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Global Illumination using Photon Maps
, 1996
"... This paper presents a two pass global illumination method based on the concept of photon maps. It represents a significant improvement of a previously described approach both with respect to speed, accuracy and versatility. In the first pass two photon maps are created by emitting packets of energy ..."
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Cited by 217 (9 self)
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This paper presents a two pass global illumination method based on the concept of photon maps. It represents a significant improvement of a previously described approach both with respect to speed, accuracy and versatility. In the first pass two photon maps are created by emitting packets of energy (photons) from the light sources and storing these as they hit surfaces within the scene. We use one high resolution caustics photon map to render caustics that are visualized directly and one low resolution photon map that is used during the rendering step. The scene is rendered using a distribution ray tracing algorithm optimized by using the information in the photon maps. Shadow photons are used to render shadows more efficiently and the directional information in the photon map is used to generate optimized sampling directions and to limit the recursion in the distribution ray tracer by providing an estimate of the radiance on all surfaces with the exception of specular...
Physically Based Lighting Calculations for Computer Graphics
, 1991
"... Realistic image generation is presented in a theoretical formulation that builds from previous work on the rendering equation. Previous and new solution techniques for the global illumination are discussed in the context of this formulation. The basic ..."
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Cited by 67 (12 self)
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Realistic image generation is presented in a theoretical formulation that builds from previous work on the rendering equation. Previous and new solution techniques for the global illumination are discussed in the context of this formulation. The basic
A Ray Tracing Method for Illumination Calculation in DiffuseSpecular Scenes
 In Proceedings of Graphics Interface '90
, 1990
"... Several ways of improving the realism of the results of traditional ray tracing are presented. The essential physical quantities of spectral radiant power and spectral radiance and their use in lighting calculations are discussed. Global illumination terms are derived by employing illumination ray t ..."
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Cited by 66 (5 self)
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Several ways of improving the realism of the results of traditional ray tracing are presented. The essential physical quantities of spectral radiant power and spectral radiance and their use in lighting calculations are discussed. Global illumination terms are derived by employing illumination ray tracing for calculation of quickly changing indirect lighting components, and radiosity ray tracing for slowly changing indirect lighting components. Direct lighting is calculated during the viewing phase allowing the use of bump maps. Finally, a method is introduced that reduces the total number of shadow rays to no more than the total number of viewing rays for a given picture. Keywords: Bump Mapping, Illumination, Radiosity, Radiance, Ray Tracing, Realism, Stratified Sampling, Texture Mapping. 1 Introduction The quest for accurate lighting models in computer graphics has taken two very different approaches in the 1980s. The first approach is based on ray tracing (point sampling) techniqu...
Illumination from Curved Reflectors
, 1992
"... A technique is presented to compute the reflected illumination from curved mirror surfaces onto other surfaces. In accordance with Fermat's principle, this is equivalent to finding extremal paths from the light source to the visible surface via the mirrors. Once pathways of illumination are found, i ..."
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Cited by 55 (0 self)
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A technique is presented to compute the reflected illumination from curved mirror surfaces onto other surfaces. In accordance with Fermat's principle, this is equivalent to finding extremal paths from the light source to the visible surface via the mirrors. Once pathways of illumination are found, irradiance is computed from the Gaussian curvature of the geometrical wavefront. Techniques from optics, differential geometry and interval analysis are applied to solve these problems. CR Categories and Subject Descriptions: I.3.3 [ Computer Graphics ]: Picture/Image Generation; I.3.7 [ Computer Graphics ]: ThreeDimensional Graphics and Realism General Terms: Algorithms Additional Keywords and Phrases: Caustics, Differential Geometry, Geometrical Optics, Global Illumination, Interval Arithmetic, Ray Tracing, Wavefronts 1. Introduction Ray tracing provides a straightforward means for synthesizing realistic images on the computer. A scene is first modeled, usually by a collection of implici...
Global illumination using local linear density estimation
 Proceedings of SIGGRAPH 97
, 1997
"... This article presents the density estimation framework for generating viewindependent 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 45 (6 self)
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This article presents the density estimation framework for generating viewindependent 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
Rendering Caustics on NonLambertian Surfaces
 Computer Graphics Forum
, 1996
"... This paper presents a new technique for rendering caustics on nonLambertian surfaces. The method is based on an extension of the photon map which removes previous restrictions limiting the usage to Lambertian surfaces. We add information about the incoming direction to the photons and this allows u ..."
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Cited by 36 (3 self)
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This paper presents a new technique for rendering caustics on nonLambertian surfaces. The method is based on an extension of the photon map which removes previous restrictions limiting the usage to Lambertian surfaces. We add information about the incoming direction to the photons and this allows us to combine the photon map with arbitrary reflectance functions. Furthermore we introduce balancing of the photon map which not only reduces the memory requirements but also significantly reduces the rendering time. We have used the method to render caustics on surfaces with reflectance functions varying from Lambertian to glossy specular. Keywords: Caustics, Photon Map, Ray Tracing, Rendering. 1 Introduction Caustics provides some of the most spectacular patterns of light in nature. Caustics are formed when light reflected from or transmitted through a specular surfaces strikes a diffuse surface. An example is the caustic formed as light shines through a glass of wine onto a table. In ...
General Calculations Using Graphics Hardware, with application to interactive caustics
, 2000
"... Graphics hardware has been developed with image production in mind, but current hardware can be exploited for much more general computation. ..."
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Cited by 36 (0 self)
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Graphics hardware has been developed with image production in mind, but current hardware can be exploited for much more general computation.
Realism in real time
 In Fourth Eurographics Workshop on Rendering
, 1993
"... With the continuous improvement in ray tracing and radiosity algorithms, image synthesis quality has reached the level of photo realism. However, efforts to achieve realtime performances by implementing ray tracing and radiosity algorithms on parallel processors and dedicated hardware have not been ..."
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Cited by 19 (7 self)
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With the continuous improvement in ray tracing and radiosity algorithms, image synthesis quality has reached the level of photo realism. However, efforts to achieve realtime performances by implementing ray tracing and radiosity algorithms on parallel processors and dedicated hardware have not been very successful so far. Increasing the number of processors introduces a corresponding growth in interprocessor communication. Caching could be effective to reduce communication, if sufficient coherence would be available in subsequent data requests. Unfortunately, standard ray tracing and radiosity do not provide enough coherence. In this paper we review the different parallel approaches and we try to ascertain those issues that are crucial for further improvement. In particular, we will focus on load and data management strategies that effect the amount of data coherence in ray tracing, and on methods to improve ray and object coherence.
Global Illumination via DensityEstimation
 Proceedings of 6th Workshop on Rendering (Dublin
, 1995
"... This paper presents a new method for the production of viewindependent global illumination solutions of complex static environments. A key innovation of this new approach is its decomposition of the problem into a loosely coupled sequence of simple modules. This approach decouples the global energy ..."
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Cited by 19 (0 self)
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This paper presents a new method for the production of viewindependent global illumination solutions of complex static environments. A key innovation of this new approach is its decomposition of the problem into a loosely coupled sequence of simple modules. This approach decouples the global energy transport computation from the construction of the displayable shaded representation of the environment. This decoupling eliminates many constraints of previous global illuminationapproaches, yieldingaccurate solutions for environments with nondiffuse surfaces and high geometric complexity. Our algorithm produces a viewindependent display mesh that represents the irradiances on surfaces in a form that allows direct display of the shaded surface. Most traditional radiosity algorithms also use a computational mesh to represent intermediate results in the light transport calculation (e.g., the piecewiseconstant global solution of Smits et al. [17]). Typically, a single representation is used for both the computational and display meshes (e.g. the static mesh used by Neumann et al. [11] and the adaptive mesh used by Teller et al. [18]). Very few display mesh solutions have been produced for environments with more than a few thousand initial surfaces. The only implementation we are aware of that has produced a display mesh for more than 10,000 initial surfaces is the system by Teller et al. [18], which was run on a model with approximately 40,000 initial surfaces. Teller et al. argue that the reason for these surprisingly small limits is the high memory overhead of the data structures associated with the computational mesh. To solve this problem, we draw on an observation by Lischinski et al. [10], that the computational mesh and the display mesh have different purposes and ch...