@incollection{groeller-2005-dia, title = "Diagnostic Relevant Visualization of Vascular Structures ", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller", year = "2005", abstract = "Traditional volume visualization techniques sometimes provide incomplete clinical information needed for applications in medical visualization. In the area of vascular visualization important features such as the lumen of a diseased vessel segment may not be visible. One way to display vascular structures for diagnostic purposes is to generate longitudinal cross-sections in order to show their lumen, wall, and surrounding tissue in a curved plane. Curved planar reformation (CPR) has proven to be an acceptable practical solution. We discuss four different methods to generate CPR images from single vessel segments: Projected CPR, stretched CPR, straightened CPR, and helical CPR. Furthermore we investigate three different methods for displaying vascular trees: Multi-path projected CPR, multi-path stretched CPR, and untangled CPR. The principle concept of each method is discussed and detailed information for the realization is given. In addition the properties, advantages and disadvantages of each method are summarized.", booktitle = "Scientific Visualization: The Visual Extraction of Knowledge from Data", editor = "G.-P. Bonneau, T. Ertl, G.M. Nielson", isbn = "3540260668", publisher = "Springer Verlag, Berlin", URL = "https://www.cg.tuwien.ac.at/research/publications/2005/groeller-2005-dia/", } @techreport{Kanitsar-2004-Dia, title = "Diagnostic Relevant Visualization of Vascular Structures", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller", year = "2004", abstract = "Traditional volume visualization techniques sometimes provide incomplete clinical information needed for applications in medical visualization. In the area of vascular visualization important features such as the lumen of a diseased vessel segment may not be visible. One way to display vascular structures for diagnostic purposes is to generate longitudinal cross-sections in order to show their lumen, wall, and surrounding tissue in a curved plane. Curved planar reformation (CPR) has proven to be an acceptable practical solution. We discuss four different methods to generate CPR images from single vessel segments: Projected CPR, stretched CPR, straightened CPR, and helical CPR. Furthermore we investigate three different methods for displaying vascular trees: Multi-path projected CPR, multi-path stretched CPR, and untangled CPR. The principle concept of each method is discussed and detailed information for the realization is given. In addition the properties, advantages and disadvantages of each method are summarized.", month = jan, number = "TR-186-2-04-02", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "curved planar reformation, computed tomography angiography, vessel analysis", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/Kanitsar-2004-Dia/", } @techreport{Kanitsar-2003-ADV, title = "Advanced Curved Planar Reformation: Flattening of Vascular Structures", author = "Armin Kanitsar and Rainer Wegenkittl and Dominik Fleischmann and Eduard Gr\"{o}ller", year = "2003", abstract = "Traditional volume visualization techniques may provide incomplete clinical information needed for many applications in medical visualization. Especially in the area of vascular visualization important features such as the patent lumen of a diseased vessel segment may not be visible. Curved Planar Reformation (CPR) has proven to be an acceptable practical solution. Existing CPR techniques, however, still have diagnostically relevant limitations. In this paper we introduce two advanced methods for efficient vessel visualization, based on the concept of CPR. Both methods benefit from relaxation of spatial coherence in favor of improved feature perception. We present a new technique to visualize the interior of a vessel in a single image. A vessel is re-sampled along a spiral around the vessel central axis. The helical spiral depicts the vessel volume. Furthermore, a method to display an entire vascular tree without mutually occluding vessels is presented. Minimal rotations around the branching points of a vessel tree eliminate occlusions. For each viewing direction the entire vessel structure is visible.", month = may, number = "TR-186-2-03-08", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "curved planar reformation, vessel analysis, computed tomography angiography", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Kanitsar-2003-ADV/", } @inproceedings{Kanitsar-2003-CTa, title = "CT angiography: Multi-path curved planar reformation of the peripheral arterial tree", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Petr Felkel and Eduard Gr\"{o}ller", year = "2003", publisher = "ECR", booktitle = "European Congress of Radiology", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Kanitsar-2003-CTa/", } @inproceedings{Bartroli-2003-Non, title = "Nonlinear Virtual Colon Unfolding", author = "Anna Vilanova i Bartroli and Rainer Wegenkittl and Eduard Gr\"{o}ller and E. Sorantin", year = "2003", publisher = "ECR", booktitle = "European Congress of Radiology", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Bartroli-2003-Non/", } @inproceedings{Kanitsar-2003-Adva, title = "Advanced Curved Planar Reformation: Flattering of Vascular Structures", author = "Armin Kanitsar and Rainer Wegenkittl and Dominik Fleischmann and Eduard Gr\"{o}ller", year = "2003", isbn = "0780381203", publisher = "IEEE", editor = "G. Turk, J. van Wijk, K. Moorhead", booktitle = "Proceedings of IEEE Visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2003/Kanitsar-2003-Adva/", } @techreport{kanitsar-2002-Chr, title = "Christmas Tree Case Study: Computed Tomography as a Tool for Mastering Complex Real World Objects with Applications in Computer Graphics", author = "Armin Kanitsar and Thomas Theu{\ss}l and Lukas Mroz and Milo\v{s} \v{S}r\'{a}mek and Anna Vilanova i Bartroli and Bal\'{a}zs Cs\'{e}bfalvi and Ji\v{r}\'{i} Hlad\r{u}vka and Stefan Guthe and Michael Knapp and Rainer Wegenkittl and Petr Felkel and Dominik Fleischmann and Werner Purgathofer and Eduard Gr\"{o}ller", year = "2002", abstract = "We report on using computed tomography (CT) as a model acquisition tool for complex objects in computer graphics. Unlike other modeling and scanning techniques the complexity of the object is irrelevant in CT, which naturally enables to model objects with, for example, concavities, holes, twists or fine surface details. Once the data is scanned, one can apply post-processing techniques aimed at its further enhancement, modification or presentation. For demonstration purposes we chose to scan a Christmas tree which exhibits high complexity which is difficult or even impossible to handle with other techniques. However, care has to be taken to achieve good scanning results with CT. Further, we illustrate the post-processing by means of data segmentation and photorealistic as well as non-photorealistic surface and volume rendering techniques.", month = mar, number = "TR-186-2-02-07", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "volume visualization, computed tomography, modeling", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/kanitsar-2002-Chr/", } @techreport{kanitsar-2002-CPRX, title = "CPR - Curved Planar Reformation", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Petr Felkel and Eduard Gr\"{o}ller", year = "2002", abstract = "Visualization of tubular structures such as blood vessels is an important topic in medical imaging. One way to display tubular structures for diagnostic purposes is to generate longitudinal cross-sections in order to show their lumen, wall, and surrounding tissue in a curved plane. This process is called Curved Planar Reformation (CPR). We present three different methods to generate CPR images. A tube-phantom was scanned with Computed Tomography (CT) to illustrate the properties of the different CPR methods. Furthermore we introduce enhancements to these methods: thick-CPR, rotating-CPR and multi-path-CPR.", month = mar, number = "TR-186-2-02-06", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "curved planar reformation, vessel analysis, computed tomography angiography", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/kanitsar-2002-CPRX/", } @article{Bartroli-2002-Pro, title = "Projected Slabs: Approximation of Perspective projection and Error Analysis", author = "Anna Vilanova i Bartroli and Rainer Wegenkittl and Eduard Gr\"{o}ller", year = "2002", journal = "Journal of Visualization and Computer Animation", number = "5", volume = "12", pages = "253--262", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Bartroli-2002-Pro/", } @inproceedings{Kanitsar-2002-CPR, title = "CPR- Curved Planar Reformation", author = "Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Petr Felkel and Eduard Gr\"{o}ller", year = "2002", publisher = "IEEE Computer Society Press", booktitle = "IEEE Visualization 2002", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Kanitsar-2002-CPR/", } @article{Wagner-2002-End, title = "Endo View: A Phantom Study of a Tracked Virtual Bronchoscopy", author = "Daniel Wagner and Rainer Wegenkittl and Eduard Gr\"{o}ller", year = "2002", journal = "Journal of WSCG", volume = "10", number = "2", pages = "493--498", URL = "https://www.cg.tuwien.ac.at/research/publications/2002/Wagner-2002-End/", } @techreport{Vilanova-2001-VCU, title = "Virtual Colon Unfolding", author = "Anna Vilanova i Bartroli and Rainer Wegenkittl and Andreas K\"{o}nig and Eduard Gr\"{o}ller", year = "2001", abstract = "The majority of virtual endoscopy techniques tries to simulate a real endoscopy. A real endoscopy does not always give the optimal information due to the physical limitations it is subject to. In this paper, we deal with the unfolding of the surface of the colon as a possible visualization technique for diagnosis and polyp detection. A new two-step technique is presented which deals with the problems of double appearance of polyps and nonuniform sampling that other colon unfolding techniques suffer from. In the first step, a distance map from a central path induces nonlinear rays for unambiguous parameterization of the surface. The second step compensates for locally varying distortions of the unfolded surface. A technique similar to magnification fields in information visualization is hereby applied. The technique produces a single view of a complete virtually dissected colon.", month = apr, number = "TR-186-2-01-08", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "Virtual Endoscopy, Volume Rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Vilanova-2001-VCU/", } @techreport{Kanitsar-2001-PVI, title = "Peripheral Vessel Investigation For Routine Clinical Use", author = "Armin Kanitsar and Rainer Wegenkittl and Petr Felkel and Dominik Fleischmann and Dominique Sandner and Eduard Gr\"{o}ller", year = "2001", abstract = "This paper is about computed tomography angiography based vessel exploration. Large image sequences of the lower extremities are investigated in a clinical environment. Two different approaches for peripheral vessel diagnosis dealing with stenosis and calcification detection are introduced. The paper presents an automated vessel-tracking tool for curved planar reformation. A user interactive segmentation tool for bone removal is proposed.", month = mar, number = "TR-186-2-01-13", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "optimal path computation, semi automated segmentation, CTA", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Kanitsar-2001-PVI/", } @misc{Capek-2001-Mul, title = "Multimodal Volume Registration Based on Spherical Markers", author = "M. Capek and W. Jaschke and R. Sweeney and R. Bale and Rainer Wegenkittl and Andreas K\"{o}nig", year = "2001", note = "In conference proceedings of the 9th International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision 2001, WSCG'2001, University of West Bohemia, Pilsen, Czech Republic, Vaclav Skala (ed.), February 2001, vol. 1, p. 17-24, ISBN 80-7082-711-2", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Capek-2001-Mul/", } @misc{Kanitsar-2001-Per, title = "Peripheral Vessel Investigation for Routine Clinical Use", author = "D. Sandner and Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller and Petr Felkel", year = "2001", note = "Proceedings of IEEE Visualization 2001, October 2001, San Diego, USA, pp. 91-98
 ", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Kanitsar-2001-Per/", } @misc{Vilanova-2001-Non, title = "Nonlinear Virtual Colon Unfolding", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller and Andreas K\"{o}nig and Anna Vilanova i Bartroli", year = "2001", note = "Proceedings of IEEE Visualization 2001, October 2001, San Diego, USA, pp. 91-98", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Vilanova-2001-Non/", } @misc{Kanitsar-2001-Aut, title = "Automated Vessel Detection at Lower Extremity Multislice CTA", author = "D. Sandner and Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller and Petr Felkel", year = "2001", note = "European Congress of Radiology 2001 (ECR 2001), March 2-6 2001, Vienna", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Kanitsar-2001-Aut/", } @misc{Kanitsar-2001-Pos, title = "Postprocessing and Visualization of Peripheral CTA Data in Clinical Environments", author = "D. Sandner and Armin Kanitsar and Dominik Fleischmann and Rainer Wegenkittl and Eduard Gr\"{o}ller and Petr Felkel", year = "2001", note = "Central European Seminar on Computer Graphics (CESCG'2001), Budmerice, Slovakia, April 23-25, 2001", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Kanitsar-2001-Pos/", } @misc{Vilanova-2001-Per, title = "Perspective Projection through Parallel Projected Slabs for Virtual Endoscopy", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller and Andreas K\"{o}nig and Anna Vilanova i Bartroli", year = "2001", note = "Proceedings of the 17th Spring Conference on Computer Graphics (SCCG'01), Budmerice, Slovakia, IEEE, April 25th-28th, 2001, pp. 287-295, ISBN 0-7695-1215-1", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Vilanova-2001-Per/", } @misc{Vilanova-2001-Vir, title = "Virtual Colon Flattening", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller and Andreas K\"{o}nig and E. Sorantin and Anna Vilanova i Bartroli", year = "2001", note = "Proceedings of VisSym'01, Joint Eurographics - IEEE TCVG Symposium on Visualization, May 28 - May 30, pages 127-136 2001, Ascona, Switzerland", URL = "https://www.cg.tuwien.ac.at/research/publications/2001/Vilanova-2001-Vir/", } @techreport{Vilanova-2000-VCF, title = "Virtual Colon Flattening", author = "Anna Vilanova i Bartroli and Rainer Wegenkittl and Andreas K\"{o}nig and Eduard Gr\"{o}ller and E. Sorantin", year = "2000", abstract = "We present a new method to visualize virtual endoscopic views. We propose to flatten the organ by the direct projection of the surface onto a set of cylinders. Two sampling strategies are presented and the introduced distortions are studied. A non-photorealistic technique is presented to enhance the perception of the images. Finally, an approximate but real-time endoscopic fly-through is possible by using the data obtained by the projection technique.", month = dec, number = "TR-186-2-00-25", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "Colon Flattening, Volume Rendering, Virtual Colonoscopy", URL = "https://www.cg.tuwien.ac.at/research/publications/2000/Vilanova-2000-VCF/", } @techreport{Mroz-2000-MasX, title = "Mastering Interactive Surface Rendering for Java-Based Diagnostic Applications", author = "Lukas Mroz and Rainer Wegenkittl and Eduard Gr\"{o}ller", year = "2000", abstract = "The display of iso-surfaces in medical data sets is an important visualization technique used by radiologists for the diagnosis of volumetric density data sets. The demands put by radiologists on such a display technique are interactivity, multiple stacked transparent surfaces and cutting planes that allow an interactive clipping of the surfaces. This paper presents a Java based, platform independent implementation of a very fast surface rendering algorithm which combines the advantages of explicit surface representation, splatting, and shear-warp projection to fulfill all these requirements. The algorithm is implemented within the context of J-Vision, an application for viewing and diagnosing medical images which is currently in use at various hospitals. ", month = apr, number = "TR-186-2-00-10", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "medical applications, surface rendering, volume visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2000/Mroz-2000-MasX/", } @techreport{Wegenkitt-2000-MIV, title = "Mastering Interactive Virtual Bronchioscopy on a Low--End PC", author = "Rainer Wegenkittl and Anna Vilanova i Bartroli and Balint Heged\"{u}s and Daniel Wagner and Martin C. Freund and Eduard Gr\"{o}ller", year = "2000", abstract = "Virtual endoscopy presents the cross-sectional acquired 3D-data of a computer tomograph as an endoluminal view. The common approach for the visualization of a virtual endoscopy is surface rendering, yielding images close to a real endoscopy. If external structures are of interest, volume rendering techniques have to be used. These methods do not display the exact shape of the inner lumen very well. For certain applications, e.g. operation planning of a trans-bronchial biopsy, both, the shape of the inner lumen as well as outer structures like blood vessels and the tumor have to be delineated. In this paper a method is described, that allows a quick and easy hybrid visualization using overlays of different visualization methods like different surfaces or volume renderings with different transfer functions in real time on a low-end PC. To achieve real time frame rates, image based rendering techniques have been used.", month = mar, number = "TR-186-2-00-13", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "visualization system, virtual endoscopy, medical visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2000/Wegenkitt-2000-MIV/", } @misc{Groeller-2000-Vis, title = "Visualization of Analytically Defined Dynamical Systems", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller and Helwig L\"{o}ffelmann", year = "2000", note = "In H. Hagen, G.M. Nielson, F. Post (eds.), Proceedings Dagstuhl'97, Scientific Visualization, IEEE Computer Society, 2000, pp. 71-82", URL = "https://www.cg.tuwien.ac.at/research/publications/2000/Groeller-2000-Vis/", } @misc{Mroz-2000-Mas, title = "Mastering Interactive Surface Rendering for Java-Based Diagnostic Applications", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller and Lukas Mroz", year = "2000", note = "IEEE Visualization 2000 Proceedings, 2000, pp. 437-440", URL = "https://www.cg.tuwien.ac.at/research/publications/2000/Mroz-2000-Mas/", } @misc{Wegenkittl-2000-Mas, title = "Mastering Interactive Virtual Bronchioscopy on a Low-End PC", author = "Freund M.C. and Rainer Wegenkittl and Eduard Gr\"{o}ller and Balint Heged\"{u}s and Daniel Wagner and Anna Vilanova i Bartroli", year = "2000", note = "IEEE Visualization 2000 Proceedings, 2000, pp. 461-464", URL = "https://www.cg.tuwien.ac.at/research/publications/2000/Wegenkittl-2000-Mas/", } @misc{Groeller-1999-Vis, title = "Visualization of Dynamical Systems.", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller and Helwig L\"{o}ffelmann", year = "1999", note = "F.Post, D. Silver (eds.) Journal Future Generation Computer Systems, Elsevier, Vol. 15(1), February 1999, pp.75-86.", URL = "https://www.cg.tuwien.ac.at/research/publications/1999/Groeller-1999-Vis/", } @techreport{Groeller-1998-VAD, title = "Visualization of Analytically Defined Dynamical Systems", author = "Eduard Gr\"{o}ller and Helwig L\"{o}ffelmann and Rainer Wegenkittl", year = "1998", abstract = "The visualization of analytically defined dynamical systems is important for a thorough understanding of the underlying system behavior. An overview of theoretical concepts concerning analytically defined dynamical systems is given. Various visualization techniques for dynamical systems are discussed. Three current research directions concerning the visualization of dynamical systems are treated in more detail. These are: texture based techniques, visualization of high-dimensional dynamical systems, and advanced streamsurface representations. ", month = feb, number = "TR-186-2-98-06", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "visualization, dynamical systems", URL = "https://www.cg.tuwien.ac.at/research/publications/1998/Groeller-1998-VAD/", } @techreport{Groeller-1998-TunVis, title = "TunVis: Visualizing specific geologic features for tunnel planning and construction", author = "Horst Otto Meinhart and Rainer Wegenkittl and Eduard Gr\"{o}ller", year = "1998", abstract = "This paper describes a method and a system for visualizing a virtual tunnel through an existing geologic formation and a method for the generation of a camera animation along the tunnel axis. The tunnel is built from geologic data coming from vertical sample drills from the mountain top along the selected tunnel axis. Its wire frame model is then edited by a geologist and image information of the rock appearance is textured onto the tunnel wall, resulting in a photorealistic representation of the expected geologic rock formations. Finally a camera animation and video options are defined to render a video sequence of the camera movement.", month = feb, number = "TR-186-2-98-08", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "visualization, geologic features, tunnel planning", URL = "https://www.cg.tuwien.ac.at/research/publications/1998/Groeller-1998-TunVis/", } @techreport{Groeller-1998-VDS, title = "Visualization of Dynamical Systems", author = "Eduard Gr\"{o}ller and Helwig L\"{o}ffelmann and Rainer Wegenkittl", year = "1998", abstract = "The visualization of analytically defined dynamical systems is important for a thorough understanding of the underlying system behavior. An introduction to analytically defined dynamical systems is given. Various visualization techniques for dynamical systems are discussed. Several current research directions concerning the visualization of dynamical systems are treated in more detail. These are: texture based techniques, visualization of high-dimensional dynamical systems, advanced streamsurface representations, local analysis - Poincare' sections, visualizing econometric models.", month = feb, number = "TR-186-2-98-07", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "visualization, dynamical systems", URL = "https://www.cg.tuwien.ac.at/research/publications/1998/Groeller-1998-VDS/", } @techreport{Wegenkittl-97-FOL, title = "Fast Oriented Line Integral Convolution for Vector Field Visualization via the Internet", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller", year = "1997", abstract = "Oriented Line Integral Convolution (OLIC) illustrates flow fields by convolving a sparse texture with an anisotropic convolution kernel. The kernel is aligned to the underlying flow of the vector field. OLIC does not only show the direction of the flow but also its orientation. This paper presents Fast Rendering of Oriented Line Integral Convolution (FROLIC), which is approximately two orders of magnitude faster than OLIC. Costly convolution operations as done in OLIC are replaced in FROLIC by approximating a streamlet through a set of disks with varying intensity. The issue of overlapping streamlets is discussed. Two efficient animation techniques for animating FROLIC images are described. FROLIC has been implemented as a Java applet. This allows researchers from various disciplines (typically with inhomogenous hardware environments) to conveniently explore and investigate analytically defined 2D vector fields.", month = mar, number = "TR-186-2-97-07", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "vector field visualization, Line Integral Convolution", URL = "https://www.cg.tuwien.ac.at/research/publications/1997/Wegenkittl-97-FOL/", } @techreport{Wegenkittl-97-VBH, title = "Visualizing the Behavior of Higher Dimensional Dynamical Systems", author = "Rainer Wegenkittl and Helwig L\"{o}ffelmann and Eduard Gr\"{o}ller", year = "1997", abstract = "In recent years scientific visualization has been driven by the need to visualize high-dimensional data sets within high-dimensional spaces. However most visualization methods are designed for showing some statistical features of the data set. This paper deals with the visualization of trajectories of high-dimensional dynamical systems which form a L^n_n data set of a smooth n-dimensional flow. Three methods that are based on the idea of parallel coordinates are presented and discussed. Visualizations done with these new methods are shown and an interactive visualization tool for the exploration of high-dimensional dynamical systems is proposed.", month = mar, number = "TR-186-2-97-08", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "dynamical system, multi-dimension visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/1997/Wegenkittl-97-VBH/", } @phdthesis{Wegenkittl-thesis, title = "Visualization of Complex Dynamical Systems", author = "Rainer Wegenkittl", year = "1997", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/1997/Wegenkittl-thesis/", } @techreport{Wegenkittl-1996-AFR, title = "Animating Flowfields: Rendering of Oriented Line Integral Convolution", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller and Werner Purgathofer", year = "1996", abstract = "Line Integral Convolution (LIC) is a common approach for the visualization of vector fields. It is well suited for visualizing the direction of a flow field, but it gives no information about the orientation of the underlying vectors. We introduce Oriented Line Integral Convolution (OLIC), where direction as well as orientation are encoded within the resulting image. This is achieved by using a low frequency input texture and a ramp like (unisotropic) convolution kernel. This method can be animated, whereby the computation of so called pixel traces fastens the calculation process. In the result section various OLICs using simple and real-world vector fields are shown.", month = dec, number = "TR-186-2-96-23", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "flowfield visualization, line integral convolution", URL = "https://www.cg.tuwien.ac.at/research/publications/1996/Wegenkittl-1996-AFR/", } @techreport{Wegenkittl-1996-SDI, title = "Simulation of Differential Interferometry and Comparison with Experimental Results", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller and Andreas Goldsteiner", year = "1996", abstract = "This paper presents the computational simulation of a differential interferometer in a Mach-Zehnder arrangement with objects located outside the center of the interferometer. The computer simulation corresponds very well to an experimental setup. This is illustrated for several basic phase objects. The theoretical models of these objects are discussed. The concept of an interactive visualization system for the analysis of phase objects is presented and finallysome results allowing a comparison between experimental and simulated interferograms are shown.", month = nov, number = "TR-186-2-96-22", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "interferometry, simulation", URL = "https://www.cg.tuwien.ac.at/research/publications/1996/Wegenkittl-1996-SDI/", } @techreport{loeffelmann-1996-CVA, title = "Classifying the Visualization of Analytically Specified Dynamical Systems", author = "Helwig L\"{o}ffelmann and Eduard Gr\"{o}ller and Rainer Wegenkittl and Werner Purgathofer", year = "1996", abstract = "In this paper we suggest a classification of visualization techniques for analytically specified dynamical systems into four different approaches. We distinguish between local properties, the topology of behavior, global properties, and classes of dynamical systems with respect to various topics of visualization. By presenting advanced visualization techniques that we applied during three recent projects, we discuss their embedding within the classification scheme The dynamical systems visualized are the ``Dynastic Cycle'', which is a model for rise and fall of dynasties in ancient China, the ``Wonderland'' model, that simulates the interactions of population growth, economic activities, and environmental pollution, and a model for mixed-mode oscillations, which occurs in chemistry. ", month = apr, number = "TR-186-2-96-15", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "visualization, dynamical systems", URL = "https://www.cg.tuwien.ac.at/research/publications/1996/loeffelmann-1996-CVA/", } @techreport{wegenkittl-1996-GTW, title = "A Guided Tour to Wonderland: Visualizing the Slow-Fast Dynamics of an Analytical Dynamical System", author = "Rainer Wegenkittl and Eduard Gr\"{o}ller and Werner Purgathofer", year = "1996", abstract = "The analysis of complex dynamical systems produces large amounts of data that have to be interpreted efficiently. Visualizing the phase space of such systems illustrates geometrically the behavior of the underlying dynamics. This work investigates the visualization of Wonderland, a four dimensional econometric model, which describes interactions between population growth, economic activity and environmental implications. Wonderland belongs to a class of interesting dynamical systems with a pronounced slow-fast dynamics, i.e., some variables are changing much faster than others. Furthermore the behavior of the Wonderland model is characterized by manifolds which are not streamsurfaces, i.e., the flow does not stay within these surfaces. This paper discusses the application and adaptation of various visualization techniques to analytical dynamical systems with special properties as mentioned above.", month = apr, number = "TR-186-2-96-11", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "vector field visualization, complex dynamical systems", URL = "https://www.cg.tuwien.ac.at/research/publications/1996/wegenkittl-1996-GTW/", } @techreport{Groeller-1995-GOW, title = "The Geometry of Wonderland", author = "Eduard Gr\"{o}ller and Rainer Wegenkittl and Alexandra Milik and Alexia Prskawetz and Gustav Feichtinger and Warren C. Sanderson", year = "1995", abstract = "We analyze Wonderland - a model of demographic,economic and environmental interactions - by combining numerical simulations with basic ideas of geometric singular perturbation theory. This theory dealing with slow-fast dynamical systems helps us to gain new insights into the system's behaviour. We give conditions for the occurrence of rapid environmental changes in Wonderland. Since the chosen approach is inherently geometric we also focus on the visualization of our results.", month = dec, number = "TR-186-2-95-17", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "dynamical system, visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/1995/Groeller-1995-GOW/", } @techreport{Groeller-1994-IDN, title = "Interactive Design of Nonlinear Functions for Iterated Function Systems", author = "Eduard Gr\"{o}ller and Rainer Wegenkittl", year = "1994", abstract = "The basic requirement for the functions of an Iterated Function System (IFS for short) is contractivity. Nevertheless the majority of recent scientific investigations is concentrating on IFSs defined through a set of contractive linear functions. Simpler handling of this kind of functions and a more predictable result is the main reason for this approach. In this work we use distorted grids (representing nonlinear functions) to specify an IFS with a higher degree of flexibility and a higher modelling capability. A program for modeling these grids with so-called high-level operations is presented. Attention is directed to the interactivity of designing the IFS and rendering its limit set. Therefore a z-Buffer for displaying the result of a stochastic algorithm is included. Example images designed with the implemented software system are presented.", month = aug, number = "TR-186-2-94-3", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", keywords = "iterated function system (IFS), nonlinear, interactive design, fractals, rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/1994/Groeller-1994-IDN/", }