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Técnica híbrida de visualização para exploração de dados volumétricos não estruturados / A hybrid visualization technique for exploring unstructured volumetric dataCateriano, Patricia Shirley Herrera 21 May 2003 (has links)
Este trabalho apresenta uma nova técnica de visualização que aproveita as vantagens do rendering volumétrico direto e do rendering de superfícies em um ambiente híbrido. O método faz uso de uma pré-visualização sobre o bordo do volume que viabiliza uma interação em tempo real com objetos volumétricos modelados por meio de malhas não estruturadas. Além disso, essa nova abordagem de visualização é paralelizável e pode se acelerada com placas gráficas comuns. / This work presents a new visualization technique that exploits the advantages of direct volume rendering and surface rendering in a hybrid environment. The method developed here makes use of a pre-visualization on the volume boundary to enable real time interaction with unstructured volumetric meshes. Furthermore, this new visualization approach can be implemented on existing parallel architectures and speed up by conventional graphical hardware.
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[en] VOLUMETRIC VISUALIZATION WITH RAY-CASTING IN A DISTRIBUTED ENVIRONMENT / [pt] VISUALIZAÇÃO VOLUMÉTRICA COM RAY-CASTING NUM AMBIENTE DISTRIBUÍDOROBERTO DE BEAUCLAIR SEIXAS 26 July 2002 (has links)
[pt] Ray-Casting é uma técnica muito usada em visualizção
volumétrica para a criação de imagens médicas, a partir
de dados obtidos por ressonância magnética (MRI) e
tomografias computadorizadas (CT). No entanto, ray-
casting tem um alto custo computacional que resulta em um
processo de visualização lento, o que compromete a
interatividade necessária para uma boa compreensão do
conjunto de dados tri-dimensionais.Este trabalho propõe
estratégias para a otimização do algoritmo de ray-casting
e para melhorar sua eficiência. Além disso, esta tese
investiga o uso em um ambiente de computação distribuída,
através de um protocolo de comunicação entre estações de
trabalho heterogêneas e não dedicadas, conectadas em uma
rede local.As idéias propostas foram implementadas em
duas versões do algoritmo, uma sequencial e uma paralela.
Os resultados obtidos com essas implementações em
conjuntos de dados reais mostram que é possível obter
tempo interativo com as máquinas disponíveis atualmente e
em condições normais de uso da rede local por outros
usuários. / [en] Ray-Casting is a useful volume visualization technique
applied to medical images such
as computer tomography (CT) and magnetic resonance image
(MRI). It has, however, a
high computational cost that results in a slow rendering
process, which compromises the
interactivity that is necessary for a good comprehension
of the three-dimensional data set.
This work proposes optimization strategies to the ray-
casting algorithm to improve
its effciency. To enhance, even further, the thesis
investigates the use of a distributed
computer environment through a communication protocol
between heterogeneous and non-
dedicate LAN-connected workstations.
The ideas proposed here were implemented in two versions
of the algorithm, one se-
quential and one parallel. Test results, obtained with
these implementations and real data
sets, show that it is possible to obtain interactive time
with the current available machines.
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Técnica híbrida de visualização para exploração de dados volumétricos não estruturados / A hybrid visualization technique for exploring unstructured volumetric dataPatricia Shirley Herrera Cateriano 21 May 2003 (has links)
Este trabalho apresenta uma nova técnica de visualização que aproveita as vantagens do rendering volumétrico direto e do rendering de superfícies em um ambiente híbrido. O método faz uso de uma pré-visualização sobre o bordo do volume que viabiliza uma interação em tempo real com objetos volumétricos modelados por meio de malhas não estruturadas. Além disso, essa nova abordagem de visualização é paralelizável e pode se acelerada com placas gráficas comuns. / This work presents a new visualization technique that exploits the advantages of direct volume rendering and surface rendering in a hybrid environment. The method developed here makes use of a pre-visualization on the volume boundary to enable real time interaction with unstructured volumetric meshes. Furthermore, this new visualization approach can be implemented on existing parallel architectures and speed up by conventional graphical hardware.
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High-resolution splattingKulka, Peter January 2001 (has links)
Volume rendering is a research area within scientific visualisation, where images are computed from volumetric data sets for visual exploration. Such data sets are typically generated by Computer aided Tomography, Magnetic Resonance Imaging, Positron Emission Tomography or gained from simulations. The data sets are usually interpreted using optical models that assign optical properties to the volume and define the illumination and shading behaviour. Volume rendering techniques may be divided into three classes: object-order, image-order or hybrid methods. Image-order or ray casting methods shoot rays from the view plane into the volume and simulate the variation of light intensities along those rays. Object-order techniques traverse the volume data set and project each volume element onto the view plane. Hybrid volume rendering techniques combine these two approaches. A very popular object-order rendering method is called splatting. This technique traverses the volume data set and projects the optical properties of each volume element onto the view plane. This thesis consists of two parts. The first part introduces two new splatting methods, collectively called high-resolution splatting, which are based on standard splatting. Both high-resolution splatting methods correct errors of splatting by applying major modifications. We propose the first method, called fast high-resolution splatting, as an alternative to standard splatting. It may be used for quick previewing, since it is faster than standard splatting and the resulting images are significantly sharper. Our second method, called complete high-resolution splatting, improves the volume reconstruction, which results in images that are very close to those produced by ray casting methods. The second part of the thesis incorporates wavelet analysis into high-resolution splatting. Wavelet analysis is a mathematical theory that decomposes volumes into multi-resolution hierarchies, which may be used to find coherence within volumes. The combination of wavelets with the high-resolution splatting method has the two advantages. Firstly the extended splatting method, called high-resolution wavelet splatting, can be directly applied to wavelet transformed volume data sets without performing an inverse transform. Secondly when visualising wavelet compressed volumes, only a small fraction of the wavelet coefficients need to be projected. For all three versions of the new high-resolution splatting method, complexity analyses, comprehensive error and performance analyses as well as implementation details are discussed.
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High-resolution splattingKulka, Peter January 2001 (has links)
Volume rendering is a research area within scientific visualisation, where images are computed from volumetric data sets for visual exploration. Such data sets are typically generated by Computer aided Tomography, Magnetic Resonance Imaging, Positron Emission Tomography or gained from simulations. The data sets are usually interpreted using optical models that assign optical properties to the volume and define the illumination and shading behaviour. Volume rendering techniques may be divided into three classes: object-order, image-order or hybrid methods. Image-order or ray casting methods shoot rays from the view plane into the volume and simulate the variation of light intensities along those rays. Object-order techniques traverse the volume data set and project each volume element onto the view plane. Hybrid volume rendering techniques combine these two approaches. A very popular object-order rendering method is called splatting. This technique traverses the volume data set and projects the optical properties of each volume element onto the view plane. This thesis consists of two parts. The first part introduces two new splatting methods, collectively called high-resolution splatting, which are based on standard splatting. Both high-resolution splatting methods correct errors of splatting by applying major modifications. We propose the first method, called fast high-resolution splatting, as an alternative to standard splatting. It may be used for quick previewing, since it is faster than standard splatting and the resulting images are significantly sharper. Our second method, called complete high-resolution splatting, improves the volume reconstruction, which results in images that are very close to those produced by ray casting methods. The second part of the thesis incorporates wavelet analysis into high-resolution splatting. Wavelet analysis is a mathematical theory that decomposes volumes into multi-resolution hierarchies, which may be used to find coherence within volumes. The combination of wavelets with the high-resolution splatting method has the two advantages. Firstly the extended splatting method, called high-resolution wavelet splatting, can be directly applied to wavelet transformed volume data sets without performing an inverse transform. Secondly when visualising wavelet compressed volumes, only a small fraction of the wavelet coefficients need to be projected. For all three versions of the new high-resolution splatting method, complexity analyses, comprehensive error and performance analyses as well as implementation details are discussed.
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High-resolution splattingKulka, Peter January 2001 (has links)
Volume rendering is a research area within scientific visualisation, where images are computed from volumetric data sets for visual exploration. Such data sets are typically generated by Computer aided Tomography, Magnetic Resonance Imaging, Positron Emission Tomography or gained from simulations. The data sets are usually interpreted using optical models that assign optical properties to the volume and define the illumination and shading behaviour. Volume rendering techniques may be divided into three classes: object-order, image-order or hybrid methods. Image-order or ray casting methods shoot rays from the view plane into the volume and simulate the variation of light intensities along those rays. Object-order techniques traverse the volume data set and project each volume element onto the view plane. Hybrid volume rendering techniques combine these two approaches. A very popular object-order rendering method is called splatting. This technique traverses the volume data set and projects the optical properties of each volume element onto the view plane. This thesis consists of two parts. The first part introduces two new splatting methods, collectively called high-resolution splatting, which are based on standard splatting. Both high-resolution splatting methods correct errors of splatting by applying major modifications. We propose the first method, called fast high-resolution splatting, as an alternative to standard splatting. It may be used for quick previewing, since it is faster than standard splatting and the resulting images are significantly sharper. Our second method, called complete high-resolution splatting, improves the volume reconstruction, which results in images that are very close to those produced by ray casting methods. The second part of the thesis incorporates wavelet analysis into high-resolution splatting. Wavelet analysis is a mathematical theory that decomposes volumes into multi-resolution hierarchies, which may be used to find coherence within volumes. The combination of wavelets with the high-resolution splatting method has the two advantages. Firstly the extended splatting method, called high-resolution wavelet splatting, can be directly applied to wavelet transformed volume data sets without performing an inverse transform. Secondly when visualising wavelet compressed volumes, only a small fraction of the wavelet coefficients need to be projected. For all three versions of the new high-resolution splatting method, complexity analyses, comprehensive error and performance analyses as well as implementation details are discussed.
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High-resolution splattingKulka, Peter January 2001 (has links)
Volume rendering is a research area within scientific visualisation, where images are computed from volumetric data sets for visual exploration. Such data sets are typically generated by Computer aided Tomography, Magnetic Resonance Imaging, Positron Emission Tomography or gained from simulations. The data sets are usually interpreted using optical models that assign optical properties to the volume and define the illumination and shading behaviour. Volume rendering techniques may be divided into three classes: object-order, image-order or hybrid methods. Image-order or ray casting methods shoot rays from the view plane into the volume and simulate the variation of light intensities along those rays. Object-order techniques traverse the volume data set and project each volume element onto the view plane. Hybrid volume rendering techniques combine these two approaches. A very popular object-order rendering method is called splatting. This technique traverses the volume data set and projects the optical properties of each volume element onto the view plane. This thesis consists of two parts. The first part introduces two new splatting methods, collectively called high-resolution splatting, which are based on standard splatting. Both high-resolution splatting methods correct errors of splatting by applying major modifications. We propose the first method, called fast high-resolution splatting, as an alternative to standard splatting. It may be used for quick previewing, since it is faster than standard splatting and the resulting images are significantly sharper. Our second method, called complete high-resolution splatting, improves the volume reconstruction, which results in images that are very close to those produced by ray casting methods. The second part of the thesis incorporates wavelet analysis into high-resolution splatting. Wavelet analysis is a mathematical theory that decomposes volumes into multi-resolution hierarchies, which may be used to find coherence within volumes. The combination of wavelets with the high-resolution splatting method has the two advantages. Firstly the extended splatting method, called high-resolution wavelet splatting, can be directly applied to wavelet transformed volume data sets without performing an inverse transform. Secondly when visualising wavelet compressed volumes, only a small fraction of the wavelet coefficients need to be projected. For all three versions of the new high-resolution splatting method, complexity analyses, comprehensive error and performance analyses as well as implementation details are discussed.
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Real time rendering of deformable and semi-transparent objects by volume rendering /Guetat, Amel, January 2008 (has links)
Mannheim, Univ., Diss., 2008.
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Real Time Rendering of Deformable and Semi-Transparent Objects by Volume RenderingGuetat, Amel, January 2008 (has links)
Mannheim, Univ., Diss., 2008.
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[en] VISUALIZATION OF 3 DIMENSION IMPLICIT MANIFOLDS IN R4 / [pt] VISUALIZAÇÃO DE VARIEDADES IMPLÍCITAS DE DIMENSÃO 3 NO R4HENRY GIOVANNY GALLEGOS VELGARA 01 April 2015 (has links)
[pt] O principal objetivo deste trabalho é apresentar um novo método para
visualização de variedades implícitas de dimensão 3 mergulhadas no R4.
Esse método consiste primeiramente de um pré-processamento em CPU
utilizando uma árvore 16-Tree e a Aritmética Intervalar para encontrar
as regiões do domínio onde a variedade se encontra. Esses dados são
posteriormente processados em GPU para efetuar a visualização, e para
isso foi utilizada uma generalização da técnica Ray Casting. / [en] The main objective of this work is to present a new method for the
visualization of implicit 3-manifolds in R4. This method consists primarily
of a preprocessing in the CPU using a 16-tree and Interval Arithmetic to
detect regions of the domain where the variety is present. These data are
then processed in the GPU to perform the visualization, and for this a
generalization of Ray Casting technique was adopted.
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