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Documents authored by Obermaier, Harald


Document
Feature-based Visualization of Dense Integral Line Data

Authors: Simon Schröder, Harald Obermaier, Christoph Garth, and Kenneth I. Joy

Published in: OASIcs, Volume 27, Visualization of Large and Unstructured Data Sets: Applications in Geospatial Planning, Modeling and Engineering - Proceedings of IRTG 1131 Workshop 2011


Abstract
Feature-based visualization of flow fields has proven as an effective tool for flow analysis. While most flow visualization techniques operate on vector field data, our visualization techniques make use of a different simulation output: Particle Tracers. Our approach solely relies on integral lines that can be easily obtained from most simulation software. The task is the visualization of dense integral line data. We combine existing methods for streamline visualization, i.e. illumination, transparency, and halos, and add ambient occlusion for lines. But, this only solves one part of the problem: because of the high density of lines, visualization has to fight with occlusion, high frequency noise, and overlaps. As a solution we propose non-automated choices of transfer functions on curve properties that help highlighting important flow features like vortices or turbulent areas. These curve properties resemble some of the original flow properties. With the new combination of existing line drawing methods and the addition of ambient occlusion we improve the visualization of lines by adding better shape and depth cues. The intelligent use of transfer functions on curve properties reduces visual clutter and helps focusing on important features while still retaining context, as demonstrated in the examples given in this work.

Cite as

Simon Schröder, Harald Obermaier, Christoph Garth, and Kenneth I. Joy. Feature-based Visualization of Dense Integral Line Data. In Visualization of Large and Unstructured Data Sets: Applications in Geospatial Planning, Modeling and Engineering - Proceedings of IRTG 1131 Workshop 2011. Open Access Series in Informatics (OASIcs), Volume 27, pp. 71-87, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2012)


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@InProceedings{schroder_et_al:OASIcs.VLUDS.2011.71,
  author =	{Schr\"{o}der, Simon and Obermaier, Harald and Garth, Christoph and Joy, Kenneth I.},
  title =	{{Feature-based Visualization of Dense Integral Line Data}},
  booktitle =	{Visualization of Large and Unstructured Data Sets: Applications in Geospatial Planning, Modeling and Engineering - Proceedings of IRTG 1131 Workshop 2011},
  pages =	{71--87},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-46-0},
  ISSN =	{2190-6807},
  year =	{2012},
  volume =	{27},
  editor =	{Garth, Christoph and Middel, Ariane and Hagen, Hans},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.VLUDS.2011.71},
  URN =		{urn:nbn:de:0030-drops-37424},
  doi =		{10.4230/OASIcs.VLUDS.2011.71},
  annote =	{Keywords: flow simulation, feature-based visualization, dense lines, ambient occlusion}
}
Document
Generation of Adaptive Streak Surfaces Using Moving Least Squares

Authors: Harald Obermaier, Martin Hering-Bertram, Jörg Kuhnert, and Hans Hagen

Published in: Dagstuhl Follow-Ups, Volume 2, Scientific Visualization: Interactions, Features, Metaphors (2011)


Abstract
We introduce a novel method for the generation of fully adaptive streak surfaces in time-varying flow fields based on particle advection and adaptive mesh refinement. Moving least squares approximation plays an important role in multiple stages of the proposed algorithm, which adaptively refines the surface based on curvature approximation and circumradius properties of the underlying Delaunay mesh. We utilize the grid-less Moving Least Squares approximation method for both curvature and surface estimation as well as vector field evaluation during particle advection. Delaunay properties of the surface triangulation are guaranteed by edge flipping operations on the progressive surface mesh. The results of this work illustrate the benefit of adaptivity techniques to streak surface generation and provide the means for a qualitative analysis of the presented approach.

Cite as

Harald Obermaier, Martin Hering-Bertram, Jörg Kuhnert, and Hans Hagen. Generation of Adaptive Streak Surfaces Using Moving Least Squares. In Scientific Visualization: Interactions, Features, Metaphors. Dagstuhl Follow-Ups, Volume 2, pp. 260-275, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2011)


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@InCollection{obermaier_et_al:DFU.Vol2.SciViz.2011.260,
  author =	{Obermaier, Harald and Hering-Bertram, Martin and Kuhnert, J\"{o}rg and Hagen, Hans},
  title =	{{Generation of Adaptive Streak Surfaces Using Moving Least Squares}},
  booktitle =	{Scientific Visualization: Interactions, Features, Metaphors},
  pages =	{260--275},
  series =	{Dagstuhl Follow-Ups},
  ISBN =	{978-3-939897-26-2},
  ISSN =	{1868-8977},
  year =	{2011},
  volume =	{2},
  editor =	{Hagen, Hans},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DFU.Vol2.SciViz.2011.260},
  URN =		{urn:nbn:de:0030-drops-32982},
  doi =		{10.4230/DFU.Vol2.SciViz.2011.260},
  annote =	{Keywords: scattered, flow, streak surface, adaptivity, moving least squares}
}
Document
On Moving Least Squares Based Flow Visualization

Authors: Harald Obermaier, Martin Hering-Bertram, Jörg Kuhnert, and Hans Hagen

Published in: OASIcs, Volume 19, Visualization of Large and Unstructured Data Sets - Applications in Geospatial Planning, Modeling and Engineering (IRTG 1131 Workshop) (2011)


Abstract
Modern simulation and measurement methods tend to produce meshfree data sets if modeling of processes or objects with free surfaces or boundaries is desired. In Computational Fluid Dynamics (CFD), such data sets are described by particle-based vector fields. This paper presents a summary of a selection of methods for the extraction of geometric features of such point-based vector fields while pointing out its challenges, limitations, and applications.

Cite as

Harald Obermaier, Martin Hering-Bertram, Jörg Kuhnert, and Hans Hagen. On Moving Least Squares Based Flow Visualization. In Visualization of Large and Unstructured Data Sets - Applications in Geospatial Planning, Modeling and Engineering (IRTG 1131 Workshop). Open Access Series in Informatics (OASIcs), Volume 19, pp. 55-63, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2011)


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@InProceedings{obermaier_et_al:OASIcs.VLUDS.2010.55,
  author =	{Obermaier, Harald and Hering-Bertram, Martin and Kuhnert, J\"{o}rg and Hagen, Hans},
  title =	{{On Moving Least Squares Based Flow  Visualization}},
  booktitle =	{Visualization of Large and Unstructured Data Sets - Applications in Geospatial Planning, Modeling and Engineering (IRTG 1131 Workshop)},
  pages =	{55--63},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-29-3},
  ISSN =	{2190-6807},
  year =	{2011},
  volume =	{19},
  editor =	{Middel, Ariane and Scheler, Inga and Hagen, Hans},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.VLUDS.2010.55},
  URN =		{urn:nbn:de:0030-drops-30979},
  doi =		{10.4230/OASIcs.VLUDS.2010.55},
  annote =	{Keywords: Moving Least Squares, Approximation, Flow, Scientific Visualization}
}
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