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Error-controlled real-time cut updates for multi-resolution volume rendering

COMPUTERS & GRAPHICS-UK 2011年第4期35卷 931-944页

作者： Carmona, Rhadames Froehlich, Bernd Cent Univ Venezuela Fac Ciencias Ctr Computac Graf Caracas 1041A Venezuela Bauhaus Univ Weimar Fak Medien D-99423 Weimar Germany

Multi-resolution techniques are required for rendering large volumetric datasets exceeding the size of the graphics card's memory or even the main memory. The cut through the multi-resolution volume representation is defined by selection criteria based on error metrics. For GPU-based volume rendering, this cut has to fit into the graphics card's memory and needs to be continuously updated clue to the interaction with the volume such as changing the area of interest, the transfer function or the viewpoint. We introduce a greedy cut update algorithm based on split-and-collapse operations for updating the cut on a frame-to-frame basis. This approach is guided by a global data-based metric based on the distortion of classified voxel data, and it takes into account a limited download budget for transferring data from main memory into the graphics card to avoid large frame rate variations. Our out-of-core support for handling very large volumes also makes use of split-and-collapse operations to generate an extended cut in the main memory. Finally, we introduce an optimal polynomial-time cut update algorithm, which maximizes the error reduction between consecutive frames. This algorithm is used to verify how close to the optimum our greedy split-and-collapse algorithm performs. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Multi-resolution volume rendering Pre-integration Data-based metrics out-of-core visualization Volume visualization

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out of core visualization using iterator aware multidimensional prefetching

Out of core visualization using iterator aware multidimensio...

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Conference on visualization and Data Analysis 2005

作者： Rhodes, PJ Tang, X Bergeron, RD Sparr, TM Univ Mississippi Dept Comp Sci Oxford MS USA

ISBN: (纸本)081945642X

visualization of multidimensional data presents special challenges for the design of efficient out-of-core data access. Elements that are nearby in the visualization may not be nearby in the underlying data file, which can severely tax the operating system's disk cache. The Granite Scientific Database System can address these problems because it is aware of the organization of the data on disk, and it knows the visualization method's pattern of access. The access pattern is expressed using a toolkit of iterators that both describe the access pattern and perform the iteration itself. Because our system has knowledge of both the data organization and the access pattern, we are able to provide significant performance improvements while hiding the details of out-of-core access from the visualization programmer. This paper presents a brief description of our disk access system placing special emphasis on the benefits offered to a visualization application. We describe a simple demonstration application that shows dramatic performance improvements when used with the 39GB Visible Woman Dataset.

关键词： out-of-core visualization caching prefetching rendering large volume datasets

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Adaptive extraction of time-varying isosurfaces

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2004年第6期10卷 683-694页

作者： Gregorski, B Senecal, J Duchaineau, MA Joy, KI Lawrence Livermore Natl Lab Ctr Appl Sci Comp Livermore CA 94551 USA Univ Calif Davis Dept Comp Sci Ctr Image Proc & Integrated Computing Davis CA 95616 USA

We present an algorithm for adaptively extracting and rendering isosurfaces from compressed time-varying volume data sets. Tetrahedral meshes defined by longest edge bisection are used to create a multiresolution representation of the volume in the spatial domain that is adapted overtime to approximate the time-varying volume. The reextraction of the isosurface at each time step is accelerated with the vertex programming capabilities of modern graphics hardware. A data layout scheme which follows the access pattern indicated by mesh refinement is used to access the volume in a spatially and temporally coherent manner. This data layout scheme allows our algorithm to be used for out-of-core visualization.

关键词： isosurfaces multiresolution techniques large isosurface visualization time-varying isosurfaces time-varying visualization out-of-core visualization

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Real-time out-of-core visualization of particle traces

Real-time out-of-core visualization of particle traces

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IEEE Symposium on Parallel and Large-Data visualization and Graphics

作者： Bruckschen, R Kuester, F Hamann, B Joy, KI Univ Calif Davis Ctr Image Proc & Integrated Computing Visualizat & Graph Res Grp Dept Comp Sci Davis CA 95616 USA

ISBN: (纸本)0780372239

visualization of particle traces provides intuitive and efficient means for the exploration and analysis of complex vector fields. This paper presents a method suitable for the real-time visualization of arbitrarily large time-varying vector fields in virtual environments. We describe an out-of-core scheme in which two distinct pre-processing and rendering components enable real-time data streaming and visualization. The presented approach yields low-latency application start-up times and small memory footprints. The described system was used to implement a "volumetric fog lance," which can emit up to 60000 particles into a flow field while maintaining an interactive frame rate of 60 frames per second. All algorithms were specifically designed to support commodity hardware. The proof-of-concept system is running on a low-cost Linux workstation equipped with a 120GB E-IDE RAID (Redundant Array of Inexpensive! Disk) system.

关键词： particle tracing scientific visualization computational fluid dynamics out-of-core visualization virtual reality

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Real-time out-of-core visualization of particle traces 01

Real-time out-of-core visualization of particle traces

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Proceedings of the IEEE 2001 symposium on parallel and large-data visualization and graphics

作者： Ralph Bruckschen Falko Kuester Bernd Hamann Kenneth I. Joy University of California Davis CA University of California Irvine CA

ISBN: (纸本)9780780372238

关键词： Computational Fluid Dynamics Scientific visualization out-of-core visualization Particle Tracing Virtual Reality

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Internet-based, out-of-core flow visualization

Internet-based, out-of-core flow visualization

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8th Meeting of the Visual Data Exploration and Analysis Conference

作者： Tourtellott, J Greger, GS RayTech Comp Inc Latham NY 12110 USA

ISBN: (纸本)0819439800

The cost of visualizing computational fluid dynamics (CFD) and other flow field data sets is increasing rapidly due to ever-increasing gad sizes that constantly strain platform memory capacity and bandwidth. To address this problem of "big data", techniques have been developed in two areas: out-of-core visualization, which exploits the fact that most flow visualizations require a very sparse traversal of the data set, and remote visualization, in which images are rendered by large-scale computing systems and transmitted via network to desktop systems. A new method, which combines out-of-core and remote techniques, offers a potentially significant improvement in both scalability and cost. By incorporating new techniques for spatial partitioning data prediction, and explicit memory management this new method enables desktop computing applications to selectively read the contents of massive data sets from remote servers connected by local or wide area networks. Initial testing has shown that local memory usage is nearly independent of data set size, overcoming the key limitation of prior out-of-core methods. By performing the visualization computations and graphics rendering on the local/desktop platform, the new method also provides a significant improvement in price-performance ratio compared to current remote visualization methods.

关键词： computational fluid dynamics out-of-core visualization network graphics particle tracing remote visualization spatial prediction storage management visualization

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Real-time refinement and simplification of adaptive triangular meshes 03

Real-time refinement and simplification of adaptive triangul...

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IEEE visualization 2003 Conference

作者： Volkov, V Li, L Inst Phys & Technol Moscow Russia

ISBN: (纸本)0780381203

In this paper we present a generic method for incremental mesh adaptation based on hierarchy of semi-regular meshes. Our method supports any refinement rule mapping vertices onto vertices such as 1-to-4 split or root3-subdivision. Resulting adaptive mesh has subdivision connectivity and hence good aspect ratio of triangles. Hierarchic representation of the mesh allows incremental local refinement and simplification operations exploiting frame-to-frame coherence. We also present an out-of-core storage layout scheme designed for semi-regular meshes of arbitrary subdivision connectivity. It provides high cache coherency in the data retrieval and relies on the interleaved storage of resolution levels and maintaining good geometrical proximity within each level. The efficiency of the proposed method is demonstrated with applications in physically-based cloth simulation, real-time terrain visualization and procedural modeling.

关键词： adaptive meshes refinement and simplification subdivision multiresoluton level of detail frame-to-frame coherence out-of-core visualization

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Accelerated isosurface extraction in time-varying fields

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2000年第2期6卷 98-107页

作者： Sutton, PM Hansen, CD Lawrence Livermore Natl Lab Livermore CA 94550 USA Univ Utah Dept Comp Sci Salt Lake City UT 84124 USA

For large time-varying data sets, memory and disk limitations can lower the performace of visualization applications. Algorithms and data structures must be explicitly designed to handle these data sets in order to achieve more interactive rates. The Temporal Branch-on-Need Octree (T-BON) extends the three-dimensional branch-on-need octree for time-varying isosurface extraction. This data structure minimizes the impact of the I/O bottleneck by reading from disk only those portions of the search structure and data necessary to construct the current isosurface. By performing a minimum of I/O and exploiting the hierarchical memory found in modern CPUs, the T-BON algorithm achieves high performance isosurface extraction in time-varying fields. This paper extends earlier work on the T-BON data structure by including techniques for better memory utilization, out-of-core isosurface extraction, and support for nonrectilinear grids. Results from testing the T-BON algorithm on large data sets show that its performance is similar to that of the three-dimensional branch-on-need octree for static data sets while providing substantial advantages for time-varying fields.

关键词： isosurface time-dependent scalar field visualization multiresolution methods octree bricking unstructured grid visualization out-of-core visualization

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Application-controlled demand paging for out-of-core visualization

Application-controlled demand paging for out-of-core visuali...

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8th Annual IEEE Conference on visualization

作者： Cox, M Ellsworth, D Intel Corp NASA Ames Res Ctr MRJMicrocomp Res Labs Santa Clara CA 95051 USA

ISBN: (纸本)1581130112

In the area of scientific visualization, input data sets are often very large. In visualization of Computational Fluid Dynamics (CFD) in particular, input data sets today can surpass 100 Gbytes, and are expected to scale with the ability of supercomputers to generate them. Some visualization tools already partition large data sets into segments, and load appropriate segments as they are needed. However, this does not remove the problem for two reasons: 1) there are data sets for which even the individual segments are too large for the largest graphics workstations, 2) many practitioners do not have access to workstations with the memory capacity required to load even a segment, especially since the state-of-the-art visualization tools tend to be developed by researchers with much more powerful machines. When the size of the data that must be accessed is larger than the size of memory, some form of virtual memory is simply required. This may be by segmentation, paging, or by paged segments. In this paper we demonstrate that complete reliance on operating system virtual memory for out-of-core visualization leads to egregious performance. We then describe a paged segment system that we have implemented, and explore the principles of memory management that can be employed by the application for out-of-core visualization. We show that application control over some of these can significantly improve performance. We show that sparse traversal can be exploited by loading only those data actually required. We show also that application control over data loading can be exploited by 1) loading data from alternative storage format tin particular 3-dimensional data stored in subcubes), 2) controlling the page size. Both of these techniques effectively reduce the total memory required by visualization at run-time. We also describe experiments we have done on remote out-of-core visualization (when pages are read by demand from remote disk) whose results are promising.

关键词： computational fluid dynamics visualization out-of-core visualization

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