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125
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 ..."
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Cited by 326 (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.
RENDERING FUR WITH THREE DIMENSIONAL TEXTURES
, 1989
"... We present a method for rendering scenes with fine detail via an object called a texel, a rendering primitive inspired by volume densities mixed with anisotropic lighting models. This technique solves a long outstanding problem in image synthesis: the rendering of furry surfaces. ..."
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Cited by 209 (0 self)
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We present a method for rendering scenes with fine detail via an object called a texel, a rendering primitive inspired by volume densities mixed with anisotropic lighting models. This technique solves a long outstanding problem in image synthesis: the rendering of furry surfaces.
Merging Virtual Objects with the Real World: Seeing Ultrasound Imagery within the Patient. Computer Graphics. Vol 26, No 2. July
, 1992
"... We describe initial results which show “live ” ultrasound echography data visualized within a pregnant human subject. The visualization is achieved by using a small video camera mounted in front of a conventional headmounted display worn by an observer. The camera’s video images are composited with ..."
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Cited by 161 (15 self)
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We describe initial results which show “live ” ultrasound echography data visualized within a pregnant human subject. The visualization is achieved by using a small video camera mounted in front of a conventional headmounted display worn by an observer. The camera’s video images are composited with computergenerated ones that contain one or more 2D ultrasound images properly transformed to the observer’s current viewing position. As the observer walks around the subject, the ultrasound images appear stationary in 3space within the subject. This kind of enhancement of the observer’s vision may have many other applications, e.g., image guided surgical procedures and on location 3D interactive architecture preview.
Area and Volume Coherence for Efficient Visualization of 3D Scalar Functions
 Computer Graphics
, 1990
"... We present an algorithm for compositing a combination of density clouds and contour surfaces used to represent a scalar function on a 3D volume subdivided into convex polyhedra. The scalar function is interpolated between values defined at the vertices, and the polyhedra are sorted in depth before ..."
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Cited by 126 (16 self)
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We present an algorithm for compositing a combination of density clouds and contour surfaces used to represent a scalar function on a 3D volume subdivided into convex polyhedra. The scalar function is interpolated between values defined at the vertices, and the polyhedra are sorted in depth before compositing. For n tetrahedra comprising a Delaunay triangulation, this sorting can always be done in O(n) time. Since a Delaunay triangulation can be efficiently computed for scattered data points, this provides a method for visualizing such data sets. The integrals for opacity and visible intensity along a ray through a convex polyhedron are computed analytically, and this computation is coherent across the polyhedron s projected area.
Fourier volume rendering
 ACM Transactions on Graphics
, 1993
"... In computer graphics we have traditionally rendered images of data sets specified spatially, Here, we present a volume rendering technique that operates on a frequency domain representation of the data set and that efficiently generates line integral projections of the spatial data it represents, Th ..."
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Cited by 115 (1 self)
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In computer graphics we have traditionally rendered images of data sets specified spatially, Here, we present a volume rendering technique that operates on a frequency domain representation of the data set and that efficiently generates line integral projections of the spatial data it represents, The motivation for this approach is that the Fourier ProjectionSlice Theorem allows us to compute 2D projections of 3D data seta using only a 2D slice of the data in the frequency domain. In general, these “Xraylike ” images can be rendered at a significantly lower computational cost than images generated by current volume rendering techniques, Additionally, assurances of image accuracy can he made.
Fast Algorithms for Volume Ray Tracing
, 1992
"... We examine various simple algorithms that exploit homogeneity and accumulated opacity for tracing rays through shaded volumes. Most of these methods have error criteria which allow them to trade quality for speed. The time vs. quality tradeoff for these adaptive methods is compared to fixed step mul ..."
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Cited by 108 (0 self)
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We examine various simple algorithms that exploit homogeneity and accumulated opacity for tracing rays through shaded volumes. Most of these methods have error criteria which allow them to trade quality for speed. The time vs. quality tradeoff for these adaptive methods is compared to fixed step multiresolution methods. These methods are also useful for general light transport in volumes. 1 Introduction We are interested in speeding volume ray tracing computations. We concentrate on the one dimensional problem of tracing a single ray, or computing the intensity at a point from a single direction. In addition to being the kernel of a simple volume ray tracer, this computation can be used to generate shadow volumes and as an element in more general light transport problems. Our data structures will be view independent to speed the production of animations of preshaded volumes and interactive viewing. In [11] Levoy introduced two key concepts which we will be expanding on: presence accel...
Interactive Ray Tracing for Volume Visualization
, 1999
"... We present a bruteforce ray tracing system for interactive volume visualization. The system runs on a conventional (distributed) sharedmemory multiprocessor machine. For each pixel we trace a ray through a volume to compute the color for that pixel. Although this method has high intrinsic computat ..."
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Cited by 103 (26 self)
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We present a bruteforce ray tracing system for interactive volume visualization. The system runs on a conventional (distributed) sharedmemory multiprocessor machine. For each pixel we trace a ray through a volume to compute the color for that pixel. Although this method has high intrinsic computational cost, its simplicity and scalability make it ideal for large datasets on current highend parallel systems. To gain efficiency several optimizations are used including a volume bricking scheme and a shallow data hierarchy. These optimizations are used in three separate visualization algorithms: isosurfacing of rectilinear data, isosurfacing of unstructured data, and maximumintensity projection on rectilinear data. The system runs interactively (i.e., several frames per second) on an SGI Reality Monster. The graphics capabilities of the Reality Monster are used only for display of the final color image.
Direct Volume Rendering with Shading via ThreeDimensional Textures
, 1996
"... A new and easytoimplement method for direct volume rendering that uses 3D texture maps for acceleration, and incorporates directional lighting, is described. The implementation, called Voltx, produces highquality images at nearly interactive speeds on workstations with hardware support for three ..."
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Cited by 87 (1 self)
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A new and easytoimplement method for direct volume rendering that uses 3D texture maps for acceleration, and incorporates directional lighting, is described. The implementation, called Voltx, produces highquality images at nearly interactive speeds on workstations with hardware support for threedimensional texture maps. Previously reported methods did not incorporate a light model, and did not address issues of multiple texture maps for large volumes. Our research shows that these extensions impact performance by about a factor of ten. Voltx supports orthographic, perspective, and stereo views. This paper describes the theory and implementation of this technique, and compares it to the shearwarp factorization approach. A rectilinear data set is converted into a threedimensional texture map containing color and opacity information. Quantized normal vectors and a lookup table provide efficiency. A new tesselation of the sphere is described, which serves as the basis for normalvec...
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 67 (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...
A Multiresolution Framework for Volume Rendering
 SYMPOSIUM ON VOLUME VISUALIZATION
, 1994
"... In this paper we present a general framework for the approximation of the volume rendering integral using multiresolution spaces. Instead of solving the integral over the original volume data set we first project it into a wavelet basis. The final integration process is then performed on the resulti ..."
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Cited by 67 (6 self)
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In this paper we present a general framework for the approximation of the volume rendering integral using multiresolution spaces. Instead of solving the integral over the original volume data set we first project it into a wavelet basis. The final integration process is then performed on the resulting coefficients directly. Depending on the used basis functions a large number of coefficients can be neglected while still achieving accurate results. This leads to a drastic reduction in the amount of memory used during the rendering process. Furthermore, this sparse representation can be integrated into the rendering process, which is reflected in the overall rendering times.