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17
Controlled Topology Simplification
 IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS
, 1996
"... We present a simple,robust, and practical method for object simplification for applications where gradual elimination of high frequency details is desired. This is accomplished by converting an object into multiresolution volume rastersusing a controlled filtering and sampling technique.Amultiresol ..."
Abstract

Cited by 72 (7 self)
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We present a simple,robust, and practical method for object simplification for applications where gradual elimination of high frequency details is desired. This is accomplished by converting an object into multiresolution volume rastersusing a controlled filtering and sampling technique.Amultiresolution trianglemesh hierarchycan then be generated by applying the Marching Cubes algorithm. We f urther propose an adaptive surface generation algorithm to reduce the number of triangles generated by the standardMarching Cubes. Our method simplifies the topology of objects in a controlled fashion. In addition, at eachlevel of detail, multilayered meshes can be used for an efficient antialiased rendering.
Interactive highquality maximum intensity projection
 Computer Graphics Forum
, 2000
"... Maximum Intensity Projection (MIP) is a volume rendering technique which is used to visualize highintensity structures within volumetric data. At each pixel the highest data value, which is encountered along a corresponding viewing ray is depicted. MIP is, for example, commonly used to extract vasc ..."
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Cited by 20 (6 self)
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Maximum Intensity Projection (MIP) is a volume rendering technique which is used to visualize highintensity structures within volumetric data. At each pixel the highest data value, which is encountered along a corresponding viewing ray is depicted. MIP is, for example, commonly used to extract vascular structures from medical data sets (angiography). Due to lack of depth information in MIP images, animation or interactive variation of viewing parameters is frequently used for investigation. Up to now no MIP algorithms exist which are of both interactive speed and high quality. In this paper we present a highquality MIP algorithm (trilinear interpolation within cells), which is up to 50 times faster than bruteforce MIP and at least 20 times faster than comparable optimized techniques. This speedup is accomplished by using an alternative storage scheme for volume cells (sorted by value) and by removing cells which do not contribute to any MIP projection (regardless of the viewing direction) in a preprocessing step. Also, a fast maximum estimation within cells is used to further speed up the algorithm. 1.
Interactive pointbased rendering of higherorder tetrahedral data
 IEEE Transactions on Visualization and Computer Graphics
, 2006
"... Computational simulations frequently generate solutions defined over very large tetrahedral volume meshes containing many millions of elements. Furthermore, such solutions may often be expressed using nonlinear basis functions. Certain solution techniques, such as discontinuous Galerkin methods, m ..."
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Cited by 11 (1 self)
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Computational simulations frequently generate solutions defined over very large tetrahedral volume meshes containing many millions of elements. Furthermore, such solutions may often be expressed using nonlinear basis functions. Certain solution techniques, such as discontinuous Galerkin methods, may even produce nonconforming meshes. Such data is difficult to visualize interactively, as it is far too large to fit in memory and many common data reduction techniques, such as mesh simplification, cannot be applied to nonconforming meshes. We introduce a pointbased visualization system for interactive rendering of large, potentially nonconforming, tetrahedral meshes. We propose methods for adaptively sampling points from nonlinear solution data and for decimating points at run time to fit GPU memory limits. Because these are streaming processes, memory consumption is independent of the input size. We also present an orderindependent point rendering method that can efficiently render volumes on the order of 20 million tetrahedra at interactive rates.
RealTime Maximum Intensity Projection
 Data Visualization '99
, 1999
"... Maximum Intensity Projection (MIP) is a volume rendering technique which is used to extract highintensity structures from volumetric data. At each pixel the highest data value encountered along the corresponding viewing ray is determined. MIP is commonly used to extract vascular structures from med ..."
Abstract

Cited by 9 (4 self)
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Maximum Intensity Projection (MIP) is a volume rendering technique which is used to extract highintensity structures from volumetric data. At each pixel the highest data value encountered along the corresponding viewing ray is determined. MIP is commonly used to extract vascular structures from medical MRI data sets (angiography). The usual way to compensate for the loss of spatial and occlusion information in MIP images is to view the data from different view points by rotating them. As the generation of MIP is usually noninteractive, this is done by calculating multiple images offline and playing them back as an animation. In this paper a new algorithm is proposed which is capable of interactively generating Maximum Intensity Projection images using parallel projection and templates. Voxels of the data set which will never contribute to a MIP due to their neighborhood are removed during a preprocessing step. The remaining voxels are stored in a way which guarantees optimal cache co...
Maximum Intensity Projection at Warp Speed
, 1999
"... Maximum Intensity Projection (MIP) is a volume rendering technique which is used to extract highintensity structures from volumetric scalar data. At each pixel the highest data value encountered along the corresponding viewing ray is determined. MIP is commonly used to extract vascular structures f ..."
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Cited by 9 (3 self)
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Maximum Intensity Projection (MIP) is a volume rendering technique which is used to extract highintensity structures from volumetric scalar data. At each pixel the highest data value encountered along the corresponding viewing ray is determined. MIP is commonly used to extract vascular structures from medical MRI data sets, i.e., angiography. The usual way to compensate for the loss of spatial and occlusion information in MIP images is to view the data from different view points by rotating them. As the generation of a MIP is usually noninteractive, this is done by calculating multiple images offline and playing them back as an animation. In this paper a novel algorithm is proposed which is capable of interactively generating Maximum Intensity Projection images even on lowend hardware using parallel projection. Two methods for preprocessing data and removing voxels which will due to their neighborhood never contribute to a MIP are discussed. The remaining voxels are stored in a way...
Antialiasing of Curves by Discrete Prefiltering
, 1997
"... Prefiltering is generally considered the ideal approach to antialiasing but is difficult to perform exactly for complex geometries such as curves or for arbitrary choice of filters. We present a discrete prefiltering technique for antialiasing Bzier curves using arbitrary filters which is numeric ..."
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Cited by 8 (2 self)
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Prefiltering is generally considered the ideal approach to antialiasing but is difficult to perform exactly for complex geometries such as curves or for arbitrary choice of filters. We present a discrete prefiltering technique for antialiasing Bzier curves using arbitrary filters which is numerically and geometrically robust and whose accuracy is controllable. CR Categories and Subject Descriptors: I.3.3 [Computer Graphics]: Picture/Image Generation  antialiasing Additional Keywords: Bzier curves, prefiltering 1 INTRODUCTION The causes of aliasing in computer generated imagery are well known and may be broken down into two components: aliasing due to inadequate sampling of the ideal image and aliasing due to incorrect or inadequate reconstruction of the displayed image from the samples. Many techniques have been proposed but there is no ideal or universal solution and compromises have to be made. As Mitchell and Netravali [29] point out, graphics has generally avoided the is...
Cerebral Blood Vessels Modeling
, 1998
"... this report, the reconstruction and modeling of cerebral vascular structures are addressed. The main contributions brought are the following: ..."
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Cited by 4 (1 self)
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this report, the reconstruction and modeling of cerebral vascular structures are addressed. The main contributions brought are the following:
Volume Interval Segmentation and Rendering
"... Direct volume rendering has seen many improvements since its inception fifteen years ago. In this paper, we segment the volume into geometrically disjoint regions that can be rendered to provide a more effective and interactive volume rendering of structured and unstructured grids. Our segmentation ..."
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Cited by 3 (0 self)
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Direct volume rendering has seen many improvements since its inception fifteen years ago. In this paper, we segment the volume into geometrically disjoint regions that can be rendered to provide a more effective and interactive volume rendering of structured and unstructured grids. Our segmentation is based upon intervals within the scalar field, producing a set of geometrically defined interval volumes. We present many advantageous properties in using interval volumes, and provide several new rendering operations or shaders to provide effective visualizations of the 3D scalar field. In particular, we demonstrate new technologies that allow interval volumes to be rendered interactively and/or used to reduce the amount of rasterization or rendering primitives in a volume renderer. We illustrate the use of interval volumes to highlight contour boundaries or material interfaces. Several surface shaders that can easily be integrated in the volume renderer are presented. To construct the interval volumes, we cast the problem one dimension higher, using a higherdimensional isosurface construction for interactive computation or segmentation. The algorithm is independent of the dimension and topology of the polyhedral cells comprising the grid, and thus offers an excellent enhancement to the volume rendering of unstructured grids. We present examples using hexahedral and tetrahedral cells from timevarying and multiattribute datasets.
Hybrid Model for Vascular Tree Structures
, 2000
"... This paper proposes a new representation scheme of the cerebral blood vessels. This model provides information on the semantics of the vascular structure: the topological relationships between vessels and the labeling of vascular accidents such as aneurysms and stenoses. In addition, the model k ..."
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Cited by 2 (2 self)
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This paper proposes a new representation scheme of the cerebral blood vessels. This model provides information on the semantics of the vascular structure: the topological relationships between vessels and the labeling of vascular accidents such as aneurysms and stenoses. In addition, the model keeps information of the inner surface geometry as well as of the vascular map volume properties, i.e. the tissue density, the blood flow velocity and the vessel wall elasticity.