Editor', for creating reliable neuron tracings from sparsely labeled in vivo datasets. The Filament Editor allows for simultaneous visualization of complex neuronal tracings and image data in a 3D viewer, proof-editing of neuronal tracings, alignment and interconnection across sections, and morphometric analysis in relation to 3D anatomical reference structures. We illustrate the functionality of the Filament Editor on the example of in vivo labeled axons and demonstrate that for the exemplary dataset the final tracing results after proof-editing are independent of the expertise of the human operator.}, language = {en} } @article{DercksenHegeOberlaender2014, author = {Dercksen, Vincent J. and Hege, Hans-Christian and Oberlaender, Marcel}, title = {The Filament Editor: An Interactive Software Environment for Visualization, Proof-Editing and Analysis of 3D Neuron Morphology}, volume = {12}, journal = {NeuroInformatics}, number = {2}, publisher = {Springer US}, doi = {10.1007/s12021-013-9213-2}, pages = {325 -- 339}, year = {2014}, language = {en} } @incollection{HlawitschkaHotzKratzetal.2014, author = {Hlawitschka, Mario and Hotz, Ingrid and Kratz, Andrea and Marai, G. Elisabeta and Moreno, Rodrigo and Scheuermann, Gerik and Stommel, Markus and Wiebel, Alexander and Zhang, Eugene}, title = {Top Challenges in the Visualization of Engineering Tensor Fields}, booktitle = {Visualization and Processing of Tensors and Higher-Order Descriptors for Multi-Field Data}, editor = {Westin, Carl-Frederic and Burgeth, Bernhard and Vilanova, Anna}, publisher = {Springer}, pages = {3 -- 15}, year = {2014}, language = {en} } @article{HochWesselAscheetal.2014, author = {Hoch, Hannelore and Wessel, Andreas and Asche, Manfred and Baum, Daniel and Beckmann, Felix and Br{\"a}unig, Peter and Ehrig, Karsten and M{\"u}hlethaler, Roland and Riesemeier, Heinrich and Staude, Andreas and Stelbrink, Bj{\"o}rn and Wachmann, Ekkehard and Weintraub, Phyllis and Wipfler, Benjamin and Wolff, Carsten and Zilch, Mathias}, title = {Non-Sexual Abdominal Appendages in Adult Insects Challenge a 300 Million Year Old Bauplan}, volume = {24}, journal = {Current Biology}, number = {1}, doi = {10.1016/j.cub.2013.11.040}, pages = {R16 -- R17}, year = {2014}, language = {en} } @article{BorongCannistraciConrad2017, author = {Borong, Shao and Cannistraci, Carlo and Conrad, Tim}, title = {Epithelial Mesenchymal Transition Network-based Feature Engineering in Lung Adenocarcinoma Prognosis Prediction Using Multiple Omic Data}, volume = {3}, journal = {Genomics and Computational Biology}, number = {3}, doi = {http://dx.doi.org/10.18547/gcb.2017.vol3.iss3.e57}, pages = {1 -- 13}, year = {2017}, abstract = {Epithelial mesenchymal transition (EMT) process has been shown as highly relevant to cancer prognosis. However, although different biological network-based biomarker identification methods have been proposed to predict cancer prognosis, EMT network has not been directly used for this purpose. In this study, we constructed an EMT regulatory network consisting of 87 molecules and tried to select features that are useful for prognosis prediction in Lung Adenocarcinoma (LUAD). To incorporate multiple molecular profiles, we obtained four types of molecular data including mRNA-Seq, copy number alteration (CNA), DNA methylation, and miRNA-Seq data from The Cancer Genome Atlas. The data were mapped to the EMT network in three alternative ways: mRNA-Seq and miRNA-Seq, DNA methylation, and CNA and miRNA-Seq. Each mapping was employed to extract five different sets of features using discretization and network-based biomarker identification methods. Each feature set was then used to predict prognosis with SVM and logistic regression classifiers. We measured the prediction accuracy with AUC and AUPR values using 10 times 10-fold cross validation. For a more comprehensive evaluation, we also measured the prediction accuracies of clinical features, EMT plus clinical features, randomly picked 87 molecules from each data mapping, and using all molecules from each data type. Counter-intuitively, EMT features do not always outperform randomly selected features and the prediction accuracies of the five feature sets are mostly not significantly different. Clinical features are shown to give the highest prediction accuracies. In addition, the prediction accuracies of both EMT features and random features are comparable as using all features (more than 17,000) from each data type.}, language = {en} } @article{LindowBaumLeborgneetal.2019, author = {Lindow, Norbert and Baum, Daniel and Leborgne, Morgan and Hege, Hans-Christian}, title = {Interactive Visualization of RNA and DNA Structures}, volume = {25}, journal = {IEEE Transactions on Visualization and Computer Graphics}, number = {1}, doi = {10.1109/TVCG.2018.2864507}, pages = {967 -- 976}, year = {2019}, abstract = {The analysis and visualization of nucleic acids (RNA and DNA) is playing an increasingly important role due to their fundamental importance for all forms of life and the growing number of known 3D structures of such molecules. The great complexity of these structures, in particular, those of RNA, demands interactive visualization to get deeper insights into the relationship between the 2D secondary structure motifs and their 3D tertiary structures. Over the last decades, a lot of research in molecular visualization has focused on the visual exploration of protein structures while nucleic acids have only been marginally addressed. In contrast to proteins, which are composed of amino acids, the ingredients of nucleic acids are nucleotides. They form structuring patterns that differ from those of proteins and, hence, also require different visualization and exploration techniques. In order to support interactive exploration of nucleic acids, the computation of secondary structure motifs as well as their visualization in 2D and 3D must be fast. Therefore, in this paper, we focus on the performance of both the computation and visualization of nucleic acid structure. We present a ray casting-based visualization of RNA and DNA secondary and tertiary structures, which enables for the first time real-time visualization of even large molecular dynamics trajectories. Furthermore, we provide a detailed description of all important aspects to visualize nucleic acid secondary and tertiary structures. With this, we close an important gap in molecular visualization.}, language = {en} } @article{AgudoJacomeHegePaetschetal.2018, author = {Agudo J{\´a}come, Leonardo and Hege, Hans-Christian and Paetsch, Olaf and P{\"o}thkow, Kai}, title = {Three-dimensional reconstruction and quantification of dislocation substructures from transmission electron microscopy stereo pairs}, volume = {195}, journal = {Ultramicroscopy}, doi = {10.1016/j.ultramic.2018.08.015}, pages = {157 -- 170}, year = {2018}, abstract = {A great amount of material properties is strongly influenced by dislocations, the carriers of plastic deformation. It is therefore paramount to have appropriate tools to quantify dislocation substructures with regard to their features, e.g., dislocation density, Burgers vectors or line direction. While the transmission electron microscope (TEM) has been the most widely-used equipment implemented to investigate dislocations, it usually is limited to the two-dimensional (2D) observation of three-dimensional (3D) structures. We reconstruct, visualize and quantify 3D dislocation substructure models from only two TEM images (stereo pairs) and assess the results. The reconstruction is based on the manual interactive tracing of filiform objects on both images of the stereo pair. The reconstruction and quantification method are demonstrated on dark field (DF) scanning (S)TEM micrographs of dislocation substructures imaged under diffraction contrast conditions. For this purpose, thick regions (>300 nm) of TEM foils are analyzed, which are extracted from a Ni-base superalloy single crystal after high temperature creep deformation. It is shown how the method allows 3D quantification from stereo pairs in a wide range of tilt conditions, achieving line length and orientation uncertainties of 3\% and 7°, respectively. Parameters that affect the quality of such reconstructions are discussed.}, language = {en} } @misc{AgudoJacomeHegePaetschetal.2018, author = {Agudo J{\´a}come, Leonardo and Hege, Hans-Christian and Paetsch, Olaf and P{\"o}thkow, Kai}, title = {Three-Dimensional Reconstruction and Quantification of Dislocation Substructures from Transmission Electron Microscopy Stereo-Pairs}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-70339}, year = {2018}, abstract = {A great amount of material properties is strongly influenced by dislocations, the carriers of plastic deformation. It is therefore paramount to have appropriate tools to quantify dislocation substructures with regard to their features, e.g., dislocation density, Burgers vectors or line direction. While the transmission electron microscope (TEM) has been the most widely-used equipment implemented to investigate dislocations, it usually is limited to the two-dimensional (2D) observation of three-dimensional (3D) structures. We reconstruct, visualize and quantify 3D dislocation substructure models from only two TEM images (stereo-pairs) and assess the results. The reconstruction is based on the manual interactive tracing of filiform objects on both images of the stereo-pair. The reconstruction and quantification method are demonstrated on dark field (DF) scanning (S)TEM micrographs of dislocation substructures imaged under diffraction contrast conditions. For this purpose, thick regions (> 300 nm) of TEM foils are analyzed, which are extracted from a Ni-base superalloy single crystal after high temperature creep deformation. It is shown how the method allows 3D quantification from stereo-pairs in a wide range of tilt conditions, achieving line length and orientation uncertainties of 3 \% and 7°, respectively. Parameters that affect the quality of such reconstructions are discussed.}, language = {en} } @inproceedings{CoconuUllmerPaaretal.2018, author = {Coconu, Liviu and Ullmer, Brygg and Paar, Philip and Liu, Jing and Konkel, Miriam and Hege, Hans-Christian}, title = {A smartphone-based tangible interaction approach for landscape visualization.}, booktitle = {PerDis '18 Proceedings of the 7th ACM International Symposium on Pervasive Displays, Munich, Germany, June 6-8, 2018}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/3205873.3210707}, pages = {no. 23}, year = {2018}, abstract = {The use of tangible interfaces for navigation of landscape scenery - for example, lost places re-created in 3D - has been pursued and articulated as a promising, impactful application of interactive visualization. In this demonstration, we present a modern, low-cost implementation of a previously-realized multimodal gallery installation. Our demonstration centers upon the versatile usage of a smartphone for sensing, navigating, and (optionally) displaying element on a physical surface in tandem with a larger, more immersive display.}, language = {en} } @inproceedings{UllmerPaarCoconuetal.2018, author = {Ullmer, Brygg and Paar, Philip and Coconu, Liviu and Liu, Jing and Konkel, Miriam and Hege, Hans-Christian}, title = {An 1834 mediterranean garden in Berlin - engaged from 2004, 2018, 2032, and 2202}, booktitle = {PerDis '18 - 7th ACM International Symposium on Pervasive Displays, Munich, Germany, June 6-8, 2018}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/3205873.3205894}, pages = {no. 12}, year = {2018}, abstract = {In 2004, a team of researchers realized a semi-immersive interactive gallery installation, visualizing an 1834 Mediterranean garden, introduced as "italienisches Kunstst{\"u}ck" (Italian legerdemain) by Peter Joseph Lenn{\´e}. The park was originally realized on the grounds of Schloss Sanssouci in Potsdam, Germany. The installation centered on highly detailed renderings of hundreds of plants projected upon a panoramic display. Interactivity was expressed with a tangible interface which (while presently dated) we believe remains without near-precedent then or since. We present the installation (experienced by roughly 20,000 visitors), focusing on the interaction aspects. We introduce new book and table/door-format mockups. Drawing upon a heuristic of the scientist-philosopher Freeman Dyson, we consider grounded future prospect variations in the contexts of 2018, 2032, and 2202. We see this exercise as prospectively generalizing to a variety of similar and widely diverse application domains.}, language = {en} } @article{BaumLindowHegeetal.2017, author = {Baum, Daniel and Lindow, Norbert and Hege, Hans-Christian and Lepper, Verena and Siopi, Tzulia and Kutz, Frank and Mahlow, Kristin and Mahnke, Heinz-Eberhard}, title = {Revealing hidden text in rolled and folded papyri}, volume = {123}, journal = {Applied Physics A}, number = {3}, doi = {10.1007/s00339-017-0808-6}, pages = {171}, year = {2017}, abstract = {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.}, language = {en} } @inproceedings{RitterProhaskaBrandetal.2011, author = {Ritter, Zully and Prohaska, Steffen and Brand, R. and Friedmann, A. and Hege, Hans-Christian and Goebbels, J{\"u}rgen and Felsenberg, Dieter}, title = {Osteocytes number and volume in osteoporotic and in healthy bone biopsies analysed using Synchrotron CT: a pilot study}, booktitle = {Proc. ISB 2011}, year = {2011}, language = {en} } @masterthesis{Krabi2011, type = {Bachelor Thesis}, author = {Krabi, Marianne}, title = {Implementierung einer Methode zur automatischen Erkennung von Nervenzellk{\"o}rpern in 3D Mikroskopbildern}, year = {2011}, language = {de} } @article{OeltzeLehmannKuhnetal.2014, author = {Oeltze, Steffen and Lehmann, Dirk J. and Kuhn, Alexander and Janiga, G{\´a}bor and Theisel, Holger and Preim, Bernhard}, title = {Blood Flow Clustering and Applications in Virtual Stenting of Intracranial Aneurysms}, volume = {20}, journal = {IEEE Transactions on Visualization and Computer Graphics, 2014}, number = {5}, organization = {Otto-von-Guericke-Universit{\"a}t Magdeburg}, issn = {0934-5892}, doi = {10.1109/TVCG.2013.2297914}, pages = {686 -- 701}, year = {2014}, language = {en} } @article{KainmuellerLameckerHelleretal.2013, author = {Kainm{\"u}ller, Dagmar and Lamecker, Hans and Heller, Markus O. and Weber, Britta and Hege, Hans-Christian and Zachow, Stefan}, title = {Omnidirectional Displacements for Deformable Surfaces}, volume = {17}, journal = {Medical Image Analysis}, number = {4}, publisher = {Elsevier}, doi = {10.1016/j.media.2012.11.006}, pages = {429 -- 441}, year = {2013}, language = {en} } @inproceedings{KastenZoufahlHegeetal.2012, author = {Kasten, Jens and Zoufahl, Andre and Hege, Hans-Christian and Hotz, Ingrid}, title = {Analysis of Vortex Merge Graphs}, booktitle = {VMV 2012: Vision, Modeling and Visualization}, publisher = {Eurographics Association}, doi = {10.2312/PE/VMV/VMV12/111-118}, pages = {111 -- 118}, year = {2012}, language = {en} } @inproceedings{KastenHotzNoacketal.2012, author = {Kasten, Jens and Hotz, Ingrid and Noack, Bernd and Hege, Hans-Christian}, title = {Vortex Merge Graphs in Two-dimensional Unsteady Flow Fields}, booktitle = {EuroVis - Short Papers}, publisher = {Eurographics Association}, address = {Vienna, Austria}, doi = {10.2312/PE/EuroVisShort/EuroVisShort2012/001-005}, pages = {1 -- 5}, year = {2012}, language = {en} } @article{KroneKozlikovaLindowetal.2016, author = {Krone, Michael and Kozl{\´i}kov{\´a}, Barbora and Lindow, Norbert and Baaden, Marc and Baum, Daniel and Parulek, Julius and Hege, Hans-Christian and Viola, Ivan}, title = {Visual Analysis of Biomolecular Cavities: State of the Art}, volume = {35}, journal = {Computer Graphics Forum}, number = {3}, issn = {1467-8659}, doi = {10.1111/cgf.12928}, pages = {527 -- 551}, year = {2016}, abstract = {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.}, language = {en} } @masterthesis{Krenz2016, type = {Bachelor Thesis}, author = {Krenz, Konstantin}, title = {How likely is it that one's standing on a ridge? Probabilistic Ridges in Gaussian Random Fields}, pages = {53}, year = {2016}, abstract = {A method is developed for computing the local probability for the presence of a ridge in a Gaussian Random field.}, language = {en} } @misc{NavaYazdaniHegevonTycowiczetal.2018, author = {Nava-Yazdani, Esfandiar and Hege, Hans-Christian and von Tycowicz, Christoph and Sullivan, T. J.}, title = {A Shape Trajectories Approach to Longitudinal Statistical Analysis}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-69759}, year = {2018}, abstract = {For Kendall's shape space we determine analytically Jacobi fields and parallel transport, and compute geodesic regression. Using the derived expressions, we can fully leverage the geometry via Riemannian optimization and reduce the computational expense by several orders of magnitude. The methodology is demonstrated by performing a longitudinal statistical analysis of epidemiological shape data. As application example we have chosen 3D shapes of knee bones, reconstructed from image data of the Osteoarthritis Initiative. Comparing subject groups with incident and developing osteoarthritis versus normal controls, we find clear differences in the temporal development of femur shapes. This paves the way for early prediction of incident knee osteoarthritis, using geometry data only.}, language = {en} } @misc{LindowBaumHege2018, author = {Lindow, Norbert and Baum, Daniel and Hege, Hans-Christian}, title = {Atomic Accessibility Radii for Molecular Dynamics Analysis}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-68468}, year = {2018}, abstract = {In molecular structure analysis and visualization, the molecule's atoms are often modeled as hard spheres parametrized by their positions and radii. While the atom positions result from experiments or molecular simulations, for the radii typically values are taken from literature. Most often, van der Waals (vdW) radii are used, for which diverse values exist. As a consequence, different visualization and analysis tools use different atomic radii, and the analyses are less objective than often believed. Furthermore, for the geometric accessibility analysis of molecular structures, vdW radii are not well suited. The reason is that during the molecular dynamics simulation, depending on the force field and the kinetic energy in the system, non-bonded atoms can come so close to each other that their vdW spheres intersect. In this paper, we introduce a new kind of atomic radius, called atomic accessibility radius', that better characterizes the accessibility of an atom in a given molecular trajectory. The new radii reflect the movement possibilities of atoms in the simulated physical system. They are computed by solving a linear program that maximizes the radii of the atoms under the constraint that non-bonded spheres do not intersect in the considered molecular trajectory. Using this data-driven approach, the actual accessibility of atoms can be visualized more precisely.}, language = {en} } @misc{PapazovHege2017, author = {Papazov, Chavdar and Hege, Hans-Christian}, title = {Blue-noise Optimized Point Sets Based on Procrustes Analysis}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-65356}, year = {2017}, abstract = {In this paper, we propose a new method for optimizing the blue noise characteristics of point sets. It is based on Procrustes analysis, a technique for adjusting shapes to each other by applying optimal elements of an appropriate transformation group. We adapt this technique to the problem at hand and introduce a very simple, efficient and provably convergent point set optimizer.}, language = {en} } @article{BanyassadyChiuKormanetal.2019, author = {Banyassady, Bahareh and Chiu, Man-Kwun and Korman, Matias and Mulzer, Wolfgang and van Renssen, Andr{\´e} and Roeloffzen, Marcel and Seiferth, Paul and Stein, Yannik and Vogtenhuber, Birgit and Willert, Max}, title = {Routing in polygonal domains}, volume = {87}, journal = {Computational Geometry, Theory and Applications}, publisher = {Elsevier}, doi = {10.1016/j.comgeo.2019.101593}, year = {2019}, abstract = {We consider the problem of routing a data packet through the visibility graph of a polygonal domain P with n vertices and h holes. We may preprocess P to obtain a "label" and a "routing table" for each vertex of P. Then, we must be able to route a data packet between any two vertices p and q of P, where each step must use only the label of the target node q and the routing table of the current node. For any fixed epsilon > 0, we present a routing scheme that always achieves a routing path whose length exceeds the shortest path by a factor of at most 1 + epsilon. The labels have O(log n) bits, and the routing tables are of size O(((epsilon^-1)+h)log n). The preprocessing time is O((n^2)log n). It can be improved to O(n^2) for simple polygons.}, language = {en} } @article{BanyassadyBarbaMulzer2020, author = {Banyassady, Bahareh and Barba, Luis and Mulzer, Wolfgang}, title = {Time-Space Trade-Offs for Computing Euclidean Minimum Spanning Trees}, volume = {11(1)}, journal = {Journal of Computational Geometry (JoCG)}, url = {http://nbn-resolving.de/https://jocg.org/index.php/jocg/article/view/473}, pages = {525 -- 547}, year = {2020}, abstract = {We present time-space trade-offs for computing the Euclidean minimum spanning tree of a set S of n point-sites in the plane. More precisely, we assume that S resides in a random-access memory that can only be read. The edges of the Euclidean minimum spanning tree EMST(S) have to be reported sequentially, and they cannot be accessed or modified afterwards. There is a parameter s in {1, ..., n} so that the algorithm may use O(s) cells of read-write memory (called the workspace) for its computations. Our goal is to find an algorithm that has the best possible running time for any given s between 1 and n. We show how to compute EMST(S) in O(((n^3)/(s^2)) log s) time with O(s) cells of workspace, giving a smooth trade-off between the two best-known bounds O(n^3) for s = 1 and O(n log n) for s = n. For this, we run Kruskal's algorithm on the "relative neighborhood graph" (RNG) of S. It is a classic fact that the minimum spanning tree of RNG(S) is exactly EMST(S). To implement Kruskal's algorithm with O(s) cells of workspace, we define s-nets, a compact representation of planar graphs. This allows us to efficiently maintain and update the components of the current minimum spanning forest as the edges are being inserted.}, language = {en} } @inproceedings{PapazovHege2017, author = {Papazov, Chavdar and Hege, Hans-Christian}, title = {Blue-noise Optimized Point Sets Based on Procrustes Analysis}, booktitle = {SIGGRAPH Asia 2017 Technical Briefs}, doi = {10.1145/3145749.3149442}, pages = {20:1 -- 20:4}, year = {2017}, language = {en} } @article{OeltzeJaffraMeuschkeNeugebaueretal.2019, author = {Oeltze-Jaffra, Steffen and Meuschke, Monique and Neugebauer, Mathias and Saalfeld, Sylvia and Lawonn, Kai and Janiga, Gabor and Hege, Hans-Christian and Zachow, Stefan and Preim, Bernhard}, title = {Generation and Visual Exploration of Medical Flow Data: Survey, Research Trends, and Future Challenges}, volume = {38}, journal = {Computer Graphics Forum}, number = {1}, publisher = {Wiley}, doi = {10.1111/cgf.13394}, pages = {87 -- 125}, year = {2019}, abstract = {Simulations and measurements of blood and air flow inside the human circulatory and respiratory system play an increasingly important role in personalized medicine for prevention, diagnosis, and treatment of diseases. This survey focuses on three main application areas. (1) Computational Fluid Dynamics (CFD) simulations of blood flow in cerebral aneurysms assist in predicting the outcome of this pathologic process and of therapeutic interventions. (2) CFD simulations of nasal airflow allow for investigating the effects of obstructions and deformities and provide therapy decision support. (3) 4D Phase-Contrast (4D PC) Magnetic Resonance Imaging (MRI) of aortic hemodynamics supports the diagnosis of various vascular and valve pathologies as well as their treatment. An investigation of the complex and often dynamic simulation and measurement data requires the coupling of sophisticated visualization, interaction, and data analysis techniques. In this paper, we survey the large body of work that has been conducted within this realm. We extend previous surveys by incorporating nasal airflow, addressing the joint investigation of blood flow and vessel wall properties, and providing a more fine-granular taxonomy of the existing techniques. From the survey, we extract major research trends and identify open problems and future challenges. The survey is intended for researchers interested in medical flow but also more general, in the combined visualization of physiology and anatomy, the extraction of features from flow field data and feature-based visualization, the visual comparison of different simulation results, and the interactive visual analysis of the flow field and derived characteristics.}, language = {en} } @article{KramerNoackBaumetal.2018, author = {Kramer, Tobias and Noack, Matthias and Baum, Daniel and Hege, Hans-Christian and Heller, Eric J.}, title = {Dust and gas emission from cometary nuclei: the case of comet 67P/Churyumov-Gerasimenko}, volume = {3}, journal = {Advances in Physics: X}, number = {1}, doi = {10.1080/23746149.2017.1404436}, pages = {1404436}, year = {2018}, abstract = {Comets display with decreasing solar distance an increased emission of gas and dust particles, leading to the formation of the coma and tail. Spacecraft missions provide insight in the temporal and spatial variations of the dust and gas sources located on the cometary nucleus. For the case of comet 67P/Churyumov-Gerasimenko (67P/C-G), the long-term obser- vations from the Rosetta mission point to a homogeneous dust emission across the entire illuminated surface. Despite the homogeneous initial dis- tribution, a collimation in jet-like structures becomes visible. We propose that this observation is linked directly to the complex shape of the nucleus and projects concave topographical features into the dust coma. To test this hypothesis, we put forward a gas-dust description of 67P/C-G, where gravitational and gas forces are accurately determined from the surface mesh and the rotation of the nucleus is fully incorporated. The emerging jet-like structures persist for a wide range of gas-dust interactions and show a dust velocity dependent bending.}, language = {en} } @inproceedings{SakuraiHegeKuhnetal.2017, author = {Sakurai, Daisuke and Hege, Hans-Christian and Kuhn, Alexander and Rust, Henning and Kern, Bastian and Breitkopf, Tom-Lukas}, title = {An Application-Oriented Framework for Feature Tracking in Atmospheric Sciences}, booktitle = {Proceedings of 2017 IEEE 7th Symposium on Large Data Analysis and Visualization (LDAV)}, doi = {10.1109/LDAV.2017.8231857}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-66685}, pages = {96 -- 97}, year = {2017}, abstract = {In atmospheric sciences, sizes of data sets grow continuously due to increasing resolutions. A central task is the comparison of spatiotemporal fields, to assess different simulations and to compare simulations with observations. A significant information reduction is possible by focusing on geometric-topological features of the fields or on derived meteorological objects. Due to the huge size of the data sets, spatial features have to be extracted in time slices and traced over time. Fields with chaotic component, i.e. without 1:1 spatiotemporal correspondences, can be compared by looking upon statistics of feature properties. Feature extraction, however, requires a clear mathematical definition of the features - which many meteorological objects still lack. Traditionally, object extractions are often heuristic, defined only by implemented algorithms, and thus are not comparable. This work surveys our framework designed for efficient development of feature tracking methods and for testing new feature definitions. The framework supports well-established visualization practices and is being used by atmospheric researchers to diagnose and compare data.}, language = {en} } @article{WilliePapPerkaetal.2015, author = {Willie, Bettina M. and Pap, Thomas and Perka, Carsten and Schmidt, Carsten Oliver and Eckstein, Felix and Arampatzis, Adamantios and Hege, Hans-Christian and Madry, Henning and Vortkamp, Andrea and Duda, Georg}, title = {OVERLOAD of joints and its role in osteoarthritis - Towards understanding and preventing progression of primary osteoarthritis}, volume = {76}, journal = {Zeitschrift f{\"u}r Rheumatologie}, number = {Suppl. 1}, doi = {10.1007/s00393-014-1561-2}, pages = {1 -- 4}, year = {2015}, abstract = {Intact joints are necessary for skeletal function and mobility in daily life. A healthy musculoskeletal system is the basis for a functional cardiovascular system as well as an intact immune system. Locomotion, physiotherapy, and various forms of patient activity are essential clinical therapies used in the treatment of neurodegeneration, stroke, diabetes, and cancer. Mobility is substantially impaired with degeneration of joints and, in advanced stages, nighttime pain and sleep disturbance are particularly cumbersome. Osteoarthritis (OA) is also known as degenerative joint disease. OA involves structural and compositional changes in the articular cartilage, as well as in the calcified cartilage, subchondral cortical bone, subchondral cancellous bone, meniscus, joint capsular tissue, and synovium; which eventually lead to degeneration of these tissues comprising synovial joints.}, language = {en} } @article{GuentherKuhnHegeetal.2017, author = {G{\"u}nther, Tobias and Kuhn, Alexander and Hege, Hans-Christian and Gross, Markus and Theisel, Holger}, title = {Progressive Monte Carlo rendering of atmospheric flow features across scales}, volume = {2}, journal = {Physical Review Fluids}, doi = {10.1103/PhysRevFluids.2.090502}, pages = {09050-1 -- 09050-3}, year = {2017}, abstract = {To improve existing weather prediction and reanalysis capabilities, high-resolution and multi-modal climate data becomes an increasingly important topic. The advent of increasingly dense numerical simulation of atmospheric phenomena, provides new means to better understand dynamic processes and to visualize structural flow patterns that remain hidden otherwise. In the presented illustrations we demonstrate an advanced technique to visualize multiple scales of dense flow fields and Lagrangian patterns therein, simulated by state-of-the-art simulation models for each scale. They provide a deeper insight into the structural differences and patterns that occur on each scale and highlight the complexity of flow phenomena in our atmosphere. This paper is associated with a poster winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original poster is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.P0030}, language = {en} } @article{MahnkeArltBaumetal.2020, author = {Mahnke, Heinz-Eberhard and Arlt, Tobias and Baum, Daniel and Hege, Hans-Christian and Herter, Felix and Lindow, Norbert and Manke, Ingo and Siopi, Tzulia and Menei, Eve and Etienne, Marc and Lepper, Verena}, title = {Virtual unfolding of folded papyri}, volume = {41}, journal = {Journal of Cultural Heritage}, publisher = {Elsevier}, doi = {10.1016/j.culher.2019.07.007}, pages = {264 -- 269}, year = {2020}, abstract = {The historical importance of ancient manuscripts is unique since they provide information about the heritage of ancient cultures. Often texts are hidden in rolled or folded documents. Due to recent impro- vements in sensitivity and resolution, spectacular disclosures of rolled hidden texts were possible by X-ray tomography. However, revealing text on folded manuscripts is even more challenging. Manual unfolding is often too risky in view of the fragile condition of fragments, as it can lead to the total loss of the document. X-ray tomography allows for virtual unfolding and enables non-destructive access to hid- den texts. We have recently demonstrated the procedure and tested unfolding algorithms on a mockup sample. Here, we present results on unfolding ancient papyrus packages from the papyrus collection of the Mus{\´e}e du Louvre, among them objects folded along approximately orthogonal folding lines. In one of the packages, the first identification of a word was achieved, the Coptic word for "Lord".}, language = {en} } @inproceedings{FroehlerdaCunhaMeloWeissenboecketal.2019, author = {Fr{\"o}hler, Bernhard and da Cunha Melo, Lucas and Weissenb{\"o}ck, Johannes and Kastner, Johann and M{\"o}ller, Torsten and Hege, Hans-Christian and Gr{\"o}ller, Eduard M. and Sanctorum, Jonathan and De Beenhouwer, Jan and Sijbers, Jan and Heinzl, Christoph}, title = {Tools for the analysis of datasets from X-ray computed tomography based on Talbot-Lau grating interferometry}, booktitle = {Proceedings of iCT 2019, (9th Conference on Industrial Computed Tomography, Padova, Italy - iCT 2019, February 13-15, 2019)}, number = {paper 52}, pages = {8}, year = {2019}, abstract = {This work introduces methods for analyzing the three imaging modalities delivered by Talbot-Lau grating interferometry X-ray computed tomography (TLGI-XCT). The first problem we address is providing a quick way to show a fusion of all three modal- ities. For this purpose the tri-modal transfer function widget is introduced. The widget controls a mixing function that uses the output of the transfer functions of all three modalities, allowing the user to create one customized fused image. A second problem prevalent in processing TLGI-XCT data is a lack of tools for analyzing the segmentation process of such multimodal data. We address this by providing methods for computing three types of uncertainty: From probabilistic segmentation algorithms, from the voxel neighborhoods as well as from a collection of results. We furthermore introduce a linked views interface to explore this data. The techniques are evaluated on a TLGI-XCT scan of a carbon-fiber reinforced dataset with impact damage. We show that the transfer function widget accelerates and facilitates the exploration of this dataset, while the uncertainty analysis methods give insights into how to tweak and improve segmentation algorithms for more suitable results.}, language = {en} }