Search Results

Now showing 1 - 7 of 7
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    Improved Sparse Seeding for 3D Electrostatic Field Lines
    (The Eurographics Association, 2015) Scharnowski, Katrin; Boblest, Sebastian; Ertl, Thomas; E. Bertini and J. Kennedy and E. Puppo
    We present an improved seeding strategy for sparse visualization of electrostatic fields. By analyzing the curvature of the field lines, we extract points of extremal field strength between charges of different sign and use them to seed field lines, which consequently connect the corresponding charges. The resulting sparse representation can be seen as an extension to classic vector field topology depicting properties otherwise hidden. Finally, by applying our method to a synthetic data set, we show its benefits over previously published work.
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    Exploratory Performance Analysis and Tuning of Parallel Interactive Volume Visualization on Large Displays
    (The Eurographics Association, 2015) Panagiotidis, Alexandros; Frey, Steffen; Ertl, Thomas; E. Bertini and J. Kennedy and E. Puppo
    We present an exploratory approach to performance analysis and tuning of interactive parallel volume visualization for large displays. While traditional approaches target non-interactive applications and focus on separate specialized views for post-mortem performance analysis, we show metrics from the GPU and volume ray casting together with the volume visualization and allow users to interact with both of them simultaneously. With this, users can explore the data set together with the corresponding metrics to investigate both the visual and the performance impact of different parameter settings jointly, like camera position, sampling density, or acceleration technique. In particular, this supports parameter tuning by providing the user not only with timings and quality measures, but also internal metrics from the GPU and the ray caster that help to understand the connection between parameter settings and their induced outcome. We demonstrate the usage and utility of our approach for performance analysis and tuning at the example of distributed volume ray casting for a high-resolution powerwall with the goal to achieve interactive frame rates with the best possible image quality.
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    Inspector Gadget: Integrating Data Preprocessing and Orchestration in the Visual Analysis Loop
    (The Eurographics Association, 2015) Krüger, Robert; Herr, Dominik; Haag, Florian; Ertl, Thomas; E. Bertini and J. C. Roberts
    Nowadays, tracking devices are small and cheap. For analysis tasks, there is no problem to obtain sufficient amounts of data. The challenge is how to make sense of the data, which often contain complex situations. Multiple data sources related to time, space, and other dimensions, with different resolution and notation have to be mapped. Visual approaches often cover an analysis loop that starts right after the preprocessing. In this paper, we contribute methods to explicitly integrate data preprocessing and orchestration into the visual analysis loop. Subsequently, the big picture can be explored in detail and hypotheses can be created, refined, and validated. We showcase our approach with multiple heterogeneous datasets from the VAST Challenge 2014.
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    Visualization of 2DWave Propagation by Huygens' Principle
    (The Eurographics Association, 2015) Heßel, Stefan; Fernandes, Oliver; Boblest, Sebastian; Offenhäuser, Philipp; Hoffmann, Malte; Beck, Andrea; Ertl, Thomas; Glass, Colin; Munz, Claus-Dieter; Sadlo, Filip; C. Dachsbacher and P. Navrátil
    We present a novel technique to visualize wave propagation in 2D scalar fields. Direct visualization of wave fronts is susceptible to visual clutter and interpretation difficulties due to space-time interference and global influence. To avoid this, we employ Huygens' principle to obtain virtual sources that provide a concise spacetime representation of the overall dynamics by means of elementary waves. We first demonstrate the utility of our overall approach by computing a dense field of virtual sources. This variant offers full insight into space-time wave dynamics in terms of elementary waves, but it reflects the full problem of inverse wave propagation and hence suffers from high costs regarding memory consumption and computation. As an alternative, we therefore provide a less accurate and less generic but more efficient approach. This alternative performs wave front extraction with subsequent Hough transform to identify potential virtual sources. We evaluate both approaches and demonstrate their strengths and weaknesses by means of a GPU-based prototype and an implementation on a Cray XC40 supercomputer, using data from different domains.
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    On the Reproducibility of Line Integral Convolution for Real-Time Illustration of Molecular Surface Shape and Salient Regions
    (The Eurographics Association, 2015) Lawonn, Kai; Krone, Michael; Ertl, Thomas; Preim, Bernhard; W. Aigner and P. Rosenthal and C. Scheidegger
    In this paper, we discuss the reproducibility of our work presented at EuroVis 2014 [LKEP14], which describes an illustrative rendering method tailored to molecular surfaces.We distinguish between the reproducibility of the data sets that were used for figures and performance analysis and the reproducibility in the sense of re-implementing the method. For the latter, we focus on each step of the algorithm and discuss the implementation challenges. We give further details and explain the most difficult parts. Additionally, we discuss how the models that were used can be recreated and the availability of the underlying data. Finally, we discuss the current state of reproducibility of our method and reflect on the problem of offering the source code of a research project in general.
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    On the Reproducibility of our Biomolecular Visualization
    (The Eurographics Association, 2015) Scharnowski, Katrin; Krone, Michael; Reina, Guido; Ertl, Thomas; W. Aigner and P. Rosenthal and C. Scheidegger
    We reflect on the reproducibility of our work presented at EuroVis 2014 [SKR 14], which applies deformable models to compare molecular surfaces. We discuss both negative and positive aspects of our work in terms of reproducibility and put the aspects in a wider, more general context, in particular for the more critical points.
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    Photoelasticity Raycasting
    (The Eurographics Association and John Wiley & Sons Ltd., 2015) Bußler, Michael; Ertl, Thomas; Sadlo, Filip; H. Carr, K.-L. Ma, and G. Santucci
    We present a novel physically-based method to visualize stress tensor fields. By incorporating photoelasticity into traditional raycasting and extending it with reflection and refraction, taking into account polarization, we obtain the virtual counterpart to traditional experimental polariscopes. This allows us to provide photoelastic analysis of stress tensor fields in arbitrary domains. In our model, the optical material properties, such as stress-optic coefficient and refractive index, can either be chosen in compliance with the subject under investigation, or, in case of stress problems that do not model optical properties or that are not transparent, be chosen according to known or even new transparent materials. This enables direct application of established polariscope methodology together with respective interpretation. Using a GPU-based implementation, we compare our technique to experimental data, and demonstrate its utility with several simulated datasets.