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  <doc>
    <id>5905</id>
    <completedYear/>
    <publishedYear/>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>reportzib</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>2016-04-04</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">MCFTLE: Monte Carlo Rendering of Finite-Time Lyapunov Exponent Fields</title>
    <abstract language="eng">Traditionally, Lagrangian fields such as finite-time Lyapunov exponents (FTLE)&#13;
are precomputed on a discrete grid and are ray casted afterwards. This, however,&#13;
introduces both grid discretization errors and sampling errors during ray marching.&#13;
In this work, we apply a progressive, view-dependent Monte Carlo-based approach&#13;
for the visualization of such Lagrangian fields in time-dependent flows. Our ap-&#13;
proach avoids grid discretization and ray marching errors completely, is consistent,&#13;
and has a low memory consumption. The system provides noisy previews that con-&#13;
verge over time to an accurate high-quality visualization. Compared to traditional&#13;
approaches, the proposed system avoids explicitly predefined fieldline seeding&#13;
structures, and uses a Monte Carlo sampling strategy named Woodcock tracking&#13;
to distribute samples along the view ray. An acceleration of this sampling strategy&#13;
requires local upper bounds for the FTLE values, which we progressively acquire&#13;
during the rendering. Our approach is tailored for high-quality visualizations of&#13;
complex FTLE fields and is guaranteed to faithfully represent detailed ridge surface&#13;
structures as indicators for Lagrangian coherent structures (LCS). We demonstrate&#13;
the effectiveness of our approach by using a set of analytic test cases and real-world numerical simulations.</abstract>
    <identifier type="issn">1438-0064</identifier>
    <identifier type="urn">urn:nbn:de:0297-zib-59054</identifier>
    <identifier type="doi">10.1111/cgf.12914</identifier>
    <note>By mistake the fourth author Hans-Christian Hege has been ommitted in the journal publication</note>
    <enrichment key="SourceTitle">Appeared in: Computer Graphics Forum 35 (2016) 381-390</enrichment>
    <author>Tobias Günther</author>
    <submitter>Alexander Kuhn</submitter>
    <author>Alexander Kuhn</author>
    <author>Hans-Christian Hege</author>
    <author>Holger Theisel</author>
    <series>
      <title>ZIB-Report</title>
      <number>16-21</number>
    </series>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Picture/Image Generation, Display algorithms, Three-Dimensional Graphics and Realism, Raytracing</value>
    </subject>
    <collection role="ccs" number="A.">General Literature</collection>
    <collection role="pacs" number="00.00.00">GENERAL</collection>
    <collection role="msc" number="65-XX">NUMERICAL ANALYSIS</collection>
    <collection role="institutes" number="vis">Visual Data Analysis</collection>
    <collection role="persons" number="hege">Hege, Hans-Christian</collection>
    <collection role="projects" number="HD(CP)2">HD(CP)2</collection>
    <collection role="institutes" number="VDcC">Visual and Data-centric Computing</collection>
    <file>https://opus4.kobv.de/opus4-zib/files/5905/ZIBReport-final-2016.pdf</file>
  </doc>
</export-example>
