EuroVis10: Eurographics/ IEEE Symposium on Visualization

Permanent URI for this collection

https://diglib.eg.org/handle/10.2312/395

Browse

Now showing 1 - 20 of 48

Video Visualization for Snooker Skill Training
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Höferlin, Markus; Grundy, Edward; Borgo, Rita; Weiskopf, Daniel; Chen, Min; Griffiths, Iwan W.; Griffiths, W.; G. Melancon, T. Munzner, and D. Weiskopf
We present a feasibility study on using video visualization to aid snooker skill training. By involving the coaches and players in the loop of intelligent reasoning, our approach addresses the difficulties of automated semantic reasoning, while benefiting from mature video processing techniques. This work was conducted in conjunction with a snooker club and a sports scientist. In particular, we utilized the principal design of the VideoPerpetuoGram (VPG) to convey spatiotemporal information to the viewers through static visualization, removing the burden of repeated video viewing. We extended the VPG design to accommodate the need for depicting multiple video streams and respective temporal attribute fields, including silhouette extrusion, spatial attributes, and non-spatial attributes. Our results and evaluation have shown that video visualization can provide snooker coaching with visually quantifiable and comparable summary records, and is thus a cost-effective means for assessing skill levels and monitoring progress objectively and consistently.
Streaming-Enabled Parallel Dataflow Architecture for Multicore Systems
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Vo, Huy T.; Osmari, Daniel K.; Summa, Brian; Comba, João L. D.; Pascucci, Valerio; Silva, Cláudio T.; G. Melancon, T. Munzner, and D. Weiskopf
We propose a new framework design for exploiting multi-core architectures in the context of visualization dataflow systems. Recent hardware advancements have greatly increased the levels of parallelism available with all indications showing this trend will continue in the future. Existing visualization dataflow systems have attempted to take advantage of these new resources, though they still have a number of limitations when deployed on shared memory multi-core architectures. Ideally, visualization systems should be built on top of a parallel dataflow scheme that can optimally utilize CPUs and assign resources adaptively to pipeline elements. We propose the design of a flexible dataflow architecture aimed at addressing many of the shortcomings of existing systems including a unified execution model for both demand-driven and event-driven models; a resource scheduler that can automatically make decisions on how to allocate computing resources; and support for more general streaming data structures which include unstructured elements. We have implemented our system on top of VTK with backward compatibility. In this paper, we provide evidence of performance improvements on a number of applications.
An Evaluation of Glyph Perception for Real Symmetric Traceless Tensor Properties
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Jankun-Kelly, T. J.; Lanka, Yagneshwara; II, J. Edward Swan; G. Melancon, T. Munzner, and D. Weiskopf
A perceptual study of four tensor glyphs for symmetric, real, traceless tensors was performed. Each glyph encodes three properties of the system: Orientation, uniaxiality (alignment along the direction of orientation), and biaxiality (alignment along a vector orthogonal to the orientation). Thirty users over two studies were asked to identify these three properties for each glyph type under a variety of permutations in order to evaluate the effectiveness of visually communicating the properties; response time was also measured. We discuss the significant differences found between the methods as guidance to the use of these glyphs for traceless tensor visualization.
Understanding Interactive Legends: a Comparative Evaluation with Standard Widgets
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Riche, Nathalie Henry; Lee, Bongshin; Plaisant, Catherine; G. Melancon, T. Munzner, and D. Weiskopf
Interactive information visualization systems rely on widgets to allow users to interact with the data and modify the representation. We define interactive legends as a class of controls combining the visual representation of static legends and interaction mechanisms of widgets. As interactive legends start to appear in popular websites, we categorize their designs for common data types and evaluate their effectiveness compare to standard widgets. Results suggest that 1) interactive legends can lead to faster perception of the mapping between data values and visual encodings and 2) interaction time is affected differently depending on the data type. Additionally, our study indicates superiority both in terms of perception and interaction of ordinal controls over numerical ones. Numerical techniques are mostly used in today s systems. By providing solutions to allowing users to modify ranges interactively, we believe that interactive legends make it possible to increase the use of ordinal techniques for visual exploration.
DTI in Context: Illustrating Brain Fiber Tracts In Situ
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Svetachov, Pjotr; Everts, Maarten H.; Isenberg, Tobias; G. Melancon, T. Munzner, and D. Weiskopf
We present an interactive illustrative visualization method inspired by traditional pen-and-ink illustration styles. Specifically, we explore how to provide context around DTI fiber tracts in the form of surfaces of the brain, the skull, or other objects such as tumors. These contextual surfaces are derived from either segmentation data or generated using interactive iso-surface extraction and are rendered with a flexible, slice-based hatching technique, controlled with ambient occlusion. This technique allows us to produce a consistent and frame-coherent appearance with precise control over the lines. In addition, we provide context through cutting planes onto which we render gray matter with stippling. Together, our methods not only facilitate the interactive exploration and illustration of brain fibers within their anatomical context but also allow us to produce high-quality images for print reproduction. We provide evidence for the success of our approach with an informal evaluation with domain experts.
GraphDice: A System for Exploring Multivariate Social Networks
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Bezerianos, Anastasia; Chevalier, Fanny; Dragicevic, Pierre; Elmqvist, Niklas; Fekete, Jean-Daniel; G. Melancon, T. Munzner, and D. Weiskopf
Social networks collected by historians or sociologists typically have a large number of actors and edge attributes. Applying social network analysis (SNA) algorithms to these networks produces additional attributes such as degree, centrality, and clustering coefficients. Understanding the effects of this plethora of attributes is one of the main challenges of multivariate SNA. We present the design of GraphDice, a multivariate network visualization system for exploring the attribute space of edges and actors. GraphDice builds upon the ScatterDice system for its main multidimensional navigation paradigm, and extends it with novel mechanisms to support network exploration in general and SNA tasks in particular. Novel mechanisms include visualization of attributes of interval type and projection of numerical edge attributes to node attributes. We show how these extensions to the original ScatterDice system allow to support complex visual analysis tasks on networks with hundreds of actors and up to 30 attributes, while providing a simple and consistent interface for interacting with network data.
Scalable Multi-view Registration for Multi-Projector Displays on Vertically Extruded Surfaces
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Sajadi, Behzad; Majumder, Aditi; G. Melancon, T. Munzner, and D. Weiskopf
Recent work have shown that it is possible to register multiple projectors on non-planar surfaces using a single uncalibrated camera instead of a calibrated stereo pair when dealing with a special class of non-planar surfaces, vertically extruded surfaces. However, this requires the camera view to contain the entire display surface. This is often an impossible scenario for large displays, especially common in visualization, edutainment, training and simulation applications. In this paper we present a new method that can achieve an accurate geometric registration even when the field-of-view of the uncalibrated camera can cover only a part of the vertically extruded display at a time. We pan and tilt the camera from a single point and employ a multi-view approach to register the projectors on the display. This allows the method to scale easily both in terms of camera resolution and display size. To the best of our knowledge, our method is the first to achieve a scalable multi-view geometric registration of large vertically extruded displays with a single uncalibrated camera. This method can also handle a different situation of having multiple similarly oriented cameras in different locations, if the camera focal length is known. Keywords: Registration, Calibration, Multi-Projector Displays, Tiled Displays
Dynamic Multi-View Exploration of Shape Spaces
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Busking, Stef; Botha, Charl P.; Post, Frits H.; G. Melancon, T. Munzner, and D. Weiskopf
Statistical shape modeling is a widely used technique for the representation and analysis of the shapes and shape variations present in a population. A statistical shape model models the distribution in a high dimensional shape space, where each shape is represented by a single point. We present a design study on the intuitive exploration and visualization of shape spaces and shape models. Our approach focuses on the dual-space nature of these spaces. The high-dimensional shape space represents the population, whereas object space represents the shape of the 3D object associated with a point in shape space. A 3D object view provides local details for a single shape. The high dimensional points in shape space are visualized using a 2D scatter plot projection, the axes of which can be manipulated interactively. This results in a dynamic scatter plot, with the further extension that each point is visualized as a small version of the object shape that it represents. We further enhance the population-object duality with a new type of view aimed at shape comparison. This new shape evolution view visualizes shape variability along a single trajectory in shape space, and serves as a link between the two spaces described above. Our three-view exploration concept strongly emphasizes linked interaction between all spaces. Moving the cursor over the scatter plot or evolution views, shapes are dynamically interpolated and shown in the object view. Conversely, camera manipulation in the object view affects the object visualizations in the other views. We present a GPU-accelerated implementation, and show the effectiveness of the three-view approach using a number of realworld cases. In these, we demonstrate how this multi-view approach can be used to visually explore important aspects of a statistical shape model, including specificity, compactness and reconstruction error.
A Multidirectional Occlusion Shading Model for Direct Volume Rendering
(The Eurographics Association and Blackwell Publishing Ltd., 2010) oltészová, Veronika; Patel, Daniel; Bruckner, Stefan; Viola, Ivan; G. Melancon, T. Munzner, and D. Weiskopf
In this paper, we present a novel technique which simulates directional light scattering for more realistic interactive visualization of volume data. Our method extends the recent directional occlusion shading model by enabling light source positioning with practically no performance penalty. Light transport is approximated using a tilted cone-shaped function which leaves elliptic footprints in the opacity buffer during slice-based volume rendering. We perform an incremental blurring operation on the opacity buffer for each slice in front-to-back order. This buffer is then used to define the degree of occlusion for the subsequent slice. Our method is capable of generating high-quality soft shadowing effects, allows interactive modification of all illumination and rendering parameters, and requires no pre-computation.
Real-Time Temporal-Coherent Color Contrast Enhancement for Dichromats
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Machado, Gustavo Mello; Oliveira, Manuel M.; G. Melancon, T. Munzner, and D. Weiskopf
We present an automatic image-recoloring technique for enhancing color contrast for dichromats whose computational cost varies linearly with the number of input pixels. Our approach can be efficiently implemented on GPUs, and we show that for typical image sizes it is up to two orders of magnitude faster than the current stateof- the-art technique. Unlike previous approaches, ours preserve temporal coherence and, therefore, is suitable for video recoloring. We demonstrate the effectiveness of our technique by integrating it into a visualization system and showing, for the first time, real-time high-quality recolored visualizations for dichromats.
Visual Analysis of Multi-Joint Kinematic Data
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Krekel, Peter R.; Valstar, Edward R.; Groot, Jurriaan de; Post, Frits H.; Nelissen, Rob G. H. H.; Botha, Charl P.; G. Melancon, T. Munzner, and D. Weiskopf
Kinematics is the analysis of motions without regarding forces or inertial effects, with the purpose of understanding joint behaviour. Kinematic data of linked joints, for example the upper extremity, i.e. the shoulder and arm joints, contains many related degrees of freedom that complicate numerical analysis. Visualisation techniques enhance the analysis process, thus improving the effectiveness of kinematic experiments. This paper describes a new visualisation system specifically designed for the analysis of multi-joint kinematic data of the upper extremity. The challenge inherent in the data is that the upper extremity is comprised of five cooperating joints with a total of fifteen degrees of freedom. The range of motion may be affected by subtle deficiencies of individual joints that are difficult to pinpoint. To highlight these subtleties our approach combines interactive filtering and multiple visualisation techniques. Our system is further differentiated by the fact that it integrates simultaneous acquisition and visual analysis of biokinematic data. Also, to facilitate complex queries, we have designed a visual query interface with visualisation and interaction elements that are based on the domain-specific anatomical representation of the data. The combination of these techniques form an effective approach specifically tailored for the investigation and comparison of large collections of kinematic data. This claim is supported by an evaluation experiment where the technique was used to inspect the kinematics of the left and right arm of a patient with a healed proximal humerus fracture, i.e. a healed shoulder fracture.
Pathline: A Tool For Comparative Functional Genomics
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Meyer, Miriah; Wong, Bang; Styczynski, Mark; Munzner, Tamara; Pfister, Hanspeter; G. Melancon, T. Munzner, and D. Weiskopf
Biologists pioneering the new field of comparative functional genomics attempt to infer the mechanisms of gene regulation by looking for similarities and differences of gene activity over time across multiple species. They use three kinds of data: functional data such as gene activity measurements, pathway data that represent a series of reactions within a cellular process, and phylogenetic relationship data that describe the relatedness of species. No existing visualization tool can visually encode the biologically interesting relationships between multiple pathways, multiple genes, and multiple species. We tackle the challenge of visualizing all aspects of this comparative functional genomics dataset with a new interactive tool called Pathline. In addition to the overall characterization of the problem and design of Pathline, our contributions include two new visual encoding techniques. One is a new method for linearizing metabolic pathways that provides appropriate topological information and supports the comparison of quantitative data along the pathway. The second is the curvemap view, a depiction of time series data for comparison of gene activity and metabolite levels across multiple species. Pathline was developed in close collaboration with a team of genomic scientists. We validate our approach with case studies of the biologists use of Pathline and report on how they use the tool to confirm existing findings and to discover new scientific insights.
Image-Based Edge Bundles: Simplified Visualization of Large Graphs
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Telea, Alexandru; Ersoy, Ozan; G. Melancon, T. Munzner, and D. Weiskopf
We present a new approach aimed at understanding the structure of connections in edge-bundling layouts. We combine the advantages of edge bundles with a bundle-centric simplified visual representation of a graph s structure. For this, we first compute a hierarchical edge clustering of a given graph layout which groups similar edges together. Next, we render clusters at a user-selected level of detail using a new image-based technique that combines distance-based splatting and shape skeletonization. The overall result displays a given graph as a small set of overlapping shaded edge bundles. Luminance, saturation, hue, and shading encode edge density, edge types, and edge similarity. Finally, we add brushing and a new type of semantic lens to help navigation where local structures overlap. We illustrate the proposed method on several real-world graph datasets.
Visualization and Analysis-Oriented Reconstruction of Material Interfaces
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Meredith, Jeremy; Childs, Hank; G. Melancon, T. Munzner, and D. Weiskopf
Reconstructing boundaries along material interfaces from volume fractions is a difficult problem, especially because the under-resolved nature of the input data allows for many correct interpretations. Worse, algorithms widely accepted as appropriate for simulation are inappropriate for visualization. In this paper, we describe a new algorithm that is specifically intended for reconstructing material interfaces for visualization and analysis requirements. The algorithm performs well with respect to memory footprint and execution time, has desirable properties in various accuracy metrics, and also produces smooth surfaces with few artifacts, even when faced with more than two materials per cell.
Matrix Trees
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Andrysco, Nathan; Tricoche, Xavier; G. Melancon, T. Munzner, and D. Weiskopf
We propose a new data representation for octrees and kd-trees that improves upon memory size and algorithm speed of existing techniques. While pointerless approaches exploit the regular structure of the tree to facilitate efficient data access, their memory footprint becomes prohibitively large as the height of the tree increases. Pointerbased trees require memory consumption proportional to the number of tree nodes, thus exploiting the typical sparsity of large trees. Yet, their traversal is slowed by the need to follow explicit pointers across the different levels. Our solution is a pointerless approach that represents each tree level with its own matrix, as opposed to traditional pointerless trees that use only a single vector. This novel data organization allows us to fully exploit the tree s regular structure and improve the performance of tree operations. By using a sparse matrix data structure we obtain a representation that is suited for sparse and dense trees alike. In particular, it uses less total memory than pointer-based trees even when the data set is extremely sparse. We show how our approach is easily implemented on the GPU and illustrate its performance in typical visualization scenarios.
Topology Aware Stream Surfaces
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Schneider, Dominic; Reich, Wieland; Wiebel, Alexander; Scheuermann, Gerik; G. Melancon, T. Munzner, and D. Weiskopf
We present an algorithm that allows stream surfaces to recognize and adapt to vector field topology. Standard stream surface algorithms either refine the surface uncontrolled near critical points which slows down the computation considerably and may lead to a poor surface approximation. Alternatively, the concerned region is omitted from the stream surface by severing it into two parts thus generating an incomplete stream surface. Our algorithm utilizes topological information to provide a fast, accurate, and complete triangulation of the stream surface near critical points. The required topological information is calculated in a preprocessing step. We compare our algorithm against the standard approach both visually and in performance.
Effective Techniques to Visualize Filament-Surface Relationships
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Kuß, Anja; Gensel, Maria; Meyer, Björn; Dercksen, Vincent J.; Prohaska, Steffen; G. Melancon, T. Munzner, and D. Weiskopf
Combined visualizations of filamentous structures and surrounding volumetric objects are common in biological and medical applications. Often, the structures spatial relationships remain unclear to the viewer. In this paper, we discuss and evaluate techniques to emphasize spatial relationships. We concentrate on the visualization of transparent objects and intersecting lines. Among various techniques, participants of an exploratory user study preferred coloring of lines, marking of line-surface intersections by glyphs, and the combination of both. These techniques were additionally evaluated in a confirmatory study in which participants were asked to judge whether a filament runs through a transparent structure. We found that the evaluated techniques significantly improve the participants performance in terms of the number of correct responses and response time. The best performance was found for the combination of line coloring and intersection glyph display.
Out-of-Core Simplification and Crack-Free LOD Volume Rendering for Irregular Grids
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Du, Zhiyan; Chiang, Yi-Jen; G. Melancon, T. Munzner, and D. Weiskopf
We propose a novel out-of-core simplification and level-of-detail (LOD) volume rendering algorithm for large irregular grids represented as tetrahedral meshes. One important feature of our algorithm is that it creates a space decomposition as required by I/O-efficient simplification and volume rendering, and simplifies both the internal and boundary portions of the sub-volumes progressively by edge collapses using the (extended) quadric error metric, while ensuring any selected LOD mesh to be crack-free (i.e., any neighboring sub-volumes in the LOD have consistent boundaries, and all the cells in the LOD do not have negative volumes), with all computations performed I/O-efficiently. This has been an elusive goal for out-of-core progressive meshes and LOD visualization, and our novel solution achieves this goal with a theoretical guarantee to be crack-free for tetrahedral meshes. As for selecting a desirable LOD mesh for volume rendering, our technique supports selective refinement LODs (where different places can have different error bounds), in addition to the basic uniform LODs (where the error bound is the same in all places). The proposed scalar-value range and view-dependent selection queries for selective refinement are especially effective in producing images of the highest quality with a much faster rendering speed. The experiments demonstrate the efficacy of our new technique.
SmallWorlds: Visualizing Social Recommendations
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Gretarsson, Brynjar; O'Donovan, John; Bostandjiev, Svetlin; Hall, Christopher; Höllerer, Tobias; G. Melancon, T. Munzner, and D. Weiskopf
We present SmallWorlds, a visual interactive graph-based interface that allows users to specify, refine and build item-preference profiles in a variety of domains. The interface facilitates expressions of taste through simple graph interactions and these preferences are used to compute personalized, fully transparent item recommendations for a target user. Predictions are based on a collaborative analysis of preference data from a user s direct peer group on a social network. We find that in addition to receiving transparent and accurate item recommendations, users also learn a wealth of information about the preferences of their peers through interaction with our visualization. Such information is not easily discoverable in traditional text based interfaces. A detailed analysis of our design choices for visual layout, interaction and prediction techniques is presented. Our evaluations discuss results from a user study in which SmallWorlds was deployed as an interactive recommender system on Facebook.
Topological Landscape Ensembles for Visualization of Scalar-Valued Functions
(The Eurographics Association and Blackwell Publishing Ltd., 2010) Harvey, William; Wang, Yusu; G. Melancon, T. Munzner, and D. Weiskopf
Visual representation techniques enable perception and exploration of scientific data. Following the topological landscapes metaphor ofWeber et al., we provide a new algorithm for visualizing scalar functions defined on simply connected domains of arbitrary dimension. For a potentially high dimensional scalar field, our algorithm produces a collection of, in some sense complete, two-dimensional terrain models whose contour trees and corresponding topological persistences are identical to those of the input scalar field. The algorithm exactly preserves the volume of each region corresponding to an arc in the contour tree. We also introduce an efficiently computable metric on terrain models we generate. Based on this metric, we develop a tool that can help the users to explore the space of possible terrain models.

Browse

Browsing EuroVis10: Eurographics/ IEEE Symposium on Visualization by Issue Date

Results Per Page

Sort Options