TY - GEN A1 - Kasten, Jens A1 - Hotz, Ingrid A1 - Hege, Hans-Christian ED - Peikert, Ronald ED - Hauser, Helwig ED - Carr, Hamish ED - Fuchs, Raphael T1 - On the Elusive Concept of Lagrangian Coherent Structures T2 - Topological Methods in Data Analysis and Visualization II Y1 - 2012 U6 - https://doi.org/10.1007/978-3-642-23175-9_14 SP - 207 EP - 220 PB - Springer ER - TY - GEN A1 - Reininghaus, Jan A1 - Kasten, Jens A1 - Weinkauf, Tino A1 - Hotz, Ingrid T1 - Combinatorial Feature Flow Fields: Tracking Critical Points in Discrete Scalar Fields N2 - We propose a combinatorial algorithm to track critical points of 2D time-dependent scalar fields. Existing tracking algorithms such as Feature Flow Fields apply numerical schemes utilizing derivatives of the data, which makes them prone to noise and involve a large number of computational parameters. In contrast, our method is robust against noise since it does not require derivatives, interpolation, and numerical integration. Furthermore, we propose an importance measure that combines the spatial persistence of a critical point with its temporal evolution. This leads to a time-aware feature hierarchy, which allows us to discriminate important from spurious features. Our method requires only a single, easy-to-tune computational parameter and is naturally formulated in an out-of-core fashion, which enables the analysis of large data sets. We apply our method to a number of data sets and compare it to the stabilized continuous Feature Flow Field tracking algorithm. T3 - ZIB-Report - 11-02 KW - data analysis KW - feature detection KW - time-varying data KW - topology-based techniques Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-12151 ER - TY - GEN A1 - Kratz, Andrea A1 - Reininghaus, Jan A1 - Hadwiger, Markus A1 - Hotz, Ingrid T1 - Adaptive Screen-Space Sampling for Volume Ray-Casting N2 - This work is concerned with adaptive screen-space sampling for volume ray-casting. The goal is to reduce the number of rays being cast into the scene and, thus, the overall number of sampling points. We guarantee reliable images through explicit error control using an error estimator that is founded in the field of finite element methods (FEM). FEM theory further provides a well-founded theory to prove the efficiency of the presented algorithm via convergence analysis. We, therefore, compare the convergence behavior of our method against uniform subdivisions and a refinement scheme that was presented in the context of CPU volume ray-casting. Minimizing the number of sampling points is of interest for rendering large datasets where each evaluation might need an expensive decompression. Furthermore, with increasing screen resolutions high-resolution images are created more efficiently with our method. T3 - ZIB-Report - 11-04 Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-12446 ER - TY - JOUR A1 - Günther, David A1 - Reininghaus, Jan A1 - Wagner, Hubert A1 - Hotz, Ingrid T1 - Memory-Efficient Computation of Persistent Homology for 3D Images using Discrete Morse Theory JF - Proc. Sibgrapi – Conference on Graphics, Patterns and Images Y1 - 2011 PB - Kluwer Academic Publishers ER - TY - CHAP A1 - Boyer, Edmond A1 - Bronstein, Alexander A1 - Bronstein, Michael A1 - Bustos, Benjamin A1 - Darom, Tal A1 - Horaud, Radu A1 - Hotz, Ingrid A1 - Keller, Yosi A1 - Keustermans, Johannes A1 - Kovnatsky, Artiom A1 - Litman, Roee A1 - Reininghaus, Jan A1 - Sipiran, Ivan A1 - Smeets, Dirk A1 - Suetens, Paul A1 - Vandermeulen, Dirk A1 - Zaharescu, Andrei A1 - Zobel, Valentin T1 - SHREC 2011: robust feature detection and description benchmark T2 - Proc. Eurographics 2011 Workshop on 3D Object Retrieval (3DOR’11) Y1 - 2011 U6 - https://doi.org/10.2312/3DOR/3DOR11/079-088 target SP - 71 EP - 78 PB - Eurographics Association ER - TY - CHAP A1 - Auer, Cornelia A1 - Hotz, Ingrid T1 - Complete Tensor Field Topology on 2D Triangulated Manifolds embedded in 3D T2 - Computer Graphics Forum (EuroVis’11) Y1 - 2011 VL - 30 IS - 3 target SP - 831 EP - 840 ER - TY - JOUR A1 - Kasten, Jens A1 - Reininghaus, Jan A1 - Hotz, Ingrid A1 - Hege, Hans-Christian T1 - Two-Dimensional Time-Dependent Vortex Regions Based on the Acceleration Magnitude JF - IEEE Transactions on Visualization and Computer Graphics Y1 - 2011 VL - 17 IS - 12 SP - 2080 EP - 2087target ER - TY - JOUR A1 - Reininghaus, Jan A1 - Kotava, N. A1 - Günther, David A1 - Kasten, Jens A1 - Hagen, Hans A1 - Hotz, Ingrid T1 - A Scale Space Based Persistence Measure for Critical Points in 2D Scalar Fields JF - Visualization and Computer Graphics, IEEE Transactions on Y1 - 2011 U6 - https://doi.org/10.1109/TVCG.2011.159 VL - 17 IS - 12 SP - 2045 EP - 2052 ER - TY - GEN A1 - Kasten, Jens A1 - Hotz, Ingrid A1 - Noack, Bernd A1 - Hege, Hans-Christian ED - Pascucci, Valerio ED - Tricoche, Xavier ED - Hagen, Hans ED - Tierny, Julien T1 - On the Extraction of Long-living Features in Unsteady Fluid Flows T2 - Topological Methods in Data Analysis and Visualization Y1 - 2011 SN - 978-3-642-15013-5 U6 - https://doi.org/10.1007/978-3-642-15014-2_10 SP - 115 EP - 126 PB - Springer CY - Berlin ER - TY - JOUR A1 - Reininghaus, Jan A1 - Löwen, Christian A1 - Hotz, Ingrid T1 - Fast Combinatorial Vector Field Topology JF - IEEE Trans. Computer Graphics and Visualization Y1 - 2011 VL - 17 IS - 10 SP - 1433 EP - 1443 ER -