An Improved Multiple Importance Sampling Heuristic for Density Estimates in Light Transport Simulations

Jendersie, Johannes; Grosch, Thorsten

An Improved Multiple Importance Sampling Heuristic for Density Estimates in Light Transport Simulations

Files

065-072.pdf (7.55 MB)

egsr_vcmvariance_sup1_v2.pdf (81.04 MB)

Date

2018

Authors

Jendersie, Johannes
Grosch, Thorsten

Publisher

The Eurographics Association

Abstract

Vertex connection and merging (VCM) is one of the most robust light transport simulation algorithms developed so far. It combines bidirectional path tracing with photon mapping using multiple importance sampling (MIS). However, there are scene setups where the current weight computation is not optimal. If different merge events on a single path have roughly the same likelihood to be found, but different photon densities, this leads to high variance samples. We show how to improve the heuristic for density estimation events to overcome this issue by including the photon density into the MIS computation. This leads to a faster convergence in VCM and related techniques. The proposed change is easy to implement and is orthogonal to other improvements of the algorithm.

        @inproceedings{10.2312:sre.20181173
,
booktitle = {Eurographics Symposium on Rendering - Experimental Ideas & Implementations
},
editor = {Jakob, Wenzel and Hachisuka, Toshiya
},
title = {{An Improved Multiple Importance Sampling Heuristic for Density Estimates in Light Transport Simulations
}},
author = {Jendersie, Johannes and 
Grosch, Thorsten
},
year = {2018
},
publisher = {The Eurographics Association
},
ISSN = {1727-3463
},
ISBN = {978-3-03868-068-0
},
DOI = {10.2312/sre.20181173
}
}