On Optimal, Minimal BRDF Sampling for Reflectance Acquisition

Jannik Boll Nielsen, Henrik Wann Jensen, Ravi Ramamoorthi

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The bidirectional reflectance distribution function (BRDF) is critical for rendering, and accurate material representation requires data-driven reflectance models. However, isotropic BRDFs are 3D functions, and measuring the reflectance of a flat sample can require a million incident and outgoing direction pairs, making the use of measured BRDFs impractical. In this paper, we address the problem of reconstructing a measured BRDF from a limited number of samples. We present a novel mapping of the BRDF space, allowing for extraction of descriptive principal components from measured databases, such as the MERL BRDF database. We optimize for the best sampling directions, and explicitly provide the optimal set of incident and outgoing directions in the Rusinkiewicz parameterization for n = {1, 2, 5, 10, 20} samples. Based on the principal components, we describe a method for accurately reconstructing BRDF data from these limited sets of samples. We validate our results on the MERL BRDF database, including favorable comparisons to previous sets of industry-standard sampling directions, as well as with BRDF measurements of new flat material samples acquired with a gantry system. As an extension, we also demonstrate how this method can be used to find optimal sampling directions when imaging a sphere of a homogeneous material; in this case, only two images are often adequate for high accuracy.
Original languageEnglish
Article number186
JournalA C M Transactions on Graphics
Volume34
Issue number6
Number of pages11
ISSN0730-0301
DOIs
Publication statusPublished - 2015
Event8th ACM SIGGRAPH Conference and Exhibition on Computer Graphics and Interactive Techniques in Asia (2015) - Kobe Convention Center, Kobe, Japan
Duration: 2 Nov 20155 Nov 2015
Conference number: 8
http://sa2015.siggraph.org/en/

Conference

Conference8th ACM SIGGRAPH Conference and Exhibition on Computer Graphics and Interactive Techniques in Asia (2015)
Number8
LocationKobe Convention Center
CountryJapan
CityKobe
Period02/11/201505/11/2015
Internet address

Bibliographical note

Published in: ACM Transactions on Graphics (TOG) - Proceedings of ACM SIGGRAPH Asia 2015

Keywords

  • Reflectance
  • BRDF
  • MERL
  • Reconstruction

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