VG06: Eurographics/IEEE VGTC Workshop on Volume Graphics 2006

Permanent URI for this collection

https://diglib.eg.org/handle/10.2312/471

Multi-Dimensional Transfer Function Design Using Sorted Histograms

[meta data] [files:
001-008.pdf
]
Lundström, Claes
; 
Ljung, Patric
; 
Ynnerman, Anders

Discontinuous Displacement Mapping for Volume Graphics

[meta data] [files:
009-016.pdf ,
1008_correa_video.mov
]
Correa, Carlos D.
; 
Silver, Deborah
; 
Chen, Min

Volumetric Density Capture From a Single Image

[meta data] [files:
017-022.pdf
]
Fuchs, Christian
; 
Chen, Tongbo
; 
Goesele, Michael
; 
Theisel, Holger
; 
Seidel, Hans-Peter

An Image-Based Modelling Approach To GPU-based Unstructured Grid Volume Rendering

[meta data] [files:
031-038.pdf
]
Shareef, Naeem
; 
Lee, Teng-Yok
; 
Shen, Han-Wei
; 
Mueller, Klaus

GPU-Accelerated D2VR

[meta data] [files:
023-030.pdf
]
Xu, Fang
; 
Mueller, Klaus

GPU-assisted Multi-field Video Volume Visualization

[meta data] [files:
047-054.pdf
]
Botchen, Ralf P.
; 
Chen, Min
; 
Weiskopf, Daniel
; 
Ertl, Thomas

Employing Complex GPU Data Structures for the Interactive Visualization of Adaptive Mesh Refinement Data

[meta data] [files:
055-058.pdf
]
Vollrath, Joachim E.
; 
Schafhitzel, Tobias
; 
Ertl, Thomas

Adaptive Sampling in Single Pass, GPU-based Raycasting of Multiresolution Volumes

[meta data] [files:
039-046.pdf
]
Ljung, Patric

Capture and Review of Interactive Volumetric Manipulations for Surgical Training

[meta data] [files:
071-074.pdf
]
Kerwin, Thomas
; 
Shen, Han-Wei
; 
Stredney, Don

Pre-integrated Flow Illustration for Tetrahedral Meshes

[meta data] [files:
063-066.pdf
]
Svakhine, N. A.
; 
Ebert, D.
; 
Tejada, E.
; 
Ertl, T.
; 
Gaither, K.

SIMD-Aware Ray-Casting

[meta data] [files:
059-062.pdf
]
Leung, Warren
; 
Neophytou, Neophytos
; 
Mueller, Klaus

Contour Nest: A Two-dimensional Representation for Three-dimensional Isosurfaces

[meta data] [files:
067-070.pdf
]
Mizuta, Shinobu
; 
Ono, Toshiki
; 
Matsuda, Tetsuya

Live Surface

[meta data] [files:
087-094.pdf
]
Armstrong, Christopher J.
; 
Barrett, William A.
; 
Price, Brian

Complementary Shape Comparison with Additional Properties

[meta data] [files:
079-086.pdf
]
Zhang, Xiaoyu

Contour-Based Surface Reconstruction using Implicit Curve Fitting, and Distance Field Filtering and Interpolation

[meta data] [files:
095-102.pdf
]
Marker, Jeffrey
; 
Braude, Ilya
; 
Museth, Ken
; 
Breen, David

Enabling Haptic Interaction with Volumetric MRI Data Through Knowledge-based Tissue Separation

[meta data] [files:
075-078.pdf
]
Lundin, Karljohan
; 
Lundström, Claes
; 
Cooper, Matthew
; 
Ynnerman, Anders

GPU-Assisted Raycasting for Cosmological Adaptive Mesh Refinement Simulations

[meta data] [files:
103-110.pdf
]
Kaehler, Ralf
; 
Wise, John
; 
Abel, Tom
; 
Hege, Hans-Christian

Diffusion-Based Tractography: Visualizing Dense White Matter Connectivity from 3D Tensor Fields

[meta data] [files:
119-126.pdf
]
Muraki, S.
; 
Fujishiro, I.
; 
Suzuki, Y.
; 
Takeshima, Y.

Interactive 3D seismic fault detection on the Graphics Hardware

[meta data] [files:
111-118.pdf
]
Jeong, Won-Ki
; 
Whitaker, Ross
; 
Dobin, Mark

BibTeX (VG06: Eurographics/IEEE VGTC Workshop on Volume Graphics 2006)
@inproceedings{
:10.2312/VG/VG06/001-008,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Multi-Dimensional Transfer Function Design Using Sorted Histograms}},

author = {
Lundström, Claes
 and 
Ljung, Patric
 and 
Ynnerman, Anders
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/001-008}

}
@inproceedings{
:10.2312/VG/VG06/009-016,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Discontinuous Displacement Mapping for Volume Graphics}},

author = {
Correa, Carlos D.
 and 
Silver, Deborah
 and 
Chen, Min
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/009-016}

}
@inproceedings{
:10.2312/VG/VG06/017-022,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Volumetric Density Capture From a Single Image}},

author = {
Fuchs, Christian
 and 
Chen, Tongbo
 and 
Goesele, Michael
 and 
Theisel, Holger
 and 
Seidel, Hans-Peter
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/017-022}

}
@inproceedings{
:10.2312/VG/VG06/031-038,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
An Image-Based Modelling Approach To GPU-based Unstructured Grid Volume Rendering}},

author = {
Shareef, Naeem
 and 
Lee, Teng-Yok
 and 
Shen, Han-Wei
 and 
Mueller, Klaus
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/031-038}

}
@inproceedings{
:10.2312/VG/VG06/023-030,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
GPU-Accelerated D2VR}},

author = {
Xu, Fang
 and 
Mueller,  Klaus
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/023-030}

}
@inproceedings{
:10.2312/VG/VG06/047-054,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
GPU-assisted Multi-field Video Volume Visualization}},

author = {
Botchen, Ralf P.
 and 
Chen, Min
 and 
Weiskopf, Daniel
 and 
Ertl, Thomas
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/047-054}

}
@inproceedings{
:10.2312/VG/VG06/055-058,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Employing Complex GPU Data Structures for the Interactive Visualization of Adaptive Mesh Refinement Data}},

author = {
Vollrath, Joachim E.
 and 
Schafhitzel, Tobias
 and 
Ertl, Thomas
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/055-058}

}
@inproceedings{
:10.2312/VG/VG06/039-046,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Adaptive Sampling in Single Pass, GPU-based Raycasting of Multiresolution Volumes}},

author = {
Ljung, Patric
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/039-046}

}
@inproceedings{
:10.2312/VG/VG06/071-074,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Capture and Review of Interactive Volumetric Manipulations for Surgical Training}},

author = {
Kerwin, Thomas
 and 
Shen, Han-Wei
 and 
Stredney,  Don
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/071-074}

}
@inproceedings{
:10.2312/VG/VG06/063-066,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Pre-integrated Flow Illustration for Tetrahedral Meshes}},

author = {
Svakhine, N. A.
 and 
Ebert, D.
 and 
Tejada, E.
 and 
Ertl, T.
 and 
Gaither,  K.
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/063-066}

}
@inproceedings{
:10.2312/VG/VG06/059-062,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
SIMD-Aware Ray-Casting}},

author = {
Leung, Warren
 and 
Neophytou,  Neophytos
 and 
Mueller,  Klaus
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/059-062}

}
@inproceedings{
:10.2312/VG/VG06/067-070,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Contour Nest: A Two-dimensional Representation for Three-dimensional Isosurfaces}},

author = {
Mizuta, Shinobu
 and 
Ono, Toshiki
 and 
Matsuda, Tetsuya
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/067-070}

}
@inproceedings{
:10.2312/VG/VG06/087-094,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Live Surface}},

author = {
Armstrong, Christopher J.
 and 
Barrett, William A.
 and 
Price, Brian
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/087-094}

}
@inproceedings{
:10.2312/VG/VG06/079-086,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Complementary Shape Comparison with Additional Properties}},

author = {
Zhang, Xiaoyu
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/079-086}

}
@inproceedings{
:10.2312/VG/VG06/095-102,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Contour-Based Surface Reconstruction using Implicit Curve Fitting, and Distance Field Filtering and Interpolation}},

author = {
Marker, Jeffrey
 and 
Braude, Ilya
 and 
Museth,  Ken
 and 
Breen,  David
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/095-102}

}
@inproceedings{
:10.2312/VG/VG06/075-078,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Enabling Haptic Interaction with Volumetric MRI Data Through Knowledge-based Tissue Separation}},

author = {
Lundin, Karljohan
 and 
Lundström, Claes
 and 
Cooper, Matthew
 and 
Ynnerman, Anders
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/075-078}

}
@inproceedings{
:10.2312/VG/VG06/103-110,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
GPU-Assisted Raycasting for Cosmological Adaptive Mesh Refinement Simulations}},

author = {
Kaehler, Ralf
 and 
Wise, John
 and 
Abel, Tom
 and 
Hege, Hans-Christian
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/103-110}

}
@inproceedings{
:10.2312/VG/VG06/119-126,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Diffusion-Based Tractography: Visualizing Dense White Matter Connectivity from 3D Tensor Fields}},

author = {
Muraki, S.
 and 
Fujishiro,  I.
 and 
Suzuki,  Y.
 and 
Takeshima, Y.
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/119-126}

}
@inproceedings{
:10.2312/VG/VG06/111-118,

booktitle = {
Volume Graphics},

editor = {
Raghu Machiraju and Torsten Moeller
},
title = {{
Interactive 3D seismic fault detection on the Graphics Hardware}},

author = {
Jeong, Won-Ki
 and 
Whitaker, Ross
 and 
Dobin, Mark
},
year = {
2006},

publisher = {
The Eurographics Association},


ISSN = {1727-8376},
ISBN = {3-905673-41-X},

DOI = {
/10.2312/VG/VG06/111-118}

}

Browse

Recent Submissions

Now showing 1 - 19 of 19
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    Item
    Multi-Dimensional Transfer Function Design Using Sorted Histograms
    (The Eurographics Association, 2006) Lundström, Claes; Ljung, Patric; Ynnerman, Anders; Raghu Machiraju and Torsten Moeller
    Multi-dimensional Transfer Functions (MDTFs) are increasingly used in volume rendering to produce high quality visualizations of complex data sets. A major factor limiting the use of MDTFs is that the available design tools have not been simple enough to reach wide usage outside of the research context, for instance in clinical medical imaging. In this paper we address this problem by defining an MDTF design concept based on improved histogram display and interaction in an exploratory process. To this end we propose sorted histograms, 2D histograms that retain the intuitive appearance of a traditional 1D histogram while conveying a second attribute. We deploy the histograms in medical visualizations using data attributes capturing domain knowledge e.g. in terms of homogeneity and typical surrounding of tissues. The resulting renderings demonstrate that the proposed concept supports a vast number of visualization possibilities based on multi-dimensional attribute data.
  • Thumbnail Image
    Item
    Discontinuous Displacement Mapping for Volume Graphics
    (The Eurographics Association, 2006) Correa, Carlos D.; Silver, Deborah; Chen, Min; Raghu Machiraju and Torsten Moeller
    Displacement mapping is commonly used for adding surface details to an object. In this paper, we outline a generalized notion of displacement mapping, which allows for unconventional features such as unorthogonal and discontinuous displacement. By lifting the restriction on the geometric properties of the displacement, we can generate many different special effects including peeling, cutting and deforming an object. These types of operations are useful for volumetric objects, where the interior of objects is represented. To address the technical difficulties associated with this generalization, we employed inverse displacement maps in 3D vector space, and devised a collection of techniques, including sampling displaced objects through a proxy geometry, computing displaced surface normals, correcting lighting artifacts at breaking points in a discontinuous displacement map, and creating composite displacement maps from primitive maps on the fly. Through a number of examples of displacement maps, we demonstrate the generality, interactivity and usability of this approach on a set of volumetric objects.
  • Thumbnail Image
    Item
    Volumetric Density Capture From a Single Image
    (The Eurographics Association, 2006) Fuchs, Christian; Chen, Tongbo; Goesele, Michael; Theisel, Holger; Seidel, Hans-Peter; Raghu Machiraju and Torsten Moeller
    We propose a new approach to capture the volumetric density of scattering media instantaneously with a single image. The volume is probed with a set of laser lines and the scattered intensity is recorded by a conventional camera. We then determine the density along the laser lines taking the scattering properties of the media into account. A specialized interpolation technique reconstructs the full density field in the volume. We apply the technique to capture the volumetric density of participating media such as smoke.
  • Thumbnail Image
    Item
    An Image-Based Modelling Approach To GPU-based Unstructured Grid Volume Rendering
    (The Eurographics Association, 2006) Shareef, Naeem; Lee, Teng-Yok; Shen, Han-Wei; Mueller, Klaus; Raghu Machiraju and Torsten Moeller
    Unstructured grid volume rendering on the GPU is an ongoing research goal. The main difficulty is how to map the irregular data efficiently to the graphics hardware. Grid cells cannot be directly processed by the pipeline since polyhedral cells are not basic graphics primitives. Thus, approaches that render directly from the grid must try to overcome inherent computational bottlenecks such as cell ordering. We present a novel image-based approach that allows for flexible sample placement and an efficient mapping to graphics hardware that can leverage current trends in hardware performance. The unstructured grid is replaced by a semi-regular data structure we call the Pixel Ray Image (PRI), which consists of a pixelized projection plane and samples defined on sampling rays that intersect the grid. Each ray is interpreted as a linear spline of scalar values. The knot count is reduced by taking advantage of coherence in the sampling direction using spline simplification. The final representation is stored in a packed fashion onto 2D textures and uploaded once to texture memory prior to rendering. We detail how to perform efficient rendering utilizing shader programming and a slice-based rendering scheme that is similar to those used by hardware-accelerated rendering approaches for regular grids.
  • Thumbnail Image
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    GPU-Accelerated D2VR
    (The Eurographics Association, 2006) Xu, Fang; Mueller, Klaus; Raghu Machiraju and Torsten Moeller
    Traditional volume rendering approaches rely on obtaining values of sampled points in volumetric space, typically on a cartesian grid. Often, this cartesian grid is not the original source of the data. For example, in tomographic imaging applications, such as used in diagnostic medical or industrial CT, the primary source of the data is the set of X-ray projections taken around the object. To enable visualization with established volume rendering methods, the volume must first be reconstructed from these projections. Since sampling is involved, this process introduces errors, adversely impacting image quality. Recently a new rendering technique was proposed, named D2VR, which skips the intermediate reconstruction step entirely and samples the projections directly. It was shown that doing so can improve image quality significantly. But despite its great promise, a shortcoming of the method was its comparatively slow rendering speed. Interactive or at least near-interactive speed, however, is critical for clinical deployment of a visualization framework. To address this shortcoming, our paper proposes a GPU-accelerated D2VR, with facilities for occlusion culling and empty space skipping to achieve further speedups.
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    GPU-assisted Multi-field Video Volume Visualization
    (The Eurographics Association, 2006) Botchen, Ralf P.; Chen, Min; Weiskopf, Daniel; Ertl, Thomas; Raghu Machiraju and Torsten Moeller
    GPU-assisted multi-field rendering provides a means of generating effective video volume visualization that can convey both the objects in a spatiotemporal domain as well as the motion status of these objects. In this paper, we present a technical framework that enables combined volume and flow visualization of a video to be synthesized using GPU-based techniques. A bricking-based volume rendering method is deployed for handling large video datasets in a scalable manner, which is particularly useful for synthesizing a dynamic visualization of a video stream. We have implemented a number of image processing filters, and in particular, we employ an optical flow filter for estimating motion flows in a video. We have devised mechanisms for combining volume objects in a scalar field with glyph and streamline geometry from an optical flow. We demonstrate the effectiveness of our approach with example visualizations constructed from two benchmarking problems in computer vision.
  • Thumbnail Image
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    Employing Complex GPU Data Structures for the Interactive Visualization of Adaptive Mesh Refinement Data
    (The Eurographics Association, 2006) Vollrath, Joachim E.; Schafhitzel, Tobias; Ertl, Thomas; Raghu Machiraju and Torsten Moeller
    We present a framework for interactively visualizing volumetric Adaptive Mesh Refinement (AMR) data. For this purpose we employ complex data structures to map the entire AMR dataset to graphics memory. This allows to apply hardware accelerated visualization algorithms previously only operating on uniform cartesian grids. For mapping the data to graphics memory we consider two approaches, a space-efficient, texture-based octree and a fast method based on page table address translation. We demonstrate the utility of our approach by extending an existing GPU raycasting implementation to render AMR data. As a first step to vector field visualization techniques we successfully integrated our framework into a commercial CFD postprocessing tool and visualized scalar properties of the vector field.
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    Item
    Adaptive Sampling in Single Pass, GPU-based Raycasting of Multiresolution Volumes
    (The Eurographics Association, 2006) Ljung, Patric; Raghu Machiraju and Torsten Moeller
    This paper presents a novel direct volume rendering technique for adaptive object- and image-space sampling density of multiresolution volumes. The raycasting is implemented entirely on the GPU in a single pass fragment program which adapts the sampling density along rays, guided by block resolutions. The multiresolution volumes are provided by a transfer function based level-of-detail scheme adaptively loading large out-of-core volumes. Adaptive image-space sampling is achieved by gathering projected basic volume block statistics for screen tiles and then allocating a level-of-detail for each tile. This combination of techniques provides a significant reduction of processing requirements while maintaining high quality rendering.
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    Capture and Review of Interactive Volumetric Manipulations for Surgical Training
    (The Eurographics Association, 2006) Kerwin, Thomas; Shen, Han-Wei; Stredney, Don; Raghu Machiraju and Torsten Moeller
    In this paper, we present a system to capture efficiently a given user s interaction with a simulation system involving the procedural removal of material inside a volume, and to allow for a full 3D, lossless reviewing of that interaction at a later date. We describe an extension of this system to enable reviewing to occur at arbitrary points in the surgical procedure. The extension uses a combination of volume snapshots and event recording to be efficient in both time and space requirements.
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    Pre-integrated Flow Illustration for Tetrahedral Meshes
    (The Eurographics Association, 2006) Svakhine, N. A.; Ebert, D.; Tejada, E.; Ertl, T.; Gaither, K.; Raghu Machiraju and Torsten Moeller
    Previous work has demonstrated the clarity and usefulness of illustrative techniques for visualizing flow data. However, previous systems were limited to applying these techniques to uniform grids. Since unstructured grids have emerged as a common basis for computing flow simulations, we present a method to apply and extend the flow illustration approach to tetrahedral meshes using pre-integrated GPU-accelerated raycasting. Our illustrative rendering techniques can also be applied for other pre-integrated volume rendering systems. Additionally, we explore new feature illustration techniques for flow visualization.
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    SIMD-Aware Ray-Casting
    (The Eurographics Association, 2006) Leung, Warren; Neophytou, Neophytos; Mueller, Klaus; Raghu Machiraju and Torsten Moeller
    With the addition of loop and branch capabilities into the GPU programming set, a more natural and free-flowing volume rendering pipeline execution mode recently emerged. While the execution of the looped fragment program is still SIMD, the numerical approximation of the volume integral is no longer broken up into multiple passes, as it was in previous approaches. Although this certainly is an improvement, due to the less tight control, the present framework lacks the capabilities to focus program flow on the relevant data. In fact, due to the GPU-native SIMD programming model, the slowest ray will now determine the rendering speed. Our paper seeks to provide solutions to enforce more control over the rendering process, with the special SIMD programming model in mind, while retaining this new and promising single-pass rendering paradigm. Our efforts were rewarded with speedups of up to 8.
  • Thumbnail Image
    Item
    Contour Nest: A Two-dimensional Representation for Three-dimensional Isosurfaces
    (The Eurographics Association, 2006) Mizuta, Shinobu; Ono, Toshiki; Matsuda, Tetsuya; Raghu Machiraju and Torsten Moeller
    Visualization of the topological structure of isosurfaces such as exclusion and inclusion plays an important role in analyzing three-dimensional (3D) scalar data like medical images, especially in selecting isosurfaces to observe. Under certain conditions, all isosurfaces in a 3D scalar field are closed surfaces having nest structure. Our purpose here is to translate closed isosurfaces in 3D space as a nest structure. Contour Tree (CT) can describe the nest structure among isosurfaces by tree structure, but it is difficult for users to understand the nest structure by direct observation of the tree shape. In this report, we propose a two-dimensional (2D) representation procedure named Contour Nest (CN) for intuitive display of the nest structure of isosurfaces. In the proposed method, nest structure of 3D isosurfaces extracted by Contour Tree is represented as 2D nest of rectangles. We have evaluated the effectiveness of the proposed method in selecting 3D isosurfaces.
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    Item
    Live Surface
    (The Eurographics Association, 2006) Armstrong, Christopher J.; Barrett, William A.; Price, Brian; Raghu Machiraju and Torsten Moeller
    Live Surface allows users to segment and render complex surfaces from 3D image volumes at interactive (sub- second) rates using a novel, cascading graph cut (CGC). The process consists of four steps. (1) Preprocessing for generation of a complete 3D watershed hierarchy followed by tracking of all catchment basin surfaces. (2) User selection of foreground and background seeds from two-dimensional, image cross-sections. (3) Segmentation of the volume by cascading through the 3D watershed hierarchy from the top, applying graph cut successively, at each level, only to catchment basins bordering the segmented surface from the previous level. (4) OpenGL render- ing for display and update of the segmented surface at interactive rates. CGC allows the entire image volume to be segmented an order of magnitude faster than existing techniques that make use of graph cut. Segmentation and rendering, combined, is accomplished in about 0.5 seconds, allowing 3D surfaces to be displayed and updated dynamically as each additional foreground seed is deposited. CGC allows the user to control and steer the seg- mentation with immediate user feedback, providing a Live Surface tool for 3D image volumes similar to the Live Wire (Intelligent Scissors) tool used in 2D images
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    Complementary Shape Comparison with Additional Properties
    (The Eurographics Association, 2006) Zhang, Xiaoyu; Raghu Machiraju and Torsten Moeller
    We present an algorithm for comparing 3D shapes by considering their pockets in the complementary space. The pockets of a closed compact surface can be represented by a 3D volumetric function. Multi-resolution dual contour trees are constructed from the pocket functions to efficiently match them in an affine-invariant way. DCTs are simplified data structures computed from contour trees (CT) of 3D functions. The DCTs capture the important features of the volumetric functions and are not sensitive to noises. Each node of a DCT corresponds to an interval volume and is tagged with geometrical, topological, and functional attributes. Similarities among shapes are compared by matching nodes from multi-resolution DCTs and calculating the score based on the attributes of the matched nodes. This method is particularly useful for comparing complicated molecular shapes, for which other properties such as electrostatic potentials can be added as additional attributes to improve performance.
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    Contour-Based Surface Reconstruction using Implicit Curve Fitting, and Distance Field Filtering and Interpolation
    (The Eurographics Association, 2006) Marker, Jeffrey; Braude, Ilya; Museth, Ken; Breen, David; Raghu Machiraju and Torsten Moeller
    This paper presents a volumetric approach to reconstructing a smooth surface from a sparse set of paral- lel binary contours, e.g. those produced via histologic imaging. It creates a volume dataset by interpolating 2D filtered distance fields. The zero isosurface embedded in the computed volume provides the desired result. MPU implicit functions are fit to the input contours, defined as binary images, to produce smooth curves with controllable error bounds. Full 2D Euclidean distance fields are then calculated from the implicit curves. A distance-dependent Gaussian filter is applied to the distance fields to smooth their medial axis discontinuities. Monotonicity-constraining cubic splines are used to construct smooth, blending slices between the input slices. A mesh that approximates the zero isosurface is then extracted from the resulting volume. The effectiveness of the approach is demonstrated on a number of complex, multi-component contour datasets.
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    Enabling Haptic Interaction with Volumetric MRI Data Through Knowledge-based Tissue Separation
    (The Eurographics Association, 2006) Lundin, Karljohan; Lundström, Claes; Cooper, Matthew; Ynnerman, Anders; Raghu Machiraju and Torsten Moeller
    Direct volume haptics can provide both guidance and extra information during exploration of volumetric data. In this paper we present a novel approach to volume haptics enabling haptic exploration of tissue shape, borders and material properties in data despite low contrast and low signal to noise ratio, as is common in medical MRI data or low dose CT data. The method uses filtering based on implicit knowledge and addresses the problem of overlapping scalar ranges through the introduction of fuzzy classification and corresponding transfer functions for material properties as well as classification-based distance masking for haptic force direction.
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    GPU-Assisted Raycasting for Cosmological Adaptive Mesh Refinement Simulations
    (The Eurographics Association, 2006) Kaehler, Ralf; Wise, John; Abel, Tom; Hege, Hans-Christian; Raghu Machiraju and Torsten Moeller
    In the recent years the advent of powerful graphics hardware with flexible, programmable fragment shaders enabled interactive raycasting implementations which perform the ray-integration on a per-pixel basis. Unlike slicebased volume rendering these approaches do not suffer from rendering artifacts caused by varying sample distances along different ray-directions or limited frame-buffer precision. They further allow a direct realization of sophisticated optical models. In this paper we investigate the applicability of GPU-assisted raycasting to block-structured, locally refined grids. We present an interactive algorithm for artifact-free, high-quality rendering of data defined on this type of grid structure and apply it to render data of time-dependent, three-dimensional galaxy and star formation simulations. We use a physically motivated emission-absorption model to map the computed temperature and density fields to color and opacity.
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    Diffusion-Based Tractography: Visualizing Dense White Matter Connectivity from 3D Tensor Fields
    (The Eurographics Association, 2006) Muraki, S.; Fujishiro, I.; Suzuki, Y.; Takeshima, Y.; Raghu Machiraju and Torsten Moeller
    In this paper, we present a novel method, called diffusion-based tractography (DBT), for visualizing diffusion tensor magnetic resonance imaging datasets. The DBT method generates 3D textures similar to the line integral convolution (LIC) by smearing 3D random dot textures. In contrast to the LIC method, which only traces a single direction, the DBT method takes into account both linear and planar diffusion components, and suppresses excessive blur by an analysis of three decomposed components. We will demonstrate that the DBT method is effective for visualizing dense white matter connectivity from 3D diffusion tensor fields and that it is suitable for hardware acceleration using commodity graphics processors.
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    Interactive 3D seismic fault detection on the Graphics Hardware
    (The Eurographics Association, 2006) Jeong, Won-Ki; Whitaker, Ross; Dobin, Mark; Raghu Machiraju and Torsten Moeller
    This paper presents a 3D, volumetric, seismic fault detection system that relies on a novel set of nonlinear filters combined with a GPU (Graphics Processing Unit) implementation, which makes interactive nonlinear, volumetric processing feasible. The method uses a 3D structure tensor to robustly measure seismic orientations. These tensors guide an anisotropic diffusion, which reduces noise in the data while enhancing the fault discontinuity and coherency along seismic strata. A fault-likelihood volume is computed using a directional variance measure, and 3D fault voxels are then extracted through a non-maximal-suppression method. We also show how the proposed algorithms are efficiently implemented with a GPU programming model, and compare this to a CPU implementation to show the benefits of using the GPU for this computationally demanding problem.