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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 ..."
Abstract

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.
Efficient ray tracing of volume data
 ACM Transactions on Graphics
, 1990
"... Volume rendering is a technique for visualizing sampled scalar or vector fields of three spatial dimensions without fitting geometric primitives to the data. A subset of these techniques generates images by computing 2D projections of a colored semitransparent volume, where the color and opacity at ..."
Abstract

Cited by 352 (4 self)
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Volume rendering is a technique for visualizing sampled scalar or vector fields of three spatial dimensions without fitting geometric primitives to the data. A subset of these techniques generates images by computing 2D projections of a colored semitransparent volume, where the color and opacity at each point are derived from the data using local operators. Since all voxels participate in the generation of each image, rendering time grows linearly with the size of the dataset. This paper presents a fronttoback imageorder volumerendering algorithm and discusses two techniques for improving its performance. The first technique employs a pyramid of binary volumes to encode spatial coherence present in the data, and the second technique uses an opacity threshold to adaptively terminate ray tracing. Although the actual time saved depends on the data, speedups of an order of magnitude have been observed for datasets of useful size and complexity. Examples from two applications are given: medical imaging and molecular graphics.
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...
Applying space subdivision techniques to volume rendering
 In Proceedings of Visualization ’90, 150–159
, 1990
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Towards Real Time Volume Rendering
, 1996
"... The task of real time rendering of today's volumetric datasets is still being tackled by several research groups. A quick calculation of the amount of computation required for realtime rendering of a high resolution volume puts us in the teraflop range. Yet, the demand to support such renderin ..."
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Cited by 6 (0 self)
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The task of real time rendering of today's volumetric datasets is still being tackled by several research groups. A quick calculation of the amount of computation required for realtime rendering of a high resolution volume puts us in the teraflop range. Yet, the demand to support such rendering capabilities is increasing due to emerging technologies such as virtual surgery simulation and rapid prototyping. There are five main approaches to overcoming this seemingly insurmountable performance barrier: (i) data reduction by means of model extraction or data simplification, (ii) realization of specialpurpose volume rendering engines, (iii) softwarebased algorithm optimization and acceleration, (iv) implementation on general purpose parallel architectures, and (v) use of contemporary oftheshelf graphics hardware. In this presentation we first describe the vision of realtime highresolution volume rendering and estimate the computing power it demands. We survey the stateofthe art in...
i ' UNC is an Equal Opportunity/Affirmative Action Institution. 1 Direct Visualization of Surfaces from Computed Tomography Data
, 1988
"... The application of direct volume visualization techniques to the presentation of CT data is explored. No surface detection or fitting of geometric primitives is involved. Images are formed by directly shading each data sample and projecting it onto the picture plane. The visualizations in this study ..."
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The application of direct volume visualization techniques to the presentation of CT data is explored. No surface detection or fitting of geometric primitives is involved. Images are formed by directly shading each data sample and projecting it onto the picture plane. The visualizations in this study are based on a hybrid physical model incorporating aspects of both surfaces and semitransparent gels. Using a surface model, shading calculations are performed at every voxel with local gradient vectors serving as surface normals. In a separate step, surface classification and enhancement operators are applied to obtain a partial opacity for every voxel. Independence of _shading and classification calculations insures an undistorted presentation of 3D shape. The use of nonbinary classification operators insure that small or poorly defined features are not lost The resulting colors and opacities are merged from back to front along view rays using volumetric compositing, an approximation to the visibility calculations required to render a semitransparent gel. The technique is simple and fast, yet produces images exhibiting smooth surface silhouettes and few other aliasing artifacts. The use of selective blurring and supersampling to further improve image quality is also described. 1.