Efficient Product Sampling using Hierarchical Thresholding
Proc. Computer Graphics International 2008, June 2008
The Visual Computer, 24 (7), pp. 465-474, July 2008.
We present an efficient method for importance
sampling the product of multiple functions. Our algorithm
computes a quick approximation of the product
on-the-fly, based on hierarchical representations of the
local maxima and averages of the individual terms. Samples
are generated by exploiting the hierarchical properties
of many low-discrepancy sequences, and thresholded
against the estimated product. We evaluate direct illumination
by sampling the triple product of environment
map lighting, surface reflectance, and a visibility function
estimated per pixel. Our results show considerable noise
reduction compared to existing state-of-the-art methods
using only the product of lighting and BRDF.
Importance sampling, rejection sampling, multiple functions,
ray tracing, visibility.
title = "Efficient Product Sampling using Hierarchical Thresholding",
author = "Fabrice Rousselle and Petrik Clarberg and Luc Leblanc and Victor Ostromoukhov and Pierre Poulin",
booktitle = "The Visual Computer",
year = 2008,
month = jul,
pages = "465--474",
volume = 24,
number = 7
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