VG-PBG08: Eurographics/IEEE VGTC on Volume and Point-Based Graphics

Permanent URI for this collection

https://diglib7.eg.org/handle/10.2312/469

A Graph-Based Approach to Symmetry Detection

[meta data] [files:
001-008.pdf
]
Berner, A.
; 
Bokeloh, M.
; 
Wand, M.
; 
Schilling, A.
; 
Seidel, H.-P.

Parallel Construction of k-Nearest Neighbor Graphs for Point Clouds

[meta data] [files:
025-031.pdf
]
Connor, M.
; 
Kumar, P.

A Survey of Methods for Moving Least Squares Surfaces

[meta data] [files:
009-023.pdf
]
Cheng, Z.-Q.
; 
Wang, Y.-Z.
; 
Li, B.
; 
Xu, K.
; 
Dang, G.
; 
Jin, S.-Y.

Harmonic Colormaps for Volume Visualization

[meta data] [files:
033-039.pdf
]
Wang, Lujin
; 
Mueller, Klaus

On Accuracy of Marching Isosurfacing Methods

[meta data] [files:
049-056.pdf
]
Wang, Cuilan
; 
Newman, Timothy S.
; 
Lee, Jong Kwan

Stroke-Based Transfer Function Design

[meta data] [files:
041-048.pdf
]
Ropinski, T.
; 
Praßni, J.
; 
Steinicke, F.
; 
Hinrichs, K.

Isosurface Ambient Occlusion and Soft Shadows with Filterable Occlusion Maps

[meta data] [files:
057-064.pdf
]
Penner, Eric
; 
Mitchell, Ross

Multiresolution Interval Volume Meshes

[meta data] [files:
065-072.pdf
]
Weiss, Kenneth
; 
Floriani, Leila De

Stereo Pseudo 3D Rendering for Web-based Display of Scientific Volumetric Data

[meta data] [files:
073-080.pdf
]
Eng, Daniel Chern-Yeow
; 
Choe, Yoonsuck

Layers for Effective Volume Rendering

[meta data] [files:
081-088.pdf
]
Raman, S.
; 
Mishchenko, O.
; 
Crawfis, R.

GPU-based Particle Systems for Illustrative Volume Rendering

[meta data] [files:
089-096.pdf
]
Pelt, R.F.P. van
; 
Vilanova, A.
; 
Wetering, H.M.M. van de

Interactive Global Light Propagation in Direct Volume Rendering using Local Piecewise Integration

[meta data] [files:
105-112.pdf
]
Hernell, Frida
; 
Ljung, Patric
; 
Ynnerman, Anders

Obscurance-based Volume Rendering Framework

[meta data] [files:
113-120.pdf
]
Ruiz, M.
; 
Boada, I.
; 
Viola, I.
; 
Bruckner, S.
; 
Feixas, M.
; 
Sbert, M.

Pre-Integrated Volume Rendering for Multi-Dimensional Transfer Functions

[meta data] [files:
097-104.pdf
]
Kraus, M.

Decomposition and Visualization of Fourth-Order Elastic-Plastic Tensors

[meta data] [files:
121-128.pdf
]
Neeman, Alisa G.
; 
Brannon, Rebecca
; 
Jeremic, Boris
; 
Gelder, Allen Van
; 
Pang, Alex

Accelerating Volume Raycasting using Occlusion Frustums

[meta data] [files:
147-154.pdf
]
Mensmann, Jörg
; 
Ropinski, Timo
; 
Hinrichs, Klaus

Adaptive Sampling and Rendering of Fluids on the GPU

[meta data] [files:
137-146.pdf
]
Zhang, Yanci
; 
Solenthaler, Barbara
; 
Pajarola, Renato

Pseudorandom Noise for Real-Time Volumetric Rendering of Fire in a Production System

[meta data] [files:
129-136.pdf
]
Vanzine, Y.
; 
Vrajitoru, D.

Smooth Mixed-Resolution GPU Volume Rendering

[meta data] [files:
163-170.pdf
]
Beyer, Johanna
; 
Hadwiger, Markus
; 
Möller, Torsten
; 
Fritz, Laura

Memory Efficient GPU-Based Ray Casting for Unstructured Volume Rendering

[meta data] [files:
155-162.pdf
]
Maximo, A.
; 
Ribeiro, S.
; 
Bentes, C.
; 
Oliveira, A.
; 
Farias, R.

BibTeX (VG-PBG08: Eurographics/IEEE VGTC on Volume and Point-Based Graphics)
@inproceedings{
10.2312:VG/VG-PBG08/001-008,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
A Graph-Based Approach to Symmetry Detection}},

author = {
Berner, A.
 and 
Bokeloh, M.
 and 
Wand, M.
 and 
Schilling, A.
 and 
Seidel, H.-P.
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/001-008}

}
@inproceedings{
10.2312:VG/VG-PBG08/025-031,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Parallel Construction of k-Nearest Neighbor Graphs for Point Clouds}},

author = {
Connor, M.
 and 
Kumar, P.
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/025-031}

}
@inproceedings{
10.2312:VG/VG-PBG08/009-023,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
A Survey of Methods for Moving Least Squares Surfaces}},

author = {
Cheng, Z.-Q.
 and 
Wang, Y.-Z.
 and 
Li, B.
 and 
Xu, K.
 and 
Dang, G.
 and 
Jin, S.-Y.
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/009-023}

}
@inproceedings{
10.2312:VG/VG-PBG08/033-039,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Harmonic Colormaps for Volume Visualization}},

author = {
Wang, Lujin
 and 
Mueller, Klaus
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/033-039}

}
@inproceedings{
10.2312:VG/VG-PBG08/049-056,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
On Accuracy of Marching Isosurfacing Methods}},

author = {
Wang, Cuilan
 and 
Newman, Timothy S.
 and 
Lee, Jong Kwan
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/049-056}

}
@inproceedings{
10.2312:VG/VG-PBG08/041-048,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Stroke-Based Transfer Function Design}},

author = {
Ropinski, T.
 and 
Praßni, J.
 and 
Steinicke, F.
 and 
Hinrichs, K.
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/041-048}

}
@inproceedings{
10.2312:VG/VG-PBG08/057-064,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Isosurface Ambient Occlusion and Soft Shadows with Filterable Occlusion Maps}},

author = {
Penner, Eric
 and 
Mitchell, Ross
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/057-064}

}
@inproceedings{
10.2312:VG/VG-PBG08/065-072,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Multiresolution Interval Volume Meshes}},

author = {
Weiss, Kenneth
 and 
Floriani, Leila De
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/065-072}

}
@inproceedings{
10.2312:VG/VG-PBG08/073-080,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Stereo Pseudo 3D Rendering for Web-based Display of Scientific Volumetric Data}},

author = {
Eng, Daniel Chern-Yeow
 and 
Choe, Yoonsuck
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/073-080}

}
@inproceedings{
10.2312:VG/VG-PBG08/081-088,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Layers for Effective Volume Rendering}},

author = {
Raman, S.
 and 
Mishchenko, O.
 and 
Crawfis, R.
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/081-088}

}
@inproceedings{
10.2312:VG/VG-PBG08/089-096,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
GPU-based Particle Systems for Illustrative Volume Rendering}},

author = {
Pelt, R.F.P. van
 and 
Vilanova, A.
 and 
Wetering, H.M.M. van de
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/089-096}

}
@inproceedings{
10.2312:VG/VG-PBG08/105-112,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Interactive Global Light Propagation in Direct Volume Rendering using Local Piecewise Integration}},

author = {
Hernell, Frida
 and 
Ljung, Patric
 and 
Ynnerman, Anders
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/105-112}

}
@inproceedings{
10.2312:VG/VG-PBG08/113-120,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Obscurance-based Volume Rendering Framework}},

author = {
Ruiz, M.
 and 
Boada, I.
 and 
Viola, I.
 and 
Bruckner, S.
 and 
Feixas, M.
 and 
Sbert, M.
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/113-120}

}
@inproceedings{
10.2312:VG/VG-PBG08/097-104,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Pre-Integrated Volume Rendering for Multi-Dimensional Transfer Functions}},

author = {
Kraus, M.
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/097-104}

}
@inproceedings{
10.2312:VG/VG-PBG08/121-128,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Decomposition and Visualization of Fourth-Order Elastic-Plastic Tensors}},

author = {
Neeman, Alisa G.
 and 
Brannon, Rebecca
 and 
Jeremic, Boris
 and 
Gelder, Allen Van
 and 
Pang, Alex
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/121-128}

}
@inproceedings{
10.2312:VG/VG-PBG08/147-154,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Accelerating Volume Raycasting using Occlusion Frustums}},

author = {
Mensmann, Jörg
 and 
Ropinski, Timo
 and 
Hinrichs, Klaus
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/147-154}

}
@inproceedings{
10.2312:VG/VG-PBG08/137-146,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Adaptive Sampling and Rendering of Fluids on the GPU}},

author = {
Zhang, Yanci
 and 
Solenthaler, Barbara
 and 
Pajarola, Renato
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/137-146}

}
@inproceedings{
10.2312:VG/VG-PBG08/129-136,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Pseudorandom Noise for Real-Time Volumetric Rendering of Fire in a Production System}},

author = {
Vanzine, Y.
 and 
Vrajitoru, D.
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/129-136}

}
@inproceedings{
10.2312:VG/VG-PBG08/163-170,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Smooth Mixed-Resolution GPU Volume Rendering}},

author = {
Beyer, Johanna
 and 
Hadwiger, Markus
 and 
Möller, Torsten
 and 
Fritz, Laura
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/163-170}

}
@inproceedings{
10.2312:VG/VG-PBG08/155-162,

booktitle = {
IEEE/ EG Symposium on Volume and Point-Based Graphics},

editor = {
Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
},
title = {{
Memory Efficient GPU-Based Ray Casting for Unstructured Volume Rendering}},

author = {
Maximo, A.
 and 
Ribeiro, S.
 and 
Bentes, C.
 and 
Oliveira, A.
 and 
Farias, R.
},
year = {
2008},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {978-3-905674-12-5},

DOI = {
10.2312/VG/VG-PBG08/155-162}

}

Browse

Recent Submissions

Now showing 1 - 20 of 20
  • Thumbnail Image
    Item
    A Graph-Based Approach to Symmetry Detection
    (The Eurographics Association, 2008) Berner, A.; Bokeloh, M.; Wand, M.; Schilling, A.; Seidel, H.-P.; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Symmetry detection aims at discovering redundancy in the form of reoccurring structures in geometric objects. In this paper, we present a new symmetry detection algorithm for geometry represented as point clouds that is based on analyzing a graph of surface features. We combine a general feature detection scheme with a RANSAC-based randomized subgraph searching algorithm in order to reliably detect reoccurring patterns of locally unique structures. A subsequent segmentation step based on a simultaneous region growing variant of the ICP algorithm is applied to verify that the actual point cloud data supports the pattern detected in the feature graphs. We apply our algorithm to synthetic and real-world 3D scanner data sets, demonstrating robust symmetry detection results in the presence of scanning artifacts and noise. The modular and flexible nature of the graph-based detection scheme allows for easy generalizations of the algorithm, which we demonstrate by applying the same technique to other data modalities such as images or triangle meshes.
  • Thumbnail Image
    Item
    Parallel Construction of k-Nearest Neighbor Graphs for Point Clouds
    (The Eurographics Association, 2008) Connor, M.; Kumar, P.; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    We present a parallel algorithm for k-nearest neighbor graph construction that uses Morton ordering. Experiments show that our approach has the following advantages over existing methods: (1) Faster construction of k-nearest neighbor graphs in practice on multi-core machines. (2) Less space usage. (3) Better cache efficiency. (4) Ability to handle large data sets. (5) Ease of parallelization and implementation.
  • Thumbnail Image
    Item
    A Survey of Methods for Moving Least Squares Surfaces
    (The Eurographics Association, 2008) Cheng, Z.-Q.; Wang, Y.-Z.; Li, B.; Xu, K.; Dang, G.; Jin, S.-Y.; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Moving least squares (MLS) surfaces representation directly defines smooth surfaces from point cloud data, on which the differential geometric properties of point set can be conveniently estimated. Nowadays, the MLS surfaces have been widely applied in the processing and rendering of point-sampled models and increasingly adopted as the standard definition of point set surfaces. We classify the MLS surface algorithms into two types: projection MLS surfaces and implicit MLS surfaces, according to employing a stationary projection or a scalar field in their definitions. Then, the properties and constrains of the MLS surfaces are analyzed. After presenting its applications, we summarize the MLS surfaces definitions in a generic form and give the outlook of the future work at last.
  • Thumbnail Image
    Item
    Harmonic Colormaps for Volume Visualization
    (The Eurographics Association, 2008) Wang, Lujin; Mueller, Klaus; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Color design forms a crucial part in visual aesthetics, and it has been shown that a visually aesthetic visualization will be looked at more carefully. An important role plays here the choice of a colormap that is composed of harmonic colors. This paper presents an interface that allows users to choose harmonic colors in volume visualization applications. In addition, it describes mechanisms by which non-harmonic colormaps can be converted to harmonic ones, but keeping lightness constant to preserve the original contrast relationships. Finally, we also show how harmonic colors can be used for the highlighting of important volume features.
  • Thumbnail Image
    Item
    On Accuracy of Marching Isosurfacing Methods
    (The Eurographics Association, 2008) Wang, Cuilan; Newman, Timothy S.; Lee, Jong Kwan; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Representational accuracy of the isosurface meshes produced by well-known marching isosurfacing methods is considered. Accuracy is determined versus the isosurface given by trilinear interpolation and quantified using a new measure of volumetric divergence. The new measure is an accurate estimate of spatial discrepancy between a produced mesh and the isosurface of trilinear interpolation. Through experimental testing using the measure, suitability of the considered methods to well-model the isosurface of trilinear interpolation's behavior on grid cell interiors is also established.
  • Thumbnail Image
    Item
    Stroke-Based Transfer Function Design
    (The Eurographics Association, 2008) Ropinski, T.; Praßni, J.; Steinicke, F.; Hinrichs, K.; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    In this paper we propose a user interface for the design of 1D transfer functions. The user can select a feature of interest by drawing one or more strokes directly onto the volume rendering near its silhouette. Based on the stroke(s), our algorithm performs a histogram analysis in order to identify the desired feature in histogram space. Once the feature of interest has been identified, we automatically generate a component transfer function, which associates optical properties with the previously determined intervals in the domain of the data values. By supporting direct interaction techniques, which are performed in the image domain, the transfer function design becomes more intuitive compared to the specification performed in the histogram domain. To be able to modify and combine the previously generated component transfer functions conveniently, we propose a user interface, which has been inspired by the layer mechanism commonly found in image processing software. With this user interface, the optical properties assigned through a component function can be altered, and the component functions to be combined into a final transfer function can be selected.
  • Thumbnail Image
    Item
    Isosurface Ambient Occlusion and Soft Shadows with Filterable Occlusion Maps
    (The Eurographics Association, 2008) Penner, Eric; Mitchell, Ross; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Volumetric data sets are often examined by displaying isosurfaces, surfaces where the data or function takes on a given value. We propose a new method for rendering isosurfaces at interactive rates while supporting dynamic ambient occlusion and/or soft shadows and requiring minimal pre-computation time. By approximating the occlusion in a region as the percentage of occluding voxels in that region, we reduce the ambient occlusion problem to the same problem faced in soft shadow mapping algorithms. In order to quickly extract the number of occluding voxels in an image region, we propose representing distributions using filterable representations such as variance shadow maps or convolution shadow maps. By choosing different sampling patterns from these maps we can dynamically approximate ambient occlusion and/or soft shadows.
  • Thumbnail Image
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    Multiresolution Interval Volume Meshes
    (The Eurographics Association, 2008) Weiss, Kenneth; Floriani, Leila De; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Interval volumes are a generalization of isosurfaces that represent the set of points between two surfaces. In this paper, we present a compact multi-resolution representation for interval volume meshes extracted from regularly sampled volume data sets. The multi-resolution model is a hierarchical tetrahedral mesh whose updates are based on the longest edge bisection (LEB) subdivision strategy for tetrahedra. Although our representation is decoupled from the scalar field, it maintains the implicit structure of the LEB model to efficiently encode mesh updates. Our representation efficiently supports selective refinement queries and requires significantly less storage than an encoding of the interval volume mesh at full resolution.
  • Thumbnail Image
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    Stereo Pseudo 3D Rendering for Web-based Display of Scientific Volumetric Data
    (The Eurographics Association, 2008) Eng, Daniel Chern-Yeow; Choe, Yoonsuck; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Advancement in high-throughput microscopy technology such as the Knife-Edge Scanning Microscopy (KESM) is enabling the production of massive amounts of high-resolution volumetric data of biological microstructures. To fully utilize these data, they should be efficiently distributed to the scientific research community (e.g., through the Internet) and should be easily annotated and analyzed. Given the volumetric nature of the data, visualizing them in 3D is important. Since we cannot assume that every end user has high-end hardware, an approach that has minimal hardware requirement will be necessary. There are several prominent applications that facilitate the viewing of large collections of images over the web. Google Maps and Google Maps-like interfaces such as Brainmaps.org allow users to pan and zoom 2D images efficiently. However, they do not yet support the rendering of volumetric data in their standard web interface. Thus, we propose a new method of rendering volumetric data over the web that directly uses the raw image stack, without any computation on the data at all. The human visual system has the capability of viewing stereo images in 2D and turn that into a 3D perception. To generate stereo images, we will need to create the effects of depth and binocular disparity using 2D images. By using simple HTML and JavaScript that are computationally cheap, we can accomplish both tasks dynamically in a standard web browser, by overlaying the images with intervening semi-opaque layers. We expect the approach presented in this paper to be applicable to a broader domain, including geology and meteorology.
  • Thumbnail Image
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    Layers for Effective Volume Rendering
    (The Eurographics Association, 2008) Raman, S.; Mishchenko, O.; Crawfis, R.; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    A multi-layer volume rendering framework is presented. The final image is obtained by compositing a number of renderings, each being represented as a separate layer. This layer-centric framework provides a rich set of 2D operators and interactions, allowing both greater freedom and a more intuitive 2D-based user interaction. We extend the concept of compositing which is traditionally thought of as pertaining to the Porter and Duff compositing operators to a more general and flexible set of functions. In addition to developing new functional compositing operators, the user can control each individual layer s attributes, such as the opacity. They can also easily add or remove a layer from the composition set, change their order in the composition, and export and import the layers in a format readily utilized in a 2D paint package. This broad space of composition functions allows for a wide variety of effects and we present several in the context of volume rendering, including two-level volume rendering, masking, and magnification. We also discuss the integration of a 3D volume rendering engine with our 2.5D layer compositing engine.
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    GPU-based Particle Systems for Illustrative Volume Rendering
    (The Eurographics Association, 2008) Pelt, R.F.P. van; Vilanova, A.; Wetering, H.M.M. van de; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Illustrative techniques are generally applied to produce stylized renderings. Various illustrative styles have been applied to volumetric data sets, producing clearer images and effectively conveying visual information. We adopt user-configurable particle systems to produce stylized renderings from the volume data, imitating traditional pen-and-ink drawings. In the following, we present an interactive GPU-based illustrative framework, called VolFlies- GPU, for rendering volume data, exploiting parallelism in both graphics hardware and particle systems. We achieve real-time interaction and prompt parametrization of the illustrative styles, using an intuitive GPGPU paradigm that delivers the computational power to drive our particle system and visualization algorithms.
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    Interactive Global Light Propagation in Direct Volume Rendering using Local Piecewise Integration
    (The Eurographics Association, 2008) Hernell, Frida; Ljung, Patric; Ynnerman, Anders; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    A novel technique for efficient computation of global light propagation in interactive DVR is presented in this paper. The approach is based on a combination of local shadows from the vicinity of each voxel with global shadows calculated at high resolution but stored in a sparser grid. The resulting intensities are then used as the initial illumination for an additional pass that computes first order scattering effects. The method captures global shadowing effects with enhanced shadows of near structures. A GPU framework is used to evaluate the illumination updates at interactive frame rates, using incremental refinements of the in-scattered light.
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    Obscurance-based Volume Rendering Framework
    (The Eurographics Association, 2008) Ruiz, M.; Boada, I.; Viola, I.; Bruckner, S.; Feixas, M.; Sbert, M.; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Obscurances, from which ambient occlusion is a particular case, is a technology that produces natural-looking lighting effects in a faster way than global illumination. Its application in volume visualization is of special interest since it permits us to generate a high quality rendering at a low cost. In this paper, we propose an obscurancebased framework that allows us to obtain realistic and illustrative volume visualizations in an interactive manner. Obscurances can include color bleeding effects without additional cost. Moreover, we obtain a saliency map from the gradient of obscurances and we show its application to enhance volume visualization and to select the most salient views.
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    Pre-Integrated Volume Rendering for Multi-Dimensional Transfer Functions
    (The Eurographics Association, 2008) Kraus, M.; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    This work presents an efficient extension of pre-integrated volume rendering for multi-dimensional transfer functions. Since even two-dimensional transfer functions can result in strong rendering artifacts that cannot be resolved by standard ray casting, we propose a space-covering volume sampling scheme that does not require additional samples of the volume data. Based on this sampling scheme, our approach computes box integrals of the transfer functions, which are evaluated with the help of a small number of texture lookups in tabulated integral functions. We demonstrate the achieved performance and improvements in image quality with a prototypical GPU (graphics processing unit) implementation.
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    Decomposition and Visualization of Fourth-Order Elastic-Plastic Tensors
    (The Eurographics Association, 2008) Neeman, Alisa G.; Brannon, Rebecca; Jeremic, Boris; Gelder, Allen Van; Pang, Alex; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Visualization of fourth-order tensors from solid mechanics has not been explored in depth previously. Challenges include the large number of components (3x3x3x3 for 3D), loss of major symmetry and loss of positive definiteness (with possibly zero or negative eigenvalues). This paper presents a decomposition of fourth-order tensors that facilitates their visualization and understanding. Fourth-order tensors are used to represent a solid's stiffness. The stiffness tensor represents the relationship between increments of stress and increments of strain. Visualizing stiffness is important to understand the changing state of solids during plastification and failure. In this work, we present a method to reduce the number of stiffness components to second-order 3x3 tensors for visualization. The reduction is based on polar decomposition, followed by eigen-decomposition on the polar "stretch". If any resulting eigenvalue is significantly lower than the others, the material has softened in that eigen-direction. The associated second-order eigentensor represents the mode of stress (such as compression, tension, shear, or some combination of these) to which the material becomes vulnerable. Thus we can visualize the physical meaning of plastification with techniques for visualizing second-order symmetric tensors.
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    Accelerating Volume Raycasting using Occlusion Frustums
    (The Eurographics Association, 2008) Mensmann, Jörg; Ropinski, Timo; Hinrichs, Klaus; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    GPU-based volume raycasting allows to produce high quality renderings on current graphics hardware. The use of such raycasters is on the rise due to their inherent flexibility as well as the advances in hardware performance and functionality. Although recent raycasting systems achieve interactive frame rates on high-end graphics hardware, further improved performance would enable more complex rendering techniques, e. g., advanced illumination models. In this paper we introduce a novel approach to empty space leaping in order to reduce the number of costly volume texture fetches during ray traversal. We generate an optimized proxy geometry for raycasting which is based on occlusion frustums obtained from previous frames. Our technique does not rely on any preprocessing, introduces no image artifacts, and in contrast to previous point-based methods works also for non-continuous view changes. Besides the technical realization and the performance results, we also discuss the potential problems of ray coherence in relation to our approach and restrictions in current GPU architectures. The presented technique has been implemented using fragment and geometry shaders and can be integrated easily into existing raycasting systems.
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    Adaptive Sampling and Rendering of Fluids on the GPU
    (The Eurographics Association, 2008) Zhang, Yanci; Solenthaler, Barbara; Pajarola, Renato; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    In this paper, we propose a novel GPU-friendly algorithm for the Smoothed Particle Hydrodynamics (SPH) simulation for weakly compressible fluids. The major goal of our algorithm is to implement a GPU-based SPH simulation that can simulate and render a large number of particles at interactive speed. Additionally, our algorithm exhibits the following three features. Firstly, our algorithm supports adaptive sampling of the fluids. Particles can be split into several sub-particles in geometrically complex regions to provide a more accurate simulation. At the same time, nearby particles deep inside the fluids are merged to a single particle to reduce the number of particles. Secondly, the fluids are visualized by directly computing the intersection between ray and an isosurface defined by the surface particles. A dynamic particle grouping algorithm and equation solver are employed to quickly find the ray-isosurface intersection. Thirdly, based on the observation that the SPH simulation is a naturally parallel algorithm, the whole SPH simulation, including the adaptive sampling of the fluids as well as surface particle rendering, is executed on the GPU to fully utilize the computational power and parallelism of modern graphics hardware. Our experimental data shows that we can simulate about 50K adaptively sampled particles, or up to 120K particles in the fixed sampling case at a rate of approximately 20 time steps per second.
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    Pseudorandom Noise for Real-Time Volumetric Rendering of Fire in a Production System
    (The Eurographics Association, 2008) Vanzine, Y.; Vrajitoru, D.; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    This paper presents an effort at developing a robust, interactive framework for rendering 3D fire in real-time in a production environment. Many techniques of rendering fire in non real-time exist and are constantly employed by the movie industry and have directly influenced and inspired real-time fire rendering, including this paper. Macrolevel behavior of fire is characterized by wind fields, temperature and moving sources and is currently processed on the CPU while micro-level behavior like turbulence, flickering, separation and shape is created on the graphics hardware. This framework provides a set of tools for level designers to wield artistic and behavioral control over fire as part of the scene. The resulting system is able to scale well, to use as few processor cycles as possible, and to efficiently integrate into an existing production environment. We present performance statistics and assess the feasibility of achieving interactive frame rates within a 3D engine framework. The framerates we obtained vary from 42 to 168 depending on the rendering conditions, and indicate that the real-time procedural fire might not be far away.
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    Smooth Mixed-Resolution GPU Volume Rendering
    (The Eurographics Association, 2008) Beyer, Johanna; Hadwiger, Markus; Möller, Torsten; Fritz, Laura; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    We propose a mixed-resolution volume ray-casting approach that enables more flexibility in the choice of downsampling positions and filter kernels, allows freely mixing volume bricks of different resolutions during rendering, and does not require modifying the original sample values. A C0-continuous function is obtained everywhere with hardware-native filtering at full speed by simply warping texture coordinates of samples in transition regions. Additionally, we propose a simple but powerful, flat texture packing scheme that supports mixing different resolution levels in a single 3D volume cache texture with a very simple and fast address translation scheme. Although this packing constrains full scalability, it enables mixing different resolution levels in GPU-based ray-casting with only a single rendering pass. We demonstrate our approach on large real-world data, obtaining a continuous scalar function and shading at brick boundaries, using single-pass ray-casting at real-time frame rates.
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    Memory Efficient GPU-Based Ray Casting for Unstructured Volume Rendering
    (The Eurographics Association, 2008) Maximo, A.; Ribeiro, S.; Bentes, C.; Oliveira, A.; Farias, R.; Hans-Christian Hege and David Laidlaw and Renato Pajarola and Oliver Staadt
    Volume ray casting algorithms benefit greatly with recent increase of GPU capabilities and power. In this paper, we present a novel memory efficient ray casting algorithm for unstructured grids completely implemented on GPU using a recent off-the-shelf nVidia graphics card. Our approach is built upon a recent CPU ray casting algorithm, called VF-Ray, that considerably reduces the memory footprint while keeping good performance. In addition to the implementation of VF-Ray in the graphics hardware, we also propose a restructuring in its data structures. As a result, our algorithm is much faster than the original software version, while using significantly less memory, it needed only one-half of its previous memory usage. Comparing our GPU implementation to other hardware-based ray casting algorithms, our approach used between three to ten times less memory. These results made it possible for our GPU implementation to handle larger datasets on GPU than previous approaches.