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BiDirectional Path Tracing
 PROCEEDINGS OF THIRD INTERNATIONAL CONFERENCE ON COMPUTATIONAL GRAPHICS AND VISUALIZATION TECHNIQUES (COMPUGRAPHICS ’93
, 1993
"... In this paper we present a new Monte Carlo rendering algorithm that seamlessly integrates the ideas of ..."
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Cited by 125 (10 self)
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In this paper we present a new Monte Carlo rendering algorithm that seamlessly integrates the ideas of
Monte Carlo Techniques for Direct Lighting Calculations
 ACM Transactions on Graphics
, 1996
"... In a distribution ray tracer, the crucial part of the direct lighting calculation is the sampling strategy for shadow ray testing. Monte Carlo integration with importance sampling is used to carry out this calculation. Importance sampling involves the design of integrandspecific probability density ..."
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Cited by 86 (8 self)
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In a distribution ray tracer, the crucial part of the direct lighting calculation is the sampling strategy for shadow ray testing. Monte Carlo integration with importance sampling is used to carry out this calculation. Importance sampling involves the design of integrandspecific probability density functions which are used to generate sample points for the numerical quadrature. Probability density functions are presented that aid in the direct lighting calculation from luminaires of various simple shapes. A method for defining a probability density function over a set of luminaires is presented that allows the direct lighting calculation to be carried out with one sample, regardless of the number of luminaires. CR Categories and Subject Descriptors: G.1.4 [Mathematical Computing]: Quadrature and Numerical Differentiation; I.3.0 [Computer Graphics]: General; I.3.7 [Computer Graphics]: ThreeDimensional Graphics and Realism. Additional Key Words and Phrases: direct lighting, importanc...
Importance Driven Path Tracing using the Photon Map
 in Eurographics Rendering Workshop
, 1995
"... : This paper presents a new importance sampling strategy for Monte Carlo ray tracing in which a rough estimate of the irradiance based on the photon map is combined with the local reflection model to construct more efficient probability density functions that can be used in an importance samplin ..."
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Cited by 54 (4 self)
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: This paper presents a new importance sampling strategy for Monte Carlo ray tracing in which a rough estimate of the irradiance based on the photon map is combined with the local reflection model to construct more efficient probability density functions that can be used in an importance sampling scheme. The algorithm gives unbiased results, handles arbitrary reflection models and it is particularly efficient in scenes with highly nonuniform indirect illumination. Initial results and comparisons with traditional importance sampling strategies indicate a reduction in the noise level of more than 70% Key Words: Global Illumination, Path Tracing, Importance Sampling, Photon Map 1 Introduction Photorealistic rendering requires accurate simulation of global illumination and much work has been done in this area in the last 10 years. The problem was actually solved in 1986 by Kajiya [6] using a method called path tracing. This method is basically a brute force Monte Carlo simulat...
A 5D Tree to Reduce the Variance of Monte Carlo Ray Tracing
"... In this paper we present a 5D tree structure to cache illumination information gained during Monte Carlo ray tracing. The structure is elegant and simple to use. It is adaptive and makes abstraction of the complexity of the input scene automatically. We then show how the information in this stru ..."
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Cited by 45 (2 self)
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In this paper we present a 5D tree structure to cache illumination information gained during Monte Carlo ray tracing. The structure is elegant and simple to use. It is adaptive and makes abstraction of the complexity of the input scene automatically. We then show how the information in this structure can be used to reduce the variance of the Monte Carlo process. Unlike earlier approaches the techniques presented here do not introduce a bias in the results.
Distribution ray tracing: Theory and practice
 In Proceedings of the Third Eurographics Workshop on Rendering
, 1992
"... Distribution ray tracing uses Monte Carlo integration to solve the rendering equation. This technique was introduced by Cook et. al, and was notable because of its simplicity and its ability to simulate areal luminaires, camera lens e ects, motion blur, and imperfect specular re ection[5]. Distribut ..."
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Cited by 24 (3 self)
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Distribution ray tracing uses Monte Carlo integration to solve the rendering equation. This technique was introduced by Cook et. al, and was notable because of its simplicity and its ability to simulate areal luminaires, camera lens e ects, motion blur, and imperfect specular re ection[5]. Distribution
The Ambient Term as a Variance Reducing Technique for Monte Carlo Ray Tracing
 IN PROCEEDINGS OF THE FIFTH EUROGRAPHICS WORKSHOP ON RENDERING
, 1994
"... Ray tracing algorithms often approximate indirect diffuse lighting by means of an ambient lighting term. In this paper we show how a similar term can be used as a variance reducing technique for stochastic ray tracing. In a theoretical derivation we prove that the technique is mathematically correct ..."
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Cited by 11 (3 self)
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Ray tracing algorithms often approximate indirect diffuse lighting by means of an ambient lighting term. In this paper we show how a similar term can be used as a variance reducing technique for stochastic ray tracing. In a theoretical derivation we prove that the technique is mathematically correct. Test results demonstrate its usefulness and effectiveness in practice.
Hierarchical Radiosity with Multiresolution Meshes
, 2000
"... The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the National Science Foundation or the United States government. Keywords: global illumination, hierarchical radiosity, f ..."
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Cited by 5 (0 self)
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The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the National Science Foundation or the United States government. Keywords: global illumination, hierarchical radiosity, face cluster hierarchies, multiresolution The hierarchical radiosity algorithm solves for the global transfer of diffuse illumination in a scene. While its potential algorithmic complexity is superior to both previous radiosity methods and distributed ray tracing, for scenes containing detailed polygonal models, or highly tessellated curved surfaces, its time performance and memory consumption are less than ideal. My thesis is that by using hierarchies similar to those of multiresolution models, the performance of the hierarchical radiosity algorithm can be made sublinear in the number of input polygons, and thus make radiosity on scenes containing detailed models tractable. The underlying goal of my thesis work has been to make highspeed radiosity solutions possible with such scenes. To achieve this goal, a new face clustering technique for automatically partitioning polygonal models has been developed. The face clusters produced
Reducing the Number of Shadow Rays in Bidirectional Path Tracing
 IN PROCEEDINGS OF WSCG 95, (PILSEN, CZECH REPUBLIC
, 1995
"... Bidirectional path tracing is a fairly new Monte Carlo algorithm for physically based rendering. Introduced as a generalisation of path tracing, the algorithm traces paths for each pixel, not only from the eye point but also from the light sources. It subsequently links the intersection points on th ..."
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Cited by 4 (1 self)
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Bidirectional path tracing is a fairly new Monte Carlo algorithm for physically based rendering. Introduced as a generalisation of path tracing, the algorithm traces paths for each pixel, not only from the eye point but also from the light sources. It subsequently links the intersection points on the respective paths by means of shadow rays. Each shadow ray determines if a lighting contribution has to be added to the estimate of the radiance of the pixel. In this paper we present a technique which reduces the number of shadow rays that are traced effectively. The resulting slight increase in the variance of the stochastic process can be undone by taking more samples. Practical tests show that the approach yields a reduction of the variance for the same amount of work.
Hybrid Radiosity/Monte Carlo Methods
 SIGGRAPH'94 Course Notes
, 1994
"... this document said that absorb and reemit was asymptotically equivalent to the photon tracking model. 8 Hybrid Radiosity/Monte Carlo Methods Radiosity Solution Gather from solution for small area zones Final (corrected) solution Figure 4: Zones with small areas have their radiance recalculated more ..."
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Cited by 3 (0 self)
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this document said that absorb and reemit was asymptotically equivalent to the photon tracking model. 8 Hybrid Radiosity/Monte Carlo Methods Radiosity Solution Gather from solution for small area zones Final (corrected) solution Figure 4: Zones with small areas have their radiance recalculated more accurately in a postprocess. iteration (each ray carries approximately the same amount of power). The other is that, unlike in [7], the zone with the most power is not searched for, or the time complexity of the method will increase from O(N log N) to O(N
The Direct Lighting Computation in Global Illumination Methods
, 1993
"... This document addresses several important issues regarding image synthesis for complex scenes. It pays particular attention to the "direct lighting computation", where the brightness of an object that is due to light that comes directly from the source (without reflection) is calculated as in Figure ..."
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Cited by 2 (1 self)
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This document addresses several important issues regarding image synthesis for complex scenes. It pays particular attention to the "direct lighting computation", where the brightness of an object that is due to light that comes directly from the source (without reflection) is calculated as in Figure 1.1. Generating an image involves three major steps. The initial step, scene specification, defines geometry, material, lighting, texture, movement, camera, etc. This step sets up a complete scene in a virtual space. The second step, rendering, produces numerical values for physical quantities that a viewer can sense. This step usually is accomplished by simulating light transport within the scene. The final step, scaling, transforms the rendered image so 1 pixel luminaire film emitted indirect direct Figure 1.1: Direct lighting, indirect lighting and emitted lighting. that it can be displayed on a device such as a cathode ray tube (CRT). This step creates an image on the CRT which gives an impression similar to the rendered image displayed on an ideal CRT with an infinite dynamic range