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Temporal Normal Distribution Functions

Lorenzo Tessari, Johannes Hanika, Carsten Dachsbacher, Marc Droske
2020 Eurographics Symposium on Rendering  
We use temporal derivatives to approximate the distribution of the surface normal seen under a pixel over the course of the shutter interval.  ...  Both approaches, however, are only valid in the far-field regime where the geometric detail is much smaller than a pixel, while the challenge of resolving highlights remains in the meso-scale.  ...  We thank Andrea Weidlich for helpful discussions on microfacet models, and Sébastien Speierer as well as the Manuka team for their help.  ... 
doi:10.2312/sr.20201132 dblp:conf/rt/TessariHDD20 fatcat:75df3vwza5fhhjbh5ahoijb6y4

A Microfacet-Based Shadowing Function to Solve the Bump Terminator Problem [chapter]

Alejandro Conty Estevez, Pascal Lecocq, Clifford Stein
2019 Ray Tracing Gems  
Our approach, based on microfacet shadowing functions, is simple and inexpensive.  ...  We present a technique to hide the abrupt shadow terminator line when strong bump or normal maps are used to emulate micro-geometry.  ...  ACKNOWLEDGMENTS This work was developed within the core development of the Arnold renderer at Sony Pictures Imageworks with Christopher Kulla and Larry Gritz.  ... 
doi:10.1007/978-1-4842-4427-2_12 fatcat:c6gmwpqp2jchfe35xicymajg3a

Modeling Bidirectional Texture Functions with Multivariate Spherical Radial Basis Functions

Yu-Ting Tsai, Kuei-Li Fang, Wen-Chieh Lin, Zen-Chung Shih
2011 IEEE Transactions on Pattern Analysis and Machine Intelligence  
Finally, a hierarchical fitting algorithm for bidirectional texture functions is developed to exploit spatial coherence and reduce computational cost.  ...  Our experimental results further reveal that the proposed representation can easily achieve high-quality approximation and real-time rendering performance.  ...  ACKNOWLEDGMENTS The authors would like to thank the anonymous reviewers for profound comments and suggestions, Dr. Xin Tong for providing BTF data, and Jia-Yin Ji for preparing the model Cloth.  ... 
doi:10.1109/tpami.2010.211 pmid:21135438 fatcat:gy27xmnzbbgyld6alt4g4ifnee

A microfacet-based BRDF generator

Michael Ashikmin, Simon Premože, Peter Shirley
2000 Proceedings of the 27th annual conference on Computer graphics and interactive techniques - SIGGRAPH '00  
A method is presented that takes as an input a 2D microfacet orientation distribution and produces a 4D bidirectional reflectance distribution function (BRDF).  ...  This method differs from previous microfacet-based BRDF models in that it uses a simple shadowing term which allows it to handle very general microfacet distributions while maintaining reciprocity and  ...  Thanks to Robert McDermott for his help with production issues. The tablecloth models were done using Maya software generously donated by Alias/Wavefront.  ... 
doi:10.1145/344779.344814 dblp:conf/siggraph/AshikminPS00 fatcat:nibmaupk2veqbj2p6pm3i7jwx4

Fabricating microgeometry for custom surface reflectance

Tim Weyrich, Pieter Peers, Wojciech Matusik, Szymon Rusinkiewicz
2009 ACM SIGGRAPH 2009 papers on - SIGGRAPH '09  
15 1 5 3 0 30 30 4 5 4 5 4 5 45 6 0 6 0 6 0 6 0 Figure 1: From left: a user-designed highlight is converted to an optimized microfacet height field.  ...  Our system begins with a user specification of a BRDF, or simply a highlight shape, and infers the required distribution of surface slopes.  ...  The content of the information does not necessarily reflect the position or the policy of the US Government, and no official endorsement should be inferred.  ... 
doi:10.1145/1576246.1531338 fatcat:c5qiz2vewrbehgofu3qmbf4dju

Fabricating microgeometry for custom surface reflectance

Tim Weyrich, Pieter Peers, Wojciech Matusik, Szymon Rusinkiewicz
2009 ACM Transactions on Graphics  
15 1 5 3 0 30 30 4 5 4 5 4 5 45 6 0 6 0 6 0 6 0 Figure 1: From left: a user-designed highlight is converted to an optimized microfacet height field.  ...  Our system begins with a user specification of a BRDF, or simply a highlight shape, and infers the required distribution of surface slopes.  ...  The content of the information does not necessarily reflect the position or the policy of the US Government, and no official endorsement should be inferred.  ... 
doi:10.1145/1531326.1531338 fatcat:pjavicy6bvh6ncytnv33mflvdu

A reflectance model for diffuse fluorescent surfaces

Alexander Wilkie, Andrea Weidlich, Caroline Larboulette, Werner Purgathofer
2006 Proceedings of the 4th international conference on Computer graphics and interactive techniques in Australasia and Southeast Asia - GRAPHITE '06  
The scene geometry is similar to that shown in figure 2.  ...  This paper aims to illustrate the reflection properties typical for diffuse fluorescent surfaces, and provides a BRDF model based on a layered microfacet approach that mimics them.  ...  The microfacet distribution function we used for the transparent varnish surface is a normalised Blinn distribution, with a single slope angle parameter m that controls its roughness for a given halfway  ... 
doi:10.1145/1174429.1174484 dblp:conf/graphite/WilkieWLP06 fatcat:ufpkdefdfjbdzj2prp3khjbg7e

Recognizing real materials from their glossy appearance

G. Ged, G. Obein, Z. Silvestri, J. Le Rohellec, F. Vienot
2010 Journal of Vision  
Microfacet distributions were derived from measured BRDFs using an inverted microfacet model. We conducted a visual ranking experiment using the pair comparison method.  ...  In everyday life, the visual system is remarkably good at recognizing materials across a wide range of viewing conditions.  ...  , =V ) is a function that takes into account the masking/shadowing of the adjacent facets; P(!) is the microfacet angular distribution function. The function P(!)  ... 
doi:10.1167/10.9.18 pmid:21187348 fatcat:t47n6mkfq5drraf7zuw25smyna

The 'Ecological' Probability Density Function for Linear Optic Flow: Implications for Neurophysiology

Jim Ivins, John Porrill, John Frisby, Guy Orban
1999 Perception  
The EFCs are circular motion or rot (rotation), radial motion or div (divergence), and two components of shearing motion def and def6 (deformation).  ...  A computational analysis of the'shape from flow' problem reveals that the deformation components are the least dependent on ego-motion. (1) [Koenderink (1986) showed Receptor (À20 deg, 20 deg) Receptor  ...  This observation raises the question whether or not a mixture of deformation and translation would produce a response in MST neurons.  ... 
doi:10.1068/p2807 pmid:10627850 fatcat:lr3dedeh25ak5ji5rxsxwobbxu

Determining the shape of reflectance reference samples for curved surface reflectors

Dmitri Lanevski, Farshid Manoocheri, Anna Vaskuri, Jacques Hameury, Robert Kersting, Christian Monte, A. Adibekyan, Elena Kononogova, Erkki Ikonen
2020 Measurement science and technology  
The method is based on studying the reflection distribution of reflective insulators and is described with an example of aluminium foil.  ...  The method's performance is validated using Monte-Carlo simulations.  ...  The EMPIR initiative is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States.  ... 
doi:10.1088/1361-6501/ab68bf fatcat:sbl52uol4nbvbkelvryh6j2x3m

Generating Materials for Augmented Reality Applications using Natural Language

Sebastian Buntin
2016 Proceedings of the 7th Augmented Human International Conference 2016 on - AH '16  
This allows an easy way to create and specify material representations for various applications. In the context of this paper, we focus on the application in augmented reality.  ...  The visual properties of a material can be described by the user using rather complex phrases in real time. These phrases then will be parsed and mapped to BRDF and texture parameters.  ...  Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage  ... 
doi:10.1145/2875194.2875195 dblp:conf/aughuman/Buntin16 fatcat:5i7hd6e2ibdi5d43o5be4xktde

Growth and properties of coherent twinning superlattice nanowires

Erin L. Wood, Frederic Sansoz
2012 Nanoscale  
These advances have opened new possibilities for properties and functionalities at the atomic and quantum scales by modulating twin densities.  ...  Although coherent twin boundaries require little energy to form in nanoscale single crystals, their influence on properties can be dramatic.  ...  Acknowledgements This work was conducted under the auspices of grant DMR-0747658 from the National Science Foundation CAREER program. Notes and references  ... 
doi:10.1039/c2nr31277h pmid:22833267 fatcat:ludanpyldvbrvlpph7syz2pg2m

Measurements of Angle-Resolved Reflectivity of PTFE in Liquid Xenon with IBEX [article]

S. Kravitz, R.J. Smith, L. Hagaman, E.P. Bernard, D.N. McKinsey, L. Rudd, L. Tvrznikova, G.D. Orebi Gann, M. Sakai
2019 arXiv   pre-print
IBEX is designed to directly measure the angular distribution of xenon scintillation light reflected off PTFE in liquid xenon.  ...  This depends on the high reflectivity of polytetrafluoroethylene (PTFE) at the xenon scintillation wavelength of 178 nm, but the angular dependence of this reflectivity is unknown.  ...  Acknowledgements The authors would like to thank Alexandre Lindote, Francisco Neves, and Cláudio Silva for helpful correspondence.  ... 
arXiv:1909.08730v3 fatcat:oiuhbrwy7va27panhsro34q3wq

Measurements of angle-resolved reflectivity of PTFE in liquid xenon with IBEX

S. Kravitz, R. J. Smith, L. Hagaman, E. P. Bernard, D. N. McKinsey, L. Rudd, L. Tvrznikova, G. D. Orebi Gann, M. Sakai
2020 European Physical Journal C: Particles and Fields  
IBEX is designed to directly measure the angular distribution of xenon scintillation light reflected off PTFE in liquid xenon.  ...  This depends on the high reflectivity of polytetrafluoroethylene (PTFE) at the xenon scintillation wavelength of 178 nm, but the angular dependence of this reflectivity is not wellunderstood.  ...  Acknowledgements The authors would like to thank Alexandre Lindote, Francisco Neves, and Cláudio Silva for helpful correspondence.  ... 
doi:10.1140/epjc/s10052-020-7800-6 fatcat:vpfjugt3efb7fod4mg3zduk4by

Enhanced sensitivity of time-resolved reflectivity measurements near Brewster's angle

P.M. Fauchet
1989 IEEE Journal of Quantum Electronics  
IBEX is designed to directly measure the angular distribution of xenon scintillation light reflected off PTFE in liquid xenon.  ...  This depends on the high reflectivity of polytetrafluoroethylene (PTFE) at the xenon scintillation wavelength of 178 nm, but the angular dependence of this reflectivity is not wellunderstood.  ...  Acknowledgements The authors would like to thank Alexandre Lindote, Francisco Neves, and Cláudio Silva for helpful correspondence.  ... 
doi:10.1109/3.28002 fatcat:phzrhekq6zcofic7tjtoywzqou
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