22 research outputs found
Interactive volume visualization of general polyhedral grids
No full textThis paper presents a novel framework for visualizing volumetric data specified on complex polyhedral grids, without the need to perform any kind of a priori tetrahedralization. These grids are composed of polyhedra that often are non-convex and have an arbitrary number of faces, where the faces can be non-planar with an arbitrary number of vertices. The importance of such grids in state-of-the-art simulation packages is increasing rapidly. We propose a very compact, face-based data structure for representing such meshes for visualization, called two-sided face sequence lists (TSFSL), as well as an algorithm for direct GPU-based ray-casting using this representation. The TSFSL data structure is able to represent the entire mesh topology in a 1D TSFSL data array of face records, which facilitates the use of efficient 1D texture accesses for visualization. In order to scale to large data sizes, we employ a mesh decomposition into bricks that can be handled independently, where each brick is then composed of its own TSFSL array. This bricking enables memory savings and performance improvements for large meshes. We illustrate the feasibility of our approach with real-world application results, by visualizing highly complex polyhedral data from commercial state-of-the-art simulation packages. © 2011 IEEE
Scalability for volume rendering and information visualization approaches in the context of scientific data
No full textSowohl in vielen Forschungsbereichen, als auch im Ingenieurwesen werden numerische Simulationen physikalischer Prozessen eingesetzt, um experimentelle Untersuchungen zu ergänzen oder gar zu ersetzen.Visualisierung gehört neben Datamining und Statistik zu den wichtigsten Werkzeugen, um die resultierenden Datenmengen zu analysieren und zu explorieren. Um mit den ständigen Weiterentwicklungen im Simulations und Modellierungsbereich mitzuhalten, müssen moderne Visualisierungstechniken flexibel und skalierbar sein. Der erste Volumsvisualisierungsansatz, welcher in dieser Arbeit beschrieben wird, benützt eine Zerlegung der Simulationsdaten in einzelne Blöcke und eine Resamplingmethode, um hoch detaillierte Simulationsgitter verarbeiten zu können. Für den Benutzer wichtige Datenregionen werden sehr genau dargestellt, während Teile geringerer Relevanz durch eine weniger detaillierte Repräsentation visualisiert werden. Aktuelle Simulationsmethoden sind in der Lage auf einer Volumszerlegung in beliebige polyhedrische Zellen zu arbeiten. Der zweite, in dieser Arbeit vorgestellte Volumsvisualisierungsansatz ermöglicht es direkt auf solch komplexen Gitterstrukturen definierte Daten darzustellen. Hierzu wird Raycasting eingesetzt, welches auf einer neuen hoch effizienten und sehr kompakten Datenstruktur arbeitet.Informationsvisualisierung kann eingesetzt werden, um tiefe Einblicke in komplexe Simulationsresultate zu gewinnen. Allerdings müssen hierzu einige Probleme hinsichtlich der Skalierbarkeit von Informationsvisualisierungsmethoden gelöst werden. Die Ansätze, welche zu diesem Zweck in dieser Arbeit beschrieben werden, helfen dabei, Visualisierungen übersichtlich zu halten, auch wenn eine große Anzahl an Datenpunkten dargestellt werden muss. Der Verlauf von wichtigen Trends wird durch das Verwischen einer Textur, welche weißes Rauschen enthält, verdeutlicht, während ein neuartiges Farbschema Zusammenhänge zwischen verschiedenen Visualisierungsmethoden darstellt. Um die Effektivität der vorgestellten Methoden zu demonstrieren, enthält diese Arbeit ein ausführliches Anwendungsbeispiel.<br /
Interactive Seismic Interpretation with Piecewise Global Energy Minimization
No full textIncreasing demands in world-wide energy consumption and oil depletion of large reservoirs have resulted in the need for exploring smaller and more complex oil reservoirs. Planning of the reservoir valorization usually starts with creating a model of the subsurface structures, including seismic faults and horizons. However, seismic interpretation and horizon tracing is a difficult and error-prone task, often resulting in hours of work needing to be manually repeated. In this paper, we propose a novel, interactive workflow for horizon interpretation based on well positions, which include additional geological and geophysical data captured by actual drillings. Instead of interpreting the volume slice-by-slice in 2D, we propose 3D seismic interpretation based on well positions. We introduce a combination of 2D and 3D minimal cost path and minimal cost surface tracing for extracting horizons with very little user input. By processing the volume based on well positions rather than slice-based, we are able to create a piecewise optimal horizon surface at interactive rates. We have integrated our system into a visual analysis platform which supports multiple linked views for fast verification, exploration and analysis of the extracted horizons. The system is currently being evaluated by our collaborating domain experts
Visual coherence for large-scale line-plot visualizations
No full textDisplaying a large number of lines within a limited amount of screen space is a task that is common to many different classes of visualization techniques such as time-series visualizations, parallel coordinates, link-node diagrams, and phase-space diagrams. This paper addresses the challenging problems of cluttering and overdraw inherent to such visualizations. We generate a 2x2 tensor field during line rasterization that encodes the distribution of line orientations through each image pixel. Anisotropic diffusion of a noise texture is then used to generate a dense, coherent visualization of line orientation. In order to represent features of different scales, we employ a multi-resolution representation of the tensor field. The resulting technique can easily be applied to a wide variety of line-based visualizations. We demonstrate this for parallel coordinates, a time-series visualization, and a phase-space diagram. Furthermore, we demonstrate how to integrate a focus+context approach by incorporating a second tensor field. Our approach achieves interactive rendering performance for large data sets containing millions of data items, due to its image-based nature and ease of implementation on GPUs. Simulation results from computational fluid dynamics are used to evaluate the performance and usefulness of the proposed method. © 2011 The Author(s).The authors thank Thomas Schultz and Andrea Kratz for valuable input on tensor-related topics, and Wolfgang Freiler for help with figures. The diesel particulate filter data set is courtesy of AVL List GmbH, Graz, Austria. Parts of this work were funded by the Austrian Research Funding Agency (FFG) in the scope of the project "AutARG" ( No. 819352
Interactive Visual Analysis of Heterogeneous Scientific Data across an Interface
No full textIn this paper, we present a systematic approach to the interactive visual exploration and analysis of heterogeneous scientific data. Based on a setup of coordinated multiple views (with linking and brushing) and heterogeneous data which consists of two blocks of scientific data (e.g., 2D and 3D data), we enable the joint, feature-based investigation across an interface. The interface specifies (a) which items in the one part of the data are related to which items in the other part, and vice versa, (b) how selections (in terms of feature extraction) are transferred between the two parts of the data, and (c) how interaction is realized during the visual analysis. We also propose strategies for visual analysis across an interface resulting in interactive and iterative refinement of features specified in different parts of the data. We demonstrate the usefulness of our approach in the context of two visual analysis scenarios with heterogeneous scientific data, i.e., a multi-run climate simulation and a complex simulation of fluid-structure interaction
Visual Coherence for Large-Scale Line-Plot Visualizations
No full textDisplaying a large number of lines within a limited amount of screen space is a task that is common to many different classes of visualization techniques such as time-series visualizations, parallel coordinates, link-node diagrams, and phase-space diagrams. This paper addresses the challenging problems of cluttering and overdraw inherent to such visualizations. We generate a 2x2 tensor field during line rasterization that encodes the distribution of line orientations through each image pixel. Anisotropic diffusion of a noise texture is then used to generate a dense, coherent visualization of line orientation. In order to represent features of different scales, we employ a multi-resolution representation of the tensor field. The resulting technique can easily be applied to a wide variety of line-based visualizations. We demonstrate this for parallel coordinates, a time-series visualization, and a phase-space diagram. Furthermore, we demonstrate how to integrate a focus+context approach by incorporating a second tensor field. Our approach achieves interactive rendering performance for large data sets containing millions of data items, due to its image-based nature and ease of implementation on GPUs. Simulation results from computational fluid dynamics are used to evaluate the performance and usefulness of the proposed method.Computer Graphics Forum30
Integrating Local Feature Detectors in the Interactive Visual Analysis of Flow Simulation Data
No full textIntegrating Local Feature Detectors in the Interactive Visual Analysis of Flow Simulation Data
No full textWe present smooth formulations of common vortex detectors that allow a seamless integration into the concept of interactive visual analysis of flow simulation data. We express the originally binary feature detectors as fuzzy-sets that can be combined using the linking and brushing concepts of interactive visual analysis. Both interaction and visualization gain from having multiple detectors concurrently available and from the ability to combine them. An application study on automotive data reveals how these vortex detectors combine and perform in praxis.Eurographics/ IEEE-VGTC Symposium on Visualizatio
Visual Coherence for Large-Scale Line-Plot Visualizations
No full textDisplaying a large number of lines within a limited amount of screen space is a task that is common to many different classes of visualization techniques such as time-series visualizations, parallel coordinates, link-node diagrams, and phase-space diagrams. This paper addresses the challenging problems of cluttering and overdraw inherent to such visualizations. We generate a 2x2 tensor field during line rasterization that encodes the distribution of line orientations through each image pixel. Anisotropic diffusion of a noise texture is then used to generate a dense, coherent visualization of line orientation. In order to represent features of different scales, we employ a multi-resolution representation of the tensor field. The resulting technique can easily be applied to a wide variety of line-based visualizations. We demonstrate this for parallel coordinates, a time-series visualization, and a phase-space diagram. Furthermore, we demonstrate how to integrate a focus+context approach by incorporating a second tensor field. Our approach achieves interactive rendering performance for large data sets containing millions of data items, due to its image-based nature and ease of implementation on GPUs. Simulation results from computational fluid dynamics are used to evaluate the performance and usefulness of the proposed method
