Results 11 - 20
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355
Efficient Image-Based Methods for Rendering Soft Shadows
, 2000
"... We present two efficient image-based approaches for computation and display of high-quality soft shadows from area light sources. Our methods are related to shadow maps and provide the associated benefits. The computation time and memory requirements for adding soft shadows to an image depend on ima ..."
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Cited by 87 (6 self)
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We present two efficient image-based approaches for computation and display of high-quality soft shadows from area light sources. Our methods are related to shadow maps and provide the associated benefits. The computation time and memory requirements for adding soft shadows to an image depend on image size and the number of lights, not geometric scene complexity. We also show that because area light sources are localized in space, soft shadow computations are particularly well suited to image-based rendering techniques. Our first approach---layered attenuation maps--- achieves interactive rendering rates, but limits sampling flexibility, while our second method---coherence-based raytracing of depth images---is not interactive, but removes the limitations on sampling and yields high quality images at a fraction of the cost of conventional raytracers. Combining the two algorithms allows for rapid previewing followed by efficient high-quality rendering.
Realtime Ray Tracing and its use for Interactive Global Illumination
- In Eurographics State of the Art Reports
, 2003
"... Research on realtime ray tracing has recently made tremendous advances. Algorithmic improvements together with optimized software implementations already allow for interactive frame rates even on a single desktop PC. Furthermore, recent research has demonstrated several options for realizing realtim ..."
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Cited by 68 (11 self)
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Research on realtime ray tracing has recently made tremendous advances. Algorithmic improvements together with optimized software implementations already allow for interactive frame rates even on a single desktop PC. Furthermore, recent research has demonstrated several options for realizing realtime ray tracing on different hardware platforms, e.g. via streaming computation on modern graphics processors (GPUs) or via the use of dedicated ray tracing chips. Together, these developments indicate that realtime ray tracing might indeed become a reality and widely available in the near future. As most of todays global illumination algorithms heavily rely on ray tracing, this availability of fast ray tracing technology creates the potential to finally compute even global illumination – the physically correct simulation of light transport – at interactive rates. In this STAR, we will first cover the different research activities for realizing realtime ray tracing on different hardware architectures – ranging from shared memory systems, over PC clusters, programmable GPUs, to custom ray tracing hardware. Based on this overview, we discuss some of the advanced issues, such as support for dynamic scenes and designs for a suitable ray tracing API. The third part of this STAR then builds on top of these techniques by presenting algorithms for interactive global illumination in complex and dynamic scenes that may contain large numbers of light sources. We believe that the improved quality and the increased realism that global illumination adds to interactive environments makes it a potential “killer application ” for future 3D graphics. 1.
Radiosity on graphics hardware
- In Proceedings of the 2004 Conference on Graphics Interface
, 2004
"... Radiosity is a widely used technique for global illumination. Typically the computation is performed offline and the result is viewed interactively. We present a technique for computing radiosity, including an adaptive subdivision of the model, using graphics hardware. Since our goal is to run at in ..."
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Cited by 62 (6 self)
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Radiosity is a widely used technique for global illumination. Typically the computation is performed offline and the result is viewed interactively. We present a technique for computing radiosity, including an adaptive subdivision of the model, using graphics hardware. Since our goal is to run at interactive rates, we exploit the computational power and programmability of modern graphics hardware. Using our system on current hardware, we have been able to compute and display a radiosity solution for a 10,000 element scene in less than one second. Key words: Graphics Hardware, Global Illumination. 1
A Beam Tracing Method for Interactive Architectural Acoustics
, 2003
"... A difficult challenge in geometrical acoustic modeling is computing propagation paths from sound sources to receivers fast enough for interactive applications. We paper describe a beam tracing method that enables interactive updates of propagation paths from a stationary source to a moving receiv ..."
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Cited by 60 (4 self)
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A difficult challenge in geometrical acoustic modeling is computing propagation paths from sound sources to receivers fast enough for interactive applications. We paper describe a beam tracing method that enables interactive updates of propagation paths from a stationary source to a moving receiver. During a precomputation phase, we trace convex polyhedral beams from the location of each sound source, constructing a "beam tree" representing the regions of space reachable by potential sequences of transmissions, diffractions, and specular reflections at surfaces of a 3D polygonal model. Then, during an interactive phase, we use the precomputed beam trees to generate propagation paths from the source(s) to any receiver location at interactive rates. The key features of our beam tracing method are: 1) it scales to support large architectural environments, 2) it models propagation due to wedge diffraction, 3) it finds all propagation paths up to a given termination criterion without exhaustive search or risk of under-sampling, and 4) it updates propagation paths at interactive rates. We demonstrate use of this method for interactive acoustic design of architectural environments.
Using History to Improve Mobile Application Adaptation
- IN PROCEEDINGS OF THE 3RD IEEE WORKSHOP ON MOBILE COMPUTING SYSTEMS AND APPLICATIONS
, 2000
"... Prior work has shown the value of changing application fidelity to adapt to varying resource levels in a mobile environment. Choosing the right fidelity requires us to predict its effect on resource consumption. In this paper, we describe a history-based mechanism for such predictions. Our approach ..."
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Cited by 60 (11 self)
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Prior work has shown the value of changing application fidelity to adapt to varying resource levels in a mobile environment. Choosing the right fidelity requires us to predict its effect on resource consumption. In this paper, we describe a history-based mechanism for such predictions. Our approach generates predictors that are specialized to the hardware on which the application runs, and to the specific input data on which it operates. We are able to predict the CPU consumption of a complex graphics application to within 20% and the energy consumption of fetching and rendering web images to within 15%.
Global illumination using local linear density estimation
- Proceedings of SIGGRAPH 97
, 1997
"... This article presents the density estimation framework for generating view-independent global illumination solutions. It works by probabilistically simulating the light flow in an environment with light particles that trace random walks originating at luminaires and then using statistical density es ..."
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Cited by 54 (6 self)
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This article presents the density estimation framework for generating view-independent global illumination solutions. It works by probabilistically simulating the light flow in an environment with light particles that trace random walks originating at luminaires and then using statistical density estimation techniques to reconstruct the lighting on each surface. By splitting the computation into separate transport and reconstruction stages, we gain many advantages including reduced memory usage, the ability to simulate nondiffuse transport, and natural parallelism. Solutions to several theoretical and practical difficulties in implementing this framework are also described. Light sources that vary spectrally and directionally are integrated into a spectral particle tracer using nonuniform rejection. A new local linear density estimation technique eliminates boundary bias and extends to arbitrary polygons. A mesh decimation algorithm with perceptual calibration is introduced to simplify the Gouraudshaded
Global Illumination of Glossy Environments using Wavelets and Importance
- ACM Transactions on Graphics
, 1996
"... We show how importance-driven refinement and a wavelet basis can be combined to provide an efficient solution to the global illumination problem with glossy and diffuse reflections. Importance is used to focus the computation on the interactions having the greatest impact on the visible solution. Wa ..."
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Cited by 54 (6 self)
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We show how importance-driven refinement and a wavelet basis can be combined to provide an efficient solution to the global illumination problem with glossy and diffuse reflections. Importance is used to focus the computation on the interactions having the greatest impact on the visible solution. Wavelets are used to provide an efficient representation of radiance, importance, and the transport operator. We discuss a number of choices that must be made when constructing a finite element algorithm for glossy global illumination. Our algorithm is based on the standard wavelet decomposition of the transport operator and makes use of a four-dimensional wavelet representation for spatially- and angularly-varying radiance distributions. We use a final gathering step to improve the visual quality of the solution. Features of our implementation include support for curved surfaces as well as texture-mapped anisotropic emission and reflection functions. 1 Introduction Radiosity algorithms assum...
Predictive Resource Management for Wearable Computing
- Proceedings of the 1st International Conference on Mobile Systems, Applications, and Services (MobiSys
, 2003
"... Achieving crisp interactive response in resource-intensive applications such as augmented reality, language translation, and speech recognition is a major challenge on resource-poor wearable hardware. In this paper we describe a solution based on multi-fidelity computation supported by predictive re ..."
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Cited by 53 (7 self)
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Achieving crisp interactive response in resource-intensive applications such as augmented reality, language translation, and speech recognition is a major challenge on resource-poor wearable hardware. In this paper we describe a solution based on multi-fidelity computation supported by predictive resource management. We show that such an approach can substantially reduce both the mean and the variance of response time. On a benchmark representative of augmented reality, we demonstrate a 60 % reduction in mean latency and a 30 % reduction in the coefficient of variation. We also show that a history-based approach to demand prediction is the key to this performance improvement. 1
A Signal-Processing Framework for Reflection
- ACM TRANSACTIONS ON GRAPHICS
, 2004
"... ... In this paper, we formalize these notions, showing that the reflected light field can be thought of in a precise quantitative way as obtained by convolving the lighting and BRDF, i.e. by filtering the incident illumination using the BRDF. Mathematically, we are able to express the frequency-spac ..."
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Cited by 47 (4 self)
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... In this paper, we formalize these notions, showing that the reflected light field can be thought of in a precise quantitative way as obtained by convolving the lighting and BRDF, i.e. by filtering the incident illumination using the BRDF. Mathematically, we are able to express the frequency-space coe#cients of the reflected light field as a product of the spherical harmonic coe#- cients of the illumination and the BRDF. These results are of practical importance in determining the well-posedness and conditioning of problems in inverse rendering---estimation of BRDF and lighting parameters from real photographs. Furthermore, we are able to derive analytic formulae for the spherical harmonic coe#cients of many common BRDF and lighting models. From this formal analysis, we are able to determine precise conditions under which estimation of BRDFs and lighting distributions are well posed and well-conditioned. Our mathematical analysis also has implications for forward rendering---especially the e#cient rendering of objects under complex lighting conditions specified by environment maps. The results, especially the analytic formulae derived for Lambertian surfaces, are also relevant in computer vision in the areas of recognition, photometric stereo and structure from motion.
Feature-based Control of Visibility Error: A Multi-resolution Clustering Algorithm for Global Illumination
- Computer Graphics (SIGGRAPH '95 Proceedings
, 1995
"... In this paper we introduce a new approach to controlling error in hierarchical clustering algorithms for radiosity. The new method ensures that just enough work is done to meet the user's quality criteria. To this end the importance of traditionally ignored visibility error is identified, and t ..."
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Cited by 45 (8 self)
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In this paper we introduce a new approach to controlling error in hierarchical clustering algorithms for radiosity. The new method ensures that just enough work is done to meet the user's quality criteria. To this end the importance of traditionally ignored visibility error is identified, and the concept of features is introduced as a way to evaluate the quality of an image. A methodology to evaluate error based on features is presented, which leads to the development of a multi-resolution visibility algorithm. An algorithm to construct a suitable hierarchy for clustering and multi-resolution visibility is also proposed. Results of the implementation show that the multiresolution approach has the potential of providing significant computational savings depending on the choice of feature size the user is interested in. They also illustrate the relevance of the featurebased error analysis. The proposed algorithms are well suited to the development of interactive lighting simulation syste...
