Proceedings: GI 2015

Visibility sweeps for joint-hierarchical importance sampling of direct lighting for stochastic volume rendering

Thomas Kroes , Martin Eisemann , Elmar Eisemann

Proceedings of Graphics Interface 2015: Halifax, Nova Scotia, Canada, 3 - 5 June 2015, 97-104

DOI 10.20380/GI2015.13

  • Bibtex

    @inproceedings{Kroes:2015:10.20380/GI2015.13,
    author = {Kroes, Thomas and Eisemann, Martin and Eisemann, Elmar},
    title = {Visibility sweeps for joint-hierarchical importance sampling of direct lighting for stochastic volume rendering},
    booktitle = {Proceedings of Graphics Interface 2015},
    series = {GI 2015},
    year = {2015},
    issn = {0713-5424},
    isbn = {978-1-4822-6003-8},
    location = {Halifax, Nova Scotia, Canada},
    pages = {97--104},
    numpages = {8},
    doi = {10.20380/GI2015.13},
    publisher = {Canadian Human-Computer Communications Society},
    address = {Toronto, Ontario, Canada},
    }

Abstract

Physically-based light transport in heterogeneous volumetric data is computationally expensive because the rendering integral (particularly visibility) has to be stochastically solved. We present a visibility estimation method in concert with an importance-sampling technique for efficient and unbiased stochastic volume rendering. Our solution relies on a joint strategy, which involves the environmental illumination and visibility inside of the volume. A major contribution of our method is a fast sweeping-plane algorithm to progressively estimate partial occlusions at discrete locations, where we store the result using an octahedral representation. We then rely on a quadtree-based hierarchy to perform a joint importance sampling. Our technique is unbiased, requires little precomputation, is highly parallelizable, and is applicable to a various volume data sets, dynamic transfer functions, and changing environmental lighting.