Rendering specular microgeometry with wave optics

Abstract

Simulation of light reflection from specular surfaces is a core problem of computer graphics. Existing solutions either make the approximation of providing only a large-area average solution in terms of a fixed BRDF (ignoring spatial detail), or are specialized for specific microgeometry (e.g. 1D scratches), or are based only on geometric optics (which is an approximation to more accurate wave optics). We design the first rendering algorithm based on a wave optics model that is also able to compute spatially-varying specular highlights with high-resolution detail on general surface microgeometry. We compute a wave optics reflection integral over the coherence area; our solution is based on approximating the phase-delay grating representation of a micron-resolution surface heightfield using Gabor kernels. We found that the appearance difference between the geometric and wave solution is more dramatic when spatial detail is taken into account. The visualizations of the corresponding BRDF lobes differ significantly. Moreover, the wave optics solution varies as a function of wavelength, predicting noticeable color effects in the highlights. Our results show both single-wavelength and spectral solution to reflection from common everyday objects, such as brushed, scratched and bumpy metals.

References

1. P. Beckmann and A. Spizzichino. 1968. The Scattering of Electromagnetic Waves from Rough Surfaces. Books on Demand. http://books.google.com/books?id=nn92AAAACAAJ
2. Laurent Belcour and Pascal Barla. 2017. A Practical Extension to Microfacet Theory for the Modeling of Varying Iridescence. ACM Trans. Graph. 36, 4, Article 65 (July 2017), 14 pages.
3. Carles Bosch, Xavier Pueyo, Stéphane Mérillou, and Djamchid Ghazanfarpour. 2004. A Physically-Based Model for Rendering Realistic Scratches. In Computer Graphics Forum, Vol. 23. Wiley Online Library, 361--370.
4. Brent Burley. 2012. Physically-Based Shading at Disney. Technical Report (2012).
5. Samuel D Butler, Stephen E Nauyoks, and Michael A Marciniak. 2015. Comparison of microfacet BRDF model to modified Beckmann-Kirchhoff BRDF model for rough and smooth surfaces. Optics Express 23, 22 (2015), 29100--29112.
6. R. L. Cook and K. E. Torrance. 1982. A Reflectance Model for Computer Graphics. ACM Trans. Graph. 1, 1 (1982), 7--24.
7. Tom Cuypers, Tom Haber, Philippe Bekaert, Se Baek Oh, and Ramesh Raskar. 2012. Reflectance Model for Diffraction. ACM Trans. Graph. 31, 5 (2012), 122:1--122:11.
8. Daljit Singh Dhillon, Jeremie Teyssier, Michael Single, Michel Milinkovitch Iarsolav Gaponenko, and Matthias Zwicker. 2014. Interactive Diffraction from Biological Nanostructures. Computer Graphics Forum 33, 8 (2014), 177--188.
9. Zhao Dong, Bruce Walter, Steve Marschner, and Donald P. Greenberg. 2015. Predicting Appearance from Measured Microgeometry of Metal Surfaces. ACM Trans. Graph. 35, 1, Article 9 (2015), 13 pages.
10. James Harvey. 1979. Fourier treatment of near-field scalar diffraction theory. American Journal of Physics 47, 11 (1979), 974--980.
11. James E. Harvey and Richard N. Pfisterer. 2016. Evolution of the transfer function characterization of surface scatter phenomena. Proc. SPIE 9961 (2016), 9961 -- 9961 - 17.
12. Xiao D. He, Kenneth E. Torrance, François X. Sillion, and Donald P. Greenberg. 1991. A Comprehensive Physical Model for Light Reflection. SIGGRAPH Comput. Graph. 25, 4 (1991), 175--186.
13. Nicolas Holzschuch and Romain Pacanowski. 2017. A Two-scale Microfacet Reflectance Model Combining Reflection and Diffraction. ACM Trans. Graph. 36, 4, Article 66 (2017), 12 pages.
14. Wenzel Jakob. 2010. Mitsuba renderer. http://www.mitsuba-renderer.org.
15. Wenzel Jakob, Miloš Hašan, Ling-Qi Yan, Jason Lawrence, Ravi Ramamoorthi, and Steve Marschner. 2014. Discrete Stochastic Microfacet Models. ACM Trans. Graph. 33, 4 (2014).
16. Andrey Krywonos. 2006. Predicting Surface Scatter Using A Linear Systems Formulation Of Non-paraxial Scalar Diffraction. PhD. Dissertation. University of Central Florida.
17. Ann M Lanari, Samuel D Butler, Michael Marciniak, and Mark F Spencer. 2017. Wave optics simulation of statistically rough surface scatter. In Earth Observing Systems XXII, Vol. 10402. International Society for Optics and Photonics, 1040215.
18. Anat Levin, Daniel Glasner, Ying Xiong, Frédo Durand, William Freeman, Wojciech Matusik, and Todd Zickler. 2013. Fabricating BRDFs at High Spatial Resolution Using Wave Optics. ACM Trans. Graph. 32, 4 (2013), 144:1--144:14.
19. L. Mandel and E. Wolf. 1995. Optical Coherence and Quantum Optics. Cambridge University Press. http://books.google.com/books?id=FeBix14iM70C
20. Heylal Mashaal, Alex Goldstein, Daniel Feuermann, and Jeffrey M. Gordon. 2012. First direct measurement of the spatial coherence of sunlight. Opt. Lett. 37, 17 (2012), 3516--3518.
21. Stéphane Mérillou, Jean-Michel Dischler, and Djamchid Ghazanfarpour. 2001. Surface scratches: measuring, modeling and rendering. The Visual Computer 17, 1 (2001), 30--45.
22. J.A. Ogilvy. 1991. Theory of wave scattering from random rough surfaces. A. Hilger.
23. Boris Raymond, Gael Guennebaud, and Pascal Barla. 2016. Multi-Scale Rendering of Scratched Materials using a Structured SV-BRDF Model. ACM Transactions on Graphics (July 2016).
24. Jos Stam. 1999. Diffraction Shaders. In SIGGRAPH 99. New York, NY, USA, 101--110.
25. Antoine Toisoul and Abhijeet Ghosh. 2017. Practical Acquisition and Rendering of Diffraction Effects in Surface Reflectance. ACM Trans. Graph. 36, 5, Article 166 (July 2017), 16 pages.
26. Zdravko Velinov, Sebastian Werner, and Matthias B. Hullin. 2018. Real-Time Rendering of Wave-Optical Effects on Scratched Surfaces. Computer Graphics Forum 37 (2) (Proc. EUROGRAPHICS) 37, 2 (2018).
27. Bruce Walter, Stephen R. Marschner, Hongsong Li, and Kenneth E. Torrance. 2007. Microfacet Models for Refraction Through Rough Surfaces (EGSR 07). 195--206.
28. Sebastian Werner, Zdravko Velinov, Wenzel Jakob, and Matthias B. Hullin. 2017. Scratch Iridescence: Wave-optical Rendering of Diffractive Surface Structure. ACM Trans. Graph. 36, 6, Article 207 (2017), 14 pages.
29. Stephen H Westin, Hongsong Li, and Kenneth E Torrance. 2004. A comparison of four brdf models. In Eurographics Symposium on Rendering, pags. 1--10.
30. Ling-Qi Yan, Miloš Hašan, Wenzel Jakob, Jason Lawrence, Steve Marschner, and Ravi Ramamoorthi. 2014. Rendering Glints on High-resolution Normal-mapped Specular Surfaces. ACM Trans. Graph. 33, 4, Article 116 (2014), 9 pages.
31. Ling-Qi Yan, Miloš Hašan, Steve Marschner, and Ravi Ramamoorthi. 2016. Position-normal Distributions for Efficient Rendering of Specular Micro structure. ACM Trans. Graph. 35, 4, Article 56 (2016), 9 pages.

Index Terms

• Computing methodologies

  • Computer graphics

    • Rendering