Conference stringclasses 6 values | Year int64 1.99k 2.03k | Title stringlengths 8 187 | DOI stringlengths 16 32 | Abstract stringlengths 128 7.15k ⌀ | Accessible bool 2 classes | Early bool 2 classes | AuthorNames-Deduped listlengths 1 24 | Award listlengths 0 2 | Resources listlengths 0 5 | ResourceLinks listlengths 0 10 |
|---|---|---|---|---|---|---|---|---|---|---|
EuroVis | 2,006 | A Granular Three Dimensional Multiresolution Transform | 10.2312/VisSym/EuroVis06/267-274 | We propose a three dimensional multi-resolution scheme to represent volumetric data in resolutions which are powers of two, resolving the rigidity of the commonly used separable Cartesian multi-resolution schemes in 3D that only allow for change of resolution by a power of eight. Through in-depth comparisons with the counterpart resampling solutions on the Cartesian lattice, we demonstrate the superiority of our subsampling scheme. We derive and document the Fourier domain analysis of this representation. Using such an analysis one can obtain ideal and discrete multidimensional filters for this multi-resolution scheme. | false | false | [
"Alireza Entezari",
"Tai Meng",
"Steven Bergner",
"Torsten Möller"
] | [] | [] | [] |
EuroVis | 2,006 | A Spectral Visualization System for Analyzing Financial Time Series Data | 10.2312/VisSym/EuroVis06/195-202 | Visual data analysis of time related data sets has attracted much research interest recently, and a number of sophisticated visualization methods have been proposed in the past. In financial analysis, however, the most important and most common visualization techniques for time series data is the traditional line- or bar chart. Although these are intuitive and make it easy to spot the effect of key events on a asset's price, and its return over a given period of time, price charts do not allow the easy perception of relative movements in terms of growth rates, which is the key feature of any price-related time series.
This paper presents a novel Growth Matrix visualization technique for analyzing assets. It extends the ability of existing chart techniques by not only visualizing asset return rates over fixed time frames, but over the full spectrum of all subintervals present in a given time frame, in a single view. At the same time, the technique allows a comparison of subinterval return rates among groups of even a few hundreds of assets. This provides a powerful way for analyzing financial data, since it allows the identification of strong and weak periods of assets as compared to global market characteristics, and thus allows a more encompassing visual classification into "good" and "poor" performers than existing chart techniques. We illustrate the technique by real-world examples showing the abilities of the new approach, and its high relevance for financial analysis tasks. | false | false | [
"Daniel A. Keim",
"Tilo Nietzschmann",
"Norman Schelwies",
"Jörn Schneidewind",
"Tobias Schreck",
"Hartmut Ziegler"
] | [] | [] | [] |
EuroVis | 2,006 | Affiliation Dynamics with an Application to Movie-Actor Biographies | 10.2312/VisSym/EuroVis06/179-186 | We propose a visualization approach for dynamic affiliation networks in which events are characterized by a set of descriptors. It uses a radial ripple metaphor to display the passing of time and conveys relations among the different constituents through appropriate layout. Our method is particularly suitable when assuming an egocentric perspective, and we illustrate it on movie-actor biographies. | false | false | [
"Ulrik Brandes",
"Martin Hoefer 0001",
"Christian Pich 0001"
] | [] | [] | [] |
EuroVis | 2,006 | An Interactive Visualization System for Quantifying Coral Structures | 10.2312/VisSym/EuroVis06/283-290 | Determining the shape of coral structures is an essential step for coral biologists to classify and compare corals. Currently, coral biologists analyze shape by performing manual measurements on photographs of coral colonies. In this paper we describe an interactive visualization system for measuring coral shapes in a robust and quantitative way. The input of the system is a CT scan of the coral, and the output consists of statistical distributions of various morphological properties. The approach is to first extract a skeleton from the CT scan, and then to perform measurements on the skeleton graph. Interactive visualization is necessary, since various features of the coral prevent the system from being fully automatic. | false | false | [
"Krzysztof Jakub Kruszynski",
"Robert van Liere",
"Jaap A. Kaandorp"
] | [] | [] | [] |
EuroVis | 2,006 | Application-Oriented Extensions of Profile Flags | 10.2312/VisSym/EuroVis06/339-346 | A glaucoma treating composition and method of treating glaucoma by administering the glaucoma treating composition to a patient are provided. The glaucoma treating composition comprises a carbostyril derivative, or acid addition salt thereof, having an intraocular pressure reducing activity in combination with an ophthalmically acceptable carrier, the barbostyril derivative being represented by the formula: wherein R1 and R2 are each lower alkyl, and the carbon-to-carbon bond between the 3-position and the 4-position of the carbostyril skeleton is a single bond or double bond. | false | false | [
"Matej Mlejnek",
"Pierre Ermes",
"Anna Vilanova",
"Rob van der Rijt",
"Harrie van den Bosch",
"Frans A. Gerritsen",
"M. Eduard Gröller"
] | [] | [] | [] |
EuroVis | 2,006 | Automating Transfer Function Design for Volume Rendering Using Hierarchical Clustering of Material Boundaries | 10.2312/VisSym/EuroVis06/243-250 | Transfer function design plays a crucial role in direct volume rendering. Furthermore, it has a major influence on the efficiency of the visualization process. We have developed a framework that facilitates the semi-automatic design of transfer functions. Similarly to other approaches we generate clusters in the transfer function domain. We created a real-time interaction with a hierarchy of clusters. This interaction effectively substitutes cumbersome settings of clustering thresholds. Our framework is also able to easily combine different clustering criteria.
We have developed two similarity measures for clustering of material boundaries. One is based on the similarity of the boundaries in the transfer function domain and the other on their spatial relation. We use the LH space as the transfer function domain. This space facilitates the clustering of material boundaries. We demonstrate our approach on several examples. | false | false | [
"Petr Sereda",
"Anna Vilanova",
"Frans A. Gerritsen"
] | [] | [] | [] |
EuroVis | 2,006 | Combining Extended Table Lens and Treemap Techniques for Visualizing Tabular Data | 10.2312/VisSym/EuroVis06/051-058 | We present a framework for visualizing large tabular data that combines two views: the table view and the treemap view. The table view extends the known table lens as follows: We cluster related elements to reduce subsampling artifacts and achieve table size independent rendering time; we use multiple-column sorting to create scenariospecific data hierarchies on the fly; and we use shaded cushions to show data structure and variation. Hierarchies built in the table view are shown in a customizable treemap view. One can choose both layout and rendering by a few clicks, effectively creating visual scenarios on-the-fly. We illustrate our framework on real-life stock data. | false | false | [
"Alexandru C. Telea"
] | [] | [] | [] |
EuroVis | 2,006 | CVSgrab: Mining the History of Large Software Projects | 10.2312/VisSym/EuroVis06/187-194 | Many software projects use Software Configuration Management systems to support their development process. Such systems accumulate in time large amounts of information useful for process accounting and auditing. We study how software developers can get insight in this information in order to understand the project context and the product artifacts. To this end, we propose several new techniques for visual mining of project evolution. Central to our approach is a file-based evolution visualization, where each project is shown as a set of horizontal stripes depicting files along the time axis. We propose several mechanisms for interactively building layouts in this display, and for correlating the evolution with the results of various software metrics. We demonstrate the usefulness of our approach on real- life data sets. | false | false | [
"Lucian Voinea",
"Alexandru C. Telea"
] | [] | [] | [] |
EuroVis | 2,006 | D2VR: High-Quality Volume Rendering of Projection-based Volumetric Data | 10.2312/VisSym/EuroVis06/211-218 | Volume rendering techniques are conventionally classified as either direct or indirect methods. Indirect methods require to transform the initial volumetric model into an intermediate geometrical model in order to efficiently visualize it. In contrast, direct volume rendering (DVR) methods can directly process the volumetric data. Modern CT scanners usually provide data as a set of samples on a rectilinear grid, which is computed from the measured projections by discrete tomographic reconstruction. Therefore the rectilinear grid can already be considered as an intermediate volume representation. In this paper we introduce direct direct volume rendering (D2VR). D2VR does not require a rectilinear grid, since it is based on an immediate processing of the measured projections. Arbitrary samples for ray casting are reconstructed from the projections by using the Filtered Back-Projection algorithm. Our method removes a lossy resampling step from the classical volume rendering pipeline. It provides much higher accuracy than traditional grid-based resampling techniques do. Furthermore we also present a novel high-quality gradient estimation scheme, which is also based on the Filtered Back-Projection algorithm. | false | false | [
"Peter Rautek",
"Balázs Csébfalvi",
"Sören Grimm",
"Stefan Bruckner",
"M. Eduard Gröller"
] | [] | [] | [] |
EuroVis | 2,006 | Data Reconstruction and Visualization Techniques for Forensic Pathology | 10.2312/VisSym/EuroVis06/323-330 | Forensic pathology is largely concerned with the determination of the cause and manner of deaths after accidents, or other circumstances in criminal investigations. A major task in that process is the documentation of surface injuries, which is traditionally done by drawing sketches, photography, or more recently by photogrammetry to generate a three-dimensional digital lesion cartography of the body surface.
In this paper, we describe a semi-automatic processing pipeline how data from 3D photogrammetry is combined and used to generate a visual surface representation of accident victims. In that course, a number of steps are performed to provide a high-quality interactive, point-based visualization of the acquired data, which can be used in a more routine way than previous forensic surface methods. | false | false | [
"Alexander Ehlert",
"Zein Salah",
"Dirk Bartz"
] | [] | [] | [] |
EuroVis | 2,006 | Direct Isosurface Extraction from Scattered Volume Data | 10.2312/VisSym/EuroVis06/099-106 | Isosurface extraction is a standard visualization method for scalar volume data and has been subject to research for decades. Nevertheless, to our knowledge, no isosurface extraction method exists that directly extracts surfaces from scattered volume data without 3D mesh generation or reconstruction over a structured grid. We propose a method based on spatial domain partitioning using a kd-tree and an indexing scheme for efficient neighbor search. Our approach consists of a geometry extraction and a rendering step. The geometry extraction step computes points on the isosurface by linearly interpolating between neighboring pairs of samples. The neighbor information is retrieved by partitioning the 3D domain into cells using a kd-tree. The cells are merely described by their index and bitwise index operations allow for a fast determination of potential neighbors. We use an angle criterion to select appropriate neighbors from the small set of candidates. The output of the geometry step is a point cloud representation of the isosurface. The final rendering step uses point-based rendering techniques to visualize the point cloud.
Our direct isosurface extraction algorithm for scattered volume data produces results of quality close to the results from standard isosurface extraction algorithms for gridded volume data (like marching cubes). In comparison to 3D mesh generation algorithms (like Delaunay tetrahedrization), our algorithm is about one order of magnitude faster for the examples used in this paper. | false | false | [
"Paul Rosenthal",
"Lars Linsen"
] | [] | [] | [] |
EuroVis | 2,006 | Efficient Surface Reconstruction from Noisy Data using Regularized Membrane Potentials | 10.2312/VisSym/EuroVis06/083-090 | null | false | false | [
"Andrei C. Jalba",
"Jos B. T. M. Roerdink"
] | [] | [] | [] |
EuroVis | 2,006 | Enhanced Visualizations of Thermographic Data in Process Industry | 10.2312/VisSym/EuroVis06/307-314 | In this paper, we describe an improved method for visualization of thermographic data in the paper and pulp process industry. We present an application that allows process operators to freely choose how absolute temperatures and time varying changes of thermographic scans should be mapped to colors and/or 3D shapes. Of the possible combinations, we selected two different forms of 3D visualizations and an existing conventional 2D map visualization. We then evaluated these visualization forms with regard to their effectiveness in experimental field studies. The field tests were carried out to measure the operators' performance in early detection of insulation damages on lime kilns. The results we obtained from the study show that the two new forms of 3D visualization lead to a reduction of the detection times by about two-thirds and one-third, respectively, when compared to the conventional 2D map representation. Since lime kiln monitoring is based on the rather generic method of continuous thermographic imaging, we suggest that these results also hold for the control and surveillance of other processes. | false | false | [
"Stefan Seipel",
"Ann-Kristin Forsberg",
"Daniel Wesslén"
] | [] | [] | [] |
EuroVis | 2,006 | Enhancing Slice-based Visualizations of Medical Volume Data | 10.2312/VisSym/EuroVis06/123-130 | Slice-based visualizations of CT and MRI data are frequently used for diagnosis, intervention planning and intraoperative navigation since they allow a precise analysis and localization. We present new techniques to enhance the visualization of cross sectional medical image data. Our work is focussed on intervention planning and intraoperative navigation. We address the following problems of slice-based visualization in these areas: the lack of a graphical overview on the positions of anatomic structures, the localization of a target structure and the display of safety zones around pathologic structures. To improve the overview, we introduce LIFTCHARTs, attached as vertical bars to a slice-based visualization. For localizing target structures, we introduce halos. These techniques restrict the occlusion of the original data to a minimum and avoid any modification of the original data. To demonstrate the usability of these visualization techniques, we show two application scenarios in which the techniques come into operation. | false | false | [
"Christian Tietjen",
"Björn Meyer",
"Stefan Schlechtweg",
"Bernhard Preim",
"Ilka Hertel",
"Gero Strauß"
] | [] | [] | [] |
EuroVis | 2,006 | Evaluating the Effectiveness of Tree Visualization Systems for Knowledge Discovery | 10.2312/VisSym/EuroVis06/067-074 | User studies, evaluations, and comparisons of tree visualization systems have so far focused on questions that can readily be answered by simple, automated queries without needing visualization. Studies are lacking on the actual use of tree visualization in discovering intrinsic, hidden, non-trivial and potentially valuable knowledge. We have thus formulated a set of tree exploration tasks not previously considered and have performed user studies and analysis to determine how visualization helps users to perform these tasks. In our study, we evaluated three systems: RINGS (a node-link representation), Treemap (a containment representation), and Windows Explorer. Our findings suggest a few ways that tree visualization helps users to perceive different aspects of hierarchical structured information. We then explain how these visual representations are able to trigger human perception to make these discoveries. | false | false | [
"Yue Wang",
"Soon Tee Teoh",
"Kwan-Liu Ma"
] | [] | [] | [] |
EuroVis | 2,006 | Fast Ray Traversal of Tetrahedral and Hexahedral Meshes for Direct Volume Rendering | 10.2312/VisSym/EuroVis06/235-242 | The importance of high-performance rendering of unstructured or curvilinear data sets has increased significantly, mainly due to its use in scientific simulations such as computational fluid dynamics and finite element computations. However, the unstructured nature of these data sets lead to rather slow implementations for ray tracing. The approaches discussed in this paper are fast and scalable towards realtime ray tracing applications.
We evaluate new algorithms for rendering tetrahedral and hexahedral meshes. In each algorithm, the first cell along a ray is found using common realtime ray tracing techniques. For traversing subsequent cells within the volume, Plucker coordinates as well as ray-bilinear patch intersection tests are used. Since the volume is rendered directly, all algorithms are applicable for isosurface rendering, maximum-intensity projection, and emissionabsorption models. | false | false | [
"Gerd Marmitt",
"Philipp Slusallek"
] | [] | [] | [] |
EuroVis | 2,006 | GPU-Accelerated Volume Splatting With Elliptical RBFs | 10.2312/VisSym/EuroVis06/013-020 | Radial Basis Functions (RBFs) have become a popular rendering primitive, both in surface and in volume rendering. This paper focuses on volume visualization, giving rise to 3D kernels. RBFs are especially convenient for the representation of scattered and irregularly distributed point samples, where the RBF kernel is used as a blending function for the space in between samples. Common representations employ radially symmetric RBFs, and various techniques have been introduced to render these, also with efficient implementations on programmable graphics hardware (GPUs). In this paper, we extend the existing work to more generalized, ellipsoidal RBF kernels, for the rendering of scattered volume data. We devise a post-shaded kernel-centric rendering approach, specifically designed to run efficiently on GPUs, and we demonstrate our renderer using datasets from subdivision volumes and computational science. | false | false | [
"Neophytos Neophytou",
"Klaus Mueller 0001",
"Kevin T. McDonnell",
"Wei Hong 0006",
"Xin Guan",
"Hong Qin",
"Arie E. Kaufman"
] | [] | [] | [] |
EuroVis | 2,006 | GPU-Based Hyperstreamlines for Diffusion Tensor Imaging | 10.2312/VisSym/EuroVis06/035-042 | We propose a new approach for the visualization of hyperstreamlines, which offers potential for better scalability than the conventional polygon-based approach. Our method circumvents the bandwidth bottleneck between the CPU and GPU by transmitting a small set of parameters for each tube segment and generates the surface directly on the GPU using the classical sphere tracing approach. This reduces the load on the CPU that would otherwise need to provide a suitable level-of-detail representation of the scene, while offering even higher quality in the resulting surfaces since every fragment is traced individually. We demonstrate the effectiveness of this approach by comparing it to the performance and output of conventional visualization tools in the application area of diffusion tensor imaging of human brain MR scans.
The method presented here can also be utilized to generate other types of surfaces on the GPU that are too complex to handle with direct ray casting and can therefore be adapted for other applications. | false | false | [
"Guido Reina",
"Katrin Bidmon",
"Frank Enders",
"Peter Hastreiter",
"Thomas Ertl"
] | [] | [] | [] |
EuroVis | 2,006 | GPUFLIC: Interactive and Accurate Dense Visualization of Unsteady Flows | 10.2312/VisSym/EuroVis06/029-034 | The paper presents an efficient and accurate implementation of Unsteady Flow LIC (UFLIC) on the Graphics Processing Unit (GPU). We obtain the same, high quality texture representation of unsteady two-dimensional flows as the original, time-consuming method but leverage the features of today's commodity hardware to achieve interactive frame rates. Despite a remarkable number of recent contributions in the field of texture-based visualization of time-dependent vector fields, the present paper is the first to provide a faithful implementation of that prominent technique fully supported by the graphics pipeline. | false | false | [
"Guo-Shi Li",
"Xavier Tricoche",
"Charles D. Hansen"
] | [] | [] | [] |
EuroVis | 2,006 | Hardware-accelerated Extraction and Rendering of Point Set Surfaces | 10.2312/VisSym/EuroVis06/021-028 | Point-based models are gaining lately considerable attention as an alternative to traditional surface meshes. In this context, Point Set Surfaces (PSS) were proposed as a modeling and rendering method with important topological and approximation properties. However, ray-tracing PSS is computationally expensive. Therefore, we propose an interactive ray-tracing algorithm for PSS implemented completely on commodity graphics hardware. We also exploit the advantages of PSS to propose a novel technique for extracting surfaces directly from volumetric data. This technique is based on the well known predictor-corrector principle from the numerical methods for solving ordinary differential equations. Our technique provides good approximations to surfaces defined by a certain property in the volume, such as iso-surfaces or surfaces located at regions of high gradient magnitude. Also, local details of the surfaces could be manipulated by changing the local polynomial approximation and the smoothing parameters used. Furthermore, the surfaces generated are smooth and low frequency noise is naturally handled. | false | false | [
"Eduardo Tejada",
"Joao Paulo Gois",
"Luis Gustavo Nonato",
"Antônio Castelo Filho",
"Thomas Ertl"
] | [] | [] | [] |
EuroVis | 2,006 | Improving the Quality of Multi-resolution Volume Rendering | 10.2312/VisSym/EuroVis06/251-258 | We propose a novel method to improve the quality of multi-resolution visualizations. We reduce aliasing artifacts by approximating the data distribution with a Gaussian basis function at each level of detail for more accurate rendering at coarser levels of detail. We then show an efficient implementation of our novel Gaussian based approximation scheme and show its superiority using numerical tests and compelling renderings. | false | false | [
"Hamid Younesy",
"Torsten Möller",
"Hamish A. Carr"
] | [] | [] | [] |
EuroVis | 2,006 | Integrated Visualization of Morphologic and Perfusion Data for the Analysis of Coronary Artery Disease | 10.2312/VisSym/EuroVis06/131-138 | We present static and dynamic techniques to visualize perfusion data and to relate perfusion data to morphologic image data. In particular, we describe the integrated analysis of MRI myocardial perfusion data with CT coronary angiographies depicting the morphology. We refined the Bull's-Eye Plot, a wide-spread and accepted analysis tool in cardiac diagnosis, to show aggregated information of perfusion data at rest and under stress. The correlation between regions of the myocard with reduced perfusion and 3d renditions of the coronary vessels can be explored within a synchronized visualization of both. With our research, we attempt to improve the diagnosis of early stage coronary artery disease. | false | false | [
"Steffen Oeltze",
"Anja Kuß",
"Frank Grothues",
"Anja Hennemuth",
"Bernhard Preim"
] | [] | [] | [] |
EuroVis | 2,006 | Integrating Dynamic Deformations into Interactive Volume Visualization | 10.2312/VisSym/EuroVis06/219-226 | Non-linear geometric deformation (or warping) is a useful tool for working with volumes. Unfortunately, the computational expense of performing the resampling needed to implement volume deformation has precluded its use in interactive applications. In this paper, we show how non-linear deformations can be integrated into interactive volume visualization allowing for dynamic deformations to be used along with interactive viewing, exploration, and manipulation tools. We describe how hardware assisted volume rendering can be adapted to resample volume deformations, leveraging programmable shaders to compute deformations and the local coordinate transformations required for shading effects. We describe how volume interaction techniques, such as ray picking and plane slicing, can be used in concert with our deformation methods. Our methods extend to simultaneous display of multiple volumes enabling comparisons. We demonstrate dynamic volume deformation at interactive rates on commodity hardware for interactive deformation control, animated deformations, and volume widgets. | false | false | [
"Tom Brunet",
"K. Evan Nowak",
"Michael Gleicher"
] | [] | [] | [] |
EuroVis | 2,006 | Knowledge-Based Out-of-Core Algorithms for Data Management in Visualization | 10.2312/VisSym/EuroVis06/107-114 | Data management is the very first issue in handling very large datasets. Many existing out-of-core algorithms used in visualization are closely coupled with application-specific logic. This paper presents two knowledgebased out-of-core prefetching algorithms that do not use hard-coded rendering-related logic. They acquire the knowledge of the access history and patterns dynamically, and adapt their prefetching strategies accordingly. We have compared the algorithms with a demand-based algorithm, as well as a more domain-specific out-of-core algorithm. We carried out our evaluation in conjunction with an example application where rendering multiple point sets in a volume scene graph put a great strain on the rendering algorithm in terms of memory management. Our results have shown that the knowledge-based approach offers a better cache-hit to disk-access trade-off. This work demonstrates that it is possible to build an out-of-core prefetching algorithm without depending on rendering-related application-specific logic. The knowledge based approach has the advantage of being generic, efficient, flexible and self-adaptive. | false | false | [
"David Chisnall",
"Min Chen 0001",
"Charles D. Hansen"
] | [] | [] | [] |
EuroVis | 2,006 | Lossless Geometry Compression for Steady-State and Time-Varying Irregular Grids | 10.2312/VisSym/EuroVis06/275-282 | In this paper we investigate the problem of lossless geometry compression of irregular-grid volume data represented as a tetrahedral mesh. We propose a novel lossless compression technique that effectively predicts, models, and encodes geometry data for both steady-state (i.e., with only a single time step) and time-varying datasets. Our geometry coder is truly lossless and also does not need any connectivity information. Moreover, it can be easily integrated with a class of the best existing connectivity compression techniques for tetrahedral meshes with a small amount of overhead information. We present experimental results which show that our technique achieves superior compression ratios, with reasonable encoding times and fast (linear) decoding times. | false | false | [
"Dan Chen",
"Yi-Jen Chiang",
"Nasir D. Memon",
"Xiaolin Wu 0001"
] | [] | [] | [] |
EuroVis | 2,006 | Multiresolution Interblock Interpolation in Direct Volume Rendering | 10.2312/VisSym/EuroVis06/259-266 | We present a direct interblock interpolation technique that enables direct volume rendering of blocked, multiresolution volumes. The proposed method smoothly interpolates between blocks of arbitrary block-wise level-of-detail (LOD) without sample replication or padding. This permits extreme changes in resolution across block boundaries and removes the interblock dependency for the LOD creation process. In addition the full data reduction from the LOD selection can be maintained throughout the rendering pipeline. Our rendering pipeline employs a flat block subdivision followed by a transfer function based adaptive LOD scheme. We demonstrate the effectiveness of our method by rendering volumes of the order of gigabytes using consumer graphics cards on desktop PC systems. | false | false | [
"Patric Ljung",
"Claes Lundström",
"Anders Ynnerman"
] | [] | [] | [] |
EuroVis | 2,006 | Natural Visualizations | 10.2312/VisSym/EuroVis06/043-050 | This paper demonstrates the prevalence of a shared characteristic between visualizations and images of nature. We have analyzed visualization competitions and user studies of visualizations and found that the more preferred, better performing visualizations exhibit more natural characteristics. Due to our brain being wired to perceive natural images [SO01], testing a visualization for properties similar to those of natural images can help show how well our brain is capable of absorbing the data. In turn, a metric that finds a visualization's similarity to a natural image may help determine the effectiveness of that visualization. We have found that the results of comparing the sizes and distribution of the objects in a visualization with those of natural standards strongly correlate to one's preference of that visualization. | false | false | [
"Steve Haroz",
"Kwan-Liu Ma"
] | [] | [] | [] |
EuroVis | 2,006 | Path Line Oriented Topology for Periodic 2D Time-Dependent Vector Fields | 10.2312/VisSym/EuroVis06/139-146 | This paper presents an approach to extracting a path line oriented topological segmentation for periodic 2D timedependent vector fields. Topological methods aiming in capturing the asymptotic behavior of path lines rarely exist because path lines are usually only defined over a fixed time-interval, making statements about their asymptotic behavior impossible. For the data class of periodic vector fields, this restriction does not apply any more. Our approach detects critical path lines as well as basins from which the path lines converge to the critical ones. We demonstrate our approach on a number of test data sets. | false | false | [
"Kuangyu Shi",
"Holger Theisel",
"Tino Weinkauf",
"Helwig Hauser",
"Hans-Christian Hege",
"Hans-Peter Seidel"
] | [] | [] | [] |
EuroVis | 2,006 | Perspective Isosurface and Direct Volume Rendering for Virtual Endoscopy Applications | 10.2312/VisSym/EuroVis06/315-322 | Virtual endoscopy has proven to be a very powerful tool in endoscopic surgery. However, most virtual endoscopy systems are restricted to rendering isosurfaces or require segmentation in order to visualize additional objects behind occluding tissue. This paper presents a system for real-time perspective direct volume and isosurface rendering, which allows to simultaneously visualize both the interesting tissue and everything that is behind. Large volume data can be viewed seamlessly from inside or outside the volume without any pre-computation or segmentation. Our system uses a novel ray-casting pipeline for GPUs that has been optimized for the requirements of virtual endoscopy and also allows easy incorporation of auxiliary geometry, e.g., for displaying parts of the endoscopic device, pointers, or grid lines for orientation purposes. We present three main applications of this system and the underlying ray-casting algorithm. Although our ray-casting approach is of general applicability, we have specifically applied it to virtual colonoscopy, virtual angioscopy, and virtual pituitary surgery. | false | false | [
"Henning Scharsach",
"Markus Hadwiger",
"André Neubauer 0002",
"Stefan Wolfsberger",
"Katja Bühler"
] | [] | [] | [] |
EuroVis | 2,006 | PhylloTrees: Phyllotactic Patterns for Tree Layout | 10.2312/VisSym/EuroVis06/059-066 | Motivations for drawing hierarchical structures are probably as diverse as datasets to visualize. This ubiquity of tree structures has lead to a manifold of tree layout algorithms and tree visualization systems. While many tree layouts exist, increasingly massive data sets, expanding computational power, and still relatively limited display space make tree layout algorithms a topic of ongoing interest. We explore the use of nature's phyllotactic patterns to inform the layout of hierarchical data. These naturally occurring patterns provide a non-overlapping, optimal packing when the total number of nodes is not known a priori. We present PhylloTrees, a family of expandable tree layouts based on these patterns. | false | false | [
"Petra Neumann 0001",
"Sheelagh Carpendale",
"Anand Agarawala"
] | [] | [] | [] |
EuroVis | 2,006 | PointCloudXplore: Visual Analysis of 3D Gene Expression Data Using Physical Views and Parallel Coordinates | 10.2312/VisSym/EuroVis06/203-210 | To allow a more rigorous understanding of animal gene regulatory networks, the Berkeley Drosophila Transcription Network Project (BDTNP) has developed a suite of methods that support quantitative, computational analysis of three-dimensional (3D) gene expression patterns with cellular resolution in early Drosophila embryos. Here we report the first components of a visualization tool, PointCloudXplore, that allows the relationships between different gene's expression to be analyzed using the BDTNP's datasets.
PointCloudXplore uses the established visualization techniques of multiple views, brushing, and linking to support the analysis of high-dimensional datasets that describe many genes' expression. Each of the views in PointCloud- Xplore shows a different gene expression data property. Brushing is used to select and emphasize data associated with defined subsets of embryo cells within a view. Linking is used to show in additional views the expression data for a group of cells that have first been highlighted as a brush in a single view, allowing further data subset properties to be determined. In PointCloudXplore, physical views of the data are linked to parallel coordinates. Physical views show the spatial relationships between different genes' expression patterns within the embryo. Parallel coordinates, on the other hand, show only some features of each gene's expression, but allow simultaneous analysis of data for many more genes than would be possible in a physical view. We have developed several extensions to standard parallel coordinates to facilitate brushing the visualization of 3D gene expression data. | false | false | [
"Oliver Rübel",
"Gunther H. Weber",
"Soile V. E. Keränen",
"Charless C. Fowlkes",
"Cris L. Luengo Hendriks",
"Lisa Simirenko",
"Nameeta Y. Shah",
"Michael B. Eisen",
"Mark D. Biggin",
"Hans Hagen",
"Damir Sudar",
"Jitendra Malik",
"David W. Knowles",
"Bernd Hamann"
] | [] | [] | [] |
EuroVis | 2,006 | Real-Time Super Resolution Contextual Close-up of Clinical Volumetric Data | 10.2312/VisSym/EuroVis06/347-354 | We present an illustrative visualization system for real-time and high quality rendering of clinical volumetric medical data. Our technique is inspired by a medical illustration technique for depicting contextual close-up views of selected regions of interest where internal anatomical features are rendered in high detail. Our method integrates four important components: decimation of original volume for interactivity, B-spline subdivision for super-resolution rendering, fast gradient quantization technique for feature extraction and GPU fragment shaders for gradient dependent rendering and transfer functions. Examples with clinical CT and MRI data demonstrate the capabilities of our system. | false | false | [
"T. Taerum",
"Mario Costa Sousa",
"Faramarz F. Samavati",
"S. Chan",
"Joseph Ross Mitchell"
] | [] | [] | [] |
EuroVis | 2,006 | Robust Surface Detection for Variance Comparison and Dimensional Measurement | 10.2312/VisSym/EuroVis06/075-082 | This paper describes a robust method for creating surface models from volume datasets with distorted density values due to artefacts and noise. Application scenario for the presented work is variance comparison and dimensional measurement of homogeneous industrial components in industrial high resolution 3D computed tomography (3D-CT). We propose a pipeline which uses common 3D image processing filters for pre-processing and segmentation of 3D-CT datasets in order to create the surface model. In particular, a pre-filtering step reduces noise and artefacts without blurring edges in the dataset. A watershed filter is applied on the gradient information of the smoothed data to create a binary dataset. Finally the surface model is constructed, using constrained elastic-surface nets to generate a smooth but feature preserving mesh of a binary volume. The major contribution of this paper is the development of the specific processing pipeline for homogeneous industrial components to handle large resolution data of industrial CT scanners. The pipeline is crucial for the following visual inspection of deviations. | false | false | [
"Christoph Heinzl",
"R. Klingesberger",
"Johann Kastner",
"M. Eduard Gröller"
] | [] | [] | [] |
EuroVis | 2,006 | Segmentation of Flow Fields using Pattern Matching | 10.2312/VisSym/EuroVis06/147-154 | Due to the amount of data nowadays, automatic detection, classification and visualization of features is necessary for a thorough inspection of flow data sets. Pattern matching using vector valued templates has already been applied successfully for the detection of features. In this paper, the approach is extended to automatically compute feature based segmentations of flow data sets. Different problems of the segmentation like the influence of thresholds, overlapping features, and classification errors are discussed. Visualizations of the segmentation display important structures of the flow and highlight the interesting features. The segmentation algorithm presented in this paper is applicable to 2D and 3D vector fields as well as to time-dependent data. | false | false | [
"Julia Ebling",
"Gerik Scheuermann"
] | [] | [] | [] |
EuroVis | 2,006 | Simultaneous Classification of Time-Varying Volume Data Based on the Time Histogram | 10.2312/VisSym/EuroVis06/171-178 | An important challenge in the application of direct volume rendering to time-varying data is the specification of transfer functions for all time steps. Very little research has been devoted to this problem, however. To address this issue we propose an approach which allows simultaneous classification of the entire time series. We explore options for transfer function specification that are based, either directly or indirectly, on the time histogram. Furthermore, we consider how to effectively provide feedback for interactive classification by exploring options for simultaneous rendering of the time series, again based on the time histogram. Finally, we apply this approach to several large time-varying data sets where we show that the important features at all times are captured with about the same effort it takes to classify one time step using conventional classification. | false | false | [
"Hiroshi Akiba",
"Nathaniel Fout",
"Kwan-Liu Ma"
] | [] | [] | [] |
EuroVis | 2,006 | Structure-accentuating Dense Flow Visualization | 10.2312/VisSym/EuroVis06/163-170 | Vector field visualization approaches can broadly be categorized into approaches that directly visualize local or integrated flow and approaches that analyze the topological structure and visualize extracted features. Our goal was to come up with a method that falls into the first category, yet reveals structural information. We have developed a dense flow visualization method that shows the overall flow behavior while accentuating structural information without performing a topological analysis. Our method is based on a geometry-based flow integration step and a texture-based visual exploration step. The flow integration step generates a density field, which is written into a texture. The density field is generated by tracing particles under the influence of the underlying vector field. When using a quasi-random seeding strategy for initialization, the resulting density is high in attracting regions and low in repelling regions. Density is measured by the number of particles per region accumulated over time. We generate one density field using forward and one using backward propagation. The density fields are explored using texture-based rendering techniques. We generate the two output images separately and blend the results, which allows us to distinguish between inflow and outflow regions. We obtained dense flow visualizations that display the overall flow behavior, emphasize critical and separating regions, and indicate flow direction in the neighborhood of these regions. We have test our method for isolated first-order singularities and real data sets. | false | false | [
"Sung W. Park",
"Hongfeng Yu 0001",
"Ingrid Hotz",
"Oliver Kreylos",
"Lars Linsen",
"Bernd Hamann"
] | [] | [] | [] |
EuroVis | 2,006 | Terrain Rendering using Spherical Clipmaps | 10.2312/VisSym/EuroVis06/091-098 | We describe a terrain rendering algorithm for spherical terrains based on clipmaps. It leverages the high geometry throughput of current GPU to render large static triangle sets. The vertices are displaced by a height map texture. Our main contribution is mapping of texture coordinates to calculate the height map sample position based on the static vertex offset and the variable view position. | false | false | [
"Malte Clasen",
"Hans-Christian Hege"
] | [] | [] | [] |
EuroVis | 2,006 | Texture Advection on Stream Surfaces: A Novel Hybrid Visualization Applied to CFD Simulation Results | 10.2312/VisSym/EuroVis06/155-162 | Stream surfaces are a classic flow visualization technique used to portray the characteristics of vector fields, and texture advection research has made rapid advances in recent years. We present a novel hybrid visualization of texture advection on stream surfaces. This approach conveys properties of the vector field that stream surfaces alone cannot. We apply the visualization technique to various patterns of flow from CFD data important to automotive engine simulation including two patterns of in-cylinder flow (swirl and tumble motion) as well as flow through a cooling jacket. In addition, we explore multiple vector fields defined at the stream surface such as velocity, vorticity, and pressure gradient. The results of our investigation highlight both the strengths and limitations of the hybrid stream surface-texture advection visualization technique and offer new insight to engineers exploring and analyzing their simulations. | false | false | [
"Robert S. Laramee",
"Christoph Garth",
"Jürgen Schneider",
"Helwig Hauser"
] | [] | [] | [] |
EuroVis | 2,006 | The alpha -histogram: Using Spatial Coherence to Enhance Histograms and Transfer Function Design | 10.2312/VisSym/EuroVis06/227-234 | The high complexity of Transfer Function (TF) design is a major obstacle to widespread routine use of Direct Volume Rendering, particularly in the case of medical imaging. Both manual and automatic TF design schemes would benefit greatly from a fast and simple method for detection of tissue value ranges. To this end, we introduce the a-histogram, an enhancement that amplifies ranges corresponding to spatially coherent materials. The properties of the a-histogram have been explored for synthetic data sets and then successfully used to detect vessels in 20 Magnetic Resonance angiographies, proving the potential of this approach as a fast and simple technique for histogram enhancement in general and for TF construction in particular. | false | false | [
"Claes Lundström",
"Anders Ynnerman",
"Patric Ljung",
"Anders Persson",
"Hans Knutsson"
] | [] | [] | [] |
EuroVis | 2,006 | Visualizing the Phonon Map | 10.2312/VisSym/EuroVis06/291-298 | In this work we present several visualization approaches for analyzing acoustic behavior inside a room. Our methods are based on the results of the phonon tracing algorithm. For a simulated phonon map we examine the influence of the room surfaces on the wave fronts during their propagation from the sound source. Our visualization is based on individual phonon and surface representations as well as scattered data interpolation. Additionally, an observation of acoustic behavior at different positions inside the room using colored and deformed spheres is possible. | false | false | [
"Eduard Deines",
"Frank Michel 0001",
"Martin Bertram 0001",
"Hans Hagen",
"Gregory M. Nielson"
] | [] | [] | [] |
EuroVis | 2,006 | Volume Composition Using Eye Tracking Data | 10.2312/VisSym/EuroVis06/115-122 | This paper presents a method to automate rendering parameter selection, simplifying tedious user interaction and improving the usability of visualization systems. Our approach acquires regions-of-interest for a dataset with an eye tracker and simple user interaction. Based on this importance information, we then automatically compute reasonable rendering parameters using a set of heuristic rules adapted from visualization experience and psychophysics experiments. While the parameter selections for a specific visualization task are subjective, our approach provides good starting results that can be refined by the user. Our system improves the interactivity of a visualization system by significantly reducing the necessary parameter selection and providing good initial rendering parameters for newly acquired datasets of similar types. | false | false | [
"Aidong Lu",
"Ross Maciejewski",
"David S. Ebert"
] | [] | [] | [] |
CHI | 2,006 | A fisheye follow-up: further reflections on focus + context | 10.1145/1124772.1124921 | Information worlds continue to grow, posing daunting challenges for interfaces. This paper tries to increase our understanding of approaches to the problem, building on the Generalized Fisheye View framework. Three issues are discussed. First a number of existing techniques are unified by the commonality of what they show, certain fisheye-related subsets, with the techniques differing only in how they show those subsets. Then the elevated importance of these subsets, and their generality, is used to discuss the possibility of non-visual fisheye-views, to attack problems not so amenable to visualization. Finally, several models are given for why these subsets might be important in user interactions, with the goal of better informing design rationales. | false | false | [
"George W. Furnas"
] | [] | [] | [] |
CHI | 2,006 | Feeling what you hear: tactile feedback for navigation of audio graphs | 10.1145/1124772.1124941 | Access to digitally stored numerical data is currently very limited for sight impaired people. Graphs and visualizations are often used to analyze relationships between numerical data, but the current methods of accessing them are highly visually mediated. Representing data using audio feedback is a common method of making data more accessible, but methods of navigating and accessing the data are often serial in nature and laborious. Tactile or haptic displays could be used to provide additional feedback to support a point-and-click type interaction for the visually impaired. A requirements capture conducted with sight impaired computer users produced a review of current accessibility technologies, and guidelines were extracted for using tactile feedback to aid navigation. The results of a qualitative evaluation with a prototype interface are also presented. Providing an absolute position input device and tactile feedback allowed the users to explore the graph using tactile and proprioceptive cues in a manner analogous to point-and-click techniques. | false | false | [
"Steven A. Wall",
"Stephen A. Brewster"
] | [] | [] | [] |
CHI | 2,006 | groupTime: preference based group scheduling | 10.1145/1124772.1124929 | As our business, academic, and personal lives continue to move at an ever-faster pace, finding times for busy people to meet has become an art. One of the most perplexing challenges facing groupware is effective asynchronous group scheduling (GS). This paper presents a lightweight interaction model for GS that can extend its reach beyond users of current group calendaring solutions. By expressing availability in terms of preferences, we create a flexible framework for GS that preserves plausible deniability while exerting social pressure to encourage honesty among users. We also propose an ontology that enables us to model user preferences with machine learning, predicting user responses to further lower cognitive load. The combination of visualization/direct manipulation with machine learning allows users to easily and efficiently optimize meeting times. We also suggest resulting design implications for this class of intelligent user interfaces. | false | false | [
"Mike Brzozowski",
"Kendra Carattini",
"Scott R. Klemmer",
"Patrick Mihelich",
"Jiang Hu",
"Andrew Y. Ng"
] | [] | [] | [] |
CHI | 2,006 | GUESS: a language and interface for graph exploration | 10.1145/1124772.1124889 | As graph models are applied to more widely varying fields, researchers struggle with tools for exploring and analyzing these structures. We describe GUESS, a novel system for graph exploration that combines an interpreted language with a graphical front end that allows researchers to rapidly prototype and deploy new visualizations. GUESS also contains a novel, interactive interpreter that connects the language and interface in a way that facilities exploratory visualization tasks. Our language, Gython, is a domain-specific embedded language which provides all the advantages of Python with new, graph specific operators, primitives, and shortcuts. We highlight key aspects of the system in the context of a large user survey and specific, real-world, case studies ranging from social and knowledge networks to distributed computer network analysis. | false | false | [
"Eytan Adar"
] | [] | [] | [] |
CHI | 2,006 | Keepin' it real: pushing the desktop metaphor with physics, piles and the pen | 10.1145/1124772.1124965 | We explore making virtual desktops behave in a more physically realistic manner by adding physics simulation and using piling instead of filing as the fundamental organizational structure. Objects can be casually dragged and tossed around, influenced by physical characteristics such as friction and mass, much like we would manipulate lightweight objects in the real world. We present a prototype, called BumpTop, that coherently integrates a variety of interaction and visualization techniques optimized for pen input we have developed to support this new style of desktop organization. | false | false | [
"Anand Agarawala",
"Ravin Balakrishnan"
] | [] | [] | [] |
CHI | 2,006 | Minimap: a web page visualization method for mobile phones | 10.1145/1124772.1124779 | The Web has become available even on mobile phones, but the current methods to view large pages on small screens have not been highly usable. Current mobile phone browsers reformat Web pages to a single column that fits the screen width. Because not all content is comprehensible in this format, browsers provide a second mode for viewing pages in the same layout as on a PC. We have developed a modeless Web page visualization method called Minimap that shows pages in a modified Original layout. We conducted a long-term usability study with 20 participants to compare the state-of-the-art mobile phone browser with this new method. 18 participants preferred the new method, and it also scored better in more detailed usability ratings. | false | false | [
"Virpi Roto",
"Andrei Popescu 0003",
"Antti Koivisto",
"Elina Vartiainen"
] | [] | [] | [] |
CHI | 2,006 | Sashay: designing for wonderment | 10.1145/1124772.1124901 | No longer confined to our offices, schools, and homes, technology is expanding at an astonishing rate across our everyday public urban landscapes. From the visible (mobile phones, laptops, and blackberries) to the invisible (GPS, WiFi, GSM, and EVDO), we find the full spectrum of digital technologies transforming nearly every facet of our urban experience. Many current urban computing systems focus on improving our efficiency and productivity in the city by providing "location services" and/or interactive navigation and mapping tools. While agreeing with the need for such systems, we are reminded that urban life spans a much wider range of emotions and experiences. Our claim is that our successful future urban technological tools will be those that incorporate the full range of urban experiences -- from improving productivity and efficiency to promoting wonderment and daydreaming. We discuss intervention as a research strategy for understanding wonderment; demonstrate an example of such a study using a matchbook experiment to expose relationships between locations and emotions within a city; and use the results to develop Sashay -- a mobile phone application that promotes wonderment by visualizing an individual's personal patterns across the invisible, manufactured geography of mobile phone cellular towers. | false | false | [
"Eric Paulos",
"Chris Beckmann"
] | [] | [] | [] |
CHI | 2,006 | Visual exploration of multivariate graphs | 10.1145/1124772.1124891 | This paper introduces PivotGraph, a software tool that uses a new technique for visualizing and analyzing graph structures. The technique is designed specifically for graphs that are "multivariate," i.e., where each node is associated with several attributes. Unlike visualizations which emphasize global graph topology, PivotGraph uses a simple grid-based approach to focus on the relationship between node attributes and connections. The interaction technique is derived from an analogy with methods seen in spreadsheet pivot tables and in online analytical processing (OLAP). Finally, several examples are presented in which PivotGraph was applied to real-world data sets. | false | false | [
"Martin Wattenberg"
] | [] | [] | [] |
CHI | 2,006 | Visualization of large hierarchical data by circle packing | 10.1145/1124772.1124851 | In this paper a novel approach is described for tree visualization using nested circles. The brother nodes at the same level are represented by externally tangent circles; the tree nodes at different levels are displayed by using 2D nested circles or 3D nested cylinders. A new layout algorithm for tree structure is described. It provides a good overview for large data sets. It is easy to see all the branches and leaves of the tree. The new method has been applied to the visualization of file systems. | false | false | [
"Weixin Wang",
"Henry (Hui) Wang",
"Guozhong Dai",
"Hongan Wang"
] | [] | [] | [] |
CHI | 2,006 | Visualizing email content: portraying relationships from conversational histories | 10.1145/1124772.1124919 | We present Themail, a visualization that portrays relationships using the interaction histories preserved in email archives. Using the content of exchanged messages, it shows the words that characterize one's correspondence with an individual and how they change over the period of the relationship.This paper describes the interface and content-parsing algorithms in Themail. It also presents the results from a user study where two main interaction modes with the visualization emerged: exploration of "big picture" trends and themes in email (haystack mode) and more detail-oriented exploration (needle mode). Finally, the paper discusses the limitations of the content parsing approach in Themail and the implications for further research on email content visualization. | false | false | [
"Fernanda B. Viégas",
"Scott A. Golder",
"Judith S. Donath"
] | [] | [] | [] |
Vis | 2,005 | 2D asymmetric tensor analysis | 10.1109/VISUAL.2005.1532770 | Analysis of degenerate tensors is a fundamental step in finding the topological structures and separatrices in tensor fields. Previous work in this area have been limited to analyzing symmetric second order tensor fields. In this paper, we extend the topological analysis to 2D general (asymmetric) second order tensor fields. We show that it is not sufficient to define degeneracies based on eigenvalues alone, but one must also include the eigenvectors in the analysis. We also study the behavior of these eigenvectors as they cross from one topological region into another. | false | false | [
"Xiaoqiang Zheng",
"Alex T. Pang"
] | [] | [] | [] |
Vis | 2,005 | A contract based system for large data visualization | 10.1109/VISUAL.2005.1532795 | VisIt is a richly featured visualization tool that is used to visualize some of the largest simulations ever run. The scale of these simulations requires that optimizations are incorporated into every operation VisIt performs. But the set of applicable optimizations that VisIt can perform is dependent on the types of operations being done. Complicating the issue, VisIt has a plugin capability that allows new, unforeseen components to be added, making it even harder to determine which optimizations can be applied. We introduce the concept of a contract to the standard data flow network design. This contract enables each component of the data flow network to modify the set of optimizations used. In addition, the contract allows for new components to be accommodated gracefully within VisIt's data flow network system. | false | false | [
"Hank Childs",
"Eric Brugger",
"Kathleen S. Bonnell",
"Jeremy S. Meredith",
"Mark C. Miller",
"Brad Whitlock",
"Nelson L. Max"
] | [] | [] | [] |
Vis | 2,005 | A feature-driven approach to locating optimal viewpoints for volume visualization | 10.1109/VISUAL.2005.1532834 | Optimal viewpoint selection is an important task because it considerably influences the amount of information contained in the 2D projected images of 3D objects, and thus dominates their first impressions from a psychological point of view. Although several methods have been proposed that calculate the optimal positions of viewpoints especially for 3D surface meshes, none has been done for solid objects such as volumes. This paper presents a new method of locating such optimal viewpoints when visualizing volumes using direct volume rendering. The major idea behind our method is to decompose an entire volume into a set of feature components, and then find a globally optimal viewpoint by finding a compromise between locally optimal viewpoints for the components. As the feature components, the method employs interval volumes and their combinations that characterize the topological transitions of isosurfaces according to the scalar field. Furthermore, opacity transfer functions are also utilized to assign different weights to the decomposed components so that users can emphasize features of specific interest in the volumes. Several examples of volume datasets together with their optimal positions of viewpoints are exhibited in order to demonstrate that the method can effectively guide naive users to find optimal projections of volumes. | false | false | [
"Shigeo Takahashi",
"Issei Fujishiro",
"Yuriko Takeshima",
"Tomoyuki Nishita"
] | [] | [] | [] |
Vis | 2,005 | A handheld flexible display system | 10.1109/VISUAL.2005.1532846 | A new close range virtual reality system is introduced that allows intuitive and immersive user interaction with computer generated objects. A projector with a special spherical lens is combined with a flexible, tracked rear projection screen that users hold in their hands. Unlike normal projectors, the spherical lens allows for a 180 degree field of view and nearly infinite depth of focus. This allows the user to move the screen around the environment and use it as a virtual "slice" to examine the interior of 3D volumes. This provides a concrete correspondence between the virtual representation of the 3D volume and how that volume would actually appear if its real counterpart was sliced open. The screen can also be used as a "magic window" to view the mesh of the volume from different angles prior to taking cross sections of it. Real time rendering of the desired 3D volume or mesh is accomplished using current graphics hardware. Additional applications of the system are also discussed. | false | false | [
"Jonathan Konieczny",
"Clement Shimizu",
"Gary W. Meyer",
"D'nardo Colucci"
] | [] | [] | [] |
Vis | 2,005 | A shader-based parallel rendering framework | 10.1109/VISUAL.2005.1532787 | Existing parallel or remote rendering solutions rely on communicating pixels, OpenGL commands, scene-graph changes or application-specific data. We propose an intermediate solution based on a set of independent graphics primitives that use hardware shaders to specify their visual appearance. Compared to an OpenGL based approach, it reduces the complexity of the model by eliminating most fixed function parameters while giving access to the latest functionalities of graphics cards. It also suppresses the OpenGL state machine that creates data dependencies making primitive re-scheduling difficult. Using a retained-mode communication protocol transmitting changes between each frame, combined with the possibility to use shaders to implement interactive data processing operations instead of sending final colors and geometry, we are able to optimize the network load. High level information such as bounding volumes is used to setup advanced schemes where primitives are issued in parallel, routed according to their visibility, merged and re-ordered when received for rendering. Different optimization algorithms can be efficiently implemented, saving network bandwidth or reducing texture switches for instance. We present performance results based on two VTK applications, a parallel iso-surface extraction and a parallel volume renderer. We compare our approach with Chromium. Results show that our approach leads to significantly better performance and scalability, while offering easy access to hardware accelerated rendering algorithms. | false | false | [
"Jérémie Allard",
"Bruno Raffin"
] | [] | [] | [] |
Vis | 2,005 | Batched multi triangulation | 10.1109/VISUAL.2005.1532797 | The multi triangulation framework (MT) is a very general approach for managing adaptive resolution in triangle meshes. The key idea is arranging mesh fragments at different resolution in a directed acyclic graph (DAG) which encodes the dependencies between fragments, thereby encompassing a wide class of multiresolution approaches that use hierarchies or DAGs with predefined topology. On current architectures, the classic MT is however unfit for real-time rendering, since DAG traversal costs vastly dominate raw rendering costs. In this paper, we redesign the MT framework in a GPU friendly fashion, moving its granularity from triangles to precomputed optimized triangle patches. The patches can be conveniently tri-stripped and stored in secondary memory to be loaded on demand, ready to be sent to the GPU using preferential paths. In this manner, central memory only contains the DAG structure and CPU workload becomes negligible. The major contributions of this work are: a new out-of-core multiresolution framework, that, just like the MT, encompasses a wide class of multiresolution structures; a robust and elegant way to build a well conditioned MT DAG by introducing the concept of V-partitions, that can encompass various state of the art multiresolution algorithms; an efficient multithreaded rendering engine and a general subsystem for the external memory processing and simplification of huge meshes. | false | false | [
"Paolo Cignoni",
"Fabio Ganovelli",
"Enrico Gobbetti",
"Fabio Marton",
"Federico Ponchio",
"Roberto Scopigno"
] | [] | [] | [] |
Vis | 2,005 | Build-by-number: rearranging the real world to visualize novel architectural spaces | 10.1109/VISUAL.2005.1532789 | We present build-by-number, a technique for quickly designing architectural structures that can be rendered photorealistically at interactive rates. We combine image-based capturing and rendering with procedural modeling techniques to allow the creation of novel structures in the style of real-world structures. Starting with a simple model recovered from a sparse image set, the model is divided into feature regions, such as doorways, windows, and brick. These feature regions essentially comprise a mapping from model space to image space, and can be recombined to texture a novel model. Procedural rules for the growth and reorganization of the model are automatically derived to allow for very fast editing and design. Further, the redundancies marked by the feature labeling can be used to perform automatic occlusion replacement and color equalization in the finished scene, which is rendered using view-dependent texture mapping on standard graphics hardware. Results using four captured scenes show that a great variety of novel structures can be created very quickly once a captured scene is available, and rendered with a degree of realism comparable to the original scene. | false | false | [
"Daniel R. Bekins",
"Daniel G. Aliaga"
] | [] | [] | [] |
Vis | 2,005 | COTS cluster-based sort-last rendering: performance evaluation and pipelined implementation | 10.1109/VISUAL.2005.1532785 | Sort-last parallel rendering is an efficient technique to visualize huge datasets on COTS clusters. The dataset is subdivided and distributed across the cluster nodes. For every frame, each node renders a full resolution image of its data using its local GPU, and the images are composited together using a parallel image compositing algorithm. In this paper, we present a performance evaluation of standard sort-last parallel rendering methods and of the different improvements proposed in the literature. This evaluation is based on a detailed analysis of the different hardware and software components. We present a new implementation of sort-last rendering that fully overlaps CPU(s), GPU and network usage all along the algorithm. We present experiments on a 3 years old 32-node PC cluster and on a 1.5 years old 5-node PC cluster, both with Gigabit interconnect, showing volume rendering at respectively 13 and 31 frames per second and polygon rendering at respectively 8 and 17 frames per second on a 1024 x 768 render area, and we show that our implementation outperforms or equals many other implementations and specialized visualization clusters. | false | false | [
"Xavier Cavin",
"Christophe Mion",
"Alain Filbois"
] | [] | [] | [] |
Vis | 2,005 | Curve-skeleton applications | 10.1109/VISUAL.2005.1532783 | Curve-skeletons are a 1D subset of the medial surface of a 3D object and are useful for many visualization tasks including virtual navigation, reduced-model formulation, visualization improvement, mesh repair, animation, etc. There are many algorithms in the literature describing extraction methodologies for different applications; however, it is unclear how general and robust they are. In this paper, we provide an overview of many curve-skeleton applications and compile a set of desired properties of such representations. We also give a taxonomy of methods and analyze the advantages and drawbacks of each class of algorithms. | false | false | [
"Nicu D. Cornea",
"Deborah Silver",
"Patrick Min"
] | [] | [] | [] |
Vis | 2,005 | Dataset traversal with motion-controlled transfer functions | 10.1109/VISUAL.2005.1532817 | In this paper, we describe a methodology and implementation for interactive dataset traversal using motion-controlled transfer functions. Dataset traversal here refers lo the process of translating a transfer function along a specific path. In scientific visualization, it is often necessary to manipulate transfer functions in order to visualize datasets more effectively. This manipulation of transfer functions is usually performed globally, i.e., a new transfer function is applied to the entire dataset. Our approach allows one to locally manipulate transfer functions while controling its movement along a traversal path. The method we propose allows the user to select a traversal path within the dataset, based on the shape of the volumetric model and manipulate a transfer function along this path. Examples of dataset traversal include the animation of transfer functions along a pre-defined path, the simulation of flow in vascular structures, and the visualization of convoluted shapes. For example, this type of traversal is often used in medical illustration to highlight flow in blood vessels. We present an interactive implementation of our method using graphics hardware, based on the decomposition of the volume. We show examples of our approach using a variety of volumetric datasets, and we also demonstrate that with our novel decomposition, the rendering process is faster. | false | false | [
"Carlos D. Correa",
"Deborah Silver"
] | [] | [] | [] |
Vis | 2,005 | Differential protein expression analysis via liquid-chromatography/mass-spectrometry data visualization | 10.1109/VISUAL.2005.1532828 | Differential protein expression analysis is one of the main challenges in proteomics. It denotes the search for proteins, whose encoding genes are differentially expressed under a given experimental setup. An important task in this context is to identify the differentially expressed proteins or, more generally, all proteins present in the sample. One of the most promising and recently widely used approaches for protein identification is to cleave proteins into peptides, separate the peptides using liquid chromatography, and determine the masses of the separated peptides using mass spectrometry. The resulting data needs to be analyzed and matched against protein sequence databases. The analysis step is typically done by searching for intensity peaks in a large number of 2D graphs. We present an interactive visualization tool for the exploration of liquid-chromatography/mass-spectrometry data in a 3D space, which allows for the understanding of the data in its entirety and a detailed analysis of regions of interest. We compute differential expression over the liquid-chromatography/mass-spectrometry domain and embed it visually in our system. Our exploration tool can treat single liquid-chromatography/mass-spectrometry data sets as well as data acquired using multi-dimensional protein identification technology. For efficiency purposes we perform a peak-preserving data resampling and multiresolution hierarchy generation prior to visualization. | false | false | [
"Lars Linsen",
"Julia Löcherbach",
"Matthias Berth",
"Jörg Bernhardt",
"Dörte Becher"
] | [] | [] | [] |
Vis | 2,005 | Distributed data management for large volume visualization | 10.1109/VISUAL.2005.1532794 | We propose a distributed data management scheme for large data visualization that emphasizes efficient data sharing and access. To minimize data access time and support users with a variety of local computing capabilities, we introduce an adaptive data selection method based on an "enhanced time-space partitioning" (ETSP) tree that assists with effective visibility culling, as well as multiresolution data selection. By traversing the tree, our data management algorithm can quickly identify the visible regions of data, and, for each region, adaptively choose the lowest resolution satisfying user-specified error tolerances. Only necessary data elements are accessed and sent to the visualization pipeline. To further address the issue of sharing large-scale data among geographically distributed collaborative teams, we have designed an infrastructure for integrating our data management technique with a distributed data storage system provided by logistical networking (LoN). Data sets at different resolutions are generated and uploaded to LoN for wide-area access. We describe a parallel volume rendering system that verifies the effectiveness of our data storage, selection and access scheme. | false | false | [
"Jinzhu Gao",
"Jian Huang 0007",
"C. Ryan Johnson",
"Scott Atchley",
"James Arthur Kohl"
] | [] | [] | [] |
Vis | 2,005 | Effectively visualizing large networks through sampling | 10.1109/VISUAL.2005.1532819 | We study the problem of visualizing large networks and develop techniques for effectively abstracting a network and reducing the size to a level that can be clearly viewed. Our size reduction techniques are based on sampling, where only a sample instead of the full network is visualized. We propose a randomized notion of "focus" that specifies a part of the network and the degree to which it needs to be magnified. Visualizing a sample allows our method to overcome the scalability issues inherent in visualizing massive networks. We report some characteristics that frequently occur in large networks and the conditions under which they are preserved when sampling from a network. This can be useful in selecting a proper sampling scheme that yields a sample with similar characteristics as the original network. Our method is built on top of a relational database, thus it can be easily and efficiently implemented using any off-the-shelf database software. As a proof of concept, we implement our methods and report some of our experiments over the movie database and the connectivity graph of the Web. | false | false | [
"Davood Rafiei",
"Stephen Curial"
] | [] | [] | [] |
Vis | 2,005 | Evaluation of fiber clustering methods for diffusion tensor imaging | 10.1109/VISUAL.2005.1532779 | Fiber tracking is a standard approach for the visualization of the results of diffusion tensor imaging (DTI). If fibers are reconstructed and visualized individually through the complete white matter, the display gets easily cluttered making it difficult to get insight in the data. Various clustering techniques have been proposed to automatically obtain bundles that should represent anatomical structures, but it is unclear which clustering methods and parameter settings give the best results. We propose a framework to validate clustering methods for white-matter fibers. Clusters are compared with a manual classification which is used as a ground truth. For the quantitative evaluation of the methods, we developed a new measure to assess the difference between the ground truth and the clusterings. The measure was validated and calibrated by presenting different clusterings to physicians and asking them for their judgement. We found that the values of our new measure for different clusterings match well with the opinions of physicians. Using this framework, we have evaluated different clustering algorithms, including shared nearest neighbor clustering, which has not been used before for this purpose. We found that the use of hierarchical clustering using single-link and a fiber similarity measure based on the mean distance between fibers gave the best results. | false | false | [
"Bart Moberts",
"Anna Vilanova",
"Jarke J. van Wijk"
] | [] | [] | [] |
Vis | 2,005 | Evolutionary morphing | 10.1109/VISUAL.2005.1532826 | We introduce a technique to visualize the gradual evolutionary change of the shapes of living things as a morph between known three-dimensional shapes. Given geometric computer models of anatomical shapes for some collection of specimens - here the skulls of the some of the extant members of a family of monkeys - an evolutionary tree for the group implies a hypothesis about the way in which the shape changed through time. We use a statistical model which expresses the value of some continuous variable at an internal point in the tree as a weighted average of the values at the leaves. The framework of geometric morphometrics can then be used to define a shape-space, based on the correspondences of landmark points on the surfaces, within which these weighted averages can be realized as actual surfaces. Our software provides tools for performing and visualizing such an analysis in three dimensions. Beginning with laser range scans of crania, we use our landmark editor to interactively place landmark points on the surface. We use these to compute a "tree-morph" that smoothly interpolates the shapes across the tree. Each intermediate shape in the morph is a linear combination of all of the input surfaces. We create a surface model for an intermediate shape by warping all the input meshes towards the correct shape and then blending them together. To do the blending, we compute a weighted average of their associated trivariate distance functions and then extract a surface from the resulting function. We implement this idea using the squared distance function, rather than the usual signed distance function, in a novel way. | false | false | [
"David F. Wiley",
"Nina Amenta",
"Dan A. Alcantara",
"Deboshmita Ghosh",
"Yong Joo Kil",
"Eric Delson",
"Will Harcourt-Smith",
"Katherine St. John",
"F. James Rohlf",
"Bernd Hamann"
] | [] | [] | [] |
Vis | 2,005 | Example-based volume illustrations | 10.1109/VISUAL.2005.1532854 | Scientific illustrations use accepted conventions and methodologies to effectively convey object properties and improve our understanding. We present a method to illustrate volume datasets by emulating example illustrations. As with technical illustrations, our volume illustrations more clearly delineate objects, enrich details, and artistically visualize volume datasets. For both color and scalar 3D volumes, we have developed an automatic color transfer method based on the clustering and similarities in the example illustrations and volume sources. As an extension to 2D Wang tiles, we provide a new, general texture synthesis method for Wang cubes that solves the edge discontinuity problem. We have developed a 2D illustrative slice viewer and a GPU-based direct volume rendering system that uses these non-periodic 3D textures to generate illustrative results similar to the 2D examples. Both applications simulate scientific illustrations to provide more information than the original data and visualize objects more effectively, while only requiring simple user interaction. | false | false | [
"Aidong Lu",
"David S. Ebert"
] | [] | [] | [] |
Vis | 2,005 | Exploiting frame-to-frame coherence for accelerating high-quality volume raycasting on graphics hardware | 10.1109/VISUAL.2005.1532799 | GPU-based raycasting offers an interesting alternative to conventional slice-based volume rendering due to the inherent flexibility and the high quality of the generated images. Recent advances in graphics hardware allow for the ray traversal and volume sampling to be executed on a per-fragment level completely on the GPU leading to interactive framerates. In this work we present optimization techniques that improve the performance and quality of GPU-based volume raycasting. We apply a hybrid image/object space approach to accelerate the ray traversal in animation sequences that works for both isosurface rendering and semi-transparent volume rendering. An empty-space-leaping technique that exploits the spatial coherence between consecutively rendered images is used to estimate the optimal initial ray sampling point for each image pixel. These can double the rendering performance for typical volumetric data sets without sacrificing image quality. The achieved speed-up allows for further improvements of image quality. We demonstrate an object space antialiasing technique based on selective super-sampling at sharp creases and silhouette edges which also benefits from exploiting frame-to-frame coherence. | false | false | [
"Thomas Klein",
"Magnus Strengert",
"Simon Stegmaier",
"Thomas Ertl"
] | [] | [] | [] |
Vis | 2,005 | Exploring 2D tensor fields using stress nets | 10.1109/VISUAL.2005.1532771 | In this article we describe stress nets, a technique for exploring 2D tensor fields. Our method allows a user to examine simultaneously the tensors' eigenvectors (both major and minor) as well as scalar-valued tensor invariants. By avoiding noise-advection techniques, we are able to display both principal directions of the tensor field as well as the derived scalars without cluttering the display. We present a CPU-only implementation of stress nets as well as a hybrid CPU/GPU approach and discuss the relative strengths and weaknesses of each. Stress nets have been used as part of an investigation into crack propagation. They were used to display the directions of maximum shear in a slab of material under tension as well as the magnitude of the shear forces acting on each point. Our methods allowed users to find new features in the data that were not visible on standard plots of tensor invariants. These features disagree with commonly accepted analytical crack propagation solutions and have sparked renewed investigation. Though developed for a materials mechanics problem, our method applies equally well to any 2D tensor field having unique characteristic directions. | false | false | [
"Andrew T. Wilson",
"Rebecca M. Brannon"
] | [] | [] | [] |
Vis | 2,005 | Extracting higher order critical points and topological simplification of 3D vector fields | 10.1109/VISUAL.2005.1532842 | 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 into areas of different flow behavior is equivalent to extracting the topological skeleton of an appropriate 2D vector field on s, if each critical point is equipped with an additional bit of information. Out of this skeleton, we create an icon which replaces the complete topological structure inside s for the visualization. We apply our method to find a simplified visual representation of clusters of critical points, leading to expressive visualizations of topologically complex 3D vector fields. | false | false | [
"Tino Weinkauf",
"Holger Theisel",
"Kuangyu Shi",
"Hans-Christian Hege",
"Hans-Peter Seidel"
] | [] | [] | [] |
Vis | 2,005 | Extraction of parallel vector surfaces in 3D time-dependent fields and application to vortex core line tracking | 10.1109/VISUAL.2005.1532851 | We introduce an approach to tracking vortex core lines in time-dependent 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 act as feature flow fields, i.e., their integration gives the vortex core structures. As part of this approach, we extract and classify local bifurcations of vortex core lines in space-time. Based on a 4D stream surface integration, we provide an algorithm to extract the complete vortex core structure. We apply our technique to a number of test data sets. | false | false | [
"Holger Theisel",
"Jan Sahner",
"Tino Weinkauf",
"Hans-Christian Hege",
"Hans-Peter Seidel"
] | [] | [] | [] |
Vis | 2,005 | Eyegaze analysis of displays with combined 2D and 3D views | 10.1109/VISUAL.2005.1532837 | Displays combining both 2D and 3D views have been shown to support higher performance on certain visualization tasks. However, it is not clear how best to arrange a combination of 2D and 3D views spatially in a display. In this study, we analyzed the eyegaze strategies of participants using two arrangements of 2D and 3D views to estimate the relative position of objects in a 3D scene. Our results show that the 3D view was used significantly more often than individual 2D views in both displays, indicating the importance of the 3D view for successful task completion. However, viewing patterns were significantly different between the two displays: transitions through centrally-placed views were always more frequent, and users avoided saccades between views that were far apart. Although the change in viewing strategy did not result in significant performance differences, error analysis indicates that a 3D overview in the center may reduce the number of serious errors compared to a 3D overview placed off to the side. | false | false | [
"Melanie Tory",
"M. Stella Atkins",
"Arthur E. Kirkpatrick",
"Marios Nicolaou",
"Guang-Zhong Yang"
] | [] | [] | [] |
Vis | 2,005 | Eyelet particle tracing - steady visualization of unsteady flow | 10.1109/VISUAL.2005.1532848 | It is a challenging task to visualize the behavior of time-dependent 3D vector fields. Most of the time an overview of unsteady fields is provided via animations, but, unfortunately, animations provide only transient impressions of momentary flow. In this paper we present two approaches to visualize time varying fields with fixed geometry. Path lines and streak lines represent such a steady visualization of unsteady vector fields, but because of occlusion and visual clutter it is useless to draw them all over the spatial domain. A selection is needed. We show how bundles of streak lines and path lines, running at different times through one point in space, like through an eyelet, yield an insightful visualization of flow structure ("eyelet lines"). To provide a more intuitive and appealing visualization we also explain how to construct a surface from these lines. As second approach, we use a simple measurement of local changes of a field over time to determine regions with strong changes. We visualize these regions with isosurfaces to give an overview of the activity in the dataset. Finally we use the regions as a guide for placing eyelets. | false | false | [
"Alexander Wiebel",
"Gerik Scheuermann"
] | [] | [] | [] |
Vis | 2,005 | Farthest point seeding for efficient placement of streamlines | 10.1109/VISUAL.2005.1532832 | We propose a novel algorithm for placement of streamlines from two-dimensional steady vector or direction fields. Our method consists of placing one streamline at a time by numerical integration starting at the furthest away from all previously placed streamlines. Such a farthest point seeding strategy leads to high quality placements by favoring long streamlines, while retaining uniformity with the increasing density. Our greedy approach generates placements of comparable quality with respect to the optimization approach from Turk and Banks, while being 200 times faster. Simplicity, robustness as well as efficiency is achieved through the use of a Delaunay triangulation to model the streamlines, address proximity queries and determine the biggest voids by exploiting the empty circle property. Our method handles variable density and extends to multiresolution. | false | false | [
"Abdelkrim Mebarki",
"Pierre Alliez",
"Olivier Devillers"
] | [] | [] | [] |
Vis | 2,005 | Fast and reproducible fiber bundle selection in DTI visualization | 10.1109/VISUAL.2005.1532778 | Diffusion tensor imaging (DTI) is an MRI-based technique for quantifying water diffusion in living tissue. In the white matter of the brain, water diffuses more rapidly along the neuronal axons than in the perpendicular direction. By exploiting this phenomenon, DTI can be used to determine trajectories of fiber bundles, or neuronal connections between regions, in the brain. The resulting bundles can be visualized. However, the resulting visualizations can be complex and difficult to interpret. An effective approach is to pre-determine trajectories from a large number of positions throughout the white matter (full brain fiber tracking) and to offer facilities to aid the user in selecting fiber bundles of interest. Two factors are crucial for the use and acceptance of this technique in clinical studies: firstly, the selection of the bundles by brain experts should be interactive, supported by real-time visualization of the trajectories registered with anatomical MRI scans. Secondly, the fiber selections should be reproducible, so that different experts will achieve the same results. In this paper we present a practical technique for the interactive selection of fiber-bundles using multiple convex objects that is an order of magnitude faster than similar techniques published earlier. We also present the results of a clinical study with ten subjects that show that our selection approach is highly reproducible for fractional anisotropy (FA) calculated over the selected fiber bundles. | false | false | [
"Jorik Blaas",
"Charl P. Botha",
"Bart Peters",
"Frans Vos",
"Frits H. Post"
] | [] | [] | [] |
Vis | 2,005 | Fast visualization by shear-warp on quadratic super-spline models using wavelet data decompositions | 10.1109/VISUAL.2005.1532816 | We develop the first approach Tor interactive volume visualization based on a sophisticated rendering method of shear-warp type, wavelet data encoding techniques, and a trivariate spline model, which has been introduced recently. As a first step of our algorithm, we apply standard wavelet expansions to represent and decimate the given gridded three-dimensional data. Based on this data encoding, we give a sophisticated version of the shear-warp based volume rendering method. Our new algorithm visits each voxel only once taking advantage of the particular data organization of octrees. In addition, the hierarchies of the data guide the local (re)construction of the quadratic super-spline models, which we apply as a pure visualization tool. The low total degree of the polynomial pieces allows to numerically approximate the volume rendering integral efficiently. Since the coefficients of the splines are almost immediately available from the given data, Bernstein-Bezier techniques can be fully employed in our algorithms. In this way, we demonstrate that these models can be successfully applied to full volume rendering of hierarchically organized data. Our computational results show that (even when hierarchical approximations are used) the new approach leads to almost artifact-free visualizations of high quality for complicated and noise-contaminated volume data sets, while the computational effort is considerable low, i.e. our current implementation yields 1-2 frames per second for parallel perspective rendering a 2563 volume data set (using simple opacity transfer functions) in a 5122 view-port. | false | false | [
"Gregor Schlosser",
"Jürgen Hesser",
"Frank Zeilfelder",
"Christian Rössl",
"Reinhard Männer",
"Günther Nürnberger",
"Hans-Peter Seidel"
] | [] | [] | [] |
Vis | 2,005 | Framework for visualizing higher-order basis functions | 10.1109/VISUAL.2005.1532776 | Techniques in numerical simulation such as the finite element method depend on basis functions for approximating the geometry and variation of the solution over discrete regions of a domain. Existing visualization systems can visualize these basis functions if they are linear, or for a small set of simple non-linear bases. However, newer numerical approaches often use basis functions of elevated and mixed order or complex form; hence existing visualization systems cannot directly process them. In this paper we describe an approach that supports automatic, adaptive tessellation of general basis functions using a flexible and extensible software architecture in conjunction with an on demand, edge-based recursive subdivision algorithm. The framework supports the use of functions implemented in external simulation packages, eliminating the need to reimplement the bases within the visualization system. We demonstrate our method on several examples, and have implemented the framework in the open-source visualization system VTK. | false | false | [
"William J. Schroeder",
"François Bertel",
"Mathieu Malaterre",
"David C. Thompson 0001",
"Philippe P. Pébay",
"Robert M. O'Bara",
"Saurabh Tendulkar"
] | [] | [] | [] |
Vis | 2,005 | Hardware-accelerated 3D visualization of mass spectrometry data | 10.1109/VISUAL.2005.1532827 | We present a system for three-dimensional visualization of complex liquid chromatography-mass spectrometry (LCMS) data. Every LCMS data point has three attributes: time, mass, and intensity. Instead of the traditional visualization of two-dimensional subsets of the data, we visualize it as a height field or terrain in 3D. Unlike traditional terrains, LCMS data has non-linear sampling and consists mainly of tall needle-like features. We adapt the level-of-detail techniques of geometry clipmaps for hardware-accelerated rendering of LCMS data. The data is cached in video memory as a set of nested rectilinear grids centered about the view frustum. We introduce a simple compression scheme and dynamically stream data from the CPU to the GPU as the viewpoint moves. Our system allows interactive investigation of complex LCMS data with close to one billion data points at up to 130 frames per second, depending on the view conditions. | false | false | [
"Jose De Corral",
"Hanspeter Pfister"
] | [] | [] | [] |
Vis | 2,005 | Hardware-accelerated simulated radiography | 10.1109/VISUAL.2005.1532815 | We present the application of hardware accelerated volume rendering algorithms to the simulation of radiographs as an aid to scientists designing experiments, validating simulation codes, and understanding experimental data. The techniques presented take advantage of 32-bit floating point texture capabilities to obtain solutions to the radiative transport equation for X-rays. The hardware accelerated solutions are accurate enough to enable scientists to explore the experimental design space with greater efficiency than the methods currently in use. An unsorted hexahedron projection algorithm is presented for curvilinear hexahedral meshes that produces simulated radiographs in the absorption-only regime. A sorted tetrahedral projection algorithm is presented that simulates radiographs of emissive materials. We apply the tetrahedral projection algorithm to the simulation of experimental diagnostics for inertial confinement fusion experiments on a laser at the University of Rochester. | false | false | [
"Daniel E. Laney",
"Steven P. Callahan",
"Nelson L. Max",
"Cláudio T. Silva",
"Steven Langer",
"Randall Frank"
] | [] | [] | [] |
Vis | 2,005 | High dynamic range volume visualization | 10.1109/VISUAL.2005.1532812 | High resolution volumes require high precision compositing to preserve detailed structures. This is even more desirable for volumes with high dynamic range values. After the high precision intermediate image has been computed, simply rounding up pixel values to regular display scales loses the computed details. In this paper, we present a novel high dynamic range volume visualization method for rendering volume data with both high spatial and intensity resolutions. Our method performs high precision volume rendering followed by dynamic tone mapping to preserve details on regular display devices. By leveraging available high dynamic range image display algorithms, this dynamic tone mapping can be automatically adjusted to enhance selected features for the final display. We also present a novel transfer function design interface with nonlinear magnification of the density range and logarithmic scaling of the color/opacity range to facilitate high dynamic range volume visualization. By leveraging modern commodity graphics hardware and out-of-core acceleration, our system can produce an effective visualization of huge volume data. | false | false | [
"Xiaoru Yuan",
"Minh X. Nguyen",
"Baoquan Chen",
"David H. Porter"
] | [
"BA"
] | [] | [] |
Vis | 2,005 | High performance volume splatting for visualization of neurovascular data | 10.1109/VISUAL.2005.1532805 | A new technique is presented to increase the performance of volume splatting by using hardware accelerated point sprites. This allows creating screen aligned elliptical splats for high quality volume splatting at very low cost on the GPU. Only one vertex per splat is stored on the graphics card. GPU generated point sprite texture coordinates are used for computing splats and per-fragment 3D-texture coordinates on the fly. Thus, only 6 bytes per splat are stored on the GPU and vertex shader load is 25% in comparison to applying textured quads. For eight predefined viewing directions, depth-sorting of the splats is performed in a pre-processing step where the resulting indices are stored on the GPU. Thereby, there is no data transfer between CPU and GPU during rendering. Post-classificative two dimensional transfer functions with lighting for scalar data and tagged volumes were implemented. Thereby, we focused on the visualization of neurovascular structures, where typically no more than 2% of the voxels contribute to the resulting 3D-representation. A comparison with a 3D-texture-based slicing algorithm showed frame rates up to 11 times higher for the presented approach on current CPUs. The presented technique was evaluated with a broad medical database and its value for highly sparse volume visualization is shown. | false | false | [
"Fernando Vega Higuera",
"Peter Hastreiter",
"Rudolf Fahlbusch",
"Günther Greiner"
] | [] | [] | [] |
Vis | 2,005 | HOT-lines: tracking lines in higher order tensor fields | 10.1109/VISUAL.2005.1532773 | Tensors occur in many areas of science and engineering. Especially, they are used to describe charge, mass and energy transport (i.e. electrical conductivity tensor, diffusion tensor, thermal conduction tensor resp.) If the locale transport pattern is complicated, usual second order tensor representation is not sufficient. So far, there are no appropriate visualization methods for this case. We point out similarities of symmetric higher order tensors and spherical harmonics. A spherical harmonic representation is used to improve tensor glyphs. This paper unites the definition of streamlines and tensor lines and generalizes tensor lines to those applications where second order tensors representations fail. The algorithm is tested on the tractography problem in diffusion tensor magnetic resonance imaging (DT-MRI) and improved for this special application. | false | false | [
"Mario Hlawitschka",
"Gerik Scheuermann"
] | [] | [] | [] |
Vis | 2,005 | Illuminated lines revisited | 10.1109/VISUAL.2005.1532772 | For the rendering of vector and tensor fields, several texture-based volumetric rendering methods were presented in recent years. While they have indisputable merits, the classical vertex-based rendering of integral curves has the advantage of better zooming capabilities as it is not bound to a fixed resolution. It has been shown that lighting can improve spatial perception of lines significantly, especially if lines appear in bundles. Although OpenGL does not directly support lighting of lines, fast rendering of illuminated lines can be achieved by using basic texture mapping. This existing technique is based on a maximum principle which gives a good approximation of specular reflection. Diffuse reflection however is essentially limited to bidirectional lights at infinity. We show how the realism can be further increased by improving diffuse reflection. We present simplified expressions for the Phong/Blinn lighting of infinitesimally thin cylindrical tubes. Based on these, we propose a fast rendering technique with diffuse and specular reflection for orthographic and perspective views and for multiple local and infinite lights. The method requires commonly available programmable vertex and fragment shaders and only two-dimensional lookup textures. | false | false | [
"Ovidio Mallo",
"Ronald Peikert",
"Christian Sigg",
"Filip Sadlo"
] | [] | [] | [] |
Vis | 2,005 | Illustration and photography inspired visualization of flows and volumes | 10.1109/VISUAL.2005.1532858 | Understanding and analyzing complex volumetrically varying data is a difficult problem. Many computational visualization techniques have had only limited success in succinctly portraying the structure of three-dimensional turbulent flow. Motivated by both the extensive history and success of illustration and photographic flow visualization techniques, we have developed a new interactive volume rendering and visualization system for flows and volumes that simulates and enhances traditional illustration, experimental advection, and photographic flow visualization techniques. Our system uses a combination of varying focal and contextual illustrative styles, new advanced two-dimensional transfer functions, enhanced Schlieren and shadowgraphy shaders, and novel oriented structure enhancement techniques to allow interactive visualization, exploration, and comparative analysis of scalar, vector, and time-varying volume datasets. Both traditional illustration techniques and photographic flow visualization techniques effectively reduce visual clutter by using compact oriented structure information to convey three-dimensional structures. Therefore, a key to the effectiveness of our system is using one-dimensional (Schlieren and shadowgraphy) and two-dimensional (silhouette) oriented structural information to reduce visual clutter, while still providing enough three-dimensional structural information for the user's visual system to understand complex three-dimensional flow data. By combining these oriented feature visualization techniques with flexible transfer function controls, we can visualize scalar and vector data, allow comparative visualization of flow properties in a succinct, informative manner, and provide continuity for visualizing time-varying datasets. | false | false | [
"Nikolai A. Svakhine",
"Yun Jang",
"David S. Ebert",
"Kelly P. Gaither"
] | [] | [] | [] |
Vis | 2,005 | Illustration-inspired techniques for visualizing time-varying data | 10.1109/VISUAL.2005.1532857 | Traditionally, time-varying data has been visualized using snapshots of the individual time steps or an animation of the snapshots shown in a sequential manner. For larger datasets with many time-varying features, animation can be limited in its use, as an observer can only track a limited number of features over the last few frames. Visually inspecting each snapshot is not practical either for a large number of time-steps. We propose new techniques inspired from the illustration literature to convey change over time more effectively in a time-varying dataset. Speedlines are used extensively by cartoonists to convey motion, speed, or change over different panels. Flow ribbons are another technique used by cartoonists to depict motion in a single frame. Strobe silhouettes are used to depict previous positions of an object to convey the previous positions of the object to the user. These illustration-inspired techniques can be used in conjunction with animation to convey change over time. | false | false | [
"Alark Joshi",
"Penny Rheingans"
] | [] | [] | [] |
Vis | 2,005 | Illustrative display of hidden iso-surface structures | 10.1109/VISUAL.2005.1532855 | Indirect volume rendering is a widespread method for the display of volume datasets. It is based on the extraction of polygonal iso-surfaces from volumetric data, which are then rendered using conventional rasterization methods. Whereas this rendering approach is fast and relatively easy to implement, it cannot easily provide an understandable display of structures occluded by the directly visible iso-surface. Simple approaches like alpha-blending for transparency when drawing the iso-surface often generate a visually complex output, which is difficult to interpret. Moreover, such methods can significantly increase the computational complexity of the rendering process. In this paper, we therefore propose a new approach for the illustrative indirect rendering of volume data in real-time. This algorithm emphasizes the silhouette of objects represented by the iso-surface. Additionally, shading intensities on objects are reproduced with a monochrome hatching technique. Using a specially designed two-pass rendering process, structures behind the front layer of the iso-surface are automatically extracted with a depth peeling method. The shapes of these hidden structures are also displayed as silhouette outlines. As an additional option, the geometry of explicitly specified inner objects can be displayed with constant translucency. Although these inner objects always remain visible, a specific shading and depth attenuation method is used to convey the depth relationships. We describe the implementation of the algorithm, which exploits the programmability of state-of-the-art graphics processing units (GPUs). The algorithm described in this paper does not require any preprocessing of the input data or a manual definition of inner structures. Since the presented method works on iso-surfaces, which are stored as polygonal datasets, it can also be applied to other types of polygonal models. | false | false | [
"Jan Fischer",
"Dirk Bartz",
"Wolfgang Straßer"
] | [] | [] | [] |
Vis | 2,005 | Interactive rendering of large unstructured grids using dynamic level-of-detail | 10.1109/VISUAL.2005.1532796 | We describe a new dynamic level-of-detail (LOD) technique that allows real-time rendering of large tetrahedral meshes. Unlike approaches that require hierarchies of tetrahedra, our approach uses a subset of the faces that compose the mesh. No connectivity is used for these faces so our technique eliminates the need for topological information and hierarchical data structures. By operating on a simple set of triangular faces, our algorithm allows a robust and straightforward graphics hardware (GPU) implementation. Because the subset of faces processed can be constrained to arbitrary size, interactive rendering is possible for a wide range of data sets and hardware configurations. | false | false | [
"Steven P. Callahan",
"João Luiz Dihl Comba",
"Peter Shirley",
"Cláudio T. Silva"
] | [] | [] | [] |
Vis | 2,005 | Interactive visual analysis and exploration of injection systems simulations | 10.1109/VISUAL.2005.1532821 | Simulations often generate large amounts of data that require use of SciVis techniques for effective exploration of simulation results. In some cases, like 1D theory of fluid dynamics, conventional SciVis techniques are not very useful. One such example is a simulation of injection systems that is becoming more and more important due to an increasingly restrictive emission regulations. There are many parameters and correlations among them that influence the simulation results. We describe how basic information visualization techniques can help in visualizing, understanding and analyzing this kind of data. The Com Vis tool is developed and used to analyze and explore the data. Com Vis supports multiple linked views and common information visualization displays such as 2D and 3D scatter-plot, histogram, parallel coordinates, pie-chart, etc. A diesel common rail injector with 2/2 way valve is used for a case study. Data sets were generated using a commercially available AVL HYDSIM simulation tool for dynamic analysis of hydraulic and hydro-mechanical systems, with the main application area in the simulation of fuel injection systems. | false | false | [
"Kresimir Matkovic",
"Mario Jelovic",
"Josip Juric",
"Zoltan Konyha",
"Denis Gracanin"
] | [] | [] | [] |
Vis | 2,005 | Interpolation and visualization for advected scalar fields | 10.1109/VISUAL.2005.1532849 | Doppler radars are useful facilities for weather forecasting. The data sampled by using Doppler radars are used to measure the distributions and densities of rain drops, snow crystals, hail stones, or even insects in the atmosphere. In this paper, we propose to build up a graphics-based software system for visualizing Doppler radar data. In the system, the reflectivity data gathered by using Doppler radars are post-processed to generate virtual cloud images which reveal the densities of precipitation in the air. An optical flow based method is adopted to compute the velocities of clouds, advected by winds. Therefore, the movement of clouds is depicted. The cloud velocities are also used to interpolate reflectivities for arbitrary time steps. Therefore, the reflectivities at any time can be produced. Our system composes of three stages. At the first stage, the raw radar data are re-sampled and filtered to create a multiple resolution data structure, based on a pyramid structure. At the second stage, a numeric method is employed to compute cloud velocities in the air and to interpolate radar reflectivity data at given time steps. The radar reflectivity data and cloud velocities are displayed at the last stage. The reflectivities are rendered by using splatting methods to produce semi-transparent cloud images. Two kinds of media are created for analyzing the reflectivity data. The first kind media consists of a group of still images of clouds which displays the distribution and density of water in the air. The second type media is a short animation of cloud images to show the formation and movement of the clouds. To show the advection of clouds, the cloud velocities are displayed by using two dimensional images. In these images, the velocities are represented by arrows and superimposed on cloud images. To enhance image quality, gradients and diffusion of the radar data are computed and used in the rendering process. Therefore the cloud structures are better portrayed. In order to achieve interactive visualization, our system is also comprised with a view-dependent visualization module. The radar data at far distance are rendered in lower resolutions, while the data closer to the eye position is rendered in details. | false | false | [
"Shyh-Kuang Ueng",
"Sheng-Chuan Wang"
] | [] | [] | [] |
Vis | 2,005 | Marching diamonds for unstructured meshes | 10.1109/VISUAL.2005.1532825 | We present a higher-order approach to the extraction of isosurfaces from unstructured meshes. Existing methods use linear interpolation along each mesh edge to find isosurface intersections. In contrast, our method determines intersections by performing barycentric interpolation over diamonds formed by the tetrahedra incident to each edge. Our method produces smoother, more accurate isosurfaces. Additionally, interpolating over diamonds, rather than linearly interpolating edge endpoints. enables us to identify up to two isosurface intersections per edge. This paper details how our new technique extracts isopoints, and presents a simple connection strategy for forming a triangle mesh isosurface. | false | false | [
"John C. Anderson",
"Janine Bennett",
"Kenneth I. Joy"
] | [] | [] | [] |
Vis | 2,005 | Multimodal exploration of the fourth dimension | 10.1109/VISUAL.2005.1532804 | We present a multimodal paradigm for exploring topological surfaces embedded in four dimensions; we exploit haptic methods in particular to overcome the intrinsic limitations of 3D graphics images and 3D physical models. The basic problem is that, just as 2D shadows of 3D curves lose structure where lines cross, 3D graphics projections of smooth 4D topological surfaces are interrupted where one surface intersects another. Furthermore, if one attempts to trace real knotted ropes or a plastic models of self-intersecting surfaces with a fingertip, one inevitably collides with parts of the physical artifact. In this work, we exploit the free motion of a computer-based haptic probe to support a continuous motion that follows the local continuity of the object being explored. For our principal test case of 4D-embedded surfaces projected to 3D, this permits us to follow the full local continuity of the surface as though in fact we were touching an actual 4D object. We exploit additional sensory cues to provide supplementary or redundant information. For example, we can use audio tags to note the relative 4D depth of illusory 3D surface intersections produced by projection from 4D, as well as providing automated refinement of the tactile exploration path to eliminate jitter and snagging, resulting in a much cleaner exploratory motion than a bare uncorrected motion. Visual enhancements provide still further improvement to the feedback: by opening a view-direction-defined cutaway into the interior of the 3D surface projection, we allow the viewer to keep the haptic probe continuously in view as it traverses any touchable part of the object. Finally, we extend the static tactile exploration framework using a dynamic mode that links each stylus motion to a change in orientation that creates at each instant a maximal-area screen projection of a neighborhood of the current point of interest. This minimizes 4D distortion and permits true metric sizes to be deduced locally at any point. All these methods combine to reveal the full richness of the complex spatial relationships of the target shapes, and to overcome many expected perceptual limitations in 4D visualization. | false | false | [
"Andrew J. Hanson",
"Hui Zhang 0006"
] | [] | [] | [] |
Vis | 2,005 | On the optimization of visualizations of complex phenomena | 10.1109/VISUAL.2005.1532782 | The problem of perceptually optimizing complex visualizations is a difficult one, involving perceptual as well as aesthetic issues. In our experience, controlled experiments are quite limited in their ability to uncover interrelationships among visualization parameters, and thus may not be the most useful way to develop rules-of-thumb or theory to guide the production of high-quality visualizations. In this paper, we propose a new experimental approach to optimizing visualization quality that integrates some of the strong points of controlled experiments with methods more suited to investigating complex highly-coupled phenomena. We use human-in-the-loop experiments to search through visualization parameter space, generating large databases of rated visualization solutions. This is followed by data mining to extract results such as exemplar visualizations, guidelines for producing visualizations, and hypotheses about strategies leading to strong visualizations. The approach can easily address both perceptual and aesthetic concerns, and can handle complex parameter interactions. We suggest a genetic algorithm as a valuable way of guiding the human-in-the-loop search through visualization parameter space. We describe our methods for using clustering, histogramming, principal component analysis, and neural networks for data mining. The experimental approach is illustrated with a study of the problem of optimal texturing for viewing layered surfaces so that both surfaces are maximally observable. | false | false | [
"Donald H. House",
"Alethea Bair",
"Colin Ware"
] | [] | [] | [] |
Vis | 2,005 | OpenGL multipipe SDK: a toolkit for scalable parallel rendering | 10.1109/VISUAL.2005.1532786 | We describe OpenGL multipipe SDK (MPK), a toolkit for scalable parallel rendering based on OpenGL. MPK provides a uniform application programming interface (API) to manage scalable graphics applications across many different graphics subsystems. MPK-based applications run seamlessly from single-processor, single-pipe desktop systems to large multi-processor, multipipe scalable graphics systems. The application is oblivious of the system configuration, which can be specified through a configuration file at run time. To scale application performance, MPK uses a decomposition system that supports different modes for task partitioning and implements optimized CPU-based composition algorithms. MPK also provides a customizable image composition interface, which can be used to apply post-processing algorithms on raw pixel data obtained from executing sub-tasks on multiple graphics pipes in parallel. This can be used to implement parallel versions of any CPU-based algorithm, not necessarily used for rendering. In this paper, we motivate the need for a scalable graphics API and discuss the architecture of MPK. We present MPK's graphics configuration interface, introduce the notion of compound-based decomposition schemes and describe our implementation. We present some results from our work on a couple of target system architectures and conclude with future directions of research in this area. | false | false | [
"Praveen Bhaniramka",
"Philippe C. D. Robert",
"Stefan Eilemann"
] | [] | [] | [] |
Vis | 2,005 | Opening the black box - data driven visualization of neural networks | 10.1109/VISUAL.2005.1532820 | Artificial neural networks are computer software or hardware models inspired by the structure and behavior of neurons in the human nervous system. As a powerful learning tool, increasingly neural networks have been adopted by many large-scale information processing applications but there is no a set of well defined criteria for choosing a neural network. The user mostly treats a neural network as a black box and cannot explain how learning from input data was done nor how performance can be consistently ensured. We have experimented with several information visualization designs aiming to open the black box to possibly uncover underlying dependencies between the input data and the output data of a neural network. In this paper, we present our designs and show that the visualizations not only help us design more efficient neural networks, but also assist us in the process of using neural networks for problem solving such as performing a classification task. | false | false | [
"Fan-Yin Tzeng",
"Kwan-Liu Ma"
] | [] | [] | [] |
Vis | 2,005 | Opening the can of worms: an exploration tool for vortical flows | 10.1109/VISUAL.2005.1532830 | Gaining a comprehensive understanding of turbulent flows still poses one of the great challenges in fluid dynamics. A well-established approach to advance this research is the analysis of the vortex structures contained in the flow. In order to be able to perform this analysis efficiently, supporting visualization tools with clearly defined requirements are needed. In this paper, we present a visualization system which matches these requirements to a large extent. The system consists of two components. The first component analyzes the flow by means of a novel combination of vortex core line detection and the /spl lambda//sub 2/ method. The second component is a vortex browser which allows for an interactive exploration and manipulation of the vortices detected and separated during the first phase. Our system improves the reliability and applicability of existing vortex detection methods and allows for a more efficient study of vortical flows which is demonstrated in an evaluation performed by experts. | false | false | [
"Simon Stegmaier",
"Ulrich Rist",
"Thomas Ertl"
] | [] | [] | [] |
Vis | 2,005 | Particle and texture based spatiotemporal visualization of time-dependent vector fields | 10.1109/VISUAL.2005.1532852 | We propose a hybrid particle and texture based approach for the visualization of time-dependent vector fields. The underlying space-time framework builds a dense vector field representation in a two-step process: 1) particle-based forward integration of trajectories in spacetime for temporal coherence, and 2) texture-based convolution along another set of paths through the spacetime for spatially correlated patterns. Particle density is controlled by stochastically injecting and removing particles, taking into account the divergence of the vector field. Alternatively, a uniform density can be maintained by placing exactly one particle in each cell of a uniform grid, which leads to particle-in-cell forward advection. Moreover, we discuss strategies of previous visualization methods for unsteady flow and show how they address issues of spatiotemporal coherence and dense visual representations. We demonstrate how our framework is capable of realizing several of these strategies. Finally, we present an efficient GPU implementation that facilitates an interactive visualization of unsteady 2D flow on Shader Model 3 compliant graphics hardware. | false | false | [
"Daniel Weiskopf",
"Frederik Schramm",
"Gordon Erlebacher",
"Thomas Ertl"
] | [] | [] | [] |
Vis | 2,005 | Phonon tracing for auralization and visualization of sound | 10.1109/VISUAL.2005.1532790 | We present a new particle tracing approach for the simulation of mid- and high-frequency sound. Inspired by the photorealism obtained by methods like photon mapping, we develop a similar method for the physical simulation of sound within rooms. For given source and listener positions, our method computes a finite-response filter accounting for the different reflections at various surfaces with frequency-dependent absorption coefficients. Convoluting this filter with an anechoic input signal reproduces a realistic aural impression of the simulated room. We do not consider diffraction effects due to low frequencies, since these can be better computed by finite elements. Our method allows the visualization of a wave front propagation using color-coded blobs traversing the paths of individual phonons. | false | false | [
"Martin Hering-Bertram",
"Eduard Deines",
"Jan Mohring",
"Jevgenijs Jegorovs",
"Hans Hagen"
] | [] | [] | [] |
Vis | 2,005 | Prefiltered Gaussian reconstruction for high-quality rendering of volumetric data sampled on a body-centered cubic grid | 10.1109/VISUAL.2005.1532810 | In this paper a novel high-quality reconstruction scheme is presented. Although our method is mainly proposed to reconstruct volumetric data sampled on an optimal body-centered cubic (BCC) grid, it can be easily adapted lo the conventional regular rectilinear grid as well. The reconstruction process is decomposed into two steps. The first step, which is considered to be a preprocessing, is a discrete Gaussian deconvolution performed only once in the frequency domain. Afterwards, the second step is a spatial-domain convolution with a truncated Gaussian kernel, which is used to interpolate arbitrary samples for ray casting. Since the preprocessing is actually a discrete prefiltering, we call our technique prefiltered Gaussian reconstruction (PGR). It is shown that the impulse response of PGR well approximates the ideal reconstruction kernel. Therefore the quality of PGR is much higher than that of previous reconstruction techniques proposed for optimally sampled data, which are based on linear and cubic box splines adapted to the BCC grid. Concerning the performance, PGR is slower than linear box-spline reconstruction but significantly faster than cubic box-spline reconstruction. | false | false | [
"Balázs Csébfalvi"
] | [] | [] | [] |
Vis | 2,005 | Profile Flags: a novel metaphor for probing of T₂ maps | 10.1109/VISUAL.2005.1532847 | This paper describes a tool for the visualization of T/sub 2/ maps of knee cartilage. Given the anatomical scan, and the T/sub 2/ map of the cartilage, we combine the information on the shape and the quality of the cartilage in a single image. The Profile Flag is an intuitive 3D glyph for probing and annotating of the underlying data. It comprises a bulletin board pin-like shape with a small flag on top of it. While moving the glyph along the reconstructed surface of an object, the curve data measured along the pin's needle and in its neighborhood are shown on the flag. The application area of the Profile Flag is manifold, enabling the visualization of profile data of dense but in-homogeneous objects. Furthermore, it extracts the essential part of the data without removing or even reducing the context information. By sticking Profile Flags into the investigated structure, one or more significant locations can be annotated by showing the local characteristics of the data at that locations. In this paper we are demonstrating the properties of the tool by visualizing T/sub 2/ maps of knee cartilage. | false | false | [
"Matej Mlejnek",
"Pierre Ermes",
"Anna Vilanova",
"Rob van der Rijt",
"Harrie van den Bosch",
"Frans A. Gerritsen",
"M. Eduard Gröller"
] | [] | [] | [] |
Vis | 2,005 | Quality mesh generation for molecular skin surfaces using restricted union of balls | 10.1109/VISUAL.2005.1532822 | Quality surface meshes for molecular models are desirable in the studies of protein shapes and functionalities. However, there is still no robust software that is capable to generate such meshes with good quality. In this paper, we present a Delaunay-based surface triangulation algorithm generating quality surface meshes for the molecular skin model. We expand the restricted union of balls along the surface and generate an /spl epsiv/-sampling of the skin surface incrementally. At the same time, a quality surface mesh is extracted from the Delaunay triangulation of the sample points. The algorithm supports robust and efficient implementation and guarantees the mesh quality and topology as well. Our results facilitate molecular visualization and have made a contribution towards generating quality volumetric tetrahedral meshes for the macromolecules. | false | false | [
"Ho-Lun Cheng",
"Xinwei Shi"
] | [] | [] | [] |
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