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Practical product importance sampling for direct illumination

Clarberg, Petrik LU and Akenine-Möller, Tomas LU (2008) Eurographics 2008 In Computer Graphics Forum 27(2). p.681-690
Abstract
We present a practical algorithm for sampling the product of environment map lighting and surface reflectance.

Our method builds on wavelet-based importance sampling, but has a number of important advantages over previous methods. Most importantly, we avoid using precomputed reflectance functions by sampling the BRDF on-the-fly. Hence, all types of materials can be handled, including anisotropic and spatially varying BRDFs, as well

as procedural shaders. This also opens up for using very high resolution, uncompressed, environment maps. Our

results show that this gives a significant reduction of variance compared to using lower resolution approximations. In addition, we study the wavelet product, and present a... (More)
We present a practical algorithm for sampling the product of environment map lighting and surface reflectance.

Our method builds on wavelet-based importance sampling, but has a number of important advantages over previous methods. Most importantly, we avoid using precomputed reflectance functions by sampling the BRDF on-the-fly. Hence, all types of materials can be handled, including anisotropic and spatially varying BRDFs, as well

as procedural shaders. This also opens up for using very high resolution, uncompressed, environment maps. Our

results show that this gives a significant reduction of variance compared to using lower resolution approximations. In addition, we study the wavelet product, and present a faster algorithm geared for sampling purposes.

For our application, the computations are reduced to a simple quadtree-based multiplication. We build the BRDF

approximation and evaluate the product in a single tree traversal, which makes the algorithm both faster and more

flexible than previous methods. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Ray tracing, Photo-realistic rendering, Computer graphics, Importance sampling
in
Computer Graphics Forum
editor
Scopigno, Roberto; Gröller, Eduard; and
volume
27
issue
2
pages
10 pages
publisher
Wiley-Blackwell
conference name
Eurographics 2008
external identifiers
  • wos:000255285500058
  • scopus:42949083149
ISSN
0167-7055
1467-8659
DOI
10.1111/j.1467-8659.2008.01166.x
language
English
LU publication?
yes
id
8dec139f-a132-4e62-ac82-8acaf9cd5d7b (old id 1152604)
date added to LUP
2008-05-27 10:40:38
date last changed
2017-11-05 03:40:57
@inproceedings{8dec139f-a132-4e62-ac82-8acaf9cd5d7b,
  abstract     = {We present a practical algorithm for sampling the product of environment map lighting and surface reflectance. <br/><br>
Our method builds on wavelet-based importance sampling, but has a number of important advantages over previous methods. Most importantly, we avoid using precomputed reflectance functions by sampling the BRDF on-the-fly. Hence, all types of materials can be handled, including anisotropic and spatially varying BRDFs, as well <br/><br>
as procedural shaders. This also opens up for using very high resolution, uncompressed, environment maps. Our <br/><br>
results show that this gives a significant reduction of variance compared to using lower resolution approximations. In addition, we study the wavelet product, and present a faster algorithm geared for sampling purposes. <br/><br>
For our application, the computations are reduced to a simple quadtree-based multiplication. We build the BRDF <br/><br>
approximation and evaluate the product in a single tree traversal, which makes the algorithm both faster and more <br/><br>
flexible than previous methods.},
  author       = {Clarberg, Petrik and Akenine-Möller, Tomas},
  booktitle    = {Computer Graphics Forum},
  editor       = {Scopigno, Roberto and Gröller, Eduard},
  issn         = {0167-7055},
  keyword      = {Ray tracing,Photo-realistic rendering,Computer graphics,Importance sampling},
  language     = {eng},
  number       = {2},
  pages        = {681--690},
  publisher    = {Wiley-Blackwell},
  title        = {Practical product importance sampling for direct illumination},
  url          = {http://dx.doi.org/10.1111/j.1467-8659.2008.01166.x},
  volume       = {27},
  year         = {2008},
}