Template-Based Sampling of Anisotropic BRDFs

Jiří Filip1

Radomír Vávra1

1Institute of Information Theory and Automation of the ASCR

Pacific Graphics 2014 (a special issue of journal Computer Graphics Forum)






Abstract

BRDFs are commonly used to represent given materials' appearance in computer graphics and related fields. Although, in the recent past, BRDFs have been extensively measured, compressed, and fitted by a variety of analytical models, most research has been primarily focused on simplified isotropic BRDFs. In this paper, we present a unique database of 150 BRDFs representing a wide range of materials; the majority exhibiting anisotropic behavior. Since time-consuming BRDF measurement represents a major obstacle in the digital material appearance reproduction pipeline, we tested several approaches estimating a very limited set of samples capable of high quality appearance reconstruction. Initially, we aligned all measured BRDFs according to the location of the anisotropic highlights. Then we propose an adaptive sampling method based on analysis of the measured BRDFs. For each BRDF, a unique sampling pattern was computed, given a predefined count of samples. Further, template-based methods are introduced based on reusing of the precomputed sampling patterns. This approach enables a more efficient measurement of unknown BRDFs while preserving the visual fidelity for the majority of tested materials. Our method exhibits better performance and stability than competing sparse sampling approaches; especially for higher numbers of samples.

Keywords

BRDF, measurement, material appearance, database, sampling

Preprint Version of the Paper

  [preprint]

@article{filip08template,
   author = {Filip, J. and Vavra, R.},
   title = {Template-Based Sampling of Anisotropic BRDFs},
   journal = {Computer Graphics Forum},
   publisher = {John Wiley & Sons Ltd.},
   volume = {33},
   number = {7},
   year = {2014},
   Doi = {10.1111/cgf.12477},
   conference = {Pacific Graphics 2014},
   pages = {91--99},
   url = {http://staff.utia.cas.cz/filip/projects/14PG} }  

Supplemental Material

  appendix [pdf]

BRDF Database Download

  BRDF database download

  • formats: binary, MATLAB, OpenEXR
  • data loading and interpolation code: C++, MATLAB


Acknowledgements
  • This research has been supported by the Czech Science Foundation grants 103/11/0335, 14-02652S, and 14-10911S. We would like to thank all revievers for time they spent by considering and improving our paper.


    Last update 11/08/2014