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Efficient product sampling using hierarchical thresholding

Rousselle, Fabrice ; Clarberg, Petrik ; Leblanc, Luc ; Ostromoukhov, Victor ; Poulin, Pierre

In: The Visual Computer, 2008, vol. 24, no. 7-9, p. 465-474

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    Titre
    • Efficient product sampling using hierarchical thresholding
    Auteur
    • Rousselle, Fabrice. University of Montreal, Station Centre-ville, PO Box 6128, H3C 3J7, Montreal, QC, Canada
    • Clarberg, Petrik. Lund University, Box 117, 221 00, Lund, Sweden
    • Leblanc, Luc. University of Montreal, Station Centre-ville, PO Box 6128, H3C 3J7, Montreal, QC, Canada
    • Ostromoukhov, Victor. University of Montreal, Station Centre-ville, PO Box 6128, H3C 3J7, Montreal, QC, Canada
    • Poulin, Pierre. University of Montreal, Station Centre-ville, PO Box 6128, H3C 3J7, Montreal, QC, Canada
    Type de document
    • Postprint
    Identifiant OAI-PMH
    • oai:doc.rero.ch:315024
    Summary
    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