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 |
|---|---|---|---|---|---|---|---|---|---|---|
Vis | 2,005 | Query-driven visualization of large data sets | 10.1109/VISUAL.2005.1532792 | We present a practical and general-purpose approach to large and complex visual data analysis where visualization processing, rendering and subsequent human interpretation is constrained to the subset of data deemed interesting by the user. In many scientific data analysis applications, "interesting" data can be defined by compound Boolean range queries of the form (temperature>1000) AND (70<pressure<90). As data sizes grow larger, a central challenge is to answer such queries as efficiently as possible. Prior work in the visualization community has focused on answering range queries for scalar fields within the context of accelerating the search phase of isosurface algorithms. In contrast, our work describes an approach that leverages state-of-the-art indexing technology from the scientific data management community called "bitmap indexing". Our implementation, which we call "DEX" (short for dextrous data explorer), uses bitmap indexing to efficiently answer multivariate, multidimensional data queries to provide input to a visualization pipeline. We present an analysis overview and benchmark results that show bitmap indexing offers significant storage and performance improvements when compared to previous approaches for accelerating the search phase of isosurface algorithms. More importantly, since bitmap indexing supports complex multidimensional, multivariate range queries, it is more generally applicable to scientific data visualization and analysis problems. In addition to benchmark performance and analysis, we apply DEX to a typical scientific visualization problem encountered in combustion simulation data analysis. | false | false | [
"Kurt Stockinger",
"John Shalf",
"Kesheng Wu",
"E. Wes Bethel"
] | [] | [] | [] |
Vis | 2,005 | Reconstructing manifold and non-manifold surfaces from point clouds | 10.1109/VISUAL.2005.1532824 | This paper presents a novel approach for surface reconstruction from point clouds. The proposed technique is general in the sense that it naturally handles both manifold and non-manifold surfaces, providing a consistent way for reconstructing closed surfaces as well as surfaces with boundaries. It is also robust in the presence of noise, irregular sampling and surface gaps. Furthermore, it is fast, parallelizable and easy to implement because it is based on simple local operations. In this approach, surface reconstruction consists of three major steps: first, the space containing the point cloud is subdivided, creating a voxel representation. Then, a voxel surface is computed using gap filling and topological thinning operations. Finally, the resulting voxel surface is converted into a polygonal mesh. We demonstrate the effectiveness of our approach by reconstructing polygonal models from range scans of real objects as well as from synthetic data. | false | false | [
"Jianning Wang",
"Manuel Menezes de Oliveira Neto",
"Arie E. Kaufman"
] | [] | [] | [] |
Vis | 2,005 | Reflection nebula visualization | 10.1109/VISUAL.2005.1532803 | Stars form in dense clouds of interstellar gas and dust. The residual dust surrounding a young star scatters and diffuses its light, making the star's "cocoon" of dust observable from Earth. The resulting structures, called reflection nebulae, are commonly very colorful in appearance due to wavelength-dependent effects in the scattering and extinction of light. The intricate interplay of scattering and extinction cause the color hues, brightness distributions, and the apparent shapes of such nebulae to vary greatly with viewpoint. We describe an interactive visualization tool for realistically rendering the appearance of arbitrary 3D dust distributions surrounding one or more illuminating stars. Our rendering algorithm is based on the physical models used in astrophysics research. The tool can be used to create virtual fly-throughs of reflection nebulae for interactive desktop visualizations, or to produce scientifically accurate animations for educational purposes, e.g., in planetarium shows. The algorithm is also applicable to investigate on-the-fly the visual effects of physical parameter variations, exploiting visualization technology to help gain a deeper and more intuitive understanding of the complex interaction of light and dust in real astrophysical settings. | false | false | [
"Marcus A. Magnor",
"Kristian Hildebrand",
"Andrei Lintu",
"Andrew J. Hanson"
] | [] | [] | [] |
Vis | 2,005 | Rendering tetrahedral meshes with higher-order attenuation functions for digital radiograph reconstruction | 10.1109/VISUAL.2005.1532809 | This paper presents a novel method for computing simulated x-ray images, or DRRs (digitally reconstructed radiographs), of tetrahedral meshes with higher-order attenuation functions. DRRs are commonly used in computer assisted surgery (CAS), with the attenuation function consisting of a voxelized CT study, which is viewed from different directions. Our application of DRRs is in intra-operative "2D-3D" registration, i.e., finding the pose of the CT dataset given a small number of patient radiographs. We register 2D patient images with a statistical tetrahedral model, which encodes the CT intensity numbers as Bernstein polynomials, and includes knowledge about typical shape variation modes. The unstructured grid is more suitable for applying deformations than a rectilinear grid, and the higher-order polynomials provide a better approximation of the actual density than constant or linear models. The infra-operative environment demands a fast method for creating the DRRs, which we present here. We demonstrate this application through the creation and use of a deformable atlas of human pelvis bones. Compared with other works on rendering unstructured grids, the main contributions of this work are: 1) Simple and perspective-correct interpolation of the thickness of a tetrahedral cell. 2) Simple and perspective-correct interpolation of front and back barycentric coordinates with respect to the cell. 3) Computing line integrals of higher-order functions. 4) Capability of applying shape deformations and variations in the attenuation function without significant performance loss. The method does not depend on for pre-integration, and does not require depth-sorting of the visualized cells. We present imaging and timing results of implementing the algorithm, and discuss the impact of using higher-order functions on the quality of the result and the performance. | false | false | [
"Ofri Sadowsky",
"Jonathan D. Cohen 0001",
"Russell H. Taylor"
] | [] | [] | [] |
Vis | 2,005 | Scale-invariant volume rendering | 10.1109/VISUAL.2005.1532808 | As standard volume rendering is based on an integral in physical space (or "coordinate space"), it is inherently dependent on the scaling of this space. Although this dependency is appropriate for the realistic rendering of semitransparent volumetric objects, it has several unpleasant consequences for volume visualization. In order to overcome these disadvantages, a new variant of the volume rendering integral is proposed, which is defined in data space instead of physical space. Apart from achieving scale invariance, this new method supports the rendering of isosurfaces of uniform opacity and color, independently of the local gradient or" the visualized scalar field. Moreover, it reveals certain structures in scalar fields even with constant transfer functions. Furthermore, it can be defined as the limit of infinitely many semitransparent isosurfaces, and is therefore based on an intuitive and at the same time precise definition. In addition to the discussion of these features of scale-invariant volume rendering, efficient adaptations of existing volume rendering algorithms and extensions for silhouette enhancement and local illumination by transmitted light are presented. | false | false | [
"Martin Kraus"
] | [] | [] | [] |
Vis | 2,005 | Sort-middle multi-projector immediate-mode rendering in Chromium | 10.1109/VISUAL.2005.1532784 | Traditionally, sort-middle is a technique that has been difficult to attain on clusters because of the tight coupling of geometry and rasterization processes on commodity graphics hardware. In this paper, we describe the implementation of a new sort-middle approach for performing immediate-mode rendering in Chromium. The Chromium Rendering System is used extensively to drive multi-projector displays on PC clusters with inexpensive commodity graphics components. By default, Chromium uses a sort-first approach to distribute rendering work to individual nodes in a PC cluster. While this sort-first approach works effectively in retained-mode rendering, it suffers from various network bottlenecks when rendering in immediate-mode. Current techniques avoid these bottlenecks by sorting vertex data as a pre-processing step and grouping vertices into specific bounding boxes, using Chromium's bounding box extension. These steps may be expensive, especially if the dataset is dynamic. In our approach, we utilize standard programmable graphics hardware and extend standard APIs to achieve a separation in the rendering pipeline. The pre-processing of vertex data or the grouping of vertices into bounding boxes are not required. Additionally, the amount of OpenGL state commands transmitted through the network are reduced. Our results indicate that the approach can attain twice the frame rates as compared to Chromium's sort-first approach when rendering in immediate-mode. | false | false | [
"Jorge Luis Williams",
"Robert E. Hiromoto"
] | [] | [] | [] |
Vis | 2,005 | Statistically quantitative volume visualization | 10.1109/VISUAL.2005.1532807 | Visualization users are increasingly in need of techniques for assessing quantitative uncertainty and error in the images produced. Statistical segmentation algorithms compute these quantitative results, yet volume rendering tools typically produce only qualitative imagery via transfer function-based classification. This paper presents a visualization technique that allows users to interactively explore the uncertainty, risk, and probabilistic decision of surface boundaries. Our approach makes it possible to directly visualize the combined "fuzzy" classification results from multiple segmentations by combining these data into a unified probabilistic data space. We represent this unified space, the combination of scalar volumes from numerous segmentations, using a novel graph-based dimensionality reduction scheme. The scheme both dramatically reduces the dataset size and is suitable for efficient, high quality, quantitative visualization. Lastly, we show that the statistical risk arising from overlapping segmentations is a robust measure for visualizing features and assigning optical properties. | false | false | [
"Joe Michael Kniss",
"Robert L. Van Uitert Jr.",
"Abraham Stephens",
"Guo-Shi Li",
"Tolga Tasdizen",
"Charles D. Hansen"
] | [] | [] | [] |
Vis | 2,005 | Strategy for seeding 3D streamlines | 10.1109/VISUAL.2005.1532831 | This paper presents a strategy for seeding streamlines in 3D flow fields. Its main goal is to capture the essential flow patterns and to provide sufficient coverage in the field while reducing clutter. First, critical points of the flow field are extracted to identify regions with important flow patterns that need to be presented. Different seeding templates are then used around the vicinity of the different critical points. Because there is significant variability in the flow pattern even for the same type of critical point, our template can change shape depending on how far the critical point is from transitioning into another type of critical point. To accomplish this, we introduce the /spl alpha/-/spl beta/ map of 3D critical points. Next, we use Poisson seeding to populate the empty regions. Finally, we filter the streamlines based on their geometric and spatial properties. Altogether, this multi-step strategy reduces clutter and yet captures the important 3D flow features. | false | false | [
"Xiaohong Ye",
"David L. Kao",
"Alex T. Pang"
] | [] | [] | [] |
Vis | 2,005 | Stream-processing points | 10.1109/VISUAL.2005.1532801 | With the growing size of captured 3D models it has become increasingly important to provide basic efficient processing methods for large unorganized raw surface-sample point data sets. In this paper we introduce a novel stream-based (and out-of-core) point processing framework. The proposed approach processes points in an orderly sequential way by sorting them and sweeping along a spatial dimension. The major advantages of this new concept are: (1) support of extensible and concatenate local operators called stream operators, (2) low main-memory usage and (3) applicability to process very large data sets out-of-core. | false | false | [
"Renato Pajarola"
] | [] | [] | [] |
Vis | 2,005 | Streaming meshes | 10.1109/VISUAL.2005.1532800 | Recent years have seen an immense increase in the complexity of geometric data sets. Today's gigabyte-sized polygon models can no longer be completely loaded into the main memory of common desktop PCs. Unfortunately, current mesh formats, which were designed years ago when meshes were orders of magnitudes smaller, do not account for this. Using such formats to store large meshes is inefficient and complicates all subsequent processing. We describe a streaming format for polygon meshes that is simple enough to replace current offline mesh formats and is more suitable for representing large data sets. Furthermore, it is an ideal input and output format for I/O-efficient out-of-core algorithms that process meshes in a streaming, possibly pipelined, fashion. This paper chiefly concerns the underlying theory and the practical aspects of creating and working with this new representation. In particular, we describe desirable qualities for streaming meshes and methods for converting meshes from a traditional to a streaming format. A central theme of this paper is the issue of coherent and compatible layouts of the mesh vertices and polygons. We present metrics and diagrams that characterize the coherence of a mesh layout and suggest appropriate strategies for improving its "streamability". To this end, we outline several out-of-core algorithms for reordering meshes with poor coherence, and present results for a menagerie of well known and generally incoherent surface meshes. | false | false | [
"Martin Isenburg",
"Peter Lindstrom 0001"
] | [] | [] | [] |
Vis | 2,005 | Surface reconstruction via contour metamorphosis: an Eulerian approach with Lagrangian particle tracking | 10.1109/VISUAL.2005.1532823 | We present a robust method for 3D reconstruction of closed surfaces from sparsely sampled parallel contours. A solution to this problem is especially important for medical segmentation, where manual contouring of 2D imaging scans is still extensively used. Our proposed method is based on a morphing process applied to neighboring contours that sweeps out a 3D surface. Our method is guaranteed to produce closed surfaces that exactly pass through the input contours, regardless of the topology of the reconstruction. Our general approach consecutively morphs between sets of input contours using an Eulerian formulation (i.e. fixed grid) augmented with Lagrangian particles (i.e. interface tracking). This is numerically accomplished by propagating the input contours as 2D level sets with carefully constructed continuous speed functions. Specifically this involves particle advection to estimate distances between the contours, monotonicity constrained spline interpolation to compute continuous speed functions without overshooting, and state-of-the-art numerical techniques for solving the level set equations. We demonstrate the robustness of our method on a variety of medical, topographic and synthetic data sets. | false | false | [
"Ola Nilsson",
"David E. Breen",
"Ken Museth"
] | [] | [] | [] |
Vis | 2,005 | Teniae coli guided navigation and registration for virtual colonoscopy | 10.1109/VISUAL.2005.1532806 | We present a new method for guiding virtual colonoscopic navigation and registration by using teniae coli as anatomical landmarks. As most existing protocols require a patient to be scanned in both supine and prone positions to increase sensitivity in detecting colonic polyps, reference and registration between scans are necessary. However, the conventional centerline approach, generating only the longitudinal distance along the colon, lacks the necessary orientation information to synchronize the virtual navigation cameras in both scanned positions. In this paper we describe a semi-automatic method to detect teniae coli from a colonic surface model reconstructed from CT colonography. Teniae coli are three bands of longitudinal smooth muscle on the surface of the colon. They form a triple helix structure from the appendix to the sigmoid colon and are ideal references for virtual navigation. Our method was applied to 3 patients resulting in 6 data sets (supine and prone scans). The detected teniae coli matched well with our visual inspection. In addition, we demonstrate that polyps visible on both scans can be located and matched more efficiently with the aid of a teniae coli guided navigation implementation. | false | false | [
"Adam Huang",
"Dave Roy",
"Marek Franaszek",
"Ronald M. Summers"
] | [] | [] | [] |
Vis | 2,005 | Texture-based visualization of uncertainty in flow fields | 10.1109/VISUAL.2005.1532853 | In this paper, we present two novel texture-based techniques to visualize uncertainty in time-dependent 2D flow fields. Both methods use semi-Lagrangian texture advection to show flow direction by streaklines and convey uncertainty by blurring these streaklines. The first approach applies a cross advection perpendicular to the flow direction. The second method employs isotropic diffusion that can be implemented by Gaussian filtering. Both methods are derived from a generic filtering process that is incorporated into the traditional texture advection pipeline. Our visualization methods allow for a continuous change of the density of flow representation by adapting the density of particle injection. All methods can be mapped to efficient GPU implementations. Therefore, the user can interactively control all important characteristics of the system like particle density, error influence, or dye injection to create meaningful illustrations of the underlying uncertainty. Even though there are many sources of uncertainties, we focus on uncertainty that occurs during data acquisition. We demonstrate the usefulness of our methods for the example of real-world fluid flow data measured with the particle image velocimetry (PIV) technique. Furthermore, we compare these techniques with an adapted multi-frequency noise approach. | false | false | [
"Ralf P. Botchen",
"Daniel Weiskopf",
"Thomas Ertl"
] | [] | [] | [] |
Vis | 2,005 | The application of GPU particle tracing to diffusion tensor field visualization | 10.1109/VISUAL.2005.1532780 | In this paper we introduce GPU particle tracing for the visualization of 3D diffusion tensor fields. For about half a million particles, reconstruction of diffusion directions from the tensor field, time integration and rendering can be done at interactive rates. Different visualization options like oriented particles of diffusion-dependent shape, stream lines or stream tubes facilitate the use of particle tracing for diffusion tensor visualization. The proposed methods provide efficient and intuitive means to show the dynamics in diffusion tensor fields, and they accommodate the exploration of the diffusion properties of biological tissue. | false | false | [
"Polina Kondratieva",
"Jens H. Krüger",
"Rüdiger Westermann"
] | [] | [] | [] |
Vis | 2,005 | The magic volume lens: an interactive focus+context technique for volume rendering | 10.1109/VISUAL.2005.1532818 | The size and resolution of volume datasets in science and medicine are increasing at a rate much greater than the resolution of the screens used to view them. This limits the amount of data that can be viewed simultaneously, potentially leading to a loss of overall context of the data when the user views or zooms into a particular area of interest. We propose a focus+context framework that uses various standard and advanced magnification lens rendering techniques to magnify the features of interest, while compressing the remaining volume regions without clipping them away completely. Some of these lenses can be interactively configured by the user to specify the desired magnification patterns, while others are feature-adaptive. All our lenses are accelerated on the GPU. They allow the user to interactively manage the available screen area, dedicating more area to the more resolution-important features. | false | false | [
"Lujin Wang",
"Ye Zhao 0004",
"Klaus Mueller 0001",
"Arie E. Kaufman"
] | [] | [] | [] |
Vis | 2,005 | The software interface to the 3D-force microscope | 10.1109/VISUAL.2005.1532829 | We have developed a real-time experiment-control and data-display system for a novel microscope, the 3D-force microscope (3DFM), which is designed for nanometer-scale and nanoNewton-force biophysical experiments. The 3DFM software suite synthesizes the several data sources from the 3DFM into a coherent view and provides control over data collection and specimen manipulation. Herein, we describe the system architecture designed to handle the several feedback loops and data flows present in the microscope and its control system. We describe the visualization techniques used in the 3DFM software suite, where used, and on which types of data. We present feedback from our scientist-users regarding the usefulness of these techniques, and we also present lessons learned from our successive implementations. | false | false | [
"David Marshburn",
"Chris Weigle",
"Benjamin G. Wilde",
"Russell M. Taylor II",
"Kalpit Desai",
"J. K. Fisher",
"Jeremy Cribb",
"E. Timothy O'Brien",
"Richard Superfine"
] | [] | [] | [] |
Vis | 2,005 | The value of visualization | 10.1109/VISUAL.2005.1532781 | The field of visualization is getting mature. Many problems have been solved, and new directions are sought for. In order to make good choices, an understanding of the purpose and meaning of visualization is needed. Especially, it would be nice if we could assess what a good visualization is. In this paper an attempt is made to determine the value of visualization. A technological viewpoint is adopted, where the value of visualization is measured based on effectiveness and efficiency. An economic model of visualization is presented, and benefits and costs are established. Next, consequences (brand limitations of visualization are discussed (including the use of alternative methods, high initial costs, subjective/less, and the role of interaction), as well as examples of the use of the model for the judgement of existing classes of methods and understanding why they are or are not used in practice. Furthermore, two alternative views on visualization are presented and discussed: viewing visualization as an art or as a scientific discipline. Implications and future directions are identified. | false | false | [
"Jarke J. van Wijk"
] | [
"TT",
"BP"
] | [] | [] |
Vis | 2,005 | The visible radio: process visualization of a software-defined radio | 10.1109/VISUAL.2005.1532791 | In this case study, a data-oriented approach is used to visualize a complex digital signal processing pipeline. The pipeline implements a frequency modulated (FM) software-defined radio (SDR). SDR is an emerging technology where portions of the radio hardware, such as filtering and modulation, are replaced by software components. We discuss how an SDR implementation is instrumented to illustrate the processes involved in FM transmission and reception. By using audio-encoded images, we illustrate the processes involved in radio, such as how filters are used to reduce noise, the nature of a carrier wave, and how frequency modulation acts on a signal. The visualization approach used in this work is very effective in demonstrating advanced topics in digital signal processing and is a useful tool for experimenting with the software radio design. | false | false | [
"Matthew Hall",
"Alex Betts",
"Donna J. Cox",
"David Pointer",
"Volodymyr V. Kindratenko"
] | [] | [] | [] |
Vis | 2,005 | Topological structures of 3D tensor fields | 10.1109/VISUAL.2005.1532841 | Tensor topology is useful in providing a simplified and yet detailed representation of a tensor field. Recently the field of 3D tensor topology is advanced by the discovery that degenerate tensors usually form lines in their most basic configurations. These lines form the backbone for further topological analysis. A number of ways for extracting and tracing the degenerate tensor lines have also been proposed. In this paper, we complete the previous work by studying the behavior and extracting the separating surfaces emanating from these degenerate lines. First, we show that analysis of eigenvectors around a 3D degenerate tensor can be reduced to 2D. That is, in most instances, the 3D separating surfaces are just the trajectory of the individual 2D separatrices which includes trisectors and wedges. But the proof is by no means trivial since it is closely related to perturbation theory around a pair of singular slate. Such analysis naturally breaks down at the tangential points where the degenerate lines pass through the plane spanned by the eigenvectors associated with the repeated eigenvalues. Second, we show that the separatrices along a degenerate line may switch types (e.g. trisectors to wedges) exactly at the points where the eigenplane is tangential to the degenerate curve. This property leads to interesting and yet complicated configuration of surfaces around such transition points. Finally, we apply the technique to several common data sets to verify its correctness. | false | false | [
"Xiaoqiang Zheng",
"Beresford N. Parlett",
"Alex T. Pang"
] | [] | [] | [] |
Vis | 2,005 | Topology-based simplification for feature extraction from 3D scalar fields | 10.1109/VISUAL.2005.1532839 | In this paper, we present a topological approach for simplifying continuous functions defined on volumetric domains. We introduce two atomic operations that remove pairs of critical points of the function and design a combinatorial algorithm that simplifies the Morse-Smale complex by repeated application of these operations. The Morse-Smale complex is a topological data structure that provides a compact representation of gradient flow between critical points of a function. Critical points paired by the Morse-Smale complex identify topological features and their importance. The simplification procedure leaves important critical points untouched, and is therefore useful for extracting desirable features. We also present a visualization of the simplified topology. | false | false | [
"Attila Gyulassy",
"Vijay Natarajan",
"Valerio Pascucci",
"Peer-Timo Bremer",
"Bernd Hamann"
] | [] | [] | [] |
Vis | 2,005 | Topology-driven surface mappings with robust feature alignment | 10.1109/VISUAL.2005.1532840 | Topological concepts and techniques have been broadly applied in computer graphics and geometric modeling. However, the homotopy type of a mapping between two surfaces has not been addressed before. In this paper, we present a novel solution to the problem of computing continuous maps with different homotopy types between two arbitrary triangle meshes with the same topology. Inspired by the rich theory of topology as well as the existing body of work on surface mapping, our newly-developed mapping techniques are both fundamental and unique, offering many attractive advantages. First, our method allows the user to change the homotopy type or global structure of the mapping with minimal intervention. Moreover, to locally affect shape correspondence, we articulate a new technique that robustly satisfies hard feature constraints, without the use of heuristics to ensure validity. In addition to acting as a useful tool for computer graphics applications, our method can be used as a rigorous and practical mechanism for the visualization of abstract topological concepts such as homotopy type of surface mappings, homology basis, fundamental domain, and universal covering space. At the core of our algorithm is a procedure for computing the canonical homology basis and using it as a common cut graph for any surface with the same topology. We demonstrate our results by applying our algorithm to shape morphing in this paper. | false | false | [
"Christopher Carner",
"Miao Jin",
"Xianfeng Gu",
"Hong Qin"
] | [] | [] | [] |
Vis | 2,005 | Understanding visualization through spatial ability differences | 10.1109/VISUAL.2005.1532836 | Little is known about the cognitive abilities which influence the comprehension of scientific and information visualizations and what properties of the visualization affect comprehension. Our goal in this paper is to understand what makes visualizations difficult. We address this goal by examining the spatial ability differences in a diverse population selected for spatial ability variance. For example, how is, spatial ability related to visualization comprehension? What makes a particular visualization difficult or time intensive for specific groups of subjects? In this paper, we present the results of an experiment designed to answer these questions. Fifty-six subjects were tested on a basic visualization task and given standard paper tests of spatial abilities. An equal number of males and females were recruited in this study in order to increase spatial ability variance. Our results show that high spatial ability is correlated with accuracy on our three-dimensional visualization test, but not with time. High spatial ability subjects also had less difficulty with object complexity and the hidden properties of an object. | false | false | [
"Maria C. Velez",
"Deborah Silver",
"Marilyn Tremaine"
] | [] | [] | [] |
Vis | 2,005 | View selection for volume rendering | 10.1109/VISUAL.2005.1532833 | In a visualization of a three-dimensional dataset, the insights gained are dependent on what is occluded and what is not. Suggestion of interesting viewpoints can improve both the speed and efficiency of data understanding. This paper presents a view selection method designed for volume rendering. It can be used to find informative views for a given scene, or to find a minimal set of representative views which capture the entire scene. It becomes particularly useful when the visualization process is non-interactive - for example, when visualizing large datasets or time-varying sequences. We introduce a viewpoint "goodness" measure based on the formulation of entropy from information theory. The measure takes into account the transfer function, the data distribution and the visibility of the voxels. Combined with viewpoint properties like view-likelihood and view-stability, this technique can be used as a guide, which suggests "interesting" viewpoints for further exploration. Domain knowledge is incorporated into the algorithm via an importance transfer function or volume. This allows users to obtain view selection behaviors tailored to their specific situations. We generate a view space partitioning, and select one representative view for each partition. Together, this set of views encapsulates the "interesting" and distinct views of the data. Viewpoints in this set can be used as starting points for interactive exploration of the data, thus reducing the human effort in visualization. In non-interactive situations, such a set can be used as a representative visualization of the dataset from all directions. | false | false | [
"Udeepta Bordoloi",
"Han-Wei Shen"
] | [] | [] | [] |
Vis | 2,005 | View-dependent rendering of multiresolution texture-atlases | 10.1109/VISUAL.2005.1532798 | Real-time rendering of massively textured 3D scenes usually involves two major problems: Large numbers of texture switches are a well-known performance bottleneck and the set of simultaneously visible textures is limited by the graphics memory. This paper presents a level-of-detail texturing technique that overcomes both problems. In a preprocessing step, the technique creates a hierarchical data structure for all textures used by scene objects, and it derives texture atlases at different resolutions. At runtime, our texturing technique requires only a small set of these texture atlases, which represent scene textures in an appropriate size depending on the current camera position and screen resolution. Independent of the number and total size of all simultaneously visible textures, the achieved frame rates are similar to that of rendering the scene without any texture switches. Since the approach includes dynamic texture loading, the total size of the textures is only limited by the hard disk capacity. The technique is applicable for any 3D scenes whose scene objects are primarily distributed in a plane, such as in the case of 3D city models or outdoor scenes in computer games. Our approach has been successfully applied to massively textured, large-scale 3D city models. | false | false | [
"Henrik Buchholz",
"Jürgen Döllner"
] | [] | [] | [] |
Vis | 2,005 | VisTrails: enabling interactive multiple-view visualizations | 10.1109/VISUAL.2005.1532788 | VisTrails is a new system that enables interactive multiple-view visualizations by simplifying the creation and maintenance of visualization pipelines, and by optimizing their execution. It provides a general infrastructure that can be combined with existing visualization systems and libraries. A key component of VisTrails is the visualization trail (vistrail), a formal specification of a pipeline. Unlike existing dataflow-based systems, in VisTrails there is a clear separation between the specification of a pipeline and its execution instances. This separation enables powerful scripting capabilities and provides a scalable mechanism for generating a large number of visualizations. VisTrails also leverages the vistrail specification to identify and avoid redundant operations. This optimization is especially useful while exploring multiple visualizations. When variations of the same pipeline need to be executed, substantial speedups can be obtained by caching the results of overlapping subsequences of the pipelines. In this paper, we describe the design and implementation of VisTrails, and show its effectiveness in different application scenarios. | false | false | [
"Louis Bavoil",
"Steven P. Callahan",
"Carlos Scheidegger",
"Huy T. Vo",
"Patricia Crossno",
"Cláudio T. Silva",
"Juliana Freire"
] | [] | [] | [] |
Vis | 2,005 | Visual analysis and exploration of fluid flow in a cooling jacket | 10.1109/VISUAL.2005.1532850 | We present a visual analysis and exploration of fluid flow through a cooling jacket. Engineers invest a large amount of time and serious effort to optimize the flow through this engine component because of its important role in transferring heat away from the engine block. In this study we examine the design goals that engineers apply in order to construct an ideal-as-possible cooling jacket geometry and use a broad range of visualization tools in order to analyze, explore, and present the results. We systematically employ direct, geometric, and texture-based flow visualization techniques as well as automatic feature extraction and interactive feature-based methodology. And we discuss the relative advantages and disadvantages of these approaches as well as the challenges, both technical and perceptual with this application. The result is a feature-rich state-of-the-art flow visualization analysis applied to an important and complex data set from real-world computational fluid dynamics simulations. | false | false | [
"Robert S. Laramee",
"Christoph Garth",
"Helmut Doleisch",
"Jürgen Schneider",
"Helwig Hauser",
"Hans Hagen"
] | [] | [] | [] |
Vis | 2,005 | Visualization in the Einstein Year 2005: a case study on explanatory and illustrative visualization of relativity and astrophysics | 10.1109/VISUAL.2005.1532845 | In this application paper, we report on over fifteen years of experience with relativistic and astrophysical visualization, which has been culminating in a substantial engagement for visualization in the Einstein Year 2005 - the 100/sup th/ anniversary of Einstein's publications on special relativity, the photoelectric effect, and Brownian motion. This paper focuses on explanatory and illustrative visualizations used to communicate aspects of the difficult theories of special and general relativity, their geometric structure, and of the related fields of cosmology and astrophysics. We discuss visualization strategies, motivated by physics education and didactics of mathematics, and describe what kind of visualization methods have proven to be useful for different types of media, such as still images in popular-science magazines, film contributions to TV shows, oral presentations, or interactive museum installations. Although our visualization tools build upon existing methods and implementations, these techniques have been improved by several novel technical contributions like image-based special relativistic rendering on GPUs, an extension of general relativistic ray tracing to manifolds described by multiple charts, GPU-based interactive visualization of gravitational light deflection, as well as planetary terrain rendering. The usefulness and effectiveness of our visualizations are demonstrated by reporting on experiences with, and feedback from, recipients of visualizations and collaborators. | false | false | [
"Daniel Weiskopf",
"Marc Borchers",
"Thomas Ertl",
"Martin Falk",
"Oliver Fechtig",
"Regine Frank",
"Frank Grave",
"Andreas King",
"Ute Kraus",
"Thomas Müller 0005",
"Hans-Peter Nollert",
"Isabel Rica Mendez",
"Hanns Ruder",
"Corvin Zahn",
"Michael Zatloukal",
"Tobias Schafhitzel",
"Sonja Schär"
] | [] | [] | [] |
Vis | 2,005 | Visualization of the genus of knots | 10.1109/VISUAL.2005.1532843 | The genus of a knot or link can be defined via Seifert surfaces. A Seifert surface of a knot or link is an oriented surface whose boundary coincides with that, knot or link. Schematic images of these surfaces are shown in every text book on knot theory, but from these it is hard to understand their shape and structure. In this paper the visualization of such surfaces is discussed. A method is presented to produce different styles of surfaces for knots and links, starting from the so-called braid representation. Also, it is shown how closed oriented surfaces can be generated in which the knot is embedded, such that the knot subdivides the surface into two parts. These closed surfaces provide a direct visualization of the genus of a knot. | false | false | [
"Jarke J. van Wijk",
"Arjeh M. Cohen"
] | [] | [] | [] |
Vis | 2,005 | Visualization of time-dependent remote adaptive mesh refinement data | 10.1109/VISUAL.2005.1532793 | Analysis of phenomena that simultaneously occur on different spatial and temporal scales requires adaptive, hierarchical schemes to reduce computational and storage demands. Adaptive mesh refinement (AMR) schemes support both refinement in space that results in a time-dependent grid topology, as well as refinement in time that results in updates at higher rates for refined levels. Visualization of AMR data requires generating data for absent refinement levels at specific time steps. We describe a solution starting from a given set of "key frames" with potentially different grid topologies. The presented work was developed in a project involving several research institutes that collaborate in the field of cosmology and numerical relativity. AMR data results from simulations that are run on dedicated compute machines and is thus stored centrally, whereas the analysis of the data is performed on the local computers of the scientists. We built a distributed solution using remote procedure calls (RPC). To keep the application responsive, we split the bulk data transfer from the RPC response and deliver it asynchronously as a binary stream. The number of network round-trips is minimized by using high level operations. In summary, we provide an application for exploratory visualization of remotely stored AMR data. | false | false | [
"Ralf Kähler",
"Steffen Prohaska",
"Andrei Hutanu",
"Hans-Christian Hege"
] | [] | [] | [] |
Vis | 2,005 | Visualization of white matter tracts with wrapped streamlines | 10.1109/VISUAL.2005.1532777 | Diffusion tensor imaging is a magnetic resonance imaging method which has gained increasing importance in neuroscience and especially in neurosurgery. It acquires diffusion properties represented by a symmetric 2nd order tensor for each voxel in the gathered dataset. From the medical point of view, the data is of special interest due lo different diffusion characteristics of varying brain tissue allowing conclusions about the underlying structures such as while matter tracts. An obvious way to visualize this data is to focus on the anisotropic areas using the major eigenvector for tractography and rendering lines for visualization of the simulation results. Our approach extends this technique to avoid line representation since lines lead 10 very complex illustrations and furthermore are mistakable. Instead, we generate surfaces wrapping bundles of lines. Thereby, a more intuitive representation of different tracts is achieved. | false | false | [
"Frank Enders",
"Natascha Sauber",
"Dorit Merhof",
"Peter Hastreiter",
"Christopher Nimsky",
"Marc Stamminger"
] | [] | [] | [] |
Vis | 2,005 | Visualization with stylized line primitives | 10.1109/VISUAL.2005.1532859 | Line primitives are a very powerful visual attribute used for scientific visualization and in particular for 3D vector-field visualization. We extend the basic line primitives with additional visual attributes including color, line width, texture and orientation. To implement the visual attributes we represent the stylized line primitives as generalized cylinders. One important contribution of our work is an efficient rendering algorithm for stylized lines, which is hybrid in the sense that it uses both CPU and GPU based rendering. We improve the depth perception with a shadow algorithm. We present several applications for the visualization with stylized lines among which are the visualizations of 3D vector fields and molecular structures. | false | false | [
"Carsten Stoll",
"Stefan Gumhold",
"Hans-Peter Seidel"
] | [] | [] | [] |
Vis | 2,005 | Visualizing data with motion | 10.1109/VISUAL.2005.1532838 | This paper describes an experimental study of three perceptual properties of motion: flicker, direction, and velocity. Our goal is to understand how to apply these properties to represent data in a visualization environment. Results from our experiments show that all three properties can encode multiple data values, but that minimum visual differences are needed to ensure rapid and accurate target detection: flicker must be coherent and must have a cycle length of 120 milliseconds or greater, direction must differ by at least 20/spl deg/, and velocity must differ by at least 0.43/spl deg/ of subtended visual angle. We conclude with an overview of how we are applying our results to real-world data, and then discuss future work we plan to pursue. | false | false | [
"Daniel E. Huber",
"Christopher G. Healey"
] | [] | [] | [] |
Vis | 2,005 | Visualizing intersecting surfaces with nested-surface techniques | 10.1109/VISUAL.2005.1532835 | This paper describes the adaptation and evaluation of existing nested-surface visualization techniques for the problem of displaying intersecting surfaces. For this work, we collaborated with a neurosurgeon who is comparing multiple tumor segmentations with the goal of increasing the segmentation accuracy and reliability. A second collaborator, a physicist, aims to validate geometric models of specimens against atomic-force microscope images of actual specimens. These collaborators are interested in comparing both surface shape and inter-surface distances. Many commonly employed techniques for visually comparing multiple surfaces (side-by-side, wireframe, colormaps, uniform translucence) do not simultaneously convey inter-surface distance and the shapes of two or more surfaces. This paper describes a simple geometric partitioning of intersecting surfaces that enables the application of existing nested-surface techniques, such as texture-modulated translucent rendering of exteriors, to a broader range of visualization problems. Three user studies investigate the performance of existing techniques and a new shadow-casting glyph technique. The results of the first user study show that texture glyphs on partitioned, intersecting surfaces can convey inter-surface distance better than directly mapping distance to a red-gray-blue color scale on a single surface. The results of the second study show similar results for conveying local surface orientation. The results of the third user study show that adding cast shadows to texture glyphs can increase the understanding of inter-surface distance in static images, but can be overpowered by the shape cues from a simple rocking motion. | false | false | [
"Chris Weigle",
"Russell M. Taylor II"
] | [] | [] | [] |
Vis | 2,005 | Visualizing tensor fields in geomechanics | 10.1109/VISUAL.2005.1532774 | The study of stress and strains in soils and structures (solids) help us gain a better understanding of events such as failure of bridges, dams and buildings, or accumulated stresses and strains in geological subduction zones that could trigger earthquakes and subsequently tsunamis. In such domains, the key feature of interest is the location and orientation of maximal shearing planes. This paper describes a method that highlights this feature in stress tensor fields. It uses a plane-in-a-box glyph which provides a global perspective of shearing planes based on local analysis of tensors. The analysis can be performed over the entire domain, or the user can interactively specify where to introduce these glyphs. Alternatively, they can also be placed depending on the threshold level of several physical relevant parameters such as double couple and compensated linear vector dipole. Both methods are tested on stress tensor fields from geomechanics. | false | false | [
"Alisa Neeman",
"Boris Jeremic",
"Alex T. Pang"
] | [] | [] | [] |
Vis | 2,005 | Visualizing the tightening of knots | 10.1109/VISUAL.2005.1532844 | The study of physical models for knots has recently received much interest in the mathematics community. In this paper, we consider the ropelength model, which considers knots tied in an idealized rope. This model is interesting in pure mathematics, and has been applied to the study of a variety of problems in the natural sciences as well. Modeling and visualizing the tightening of knots in this idealized rope poses some interesting challenges in computer graphics. In particular, self-contact in a deformable rope model is a difficult problem which cannot be handled by standard techniques. In this paper, we describe a solution based on reformulating the contact problem and using constrained-gradient techniques from nonlinear optimization. The resulting animations reveal new properties of the tightening flow and provide new insights into the geometric structure of tight knots and links. | false | false | [
"Jason Cantarella",
"Michael Piatek",
"Eric J. Rawdon"
] | [] | [] | [] |
Vis | 2,005 | VolQD: direct volume rendering of multi-million atom quantum dot simulations | 10.1109/VISUAL.2005.1532811 | In this work we present a hardware-accelerated direct volume rendering system for visualizing multivariate wave functions in semiconducting quantum dot (QD) simulations. The simulation data contains the probability density values of multiple electron orbitals for up to tens of millions of atoms, computed by the NEMO3-D quantum device simulator software run on large-scale cluster architectures. These atoms form two interpenetrating crystalline face centered cubic lattices (FCC), where each FCC cell comprises the eight corners of a cubic cell and six additional face centers. We have developed compact representation techniques for the FCC lattice within PC graphics hardware texture memory, hardware-accelerated linear and cubic reconstruction schemes, and new multi-field rendering techniques utilizing logarithmic scale transfer functions. Our system also enables the user to drill down through the simulation data and execute statistical queries using general-purpose computing on the GPU (GPGPU). | false | false | [
"Wei Qiao",
"David S. Ebert",
"Alireza Entezari",
"Marek Korkusinski",
"Gerhard Klimeck"
] | [] | [] | [] |
Vis | 2,005 | Volume rendering of smoke propagation CFD data | 10.1109/VISUAL.2005.1532813 | The evacuation of buildings in the event of a fire requires careful planning of ventilation and evacuation routes during early architectural design stages. Different designs are evaluated by simulating smoke propagation using computational fluid dynamics (CFD). Visibility plays a decisive role in finding the nearest fire exit. This paper presents real-time volume rendering of transient smoke propagation conforming to standardized visibility distances. We visualize time dependent smoke particle concentration on unstructured tetrahedral meshes using a direct volume rendering approach. Due to the linear transfer function of the optical model commonly used in fire protection engineering, accurate pre-integration of diffuse color across tetrahedra can be carried out with a single 2D texture lookup. We reduce rounding errors during frame buffer blending by applying randomized dithering if high accuracy frame buffers are unavailable on the target platform. A simple absorption-based lighting model is evaluated in a preprocessing step using the same rendering approach. Back-illuminated exit signs are commonly used to indicate the escape route. As light emitting objects are visible further than reflective objects, the transfer function in front of illuminated exit signs must be adjusted with a deferred rendering pass. | false | false | [
"Oliver Staubli",
"Christian Sigg",
"Ronald Peikert",
"Markus H. Gross",
"Daniel Gubler"
] | [] | [] | [] |
Vis | 2,005 | VolumeExplorer: roaming large volumes to couple visualization and data processing for oil and gas exploration | 10.1109/VISUAL.2005.1532802 | In this paper, we present a volume roaming system dedicated to oil and gas exploration. Our system combines probe-based volume rendering with data processing and computing. The daily oil production and the estimation of the world proven-reserves directly affect the barrel price and have a strong impact on the economy. Among others, production and correct estimation are linked to the accuracy of the sub-surface model used for predicting oil reservoirs shape and size. Geoscientists build this model from the interpretation of seismic data, i.e. 3D images of the subsurface obtained from geophysical surveys. Our system couples visualization and data processing for the interpretation of seismic data. It is based on volume roaming along with efficient volume paging to manipulate the multi-gigabyte data sets commonly acquired during seismic surveys. Our volume rendering lenses implement high quality pre-integrated volume rendering with accurate lighting. They use a generic multi-modal volume rendering system that blends several volumes in the spirit of the "stencil" paradigm used in 2D painting programs. In addition, our system can interactively display non-polygonal isosurfaces painted with an attribute. Beside the visualization algorithms, automatic extraction of local features of the subsurface model also take full advantage of the volume paging. | false | false | [
"Laurent Castanie",
"Bruno Lévy 0001",
"Fabien Bosquet"
] | [] | [] | [] |
Vis | 2,005 | VolumeShop: an interactive system for direct volume illustration | 10.1109/VISUAL.2005.1532856 | Illustrations play a major role in the education process. Whether used to teach a surgical or radiologic procedure, to illustrate normal or aberrant anatomy, or to explain the functioning of a technical device, illustration significantly impacts learning. Although many specimens are readily available as volumetric data sets, particularly in medicine, illustrations are commonly produced manually as static images in a time-consuming process. Our goal is to create a fully dynamic three-dimensional illustration environment which directly operates on volume data. Single images have the aesthetic appeal of traditional illustrations, but can be interactively altered and explored. In this paper we present methods to realize such a system which combines artistic visual styles and expressive visualization techniques. We introduce a novel concept for direct multi-object volume visualization which allows control of the appearance of inter-penetrating objects via two-dimensional transfer functions. Furthermore, a unifying approach to efficiently integrate many non-photorealistic rendering models is presented. We discuss several illustrative concepts which can be realized by combining cutaways, ghosting, and selective deformation. Finally, we also propose a simple interface to specify objects of interest through three-dimensional volumetric painting. All presented methods are integrated into VolumeShop, an interactive hardware-accelerated application for direct volume illustration. | false | false | [
"Stefan Bruckner",
"M. Eduard Gröller"
] | [] | [] | [] |
InfoVis | 2,005 | A note on space-filling visualizations and space-filling curves | 10.1109/INFVIS.2005.1532145 | A recent line of treemap research has focused on layout algorithms that optimize properties such as stability, preservation of ordering information, and aspect ratio of rectangles. No ideal treemap layout algorithm has been found, and so it is natural to explore layouts that produce nonrectangular regions. This note describes a connection between space-filling visualizations and the mathematics of space-filling curves, and uses that connection to characterize a family of layout algorithms which produce nonrectangular regions but enjoy geometric continuity under changes to the data and legibility even for highly unbalanced trees. | false | false | [
"Martin Wattenberg"
] | [] | [] | [] |
InfoVis | 2,005 | A sky dome visualisation for identification of astronomical orientations | 10.1109/INFVIS.2005.1532123 | It has long been known that ancient temples were frequently oriented along the cardinal directions or to certain points along the horizon where Sun or Moon rise or set on special days of the year. In the last decades, archaeologists have found evidence of even older building structures buried in the soil, with doorways that also appear to have distinct orientations. This paper presents a novel diagram combining archaeological maps with a folded-apart, flattened view of the whole sky, showing the local horizon and the daily paths of Sun, Moon and brighter stars. By use of this diagram, interesting groupings of astronomical orientation directions, e.g. to certain Sunrise and Sunset points could be identified, which were evidently used to mark certain days of the year. Orientations to a few significant stars very likely indicated the beginning of the agricultural year in the middle neolithic period | false | false | [
"Georg Zotti",
"M. Eduard Gröller"
] | [] | [] | [] |
InfoVis | 2,005 | Adapting the cognitive walkthrough method to assess the usability of a knowledge domain visualization | 10.1109/INFVIS.2005.1532147 | The usability of knowledge domain visualization (KDViz) tools can be assessed at several levels. Cognitive walkthrough (CW) is a well known usability inspection method that focuses on how easily users can learn software through exploration. Typical applications of CW follow structured tasks where user goals and action sequences that lead to achievement of the goals are well defined. KDViz and other information visualization tools, however, are typically designed for users to explore data and user goals and actions are less well understood. In this paper, we describe how the traditional CW method may be adapted for assessing the usability of these systems. We apply the adapted version of CW to CiteSpace, a KDViz tool that uses bibliometric analyses to create visualizations of scientific literatures. We describe usability issues identified by the adapted CW and discuss how CiteSpace supported the completion of tasks, such as identifying research fronts, and the achievement of goals. Finally, we discuss improvements to the adapted CW and issues to be addressed before applying it to a wider range of KDViz tools. | false | false | [
"Kenneth R. Allendoerfer",
"Serge Aluker",
"Gulshan Panjwani",
"Jason M. Proctor",
"David Sturtz",
"Mirjana Vukovic",
"Chaomei Chen"
] | [] | [] | [] |
InfoVis | 2,005 | An evaluation of content browsing techniques for hierarchical space-filling visualizations | 10.1109/INFVIS.2005.1532132 | Space-filling visualizations, such as the TreeMap, are well suited for displaying the properties of nodes in hierarchies. To browse the contents of the hierarchy, the primary mode of interaction is by drilling down through many successive layers. In this paper we introduce a distortion algorithm based on fisheye and continuous zooming techniques for browsing data in the TreeMap representation. The motivation behind the distortion approach is for assisting users to rapidly browse information displayed in the TreeMap without opening successive layers of the hierarchy. Two experiments were conducted to evaluate the new approach. In the first experiment (N=20) the distortion approach is compared to the drill down method. Results show that subjects are quicker and more accurate in locating targets of interest using the distortion method. The second experiment (N=12) evaluates the effectiveness of the two approaches in a task requiring context, we define as the context browsing task. The results show that subjects are quicker and more accurate in locating targets with the distortion technique in the context browsing task. | false | false | [
"Kang Shi",
"Pourang Irani",
"Pak Ching Li"
] | [] | [] | [] |
InfoVis | 2,005 | An interactive 3D integration of parallel coordinates and star glyphs | 10.1109/INFVIS.2005.1532141 | Parallel coordinates are a powerful method for visualizing multidimensional data but, when applied to large data sets, they become cluttered and difficult to read. Star glyphs, on the other hand, can be used to display either the attributes of a data item or the values across all items for a single attribute. Star glyphs may readily provide a quick impression; however, since the full data set require multiple glyphs, overall readings are more difficult. We present parallel glyphs, an interactive integration of the visual representations of parallel coordinates and star glyphs that utilizes the advantages of both representations to offset the disadvantages they have separately. We discuss the role of uniform and stepped colour scales in the visual comparison of non-adjacent items and star glyphs. Parallel glyphs provide capabilities for focus-in-context exploration using two types of lenses and interactions specific to the 3D space. | false | false | [
"Elena Fanea",
"Sheelagh Carpendale",
"Tobias Isenberg 0001"
] | [] | [] | [] |
InfoVis | 2,005 | An optimization-based approach to dynamic visual context management | 10.1109/INFVIS.2005.1532146 | We are building an intelligent multimodal conversation system to aid users in exploring large and complex data sets. To tailor to diverse user queries introduced during a conversation, we automate the generation of system responses, including both spoken and visual outputs. In this paper, we focus on the problem of visual context management, a process that dynamically updates an existing visual display to effectively incorporate new information requested by subsequent user queries. Specifically, we develop an optimization based approach to visual context management. Compared to existing approaches, which normally handle predictable visual context updates, our work offers two unique contributions. First, we provide a general computational framework that can effectively manage a visual context for diverse, unanticipated situations encountered in a user system conversation. Moreover, we optimize the satisfaction of both semantic and visual constraints, which otherwise are difficult to balance using simple heuristics. Second, we present an extensible representation model that uses feature based metrics to uniformly define all constraints. We have applied our work to two different applications and our evaluation has shown the promise of this work. | false | false | [
"Zhen Wen",
"Michelle X. Zhou",
"Vikram Aggarwal"
] | [] | [] | [] |
InfoVis | 2,005 | Baby names, visualization, and social data analysis | 10.1109/INFVIS.2005.1532122 | The Name Voyager, a Web based visualization of historical trends in baby naming, has proven remarkably popular. This paper discusses the interaction techniques it uses for smooth visual exploration of thousands of time series. We also describe design decisions behind the application and lessons learned in creating an application that makes do-it-yourself data mining popular. The prime lesson, it is hypothesized, is that an information visualization tool may be fruitfully viewed not as a tool but as part of an online social environment. In other words, to design a successful exploratory data analysis tool, one good strategy is to create a system that enables "social" data analysis | false | false | [
"Martin Wattenberg"
] | [] | [] | [] |
InfoVis | 2,005 | Dig-CoLa: directed graph layout through constrained energy minimization | 10.1109/INFVIS.2005.1532130 | We describe a new method for visualization of directed graphs. The method combines constraint programming techniques with a high performance force directed placement (FDP) algorithm so that the directed nature of the graph is highlighted while useful properties of FDP - such as emphasis of symmetries and preservation of proximity relations - are retained. Our algorithm automatically identifies those parts of the digraph that contain hierarchical information and draws them accordingly. Additionally, those parts that do not contain hierarchy are drawn at the same quality expected from a nonhierarchical, undirected layout algorithm. An interesting application of our algorithm is directional multidimensional scaling (DMDS). DMDS deals with low dimensional embedding of multivariate data where we want to emphasize the overall flow in the data (e.g. chronological progress) along one of the axes. | false | false | [
"Tim Dwyer",
"Yehuda Koren"
] | [
"BP"
] | [] | [] |
InfoVis | 2,005 | Dynamic visualization of graphs with extended labels | 10.1109/INFVIS.2005.1532131 | The paper describes a novel technique to visualize graphs with extended node and link labels. The lengths of these labels range from a short phrase to a full sentence to an entire paragraph and beyond. Our solution is different from all the existing approaches that almost always rely on intensive computational effort to optimize the label placement problem. Instead, we share the visualization resources with the graph and present the label information in static, interactive, and dynamic modes without the requirement for tackling the intractability issues. This allows us to reallocate the computational resources for dynamic presentation of real time information. The paper includes a user study to evaluate the effectiveness and efficiency of the visualization technique. | false | false | [
"Pak Chung Wong",
"Patrick Mackey",
"Ken Perrine",
"James R. Eagan",
"Harlan Foote",
"James J. Thomas"
] | [] | [] | [] |
InfoVis | 2,005 | Elastic hierarchies: combining treemaps and node-link diagrams | 10.1109/INFVIS.2005.1532129 | We investigate the use of elastic hierarchies for representing trees, where a single graphical depiction uses a hybrid mixture, or "interleaving", of more basic forms at different nodes of the tree. In particular, we explore combinations of node link and treemap forms, to combine the space efficiency of treemaps with the structural clarity of node link diagrams. A taxonomy is developed to characterize the design space of such hybrid combinations. A software prototype is described, which we used to explore various techniques for visualizing, browsing and interacting with elastic hierarchies, such as side by side overview and detail views, highlighting and rubber banding across views, visualization of multiple foci, and smooth animations across transitions. The paper concludes with a discussion of the characteristics of elastic hierarchies and suggestions for research on their properties and uses. | false | false | [
"Shengdong Zhao",
"Michael J. McGuffin",
"Mark H. Chignell"
] | [] | [] | [] |
InfoVis | 2,005 | Flow map layout | 10.1109/INFVIS.2005.1532150 | Cartographers have long used flow maps to show the movement of objects from one location to another, such as the number of people in a migration, the amount of goods being traded, or the number of packets in a network. The advantage of flow maps is that they reduce visual clutter by merging edges. Most flow maps are drawn by hand and there are few computer algorithms available. We present a method for generating flow maps using hierarchical clustering given a set of nodes, positions, and flow data between the nodes. Our techniques are inspired by graph layout algorithms that minimize edge crossings and distort node positions while maintaining their relative position to one another. We demonstrate our technique by producing flow maps for network traffic, census data, and trade data. | false | false | [
"Doantam Phan",
"Ling Xiao",
"Ron B. Yeh",
"Pat Hanrahan",
"Terry Winograd"
] | [] | [] | [] |
InfoVis | 2,005 | Graph-theoretic scagnostics | 10.1109/INFVIS.2005.1532142 | We introduce Tukey and Tukey scagnostics and develop graph-theoretic methods for implementing their procedure on large datasets. | false | false | [
"Leland Wilkinson",
"Anushka Anand",
"Robert L. Grossman"
] | [
"TT"
] | [] | [] |
InfoVis | 2,005 | Highlighting conflict dynamics in event data | 10.1109/INFVIS.2005.1532135 | We present a method for visual summary of bilateral conflict structures embodied in event data. Such data consists of actors linked by time stamped events, and may be extracted from various sources such as news reports and dossiers. When analyzing political events, it is of particular importance to be able to recognize conflicts and actors involved in them. By projecting actors into a conflict space, we are able to highlight the main opponents in a series of tens of thousands of events, and provide a graphic overview of the conflict structure. Moreover, our method allows for smooth animation of the dynamics of a conflict. | false | false | [
"Ulrik Brandes",
"Daniel Fleischer",
"Jürgen Lerner"
] | [] | [] | [] |
InfoVis | 2,005 | Importance-driven visualization layouts for large time series data | 10.1109/INFVIS.2005.1532148 | Time series are an important type of data with applications in virtually every aspect of the real world. Often a large number of time series have to be monitored and analyzed in parallel. Sets of time series may show intrinsic hierarchical relationships and varying degrees of importance among the individual time series. Effective techniques for visually analyzing large sets of time series should encode the relative importance and hierarchical ordering of the time series data by size and position, and should also provide a high degree of regularity in order to support comparability by the analyst. In this paper, we present a framework for visualizing large sets of time series. Based on the notion of inter time series importance relationships, we define a set of objective functions that space-filling layout schemes for time series data should obey. We develop an efficient algorithm addressing the identified problems by generating layouts that reflect hierarchy and importance based relationships in a regular layout with favorable aspect ratios. We apply our technique to a number of real world data sets including sales and stock data, and we compare our technique with an aspect ratio aware variant of the well known TreeMap algorithm. The examples show the advantages and practical usefulness of our layout algorithm. | false | false | [
"Ming C. Hao",
"Umeshwar Dayal",
"Daniel A. Keim",
"Tobias Schreck"
] | [] | [] | [] |
InfoVis | 2,005 | Interactive Sankey diagrams | 10.1109/INFVIS.2005.1532152 | We present a system that allows users to interactively explore complex flow scenarios represented as Sankey diagrams. Our system provides an overview of the flow graph and allows users to zoom in and explore details on demand. The support for quantitative flow tracing across the flow graph as well as representations at different levels of detail facilitate the understanding of complex flow situations. The energy flow in a city serves as a sample scenario for our system. Different forms of energy are distributed within the city and they are transformed into heat, electricity, or other forms of energy. These processes are visualized and interactively explored. In addition our system can be used as a planning tool for the exploration of alternative scenarios by interactively manipulating different parameters in the energy flow network. | false | false | [
"Patrick Riehmann",
"Manfred Hanfler",
"Bernd Fröhlich 0001"
] | [] | [] | [] |
InfoVis | 2,005 | Interactive visualization of genealogical graphs | 10.1109/INFVIS.2005.1532124 | The general problem of visualizing "family trees", or genealogical graphs, in 2D, is considered. A graph theoretic analysis is given, which identifies why genealogical graphs can be difficult to draw. This motivates some novel graphical representations, including one based on a dual tree, a subgraph formed by the union of two trees. Dual trees can be drawn in various styles, including an indented outline style, and allow users to browse general multitrees in addition to genealogical graphs, by transitioning between different dual tree views. A software prototype for such browsing is described, that supports smoothly animated transitions, automatic camera framing, rotation of subtrees, and a novel interaction technique for expanding or collapsing subtrees to any depth with a single mouse drag | false | false | [
"Michael J. McGuffin",
"Ravin Balakrishnan"
] | [] | [] | [] |
InfoVis | 2,005 | Low-level components of analytic activity in information visualization | 10.1109/INFVIS.2005.1532136 | Existing system level taxonomies of visualization tasks are geared more towards the design of particular representations than the facilitation of user analytic activity. We present a set of ten low level analysis tasks that largely capture people's activities while employing information visualization tools for understanding data. To help develop these tasks, we collected nearly 200 sample questions from students about how they would analyze five particular data sets from different domains. The questions, while not being totally comprehensive, illustrated the sheer variety of analytic questions typically posed by users when employing information visualization systems. We hope that the presented set of tasks is useful for information visualization system designers as a kind of common substrate to discuss the relative analytic capabilities of the systems. Further, the tasks may provide a form of checklist for system designers. | false | false | [
"Robert A. Amar",
"James R. Eagan",
"John T. Stasko"
] | [] | [] | [] |
InfoVis | 2,005 | Multivariate glyphs for multi-object clusters | 10.1109/INFVIS.2005.1532140 | Aggregating items can simplify the display of huge quantities of data values at the cost of losing information about the attribute values of the individual items. We propose a distribution glyph, in both two- and three-dimensional forms, which specifically addresses the concept of how the aggregated data is distributed over the possible range of values. It is capable of displaying distribution, variability and extent information for up to four attributes at a time of multivariate, clustered data. User studies validate the concept, showing that both glyphs are just as good as raw data and the 3D glyph is better for answering some questions. | false | false | [
"Eleanor Boyle Chlan",
"Penny Rheingans"
] | [] | [] | [] |
InfoVis | 2,005 | Parallel sets: visual analysis of categorical data | 10.1109/INFVIS.2005.1532139 | The discrete nature of categorical data makes it a particular challenge for visualization. Methods that work very well for continuous data are often hardly usable with categorical dimensions. Only few methods deal properly with such data, mostly because of the discrete nature of categorical data, which does not translate well into the continuous domains of space and color. Parallel sets is a new visualization method that adopts the layout of parallel coordinates, but substitutes the individual data points by a frequency based representation. This abstracted view, combined with a set of carefully designed interactions, supports visual data analysis of large and complex data sets. The technique allows efficient work with meta data, which is particularly important when dealing with categorical datasets. By creating new dimensions from existing ones, for example, the user can filter the data according to his or her current needs. We also present the results from an interactive analysis of CRM data using parallel sets. We demonstrate how the flexible layout eases the process of knowledge crystallization, especially when combined with a sophisticated interaction scheme. | false | false | [
"Fabian Bendix",
"Robert Kosara",
"Helwig Hauser"
] | [] | [] | [] |
InfoVis | 2,005 | PRISAD: a partitioned rendering infrastructure for scalable accordion drawing | 10.1109/INFVIS.2005.1532127 | We present PRISAD, the first generic rendering infrastructure for information visualization applications that use the accordion drawing technique: rubber sheet navigation with guaranteed visibility for marked areas of interest. Our new rendering algorithms are based on the partitioning of screen space, which allows us to handle dense dataset regions correctly. The algorithms in previous work led to incorrect visual representations because of overculling, and to inefficiencies due to overdrawing multiple items in the same region. Our pixel based drawing infrastructure guarantees correctness by eliminating overculling, and improves rendering performance with tight bounds on overdrawing. PRITree and PRISeq are applications built on PRISAD, with the feature sets of TreeJuxtaposer and SequenceJuxtaposer, respectively. We describe our PRITree and PRISeq dataset traversal algorithms, which are used for efficient rendering, culling, and layout of datasets within the PRISAD framework. We also discuss PRITree node marking techniques, which offer order-of-magnitude improvements to both memory and time performance versus previous range storage and retrieval techniques. Our PRITree implementation features a five fold increase in rendering speed for nontrivial tree structures, and also reduces memory requirements in some real world datasets by up to eight times, so we are able to handle trees of several million nodes. PRISeq renders fifteen times faster and handles datasets twenty times larger than previous work. | false | false | [
"James Slack",
"Kristian Hildebrand",
"Tamara Munzner"
] | [] | [] | [] |
InfoVis | 2,005 | Revealing structure within clustered parallel coordinates displays | 10.1109/INFVIS.2005.1532138 | In order to gain insight into multivariate data, complex structures must be analysed and understood. Parallel coordinates is an excellent tool for visualizing this type of data but has its limitations. This paper deals with one of its main limitations - how to visualize a large number of data items without hiding the inherent structure they constitute. We solve this problem by constructing clusters and using high precision textures to represent them. We also use transfer functions that operate on the high precision textures in order to highlight different aspects of the cluster characteristics. Providing predefined transfer functions as well as the support to draw customized transfer functions makes it possible to extract different aspects of the data. We also show how feature animation can be used as guidance when simultaneously analysing several clusters. This technique makes it possible to visually represent statistical information about clusters and thus guides the user, making the analysis process more efficient. | false | false | [
"Jimmy Johansson 0001",
"Patric Ljung",
"Mikael Jern",
"Matthew Cooper 0001"
] | [] | [] | [] |
InfoVis | 2,005 | Simple 3D glyphs for spatial multivariate data | 10.1109/INFVIS.2005.1532137 | We present an effort to evaluate the possible utility of a new type of 3D glyphs intended for visualizations of multivariate spatial data. They are based on results from vision research suggesting that our perception of metric 3D structure is distorted and imprecise relative to the actual scene before us (e.g., "metric 3D structure in visualizations" by M. Lind et al. (2003)); only a class of qualitative properties of the scene is perceived with accuracy. These properties are best characterized as being invariant over affine but not Euclidean transformations. They are related, but not identical to, the non-accidental properties (NAPs) described by Lowe in "perceptual organization and visual recognition" (1984) on which the notion of geons is based in "recognition by components - a theory of image understanding" by I. Biederman (1987). A large number of possible 3D glyphs for the visualization of spatial data can be constructed using such properties. One group is based on the local sign of surface curvature. We investigated these properties in a visualization experiment. The results are promising and the implications for visualization are discussed. | false | false | [
"Camilla Forsell",
"Stefan Seipel",
"Mats Lind"
] | [] | [] | [] |
InfoVis | 2,005 | Temporal visualization of planning polygons for efficient partitioning of geo-spatial data | 10.1109/INFVIS.2005.1532149 | Partitioning of geo-spatial data for efficient allocation of resources such as schools and emergency health care services is driven by a need to provide better and more effective services. Partitioning of spatial data is a complex process that depends on numerous factors such as population, costs incurred in deploying or utilizing resources and target capacity of a resource. Moreover, complex data such as population distributions are dynamic i.e. they may change over time. Simple animation may not effectively show temporal changes in spatial data. We propose the use of three temporal visualization techniques -wedges, rings and time slices - to display the nature of change in temporal data in a single view. Along with maximizing resource utilization and minimizing utilization costs, a partition should also ensure the long term effectiveness of the plan. We use multi-attribute visualization techniques to highlight the strengths and identify the weaknesses of a partition. Comparative visualization techniques allow multiple partitions to be viewed simultaneously. Users can make informed decisions about how to partition geo spatial data by using a combination of our techniques for multi-attribute visualization, temporal visualization and comparative visualization. | false | false | [
"Poonam Shanbhag",
"Penny Rheingans",
"Marie desJardins"
] | [] | [] | [] |
InfoVis | 2,005 | The visual code navigator: an interactive toolset for source code investigation | 10.1109/INFVIS.2005.1532125 | We present the Visual Code Navigator, a set of three interrelated visual tools that we developed for exploring large source code software projects from three different perspectives, or views: the syntactic view shows the syntactic constructs in the source code. The symbol view shows the objects a file makes available after compilation, such as function signatures, variables, and namespaces. The evolution view looks at different versions in a project lifetime of a number of selected source files. The views share one code model, which combines hierarchical syntax based and line based information from multiple source files versions. We render this code model using a visual model that extends the pixel-filling, space partitioning properties of shaded cushion treemaps with novel techniques. We discuss how our views allow users to interactively answer complex questions on various code elements by simple mouse clicks. We validate the efficiency and effectiveness of our toolset by an informal user study on the source code of VTK, a large, industry-size C++ code base | false | false | [
"Gerard Lommerse",
"Freek Nossin",
"Lucian Voinea",
"Alexandru C. Telea"
] | [] | [] | [] |
InfoVis | 2,005 | Turning information visualization innovations into commercial products: lessons to guide the next success | 10.1109/INFVIS.2005.1532153 | As information visualization matures as an academic research field, commercial spinoffs are proliferating, but success stories are harder to find. This is the normal process of emergence for new technologies, but the panel organizers believe that there are certain strategies that facilitate success. To teach these lessons, we have invited several key figures who are seeking to commercialize information visualization tools. The panelists make short presentations, engage in a moderated discussion, and respond to audience questions. | false | false | [
"Ben Shneiderman",
"Ramana Rao",
"Keith Andrews",
"Christopher Ahlberg",
"Dominique Brodbeck",
"Tony Jewitt",
"Jock D. Mackinlay"
] | [] | [] | [] |
InfoVis | 2,005 | Turning the bucket of text into a pipe | 10.1109/INFVIS.2005.1532133 | Many visual analysis tools operate on a fixed set of data. However, professional information analysts follow issues over a period of time and need to be able to easily add new documents to an ongoing exploration. Some analysts handle documents in a moving window of time, with new documents constantly added and old ones aging out. This paper describes both the user interaction and the technical implementation approach for a visual analysis system designed to support constantly evolving text collections. | false | false | [
"Elizabeth G. Hetzler",
"Vernon L. Crow",
"Deborah A. Payne",
"Alan Turner"
] | [] | [] | [] |
InfoVis | 2,005 | Two-tone pseudo coloring: compact visualization for one-dimensional data | 10.1109/INFVIS.2005.1532144 | A new pseudo coloring technique for large scale one-dimensional datasets is proposed. For visualization of a large scale dataset, user interaction is indispensable for selecting focus areas in the dataset. However, excessive switching of the visualized image makes it difficult for the user to recognize overview/ detail and detail/ detail relationships. The goal of this research is to develop techniques for visualizing details as precisely as possible in overview display. In this paper, visualization of a one-dimensional but very large dataset is considered. The proposed method is based on pseudo coloring, however, each scalar value corresponds to two discrete colors. By painting with two colors at each value, users can read out the value precisely. This method has many advantages: it requires little image space for visualization; both the overview and details of the dataset are visible in one image without distortion; and implementation is very simple. Several application examples, such as meteorological observation data and train convenience evaluation data, show the effectiveness of the method. | false | false | [
"Takafumi Saito",
"Hiroko Miyamura",
"Mitsuyoshi Yamamoto",
"Hiroki Saito",
"Yuka Hoshiya",
"Takumi Kaseda"
] | [] | [] | [] |
InfoVis | 2,005 | Visual correlation for situational awareness | 10.1109/INFVIS.2005.1532134 | We present a novel visual correlation paradigm for situational awareness (SA) and suggest its usage in a diverse set of applications that require a high level of SA. Our approach is based on a concise and scalable representation, which leads to a flexible visualization tool that is both clear and intuitive to use. Situational awareness is the continuous extraction of environmental information, its integration with previous knowledge to form a coherent mental picture, and the use of that picture in anticipating future events. In this paper we build on our previous work on visualization for network intrusion detection and show how that approach can be generalized to encompass a much broader class of SA systems. We first propose a generalization that is based on what we term, the w/sup 3/ premise, namely that each event must have at least the what, when and where attributes. We also present a second generalization, which increases flexibility and facilitates complex visual correlations. Finally, we demonstrate the generality of our approaches by applying our visualization paradigm in a collection of diverse SA areas. | false | false | [
"Yarden Livnat",
"James Agutter",
"Shaun Moon",
"Stefano Foresti"
] | [] | [] | [] |
InfoVis | 2,005 | Visualization of graphs with associated timeseries data | 10.1109/INFVIS.2005.1532151 | The most common approach to support analysis of graphs with associated time series data include: overlay of data on graph vertices for one timepoint at a time by manipulating a visual property (e.g. color) of the vertex, along with sliders or some such mechanism to animate the graph for other timepoints. Alternatively, data from all the timepoints can be overlaid simultaneously by embedding small charts into graph vertices. These graph visualizations may also be linked to other visualizations (e.g., parallel co-ordinates) using brushing and linking. This paper describes a study performed to evaluate and rank graph+timeseries visualization options based on users' performance time and accuracy of responses on predefined tasks. The results suggest that overlaying data on graph vertices one timepoint at a time may lead to more accurate performance for tasks involving analysis of a graph at a single timepoint, and comparisons between graph vertices for two distinct timepoints. Overlaying data simultaneously for all the timepoints on graph vertices may lead to more accurate and faster performance for tasks involving searching for outlier vertices displaying different behavior than the rest of the graph vertices for all timepoints. Single views have advantage over multiple views on tasks that require topological information. Also, the number of attributes displayed on nodes has a non trivial influence on accuracy of responses, whereas the number of visualizations affect the performance time. | false | false | [
"Purvi Saraiya",
"Peter Lee 0005",
"Chris North 0001"
] | [] | [] | [] |
InfoVis | 2,005 | Visualizing coordination in situ | 10.1109/INFVIS.2005.1532143 | Exploratory visualization environments allow users to build and browse coordinated multiview visualizations interactively. As the number of views and amount of coordination increases, conceptualizing coordination structure becomes more and more important for successful data exploration. Integrated metavisualization is exploratory visualization of coordination and other interactive structure directly inside a visualization's own user interface. This paper presents a model of integrated metavisualization, describes the problem of capturing dynamic interface structure as visualizable data, and outlines three general approaches to integration. Metavisualization has been implemented in improvise, using views, lenses, and embedding to reveal the dynamic structure of its own highly coordinated visualizations. | false | false | [
"Chris E. Weaver"
] | [] | [] | [] |
InfoVis | 2,005 | Vizster: visualizing online social networks | 10.1109/INFVIS.2005.1532126 | Recent years have witnessed the dramatic popularity of online social networking services, in which millions of members publicly articulate mutual "friendship" relations. Guided by ethnographic research of these online communities, we have designed and implemented a visualization system for playful end-user exploration and navigation of large scale online social networks. Our design builds upon familiar node link network layouts to contribute customized techniques for exploring connectivity in large graph structures, supporting visual search and analysis, and automatically identifying and visualizing community structures. Both public installation and controlled studies of the system provide evidence of the system's usability, capacity for facilitating discovery, and potential for fun and engaged social activity | false | false | [
"Jeffrey Heer",
"danah boyd"
] | [] | [] | [] |
InfoVis | 2,005 | Voronoi treemaps | 10.1109/INFVIS.2005.1532128 | Treemaps are a well known method for the visualization of attributed hierarchical data. Previously proposed treemap layout algorithms are limited to rectangular shapes, which cause problems with the aspect ratio of the rectangles as well as with identifying the visualized hierarchical structure. The approach of Voronoi treemaps presented in this paper eliminates these problems through enabling subdivisions of and in polygons. Additionally, this allows for creating treemap visualizations within areas of arbitrary shape, such as triangles and circles, thereby enabling a more flexible adaptation of treemaps for a wider range of applications. | false | false | [
"Michael Balzer",
"Oliver Deussen"
] | [] | [] | [] |
EuroVis | 2,005 | A Simple and Novel Seed-Set Finding Approach for Iso-Surface Extraction | 10.2312/VisSym/EuroVis05/125-132 | Iso-surface extraction is one of the most important approaches for volume rendering, and iso-contouring is one of the most effective methods for iso-surface extraction. Unlike most other methods having their search domain to be the whole dataset, iso-contouring does its search only on a relatively small subset of the original data-set. This subset, called a seed-set, has the property that every iso-surface must intersect with it, and it could be built at the preprocessing time. When an iso-value is given at the run time, iso-contouring algorithm starts from the intersected cells in the seed-set, and gradually propagates to form the whole iso-surface. As smaller seed-sets offer less cell searching time, most existing iso-contouring algorithms concentrates on how to identify an optimal seed-set. In this paper, we propose a new and linear-time approach for seed-set construction. This presented algorithm could reduce the size of the generated seed-sets by up to one or two orders of magnitude, compared with other previously proposed fast (linear time) algorithms. | false | false | [
"Chiang-Han Hung",
"Chuan-Kai Yang"
] | [] | [] | [] |
EuroVis | 2,005 | Analysis and Visualization of 3-C PIV Images from HART II using Image Processing Methods | 10.2312/VisSym/EuroVis05/161-168 | In this paper, three-component particle image velocimetry (3-C PIV) measurements within the wake of a helicopter rotor from the HART II test are analyzed. These PIV-images are quite a challenge as the noise due to the measurement method and the inherent turbulence of the flow can not be distinguished. Furthermore, features are often hidden by a mean flow, which is influenced by vortices and therefore not easy to determine. The authors present some image processing methods adapted to these vector fields for the computation of position, size, and direction of the vortices in this data. These methods are quite robust in terms of noise and independent of any mean flow and therefore appropriate for this analysis. The results of the analysis allow a more descriptive and intuitive visualization of the vortices. | false | false | [
"Julia Ebling",
"Gerik Scheuermann",
"Berend G. van der Wall"
] | [] | [] | [] |
EuroVis | 2,005 | ArcTrees: Visualizing Relations in Hierarchical Data | 10.2312/VisSym/EuroVis05/053-060 | In this paper we present, ARCTREES, a novel way of visualizing hierarchical and non-hierarchical relations within one interactive visualization. Such a visualization is challenging because it must display hierarchical information in a way that the user can keep his or her mental map of the data set and include relational information without causing misinterpretation. We propose a hierarchical view derived from traditional Treemaps and augment this view with an arc diagram to depict relations. In addition, we present interaction methods that allow the exploration of the data set using Focus+Context techniques for navigation. The development was motivated by a need for understanding relations in structured documents but it is also useful in many other application domains such as project management and calendars. | false | false | [
"Petra Neumann 0001",
"Stefan Schlechtweg",
"Sheelagh Carpendale"
] | [] | [] | [] |
EuroVis | 2,005 | BioBrowser: A Framework for Fast Protein Visualization | 10.2312/VisSym/EuroVis05/287-294 | This paper presents a protein visualization system called BioBrowser, which provides high quality images at interactive frame rates for molecules of extreme size and complexity. This is achieved by a shift in the tessellation approach: triangle meshes are not produced a priori on a 'just-in-case' basis. Instead, tessellation happens 'justin- time' given a certain camera position, image size and interaction demand. Thus, our approach is based on multiresolution meshes and on new extensions of graphics hardware. The paper shows how to reduce geometric data by using subdivision surfaces for ribbon structures and molecular surfaces and by using billboards instead of spheres consisting of triangles. It also shows how to use fragment shaders to create a three dimensional appearance and realistic sphere intersections. The combination of these approaches leads to an image quality not yet seen in interactive visualization environments for molecules of that size/complexity. All the above methods are combined to gain a high performance configurable visualization system on standard hardware. | false | false | [
"Andreas Halm",
"Lars Offen",
"Dieter W. Fellner"
] | [] | [] | [] |
EuroVis | 2,005 | Combining Silhouettes, Surface, and Volume Rendering for Surgery Education and Planning | 10.2312/VisSym/EuroVis05/303-310 | We introduce a flexible combination of volume, surface, and line rendering. We employ object-based edge detection because this allows a flexible parametrization of the generated lines. Our techniques were developed mainly for medical applications using segmented patient-individual volume datasets. In addition, we present an evaluation of the generated visualizations with 8 medical professionals and 25 laypersons. Integration of lines in conventional rendering turned out to be appropriate. | false | false | [
"Christian Tietjen",
"Tobias Isenberg 0001",
"Bernhard Preim"
] | [] | [] | [] |
EuroVis | 2,005 | Dense Geometric Flow Visualization | 10.2312/VisSym/EuroVis05/021-028 | We present a flow visualization technique based on rendering geometry in a dense, uniform distribution. Flow is integrated using particle advection. By adopting ideas from texture-based techniques and taking advantage of parallelism and programmability of contemporary graphics hardware, we generate streamlines and pathlines addressing both steady and unsteady flow. Pipelining is used to manage seeding, advection, and expiration of streamlines/ pathlines with constant lifetime. We achieve high numerical accuracy by enforcing short particle lifetimes and employing a fourth-order integration method. The occlusion problem inherent to dense volumetric representations is addressed by applying multi-dimensional transfer functions (MDTFs), restricting particle attenuation to regions of certain physical behavior, or features. Geometry is rendered in graphics hardware using techniques such as depth sorting, illumination, haloing, flow orientation, and depth-based color attenuation to enhance visual perception. We achieve dense geometric three-dimensional flow visualization with interactive frame rates. | false | false | [
"Sung W. Park",
"Brian Budge",
"Lars Linsen",
"Bernd Hamann",
"Kenneth I. Joy"
] | [] | [] | [] |
EuroVis | 2,005 | Discovering High-level Parameters for Visualization Design | 10.2312/VisSym/EuroVis05/255-262 | In most graphics and visualization applications, the effects of the mapping parameters on the output domain are multidimensional, non-linear and discontinuous. The complexity of such mapping often makes it difficult for a user to manually explore and manipulate the design parameter space to produce the desired output. Computer assistance is therefore useful in setting the mapping parameter values to generate desired outputs. Existing systems rely on exploring the entire input parameter space, which can be time and resource-intensive, particularly if the number of input parameters is large. We introduce a new approach to handling a large number of mapping parameters more efficiently. The basis for our approach is the identification of a small and effective set of highlevel parameters that can be associated directly with the characteristics of the outputs. Users will have a better understanding of this small set of high-level parameters and can easily modify their values interactively to produce the desired outputs. We demonstrate this technique in manipulating mapping parameters for a non-photorealistic volume rendering application. | false | false | [
"Srinivas Bhagavatula",
"Penny Rheingans",
"Marie desJardins"
] | [] | [] | [] |
EuroVis | 2,005 | Dynamically Modelling Interaction | 10.2312/VisSym/EuroVis05/009-011 | Technological advances are increasing the use of dynamic or changing displays, in many forms of interface. The increasing amount of information held on the Internet and in private government and commercial databases also requires more innovative approaches to retrieval and browsing than existing text-based search engines can provide. | false | false | [
"Jon May"
] | [] | [] | [] |
EuroVis | 2,005 | Extending and Simplifying Transfer Function Design in Medical Volume Rendering Using Local Histograms | 10.2312/VisSym/EuroVis05/263-270 | Direct Volume Rendering (DVR) is known to be of diagnostic value in the analysis of medical data sets. However, its deployment in everyday clinical use has so far been limited. Two major challenges are that the current methods for Transfer Function (TF) construction are too complex and that the tissue separation abilities of the TF need to be extended. In this paper we propose the use of histogram analysis in local neighborhoods to address both these conflicting problems. To reduce TF construction difficulty, we introduce Partial Range Histograms in an automatic tissue detection scheme, which in connection with Adaptive Trapezoids enable efficient TF design. To separate tissues with overlapping intensity ranges, we propose a fuzzy classification based on local histograms as a second TF dimension. This increases the power of the TF, while retaining intuitive presentation and interaction. | false | false | [
"Claes Lundström",
"Patric Ljung",
"Anders Ynnerman"
] | [] | [] | [] |
EuroVis | 2,005 | Galilean Invariant Extraction and Iconic Representation of Vortex Core Lines | 10.2312/VisSym/EuroVis05/151-160 | While vortex region quantities are Galilean invariant, most methods for extracting vortex cores depend on the frame of reference. We present an approach to extracting vortex core lines independently of the frame of reference by extracting ridge and valley lines of Galilean invariant vortex region quantities. We discuss a generalization of this concept leading to higher dimensional features. For the visualization of extracted line features we use an iconic representation indicating their scale and extent. We apply our approach to datasets from numerical simulations and experimental measurements. | false | false | [
"Jan Sahner",
"Tino Weinkauf",
"Hans-Christian Hege"
] | [] | [] | [] |
EuroVis | 2,005 | GVis: A Scalable Visualization Framework for Genomic Data | 10.2312/VisSym/EuroVis05/191-198 | This paper describes a framework we have developed for the visual analysis of large-scale phylogeny hierarchies populated with the genomic data of various organisms. This framework allows the user to quickly browse the phylogeny hierarchy of organisms from the highest level down to the level of an individual genome for the desired organism of interest. Based on this framework, the user can initiate gene-finding and gene-matching analyses and view the resulting annotated coding potential graphs in the same multi-scale visualization framework, permitting correlative analysis and further investigation. This paper introduces our framework and describes the data structures and algorithms that support it. | false | false | [
"Jin Hong 0003",
"Dong Hyun Jeong",
"Christopher D. Shaw",
"William Ribarsky",
"Mark Borodovsky",
"Chang Geun Song"
] | [] | [] | [] |
EuroVis | 2,005 | Hardware-Accelerated Glyphs for Mono- and Dipoles in Molecular Dynamics Visualization | 10.2312/VisSym/EuroVis05/177-182 | We present a novel visualization method for mono- and dipolar molecular simulations from thermodynamics that takes advantage of modern graphics hardware to interactively render specifically tailored glyphs. Our approach allows domain experts to visualize the results of molecular dynamics simulations with a higher number of particles than before and furthermore offers much better visual quality. We achieve this by transferring only visualization parameters to the GPU and by generating implicit surfaces directly in the fragment program. As a result, we can render up to 500.000 glyphs with about 10 fps displaying all the simulation results as geometrical properties that resemble the classical abstract representation used in this research area. Thus we enable researchers to visually assess the results of simulations of greater scale than before. We believe that the proposed method can be generalized to create other kinds of parametrized surfaces directly on graphics hardware to overcome the bandwidth bottleneck that exists between CPU and GPU. | false | false | [
"Guido Reina",
"Thomas Ertl"
] | [] | [] | [] |
EuroVis | 2,005 | High-Quality Rendering of Compressed Volume Data Formats | 10.2312/VisSym/EuroVis05/077-084 | Rendering directly from packed or compressed volume data formats using graphics hardware has advantages in terms of memory consumption and bandwidth, but results in lower-quality images due to the prohibitive cost of performing interpolation and gradient-based shading on the reconstructed data. The problem with the existing method lies in its close coupling of decompression and interpolation. We demonstrate that deferred filtering overcomes this problem by using a two-pass decompression and rendering strategy. With this method interpolation and gradient calculations are very efficient, allowing high quality rendering directly from packed or compressed volume data. We evaluate the cost of creating interpolated, gradient-shaded renderings using traditional on-the-fly decompression and deferred filtering, and show that deferred filtering can provide up to twenty times speed-up for high quality rendering. | false | false | [
"Nathaniel Fout",
"Hiroshi Akiba",
"Kwan-Liu Ma",
"Aaron E. Lefohn",
"Joe Kniss"
] | [] | [] | [] |
EuroVis | 2,005 | High-Quality Volume Rendering with Resampling in the Frequency Domain | 10.2312/VisSym/EuroVis05/085-092 | This work introduces a volume rendering technique that is conceptually based on the shear-warp factorization. We propose to perform the shear transformation in the frequency domain. Unlike the standard shear-warp algorithm, we allow for arbitrary sampling distances along the viewing rays, independent from the view direction. The accurate scaling of the volume slices is achieved by using the zero padding interpolation property. Finally, a high quality gradient estimation scheme is presented which uses the derivative theorem of the Fourier transform. Experimental results show that the presented method outperforms established algorithms in the quality of the produced images. If the data is sampled above the Nyquist rate the presented method is capable of a perfect reconstruction of the original function. | false | false | [
"Martin Artner",
"Torsten Möller",
"Ivan Viola",
"M. Eduard Gröller"
] | [] | [] | [] |
EuroVis | 2,005 | Illustrative Context-Preserving Volume Rendering | 10.2312/VisSym/EuroVis05/069-076 | In volume rendering it is very difficult to simultaneously visualize interior and exterior structures while preserving clear shape cues. Very transparent transfer functions produce cluttered images with many overlapping structures, while clipping techniques completely remove possibly important context information. In this paper we present a new model for volume rendering, inspired by techniques from illustration that provides a means of interactively inspecting the interior of a volumetric data set in a feature-driven way which retains context information. The context-preserving volume rendering model uses a function of shading intensity, gradient magnitude, distance to the eye point, and previously accumulated opacity to selectively reduce the opacity in less important data regions. It is controlled by two user-specified parameters. This new method represents an alternative to conventional clipping techniques, shares their easy and intuitive user control, but does not suffer from the drawback of missing context information. | false | false | [
"Stefan Bruckner",
"Sören Grimm",
"Armin Kanitsar",
"M. Eduard Gröller"
] | [] | [] | [] |
EuroVis | 2,005 | Interactive Methods for Exploring Particle Simulation Data | 10.2312/VisSym/EuroVis05/279-286 | In this work, we visualize high-dimensional particle simulation data using a suite of scatter plot-based visualizations coupled with interactive selection tools. We use traditional 2D and 3D projection scatter plots as well as a novel oriented disk rendering style to convey various information about the data. Interactive selection tools allow physicists to manually classify ''interesting'' sets of particles that are highlighted across multiple, linked views of the data. The power of our application is the ability to correspond new visual representations of the simulation data with traditional, well understood visualizations. This approach supports the interactive exploration of the high-dimensional space while promoting discovery of new particle behavior. | false | false | [
"Christopher S. Co",
"Alex Friedman",
"David P. Grote",
"Jean-Luc Vay",
"E. Wes Bethel",
"Kenneth I. Joy"
] | [] | [] | [] |
EuroVis | 2,005 | Interactive rendering of massive terrains on PC clusters | 10.2312/VisSym/EuroVis05/133-141 | We describe a parallel framework for interactive smooth rendering of massive terrains. We define a parallelization scheme for level of detail algorithms in cluster-based environments. The scheme relies on modern PC clusters capabilities to address the scalability issue of level of detail algorithms. To achieve this, we propose an eficient tile-based data partitioning method that allows both reducing load imbalance and solving the well-known border problem. At runtime level of detail computations are performed in parallel on cluster nodes. A hierarchical view frustum culling combined to a compression mechanism harnessing the frame-to-frame coherence are used to drastically reduce the inter-tasks communication overhead. We take into account level of detail algorithms visual quality issue by providing geomorphing and texturing supports. We are able to interactively and smoothly render terrains composed of hundreds of millions to billions of polygons on a cluster of 8 PCs. | false | false | [
"Valérie Gouranton",
"Souley Madougou",
"Emmanuel Melin",
"Cyril Nortet"
] | [] | [] | [] |
EuroVis | 2,005 | Interactive Visualization for Neck-Dissection Planning | 10.2312/VisSym/EuroVis05/295-302 | In this paper, we present visualization techniques for neck dissection planning. These interventions are carried out to remove lymph node metastasis in the neck region. 3d visualization is intended to explore and to quantify anatomic and pathologic structures and thus support decisions concerning the surgical strategy. For this purpose we developed and combined visualization and interaction techniques such as cutaway views, silhouettes and colorcoded distances. In addition, a standardized procedure for processing and visualization of the patient data is presented. | false | false | [
"Arno Krüger",
"Christian Tietjen",
"Jana Hintze",
"Bernhard Preim",
"Ilka Hertel",
"Gero Strauß"
] | [] | [] | [] |
EuroVis | 2,005 | Isosurface Extraction Using Fixed-Sized Buckets | 10.2312/VisSym/EuroVis05/207-214 | We present a simple and output optimal algorithm for accelerated isosurface extraction from volumetric data sets. Output optimal extraction algorithms perform an amount of work dominated by the size of the (output) isosurface rather than the size of the (input) data set. While several optimal methods have been proposed to accelerate isosurface extraction, these algorithms are relatively complicated to implement or require quantized values as input. Our method is based on a straightforward array data structure that only requires an auxiliary sorting routine for construction. The method works equally well for floating point data as it does for quantized data sets. We demonstrate how the data structure can exploit coherence between isosurfaces by performing searches incrementally. We show results for real application data validating the method's optimality. | false | false | [
"Kenneth W. Waters",
"Christopher S. Co",
"Kenneth I. Joy"
] | [] | [] | [] |
EuroVis | 2,005 | Localized Flow Analysis of 2D and 3D Vector Fields | 10.2312/VisSym/EuroVis05/143-150 | In this paper we present an approach to the analysis of the contribution of a small subregion in a dataset to the global flow. To this purpose, we subtract the potential flow that is induced by the boundary of the sub-domain from the original flow. Since the potential flow is free of both divergence and rotation, the localized flow field retains the original features. In contrast to similar approaches, by making explicit use of the boundary flow of the subregion, we manage to isolate the region-specific flow that contains exactly the local contribution of the considered subdomain to the global flow. In the remainder of the paper, we describe an implementation on unstructured grids in both two and three dimensions. We discuss the application of several widely used feature extraction methods on the localized flow, with an emphasis on topological schemes. | false | false | [
"Alexander Wiebel",
"Christoph Garth",
"Gerik Scheuermann"
] | [] | [] | [] |
EuroVis | 2,005 | Mail Explorer - Spatial and Temporal Exploration of Electronic Mail | 10.2312/VisSym/EuroVis05/247-254 | In today's world, e-mail has become one of the most important means of communication in business and private lives due to its efficiency. However, the problems start as soon as mail volumes go beyond the scope of human information processing capabilities. Firstly, time does not allow for leaving certain messages unanswered for a long time, and in certain cases, for reading all messages. Secondly, the dilemma of electronic filters leaves a choice of too many junk mails getting through versus a risk of solicited mails being dumped.
In this paper we present a new interactive visual data mining approach for analyzing individual e-mail communication. It combines classical visual analytics (help to identify pattern such as peaks and trends over time) with geo-spatial map distortions (help to understand the routes of e-mails). Experiments show that our visual e-mail explorer produces useful and interesting visualizations of large collections of e-mail and is practical for exploring temporal and geo-spatial patterns hidden in the e-mail data. | false | false | [
"Daniel A. Keim",
"Florian Mansmann",
"Christian Panse",
"Jörn Schneidewind",
"Mike Sips"
] | [] | [] | [] |
EuroVis | 2,005 | MoireTrees: Visualization and Interaction for Multi-Hierarchical Data | 10.2312/VisSym/EuroVis05/231-238 | Visualizing hierarchical data is one of the core areas of information visualization. Most of these techniques focus on single hierarchies—hierarchies with a single root element and a single path to each element. In contrast, this work focuses on the browsing of multi-hierarchies—hierarchies with multiple roots or multiple paths per element. A radial focus+context display algorithm and interaction methods are introduced to explore such multi-hierarchical data. A series of examples demonstrate the effectiveness of our new visualization. | false | false | [
"Mahnas Jean Mohammadi-Aragh",
"T. J. Jankun-Kelly"
] | [] | [] | [] |
EuroVis | 2,005 | Non-manifold Mesh Extraction from Time-varying Segmented Volumes used for Modeling a Human Heart | 10.2312/VisSym/EuroVis05/199-206 | We present a new algorithm extracting and fairing surfaces from segmented volumes composed of multiple materials. In a first pass, the material boundaries in the volume are smoothed considering signed distance functions for the individual materials. Second, we apply a marching-cubes-like contouring method providing initial meshes defining material boundaries. Non-manifold features emerge along lines where more than two materials encounter. Finally, the mesh geometry is relaxed in a constrained fairing process. We use our algorithm to construct a heart model from segmented time-varying magnetic resonance images. Information concerning the heart ontology is used to merge certain structures to functional units. | false | false | [
"Martin Bertram 0001",
"Gerd Reis",
"Rolf Hendrik van Lengen",
"Sascha Köhn",
"Hans Hagen"
] | [] | [] | [] |
EuroVis | 2,005 | Pointillist and Glyph-based Visualization of Nanoparticles in Formation | 10.2312/VisSym/EuroVis05/169-176 | In this paper we offer new, texture-based methods for the visualization of multivariate data. These methods aim to more effectively convey the results of calculations simulating the formation of nanoparticles in turbulent fl ows. In these simulations, an entire distribution of nanoparticles is computed at every point across a two-dimensional slice of the data space, for every time step. Previous visualization methods have relied on multiple separate images to convey summary statistics about the datasets, including mean diameter and standard deviation of particle sizes. We introduce new methods based on texture which aim to enable the integrated understanding of the entire distribution of values at each point across the domain in terms of both summary statistics at each point and particle counts for various sizes of particles. Pointillism is used to represent the data at each point across the data range as a high-resolution texture. Circular glyphs can also be used to form a more discrete, spot-based texture, in which different characteristics of the distribution are encoded in various features of the spots. | false | false | [
"P. Coleman Saunders",
"Victoria Interrante",
"Sean C. Garrick"
] | [] | [] | [] |
EuroVis | 2,005 | Real-Time Advection and Volumetric Illumination for the Visualization of 3D Unsteady Flow | 10.2312/VisSym/EuroVis05/013-020 | This paper presents an interactive technique for the dense texture-based visualization of unsteady 3D flow, taking into account issues of computational efficiency and visual perception. High efficiency is achieved by a novel 3D GPU-based texture advection mechanism that implements logical 3D grid structures by physical memory in the form of 2D textures. This approach results in fast read and write access to physical memory, independent of GPU architecture. Slice-based direct volume rendering is used for the final display. A real-time computation of gradients is employed to achieve volume illumination. Perception-guided volume shading methods are included, such as halos, cool/warm shading, or color-based depth cueing. The problems of clutter and occlusion are addressed by supporting a volumetric importance function that enhances features of the flow and reduces visual complexity in less interesting regions. | false | false | [
"Daniel Weiskopf",
"Tobias Schafhitzel",
"Thomas Ertl"
] | [] | [] | [] |
EuroVis | 2,005 | Scalable, Robust Visualization of Very Large Trees | 10.2312/VisSym/EuroVis05/037-044 | The TreeJuxtaposer system [MGT*03] allowed visual comparison of large trees with guaranteed visibility of landmarks and Focus+Context navigation. While that system allowed exploration and comparison of larger datasets than previous work, it was limited to a single tree of 775,000 nodes by a large memory footprint. In this paper, we describe the theoretical limitations to TreeJuxtaposer's architecture that severely restrict its scalability. We provide two scalable, robust solutions to these limitations: TJC and TJC-Q. TJC is a system that supports browsing trees up to 15 million nodes by exploiting leading-edge graphics hardware while TJC-Q allows browsing trees up to 5 million nodes on commodity platforms. Both of these systems use a fast new algorithm for drawing and culling and benefit from a complete redesign of all data structures for more efficient memory usage and reduced preprocessing time. | false | false | [
"Dale Beermann",
"Tamara Munzner",
"Greg Humphreys"
] | [] | [] | [] |
EuroVis | 2,005 | Spatialized Transfer Functions | 10.2312/VisSym/EuroVis05/271-278 | Multi-dimensional transfer functions are an efficient way to visualize features in scalar volume data produced by CT or MRI scanners. However, the optimal transfer function is difficult to find in general. We present an automatic yet powerful method for the automatic setup of multi-dimensional transfer functions by adding spatial information to the histogram of a volume. Using this information we can easily classify the histogram and derive a transfer function by assigning unique colors to each class of the histogram.
Each feature can be selected interactively by pointing and clicking at the corresponding class in the transfer function. In order to render the classified volume with adequate quality we propose an extension of the wellknown pre-integration technique. Furthermore, we demonstrate the flexibility of our approach by giving examples for the imaging of segmented, diffusion-tensor and multi-modal data. | false | false | [
"Stefan Röttger",
"Michael Bauer 0002",
"Marc Stamminger"
] | [] | [] | [] |
EuroVis | 2,005 | Spline-Based Gradient Filters For High-Quality Refraction Computations in Discrete Datasets | 10.2312/VisSym/EuroVis05/215-222 | Based on the finding that refraction imposes significantly higher demands onto gradient filters than illumination and shading, we evaluate the family of spline filters as a good alternative to the cubic filters, which so far have served as the gold standard of efficient yet high-quality interpolation filters in present visualization applications. Using a regular background texture to visualize the refractive properties of the volumetric object, we also describe an efficient scheme to achieve the effects of supersampling without incurring any extra raycasting overhead. Our results indicate that splines can be superior to the Catmull-Rom filter, with potentially less computational overhead, also offering a convenient means to adjust the extent of lowpassing and smoothing. | false | false | [
"Shengying Li",
"Klaus Mueller 0001"
] | [] | [] | [] |
EuroVis | 2,005 | The i-Disc - A Tool To Visualize and Explore Topic Maps | 10.2312/VisSym/EuroVis05/045-052 | We present the i-Disc, a tool to interactively visualize and explore medium sized topic maps. Topic maps contain two basic structures: the topic hierarchy and the associations between topics. Our system presents the topic hierarchy in a radial planar layout by encoding different hierarchy levels as separate rings. Associations are displayed on demand as three-dimensional arcs across the topic landscape. By separating these two topic map structures into different spatial dimensions, we untangle the often complex topic map graph.
A perspective rendering of our layout generates a natural focus and context display. Our elementary circular design allows quick perception of the overall topic map structure while interactive navigation and exploration provide access to details on demand. The tool is implemented as a client-server application and integrates seamlessly into existing web based environments. | false | false | [
"Tobias Hofmann",
"Hendrik Wendler",
"Bernd Froehlich 0001"
] | [] | [] | [] |
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