@proceedings {531, title = {Hierarchical Poisson-Disk Sampling for Fiber Stipples}, year = {2013}, month = {09/2013}, pages = {19-23}, publisher = {Eurographics}, address = {Leipzig}, doi = {10.2312/PE.VMLS.VMLS2013.019-023}, author = {Mario Hlawitschka and Mathias Goldau and Alexander Wiebel and Heine, C. and Gerik Scheuermann} } @conference {536, title = {Visualizing Linear Neighborhoods in Non-Linear Vector Fields}, booktitle = {PacificVis}, year = {2013}, doi = {target}, author = {Stefan Koch and Alexander Wiebel and Jens Kasten and Mario Hlawitschka} } @inbook { RSH*:2012, title = {Combinatorial Vector Field Topology in Three Dimensions}, booktitle = {Topological Methods in Data Analysis and Visualization II}, year = {2012}, pages = {47-59}, publisher = {Springer}, organization = {Springer}, address = {Berlin, Germany}, url = {http://www.informatik.uni-leipzig.de/~reich/TopoInVisWieland2011.pdf}, author = {Wieland Reich and Schneider, D. and Heine, C. and Alexander Wiebel and Chen, G. and Gerik Scheuermann}, editor = {Ronny Peikert and Hauser, H. and Fuchs, R.} } @inbook { WKS:2012, title = {Glyphs for Non-Linear Vector Field Singularities}, booktitle = {Topological Methods in Data Analysis and Visualization II}, year = {2012}, pages = {177-190}, publisher = {Springer}, organization = {Springer}, address = {Berlin, Germany}, author = {Alexander Wiebel and Stefan Koch and Gerik Scheuermann}, editor = {Ronny Peikert and Hauser, H. and Fuchs, R.} } @conference { GWG*:2011, title = {Fiber Stippling: An Illustrative Rendering for Probabilistic Diffusion Tractography}, booktitle = {IEEE BioVis Proceedings}, year = {2011}, pages = {23-30}, abstract = {One of the most promising avenues for compiling anatomical brain connectivity data arises from diffusion magnetic resonance imaging (dMRI). dMRI provides a rather novel family of medical imaging techniques with broad application in clinical as well as basic neuroscience as it offers an estimate of the brain{\textquoteright}s fiber structure completely non-invasively and in vivo. A convenient way to reconstruct neuronal fiber pathways and to characterize anatomical connectivity from this data is the computation of diffusion tractograms. In this paper, we present a novel and effective method for visualizing probabilistic tractograms within their anatomical context. Our illustrative rendering technique, called fiber stippling, is inspired by visualization standards as found in anatomical textbooks. These illustrations typically show slice-based projections of fiber pathways and are typically hand-drawn. Applying the automatized technique to diffusion tractography, we demonstrate its expressiveness and intuitive usability as well as a more objective way to present white-matter structure in the human brain.}, author = {Mathias Goldau and Alexander Wiebel and Nico Stephan Gorbach and Corina Melzer and Mario Hlawitschka and Gerik Scheuermann and Tittgemeyer, Marc} } @conference { GWH*:2011, title = {Visualizing DTI Parameters on Boundary Surfaces of White Matter Fiber Bundles}, booktitle = {IASTED International Conference on Computer Graphics and Imaging} publisher = {ACTA Press}, year = {2011}, pages = {53-61}, publisher = {ACTA Press}, organization = {ACTA Press}, abstract = {Diffusion magnetic resonance imaging is so far the only medical imaging modality that has the potential for probing anatomical brain connectivity in vivo. Specifically, it provides the data basis for a set of techniques allowing for tracking of fiber bundles in the brain{\textquoteright}s white matter. Furthermore, due to the micro-structural basis of the diffusion process, fiber integrity might be estimated. Typically, this is achieved by tensor-derived parameters, such as by fractional anisotropy (FA), which allows for a quantification of the directionality of local diffusion properties. In neuroscience, such parameterization of the diffusion tensor has greatly stimulated studies of localized brain changes, related to development, aging, or various neurological and psychiatric diseases. However, thus far, there is no satisfactory solution for the visualization and assessment of such parameters along fiber bundles. In this paper, we present a novel technique to visualize changes of tensor-derived parameters along clusters of the trajectories obtained from diffusion tractography. This visualization approach consists of two steps: First, an automatic local aggregation of data values around the trajectories for quantitative analysis and visualization on the fiber bundle boundary and second, a color-coded slice that is intuitively movable along the bundle for interactive exploration of the bundle{\textquoteright}s parameters.}, isbn = {978-0-88986-865-6}, author = {Mathias Goldau and Alexander Wiebel and Mario Hlawitschka and Gerik Scheuermann} } @article { WWS*:2010, title = {Accelerated Streak Line Computation Using Adaptive Refinement}, journal = {Journal of WSCG}, volume = {18}, year = {2010}, pages = {17-23}, author = {Alexander Wiebel and Wang, Q. and Schneider, D. and Gerik Scheuermann} } @article { BWF*:2010, title = {Illustrative Stream Surfaces}, journal = {IEEE Transactions on Visualization and Computer Graphics}, volume = {16}, number = {6}, year = {2010}, pages = {1329-1338}, author = {Born, Silvia and Alexander Wiebel and Friedrich, Jan and Gerik Scheuermann and Bartz, Dirk} } @booklet {eichelbaum2010d, title = {OpenWalnut: A New Tool for Multi-modal Visualization of the Human Brain}, year = {2010}, abstract = {In the course of the ongoing research into neurological diseases and the function and anatomy of the brain, a large variety of examination techniques has evolved. The different techniques aim at findings for different research questions or different viewpoints of a single task. Considering the different applications, it is evident that, for many research areas, only a combination of multiple techniques can help answering the posed questions. To name only one example, the combination of dwMRI and fMRI with an anatomical context provided by T1 MRI images is very common. To be able to analyze the data measured by the different techniques, a tool that can efficiently visualize the different modalities simultaneously is needed. The software (called {\em OpenWalnut}) we will present in this poster aims at exactly this task. It does not only allow to display the different modalities together, but also provides tools to analyze their interdependence and relations. In the following, we will provide you with an overview of OpenWalnut{\textquoteright}s features. Its simplicity, making it a useful visualization tool, on the one hand and its powerful and generic framework for computer scientist researchers on the other hand.}, author = {Eichelbaum, Sebastian and Mathias Goldau and Stefan Philips and Andr{\'e} Reichenbach and Ralph Schurade and Alexander Wiebel} } @conference {eichelbaum2010e, title = {OpenWalnut - An Open-Source Visualization System}, booktitle = {Proceedings of the 6th High-End Visualization Workshop}, year = {2010}, month = {December}, pages = {67{\textendash}78}, abstract = {In the last years a variety of open-source software packages focusing on visualization of human brain data have evolved. Many of them are designed to be used in a pure academic environment and are optimized for certain tasks or special data. The open source visualization system we introduce here is called \emph{OpenWalnut}. It is designed and developed to be used by neuroscientists during their research, which enforces the framework to be designed to be very fast and responsive on the one side, but easily extendible on the other side. \emph{OpenWalnut} is a very application-driven tool and the software is tuned to ease its use. Whereas we introduce \emph{OpenWalnut} from a user{\textquoteright}s point of view, we will focus on its architecture and strengths for visualization researchers in an academic environment.}, author = {Eichelbaum, Sebastian and Mario Hlawitschka and Alexander Wiebel and Gerik Scheuermann}, editor = {Werner benger and Andreas Gerndt and Simon Su and Wolfram Schoor and Michael Koppitz and Wolfgang Kapferer and Hans-Peter Bischof and Massimo Di Pierro} } @inbook { WCW*:2010, title = {Topological Flow Structures in a Mathematical Model for Rotation-Mediated Cell Aggregation}, booktitle = {Topological Methods in Data Analysis and Visualization}, year = {2010}, pages = {193-204}, publisher = {Springer}, organization = {Springer}, author = {Alexander Wiebel and Chan, R. and Wolf, C. and Robitzki, A. and Stevens, A. and Gerik Scheuermann}, editor = {Pascucci, V. and Tricoche, X. and Hans Hagen and Tierny, J.} } @article { SRW*:2010, title = {Topology Aware Stream Surfaces}, journal = {Computer Graphics Forum}, volume = {29}, number = {3}, year = {2010}, pages = {1153-1161}, url = {http://www.informatik.uni-leipzig.de/~reich/eurovis2010.pdf}, author = {Schneider, D. and Wieland Reich and Alexander Wiebel and Gerik Scheuermann} } @conference { WRK*:2010, title = {Vector Field Topology in the Context of Separation and Attachment of Flows}, booktitle = {Foundations of Topological Analysis Workshop}, year = {2010}, note = {Co-located with IEEE VisWeek 2010}, url = {http://www.informatik.uni-leipzig.de/~reich/wiebelworkshop2010.pdf}, author = {Alexander Wiebel and Wieland Reich and Stefan Koch and Gerik Scheuermann} } @conference {eichelbaum2010c, title = {Visualization of Effective Connectivity of the Brain}, booktitle = {Proceedings of the 15th International Workshop on Vision, Modeling and Visualization (VMV) Workshop 2010}, year = {2010}, pages = {155-162}, abstract = {Diffusion tensor images and higher-order diffusion images are the foundation for neuroscience researchers who are trying to gain insight into the connectome, the wiring scheme of the brain. Although modern imaging devices allow even more detailed anatomical measurements, these pure anatomical connections are not sufficient for understanding how the brain processes external stimuli. Anatomical connections constraint the causal influences between several areas of the brain, as they mediate causal influence between them. Therefore, neuroscientists developed models to represent the causal coherence between several pre-defined areas of the brain, which has been measured using fMRI, MEG, or EEG. The dynamic causal modeling (DCM) technique is one of these models and has been improved to use anatomical connection as informed priors to build the effective connectivity model. In this paper, we present a visualization method allowing neuroscientists to perceive both, the effective connectivity and the underlying anatomical connectivity in an intuitive way at the same time. The metaphor of moving information packages is used to show the relative intensity of information transfer inside the brain using a GPU based animation technique. We provide an interactive way to selectively view one or multiple effective connections while conceiving their anatomical connectivity. Additional anatomical context is supplied to give further orientation cues.}, author = {Eichelbaum, Sebastian and Alexander Wiebel and Mario Hlawitschka and Anwander, A. and Thomas R. Kn{\"o}sche and Gerik Scheuermann}, editor = {Reinhard Koch and Andreas Kolb and Christof Rezk-Salama} } @conference { SHH*:2010, title = {Visualizing White Matter Fiber Tracts with Optimally Fitted Curved Dissection Surfaces}, booktitle = {Proceedings of the Eurographics Workshop on Visual Computing for Biomedicine, VCBM 2010}, year = {2010}, pages = {41-48}, publisher = {Eurographics Association}, organization = {Eurographics Association}, author = {Ralph Schurade and Mario Hlawitschka and Bernd Hamann and Gerik Scheuermann and Thomas R. Kn{\"o}sche and Anwander, A.}, editor = {Bartz, Dirk and Botha, C. and Hornegger, J. and Machiraju, R. and Alexander Wiebel and Preim, B.} } @inbook { WTS:2009, title = {Extraction of Separation Manifolds using Topological Structures in Flow Cross Sections}, booktitle = {Topology-Based Methods in Visualization II}, year = {2009}, pages = {31-44}, publisher = {Springer}, organization = {Springer}, address = {Berlin, Germany}, author = {Alexander Wiebel and Tricoche, X. and Gerik Scheuermann}, editor = {Hege, H.-C. and Polthier, K. and Gerik Scheuermann} } @conference { WGH*:2009, title = {FAnToM - Lessons Learned from Design, Implementation, Administration, and Use of a Visualization System for Over 10 Years}, booktitle = {Refactoring Visualization from Experience (ReVisE) 2009}, year = {2009}, note = {co-located with IEEE Visualization 2009}, month = {October}, address = {Atlantic City, NJ, USA}, author = {Alexander Wiebel and Garth, C. and Mario Hlawitschka and Wischgoll, T. and Gerik Scheuermann} } @article { SWS:2009, title = {Smooth Stream Surfaces of 4th Order Precision}, journal = {Computer Graphics Forum}, volume = {28}, number = {3}, year = {2009}, pages = {871-878}, author = {Schneider, D. and Alexander Wiebel and Gerik Scheuermann} } @article { SWC*:2008, title = {Interactive Comparison of Scalar Fields Based on Largest Contours with Applications to Flow Visualization}, journal = {IEEE Transaction on Visualization and Computer Graphics}, volume = {14}, number = {6}, year = {2008}, pages = {1475-1482}, author = {Schneider, D. and Alexander Wiebel and Carr, Hamish and Mario Hlawitschka and Gerik Scheuermann} } @article {499, title = {Lagrangian Visualization of Flow-Embedded Surface Structures}, journal = {Computer Graphics Forum}, volume = {27}, year = {2008}, pages = {774}, chapter = {767}, author = {Garth, C. and Alexander Wiebel and Tricoche, X. and Joy, K. and Gerik Scheuermann} } @article { WGS:2007, title = {Computation of Localized Flow for Steady and Unsteady Vector Fields and its Applications}, journal = {IEEE Transactions on Visualization and Computer Graphics}, volume = {13}, number = {4}, year = {2007}, pages = {641-651}, author = {Alexander Wiebel and Garth, C. and Gerik Scheuermann} } @conference { SWS:2007, title = {Efficient Construction of Flow Structures}, booktitle = {IASTED VIIP 2007 Proceedings}, year = {2007}, pages = {135-140}, publisher = {IASTED}, organization = {IASTED}, author = {Sazbrunn, T. and Alexander Wiebel and Gerik Scheuermann} } @article { WTS*:2007, title = {Generalized Streak Lines: Analysis and Visualization of Boundary Induced Vortices}, journal = {IEEE Transactions on Visualization and Computer Graphics}, volume = {13}, number = {6}, year = {2007}, pages = {1735-1742}, author = {Alexander Wiebel and Tricoche, X. and Schneider, D. and J{\"a}nicke, H. and Gerik Scheuermann} } @article { JWS*:2007, title = {Multifield Visualization Using Local Statistical Complexity}, journal = {IEEE Transactions on Visualization and Computer Graphics}, volume = {13}, number = {6}, year = {2007}, pages = {1384-1391}, author = {J{\"a}nicke, H. and Alexander Wiebel and Gerik Scheuermann and Kollmann, W.} } @conference { EWG*:2007, title = {Topology Based Flow Analysis and Superposition Effects}, booktitle = {Topology-Based Methods in Visualization}, year = {2007}, pages = {91-104}, publisher = {Springer}, organization = {Springer}, address = {Berlin, Germany}, author = {Ebling, J. and Alexander Wiebel and Garth, C. and Gerik Scheuermann} } @conference { WS:2005, title = {Eyelet Particle Tracing - Steady Visualization of Unsteady Flow}, booktitle = {IEEE Visualization 2005 Proceedings}, year = {2005}, pages = {607-614}, publisher = {IEEE Computer Society}, organization = {IEEE Computer Society}, address = {Los Alamitos, CA, USA}, author = {Alexander Wiebel and Gerik Scheuermann}, editor = {Silva, C. T. and Gr{\"o}ller, E. and Rushmeier, H.} } @conference { WGS:2005, title = {Localized Flow Analysis of 2D and 3D Vector Fields}, booktitle = {Data Visualization 2005: Proceedings of EuroVis 2005}, year = {2005}, pages = {143-150}, publisher = {Eurographics Association}, organization = {Eurographics Association}, address = {Aire-la-Ville, Switzerland}, author = {Alexander Wiebel and Garth, C. and Gerik Scheuermann}, editor = {Brodlie, K. W. and Duke, D. J. and Joy, K.} }