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Displaying 1-35 out of 35 total
Semi-Automatic Vortex Extraction in 4D PC-MRI Cardiac Blood Flow Data using Line Predicates
Found in: IEEE Transactions on Visualization and Computer Graphics
By Benjamin Kohler,Rocco Gasteiger,Uta Preim,Holger Theisel,Matthias Gutberlet,Bernhard Preim
Issue Date:December 2013
pp. 2773-2782
Cardiovascular diseases (CVD) are the leading cause of death worldwide. Their initiation and evolution depends strongly on the blood flow characteristics. In recent years, advances in 4D PC-MRI acquisition enable reliable and time-resolved 3D flow measurin...
 
Interactive Separating Streak Surfaces
Found in: IEEE Transactions on Visualization and Computer Graphics
By Florian Ferstl, Kai Bürger, Holger Theisel, Rüdiger Westermann
Issue Date:November 2010
pp. 1569-1577
Streak surfaces are among the most important features to support 3D unsteady flow exploration, but they are also among the computationally most demanding. Furthermore, to enable a feature driven analysis of the flow, one is mainly interested in streak surf...
 
Streak Lines as Tangent Curves of a Derived Vector Field
Found in: IEEE Transactions on Visualization and Computer Graphics
By Tino Weinkauf, Holger Theisel
Issue Date:November 2010
pp. 1225-1234
Characteristic curves of vector fields include stream, path, and streak lines. Stream and path lines can be obtained by a simple vector field integration of an autonomous ODE system, i.e., they can be described as tangent curves of a vector field. This fac...
 
Interactive Streak Surface Visualization on the GPU
Found in: IEEE Transactions on Visualization and Computer Graphics
By Kai Buerger, Florian Ferstl, Holger Theisel, Rüdiger Westermann
Issue Date:November 2009
pp. 1259-1266
In this paper we present techniques for the visualization of unsteady flows using streak surfaces, which allow for the first time an adaptive integration and rendering of such surfaces in real-time. The techniques consist of two main components, which are ...
 
Smoke Surfaces: An Interactive Flow Visualization Technique Inspired by Real-World Flow Experiments
Found in: IEEE Transactions on Visualization and Computer Graphics
By Wolfram von Funck, Tino Weinkauf, Holger Theisel, Hans-Peter Seidel
Issue Date:November 2008
pp. 1396-1403
Smoke rendering is a standard technique for flow visualization. Most approaches are based on a volumetric, par ticle based, or image based representation of the smoke. This paper introduces an alternative representation of smoke structures: as semi-transpa...
 
Topological Visualization of Brain Diffusion MRI Data
Found in: IEEE Transactions on Visualization and Computer Graphics
By Thomas Schultz, Holger Theisel, Hans-Peter Seidel
Issue Date:November 2007
pp. 1496-1503
Topological methods give concise and expressive visual representations of flow fields. The present work suggests a comparable method for the visualization of human brain diffusion MRI data. We explore existing techniques for the topological analysis of gen...
 
Orthographic Star Coordinates
Found in: IEEE Transactions on Visualization and Computer Graphics
By Dirk J. Lehmann,Holger Theisel
Issue Date:December 2013
pp. 2615-2624
Star coordinates is a popular projection technique from an nD data space to a 2D/3D visualization domain. It is defined by setting n coordinate axes in the visualization domain. Since it generally defines an affine projection, strong distortions can occur:...
 
Detecting People Carrying Objects Utilizing Lagrangian Dynamics
Found in: 2012 9th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS)
By Tobias Senst,Alexander Kuhn,Holger Theisel,Thomas Sikora
Issue Date:September 2012
pp. 398-403
The availability of dense motion information in computer vision domain allows for the effective application of Lagrangian techniques that have their origin in fluid flow analysis and dynamical systems theory. A well established technique that has been prov...
 
Flow Visualization and Analysis Using Streak and Time Lines
Found in: Computing in Science & Engineering
By Tino Weinkauf,Holger Theisel
Issue Date:September 2012
pp. 78-84
Novel mathematical descriptions of streak and time lines lead to new methods for visualizing and analyzing flow fields. They enable faster computations and new feature-based methods.
 
As-Perpendicular-as-possible surfaces for flow visualization
Found in: Visualization Symposium, IEEE Pacific
By Maik Schulze,Christian Rossl,Tobias Germer,Holger Theisel
Issue Date:March 2012
pp. 153-160
We define APAP surfaces, surfaces that are as perpendicular as possible to steady 3D vector fields, and present a method to construct discrete representations of them. Since, in general, a perfectly perpendicular surface to a vector field does not exist, w...
 
A benchmark for evaluating FTLE computations
Found in: Visualization Symposium, IEEE Pacific
By Alexander Kuhn,Christian Rossl,Tino Weinkauf,Holger Theisel
Issue Date:March 2012
pp. 121-128
The Finite Time Lyapunov Exponent (FTLE) has become a widespread tool for analyzing unsteady flow behavior. For its computation, several numerical methods have been introduced, which provide trade-offs between performance and accuracy. In order to decide w...
 
Features in Continuous Parallel Coordinates
Found in: IEEE Transactions on Visualization and Computer Graphics
By Dirk J. Lehmann,Holger Theisel
Issue Date:December 2011
pp. 1912-1921
Continuous Parallel Coordinates (CPC) are a contemporary visualization technique in order to combine several scalar fields, given over a common domain. They facilitate a continuous view for parallel coordinates by considering a smooth scalar field instead ...
 
Streamline Embedding for 3D Vector Field Exploration
Found in: IEEE Transactions on Visualization and Computer Graphics
By Christian Rössl,Holger Theisel
Issue Date:March 2012
pp. 407-420
We propose a new technique for visual exploration of streamlines in 3D vector fields. We construct a map from the space of all streamlines to points in {\hbox{\rlap{I}\kern 2.0pt{\hbox{R}}}}^n based on the preservation of the Hausdorff metric in streamline...
 
Uncertain topology of 3D vector fields
Found in: 2011 IEEE Pacific Visualization Symposium (PacificVis)
By Mathias Otto,Tobias Germer,Holger Theisel
Issue Date:March 2011
pp. 67-74
We present a technique to visualize global uncertainty in stationary 3D vector fields by a topological approach. We start from an existing approach for 2D uncertain vector field topology and extend this into 3D space. For this a number of conceptional and ...
 
Automated Analytical Methods to Support Visual Exploration of High-Dimensional Data
Found in: IEEE Transactions on Visualization and Computer Graphics
By Andrada Tatu, Georgia Albuquerque, Martin Eisemann, Peter Bak, Holger Theisel, Marcus Magnor, Daniel Keim
Issue Date:May 2011
pp. 584-597
Visual exploration of multivariate data typically requires projection onto lower dimensional representations. The number of possible representations grows rapidly with the number of dimensions, and manual exploration quickly becomes ineffective or even unf...
 
Discontinuities in Continuous Scatter Plots
Found in: IEEE Transactions on Visualization and Computer Graphics
By Dirk J. Lehmann, Holger Theisel
Issue Date:November 2010
pp. 1291-1300
The concept of continuous scatterplot (CSP) is a modern visualization technique. The idea is to define a scalar density value based on the map between an n-dimensional spatial domain and an m-dimensional data domain, which describe the CSP space. Usually t...
 
Stable Feature Flow Fields
Found in: IEEE Transactions on Visualization and Computer Graphics
By Tino Weinkauf, Holger Theisel, Allen Van Gelder, Alex Pang
Issue Date:June 2011
pp. 770-780
Feature Flow Fields are a well-accepted approach for extracting and tracking features. In particular, they are often used to track critical points in time-dependent vector fields and to extract and track vortex core lines. The general idea is to extract th...
 
Crease Surfaces: From Theory to Extraction and Application to Diffusion Tensor MRI
Found in: IEEE Transactions on Visualization and Computer Graphics
By Thomas Schultz, Holger Theisel, Hans-Peter Seidel
Issue Date:January 2010
pp. 109-119
Crease surfaces are two-dimensional manifolds along which a scalar field assumes a local maximum (ridge) or a local minimum (valley) in a constrained space. Unlike isosurfaces, they are able to capture extremal structures in the data. Creases have a long t...
 
Visualizing Transport Structures of Time-Dependent Flow Fields
Found in: IEEE Computer Graphics and Applications
By Kuangyu Shi, Holger Theisel, Tino Weinkauf, Hans-Christian Hege, Hans-Peter Seidel
Issue Date:September 2008
pp. 24-36
This article focuses on the transport characteristics of physical properties in fluids—in particular, visualizing the finite-time transport structure of property advection. Applied to a well-chosen set of property fields, the proposed approach yields struc...
 
Explicit Control of Vector Field Based Shape Deformations
Found in: Computer Graphics and Applications, Pacific Conference on
By Wolfram von Funck, Holger Theisel, Hans-Peter Seidel
Issue Date:November 2007
pp. 291-300
Vector Field Based Shape Deformations (VFSD) have been introduced as an efficient method to deform shapes in a volume-preserving foldover-free manner. However, mainly simple implicitly defined shapes like spheres or cylinders have been explored as deformat...
 
Extracting Higher Order Critical Points and Topological Simplification of 3D Vector Fields
Found in: Visualization Conference, IEEE
By Tino Weinkauf, Holger Theisel, Kuangyu Shi, Hans-Christian Hege, Hans-Peter Seidel
Issue Date:October 2005
pp. 71
This paper presents an approach to extracting and classifying higher order critical points of 3D vector fields. To do so, we place a closed convex surface s around the area of interest. Then we show that the complete 3D classification of a critical point i...
 
Extraction of Parallel Vector Surfaces in 3D Time-Dependent Fields and Application to Vortex Core Line Tracking
Found in: Visualization Conference, IEEE
By Holger Theisel, Jan Sahner, Tino Weinkauf, Hans-Christian Hege, Hans-Peter Seidel
Issue Date:October 2005
pp. 80
We introduce an approach to tracking vortex core lines in timedependent 3D flow fields which are defined by the parallel vectors approach. They build surface structures in the 4D space-time domain. To extract them, we introduce two 4D vector fields which a...
 
Topological Methods for 2D Time-Dependent Vector Fields Based on Stream Lines and Path Lines
Found in: IEEE Transactions on Visualization and Computer Graphics
By Holger Theisel, Tino Weinkauf, Hans-Christian Hege, Hans-Peter Seidel
Issue Date:July 2005
pp. 383-394
This paper describes approaches to topologically segmenting 2D time-dependent vector fields. For this class of vector fields, two important classes of lines exist: stream lines and path lines. Because of this, two segmentations are possible: either concern...
 
Stream Line and Path Line Oriented Topology for 2D Time-Dependent Vector Fields
Found in: Visualization Conference, IEEE
By Holger Theisel, Tino Weinkauf, Hans-Christian Hege, Hans-Peter Seidel
Issue Date:October 2004
pp. 321-328
Topological methods aim at the segmentation of a vector field into areas of different flow behavior. For 2D time-dependent vector fields, two such segmentations are possible: either concerning the behavior of stream lines, or of path lines. While stream li...
 
Normal Based Estimation of the Curvature Tensor for Triangular Meshes
Found in: Computer Graphics and Applications, Pacific Conference on
By Holger Theisel, Christian Rössl, Rhaleb Zayer, Hans-Peter Seidel
Issue Date:October 2004
pp. 288-297
We introduce a new technique for estimating the curvature tensor of a triangular mesh. The input of the algorithm is only a single triangle equipped with its (exact or estimated) vertex normals. This way we get a smooth function of the curvature tensor ins...
 
M^3: Marker-Free Model Reconstruction and Motion Tracking from 3D Voxel Data
Found in: Computer Graphics and Applications, Pacific Conference on
By Edilson de Aguiar, Christian Theobalt, Marcus Magnor, Holger Theisel, Hans-Peter Seidel
Issue Date:October 2004
pp. 101-110
In computer animation, human motion capture from video is a widely used technique to acquire motion parameters. The acquisition process typically requires an intrusion into the scene in the form of optical markers which are used to estimate the parameters ...
 
Saddle Connectors - An Approach to Visualizing the Topological Skeleton of Complex 3D Vector Fields
Found in: Visualization Conference, IEEE
By Holger Theisel, Tino Weinkauf, Hans-Christian Hege, Hans-Peter Seidel
Issue Date:October 2003
pp. 30
One of the reasons that topological methods have a limited popularity for the visualization of complex 3D flow fields is the fact that such topological structures contain a number of separating stream surfaces. Since these stream surfaces tend to hide each...
 
Combining Topological Simplification and Topology Preserving Compression for 2D Vector Fields
Found in: Computer Graphics and Applications, Pacific Conference on
By Holger Theisel, Christian Rössl, Hans-Peter Seidel
Issue Date:October 2003
pp. 419
Topological simplification techniques and topology preserving compression approaches for 2D vector fields have been developed quite independently of each other. In this paper we propose a combination of both approaches: a vector field should be compressed ...
 
The Curvature of Characteristic Curves on Surfaces
Found in: IEEE Computer Graphics and Applications
By Holger Theisel, Gerald Farin
Issue Date:November 1997
pp. 88-96
This article shows how to compute the curvature and geodesic curvature of characteristic curves on surfaces, such as contour lines, lines of curvature, asymptotic lines, isophotes, and reflection lines. For particular surface curves the authors introduce t...
 
Vortex Cores of Inertial Particles
Found in: IEEE Transactions on Visualization and Computer Graphics
By Tobias Guenther,Holger Theisel
Issue Date:February 2015
pp. 1
The cores of massless, swirling particle motion are an indicator for vortex-like behavior in vector fields and to this end, a number of coreline extractors have been proposed in the literature. Though, many practical applications go beyond the study of the...
 
Semi-Automatic Vortex Extraction in 4D PC-MRI Cardiac Blood Flow Data using Line Predicates
Found in: IEEE Transactions on Visualization and Computer Graphics
By Benjamin Kohler,Rocco Gasteiger,Uta Preim,Holger Theisel,Matthias Gutberlet,Bernhard Preim
Issue Date:December 2013
pp. 2773-2782
Cardiovascular diseases (CVD) are the leading cause of death worldwide. Their initiation and evolution depends strongly on the blood flow characteristics. In recent years, advances in 4D PC-MRI acquisition enable reliable and time-resolved 3D flow measurin...
 
Orthographic Star Coordinates
Found in: IEEE Transactions on Visualization and Computer Graphics
By Dirk J. Lehmann,Holger Theisel
Issue Date:December 2013
pp. 2615-2624
Star coordinates is a popular projection technique from an nD data space to a 2D/3D visualization domain. It is defined by setting n coordinate axes in the visualization domain. Since it generally defines an affine projection, strong distortions can occur:...
 
Opacity optimization for 3D line fields
Found in: ACM Transactions on Graphics (TOG)
By Christian Rössl, Holger Theisel, Tobias Günther
Issue Date:July 2013
pp. 1-8
For the visualization of dense line fields, the careful selection of lines to be rendered is a vital aspect. In this paper, we present a global line selection approach that is based on an optimization process. Starting with an initial set of lines that cov...
     
Vector field based shape deformations: Copyright restrictions prevent ACM from providing the full text for this work.
Found in: ACM SIGGRAPH 2006 Papers (SIGGRAPH '06)
By Hans-Peter Seidel, Holger Theisel, Wolfram von Funck
Issue Date:July 2006
pp. 73-es
We present an approach to define shape deformations by constructing and interactively modifying C1 continuous time-dependent divergence-free vector fields. The deformation is obtained by a path line integration of the mesh vertices. This way, the deformati...
     
Vector field based shape deformations: Copyright restrictions prevent ACM from providing the full text for this work.
Found in: Material presented at the ACM SIGGRAPH 2006 conference (SIGGRAPH '06)
By Hans-Peter Seidel, Holger Theisel, Wolfram von Funck
Issue Date:July 2006
pp. 73-es
We present an approach to define shape deformations by constructing and interactively modifying C1 continuous time-dependent divergence-free vector fields. The deformation is obtained by a path line integration of the mesh vertices. This way, the deformati...
     
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