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48
Volume Rendering
, 1988
"... A technique for rendering images Of volumes containing mixtures of materials is presented. The shading model allows both the interior of a material and the boundary between materials to be colored. Image projection is performed by simulating the absorption of light along the ray path to the eye. The ..."
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Cited by 403 (2 self)
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A technique for rendering images Of volumes containing mixtures of materials is presented. The shading model allows both the interior of a material and the boundary between materials to be colored. Image projection is performed by simulating the absorption of light along the ray path to the eye. The algorithms used are designed to avoid artifacts caused by aliasing and quantization and can be efficiently implemented on an image computer. Images from a variety of applications are shown.
Accelerating Volume Animation by SpaceLeaping
, 1993
"... f i In this paper we present a method for speeding the process of volume rendering a sequence o mages. Speedup is based on exploiting coherency between consecutive images to shorten the n path rays take through the volume. This is achieved by providing each ray with information eeded to leap over th ..."
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Cited by 69 (9 self)
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f i In this paper we present a method for speeding the process of volume rendering a sequence o mages. Speedup is based on exploiting coherency between consecutive images to shorten the n path rays take through the volume. This is achieved by providing each ray with information eeded to leap over the empty space and commence volume traversal at the vicinity of mean  b ingful data. The algorithm starts by projecting the volume into a Cbuffer (Coordinates uffer) which stores, at each pixel location, the objectspace coordinates of the first nonempty s t voxel visible from that pixel. For each change in the viewing parameters, the Cbuffer i ransformed accordingly. In the case of rotation the transformed Cbuffer goes through a pro  b cess of eliminating coordinates that possibly became hidden. The remaining values in the C uffer serve as an estimate of the point where the new rays should start their volume traverc sal. This spaceleaping method can be combined with existing accele...
TemplateBased Volume Viewing
, 1992
"... We present an efficient threephase algorithm for volume viewing that is based on exploit  t ing coherency between rays in parallel projection. The algorithm starts by building a ray emplate and determining a special plane for projection  the baseplane. Parallel rays are cast t into the volume ..."
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Cited by 65 (17 self)
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We present an efficient threephase algorithm for volume viewing that is based on exploit  t ing coherency between rays in parallel projection. The algorithm starts by building a ray emplate and determining a special plane for projection  the baseplane. Parallel rays are cast t into the volume from within the projected region of the volume on the baseplane, by repeating he sequence of steps specified in the raytemplate. We carefully choose the type of line to be s employed and the way the template is being placed on the baseplane in order to assure uniform ampling of the volume by the discrete rays. We conclude by describing an optimized software K implementation of our algorithm and reporting its performance. eywords: volume rendering, ray casting, template, parallel projection 1. Introduction Volume visualization is the process of converting complex volume data to a format that is p amenable to human understanding while maintaining the integrity and accuracy of the data. Th...
Constructive Volume Geometry
 Computer Graphics Forum
, 2000
"... We present an algebraic framework, called Constructive Volume Geometry (CVG), for modelling complex spatial objects using combinational operations. By utilising scalar fields as fundamental building blocks, CVG provides highlevel algebraic representations of objects that are defined mathematically ..."
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Cited by 46 (17 self)
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We present an algebraic framework, called Constructive Volume Geometry (CVG), for modelling complex spatial objects using combinational operations. By utilising scalar fields as fundamental building blocks, CVG provides highlevel algebraic representations of objects that are defined mathematically or built upon sampled or simulated datasets. It models amorphous phenomena as well as solid objects, and describes the interior as well as the exterior of objects. We also describe a hierarchical representation scheme for CVG, and a direct rendering method with a new approach for consistent sampling. The work has demonstrated the feasibility of combining a variety of graphics data types in a coherent modelling scheme.
A practical evaluation of popular volume rendering algorithms
 IN PROCEEDINGS OF THE 2000 IEEE SYMPOSIUM ON VOLUME VISUALIZATION
, 2000
"... This paper evaluates and compares four volume rendering algorithms that have become rather popular for rendering datasets described on uniform rectilinear grids: raycasting, splatting, shearwarp, and hardwareassisted 3D texturemapping. In order to assess both the strengths and the weaknesses of t ..."
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Cited by 25 (2 self)
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This paper evaluates and compares four volume rendering algorithms that have become rather popular for rendering datasets described on uniform rectilinear grids: raycasting, splatting, shearwarp, and hardwareassisted 3D texturemapping. In order to assess both the strengths and the weaknesses of these algorithms in a wide variety of scenarios, a set of reallife benchmark datasets with different characteristics was carefully selected. In the rendering, all algorithmindependent image synthesis parameters, such as viewing matrix, transfer functions, and optical model, were kept constant to enable a fair comparison of the rendering results. Both image quality and computational complexity were evaluated and compared, with the aim of providing both researchers and practitioners with guidelines on which algorithm is most suited in which scenario. Our analysis also indicates the current weaknesses in each algorithm’s pipeline, and possible solutions to these as well as pointers for future research are offered.
VirEn: A Virtual Endoscopy System
 Machine GRAPHICS & VISION
, 1999
"... Virtual endoscopy systems are promising tools for the simplification of daily clinical procedures. In this paper, a conceptual framework for a virtual endoscopy system (VirEn) is proposed, which is intended to be a highly interactive system. Research efforts have concentrated on the generation of an ..."
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Cited by 12 (4 self)
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Virtual endoscopy systems are promising tools for the simplification of daily clinical procedures. In this paper, a conceptual framework for a virtual endoscopy system (VirEn) is proposed, which is intended to be a highly interactive system. Research efforts have concentrated on the generation of an optimal path for the automated navigation of the data set. Extensions to existing thinning algorithms used to generate the optimal path are presented and discussed. First results produced with VirEn are shown. Keywords: Volume Visualization, Virtual Endoscopy, Navigation, Thinning 1 Introduction In recent years, the importance of medical imaging in patients care systems is increasing due to the evolution of 3D imaging modalities, like CT or MRI. Computer graphics techniques for the visualization of the acquired 3D imaging data sets are topics of research. Virtual endoscopy is a promising new technique to explore hollow organs and anatomical cavities. The fields of application are manifold...
Voxels versus Polygons: A Comparative Approach for Volume Graphics
 IN PROC. OF VOLUME GRAPHICS
, 1999
"... The decision to use either the Direct Volume Rendering paradigm or the Indirect Volume Rendering paradigm to visualize a volume dataset is a topical question in Volume Graphics. Unfortunately, it seems that this question has not been sufficiently addressed so far and is not easy to answer. In th ..."
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Cited by 11 (7 self)
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The decision to use either the Direct Volume Rendering paradigm or the Indirect Volume Rendering paradigm to visualize a volume dataset is a topical question in Volume Graphics. Unfortunately, it seems that this question has not been sufficiently addressed so far and is not easy to answer. In this paper, we discuss some of the advantages and disadvantages of one candidate for each of these paradigms; Ray Casting for Direct Volume Rendering and Marching Cubes for Indirect Volume Rendering. The discussion is based on two cartesian grid scalar data fields, a CT scan of a lobster  immersed in resin, and a MRI scan of a human head. These datasets have interesting properties which show different features using different Volume Rendering techniques. Two measurements are considered for our discussion; visual quality and the consumption of resources, such as time and memory.
DataParallel Volume Rendering Algorithms
, 1995
"... this paper we consider a general scheme for parallel volume rendering, described in Section 2. We describe an algorithm in this paper that has an extremely efficient implementation on distributed memory MIMD architectures and is suitable for hardware implementation based on the image composition arc ..."
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Cited by 11 (5 self)
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this paper we consider a general scheme for parallel volume rendering, described in Section 2. We describe an algorithm in this paper that has an extremely efficient implementation on distributed memory MIMD architectures and is suitable for hardware implementation based on the image composition architectures [15]. This data parallel scheme assigns a portion of the volume to each processor which renders it with any one of the above mentioned rendering algorithms. The resulting images from all processors are then combined (composited) in visibility order to form the final image. As viewing and shading parameters change, 3D voxel data is not communicated between processors. Communication involves only 2D partial images. In Section 3 we report on specific rendering algorithms that can be executed in each processor to generate the image of the local subvolume. These algorithms take advantage of vector processing or pipelining capabilities available on some parallel machines (e.g., CRAY YMP, Intel Paragon, IBM Power Visualization System). Section 4 contains performance analysis and provides results of numerical experiments examining various aspects of the proposed algorithm and its variations, while Section 5 contains concluding remarks and future plans. 2. Volume Rendering by Parallel Image Composition
Voxels as a Computational Representation of Geometry
 in The Computational Representation of Geometry. SIGGRAPH '94 Course Notes
, 1994
"... This paper is a survey of volume visualization, volume graphics, and volume rendering techniques. It focuses specifically on the use of the voxel representation and volumetric techniques for geometric applications. 1. Introduction Volume data are 3D entities that may have information inside them, ..."
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Cited by 8 (0 self)
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This paper is a survey of volume visualization, volume graphics, and volume rendering techniques. It focuses specifically on the use of the voxel representation and volumetric techniques for geometric applications. 1. Introduction Volume data are 3D entities that may have information inside them, might not consist of surfaces and edges, or might be too voluminous to be represented geometrically . Volume visualization is a method of extracting meaningful information from volumetric data using interactive graphics and imaging, and it is concerned with volume data representation, modeling, manipulation, and rendering [49]. Volume data are obtained by sampling, simulation, or modeling techniques. For example, a sequence of 2D slices obtained from Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) is 3D reconstructed into a volume model and visualized for diagnostic purposes or for planning of treatment or surgery. The same technology is often used with industrial CT for nondes...