Published in ACM Transactions on Graphics, Volume 29, Issue 4 (SIGGRAPH 2010)

Manifold Bootstrapping for SVBRDF Capture

rendering resutls

Renderings of high-resolution SVBRDFs reconstructed by our method from two-phase, low-dimensional captured data: (a) anisotropic brushed metal, (b) satin with complex needlework, (c) wrinkled glossy paper, (d) weathered copper.

Abstract

Manifold bootstrapping is a new method for data-driven modeling of real-world, spatially-varying reflectance, based on the idea that reflectance over a given material sample forms a low-dimensional manifold. It provides a high-resolution result in both the spatial and angular domains by decomposing reflectance measurement into two lower-dimensional phases. The first acquires representatives of high angular dimension but sampled sparsely over the surface, while the second acquires keys of low angular dimension but sampled densely over the surface.

We develop a hand-held, high-speed BRDF capturing device for phase one measurements. A condenser-based optical setup collects a dense hemisphere of rays emanating from a single point on the target sample as it is manually scanned over it, yielding 10 BRDF point measurements per second. Lighting directions from 6 LEDs are applied at each measurement; these are amplified to a full 4D BRDF using the general (NDF-tabulated) microfacet model. The second phase captures N=20-200 images of the entire sample from a fixed view and lit by a varying area source. We show that the resulting N-dimensional keys capture much of the distance information in the original BRDF space, so that they effectively discriminate among representatives, though they lack sufficient angular detail to reconstruct the SVBRDF by themselves. At each surface position, a local linear combination of a small number of neighboring representatives is computed to match each key, yielding a highresolution SVBRDF. A quick capture session (10-20 minutes) on simple devices yields results showing sharp and anisotropic specularity and rich spatial detail.

Keywords

SVBRDF, appearance capture

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BibTex

@article{Dong:2010:MBS,
 author = {Dong, Yue and Wang, Jiaping and Tong, Xin
 and Snyder, John and Lan, Yanxiang and Ben-Ezra, 
 Moshe and Guo, Baining},
 title = {Manifold bootstrapping for SVBRDF capture},
 journal = {ACM Trans. Graph.},
 issue_date = {July 2010},
 volume = {29},
 number = {4},
 month = jul,
 year = {2010},
 issn = {0730-0301},
 pages = {98:1--98:10},
 articleno = {98},
 numpages = {10},
 url = {http://doi.acm.org/10.1145/1778765.1778835},
 doi = {10.1145/1778765.1778835},
 acmid = {1778835},
 publisher = {ACM},
 address = {New York, NY, USA},
} 
	

Acknowledgements

The authors would like to thank Steve Lin for paper proofreading and video dubbing. The authors are grateful to the anonymous reviewers for their helpful suggestions and comments.