1 / 29

Diffraction Model for Diffraction

Diffraction Model for Diffraction. (1). Tom Cuypers 1,2 Se Baek Oh 3 Tom Haber 1 Philippe Bekaert 1 Ramesh Raskar 3. (2). (3). Represent light as particles travelling in straight lines Simple mathematics Realistic rendering of light phenomena Efficient. Geometric Optics. Wave Phenomena.

sora
Download Presentation

Diffraction Model for Diffraction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Diffraction Model for Diffraction (1) Tom Cuypers1,2Se Baek Oh3Tom Haber1Philippe Bekaert1Ramesh Raskar3 (2) (3)

  2. Represent light as particles travelling in straight lines Simple mathematics Realistic rendering of light phenomena Efficient Geometric Optics

  3. Wave Phenomena

  4. Goal Wave BSDF

  5. Related Work • Phase Tracking • Make changes tocurrent software • Slow Moravec – 3D Graphics and the Wave Theory (Siggraph 1981) Ziegler et al. - Lighting and Occlusion in a Wave-Based Framework (Eurographics 2008)

  6. Related Work • Phase Tracking • Diffractionshaders • Assumptionsaboutlocationobserverand light Stam – Diffraction Shaders (Siggraph 1999) Rendering Iridescent Colors of Optical Disks - Sun et a (Siggraph 2006)

  7. Related Work • Phase Tracking • Diffractionshaders • Edgediffraction • Make changes tocurrentsoftware Nicolas Tsingos, Thomas Funkhouser, Addy Nganand Ingrid Carlbom– Modeling Acoustics in Virtual Environments Using the Uniform Theory of Diffraction. (Siggraph 2001)

  8. Wigner Distribution Function • Fourieroptics light representation • Simulatingdiffractionandinterference • Relationshipwithgeometricoptics ’

  9. Spatial Frequency θ λ } 1 u

  10. Wigner Distribution Function • Simulate parallel waves as rays • Propagation of light u z = 0 Zhang and Levoy – Wigner Distribution and How They Relate to the Light Field – ICCP 2009 Oh et al. – Rendering Wave Effects with Augmented Light Fields - Eurographics 2010 x

  11. Wigner Distribution Function • Simulate parallel waves as rays • Propagation of light • Projection Zhang and Levoy – Wigner Distribution and How They Relate to the Light Field – ICCP 2009 Oh et al. – Rendering Wave Effects with Augmented Light Fields - Eurographics 2010

  12. Interaction u u Assumption 2 Microsurfaceinfinitlythin Assumption 1 Coherent Light (laser) x x

  13. Propagation u u I x x x I x

  14. Calculating WDF • Description of the microsurface: t(x) • Amplitude[ t(x) ]: amount of light transmittedon x • Phase[t(x) ]: delay of light on x (duetorefraction index) • Orientation of the incomingplanewave () 2A

  15. Rendering Equation Reflected Light Description of the microstructure t(x) : ) Wave BSDF

  16. Wave BSDF x

  17. Wave BSDF Θ Θ x x

  18. Statistical Wave BSDF • Microsurfacenotalwaysknown • Describemicrosurface as • Heightfunction h(x) • Variance 0 100 200

  19. Limitations • Paraxialregion: more accurate closer to the normal • Surfacesinfinitelythin • No interreflections

  20. Benefits Works in near- and far-field

  21. Benefits Works in near- and far-field

  22. Benefits Minimal changes torendering software PhysicallyBased Ray Tracing (PBRT)

  23. Benefits Minimalcode function W = wigner(Ex) N = length(Ex); x = ifftshift(((0:N-1)'-N/2)*2*pi/(N-1)); X = (0:N-1)-N/2; EX1 = ifft( (fft(Ex)*ones(1,N)).*exp( i*x*X/2 )); EX2 = ifft( (fft(Ex)*ones(1,N)).*exp( -i*x*X/2 )); W = (fftshift(fft(fftshift(EX1.*conj(EX2), 2), [], 2), 2));

  24. Benefits Importance sampling efficientrendering

  25. Benefits • Wigner Distribution Function • Non negative results • Coherent and partially coherent light

  26. Future Research • Wigner distribution extensions • Non-linear materials • Thick materials • Non-paraxial region • Polarization • Sound rendering • Inverse problem – scanning

  27. Conclusion • Simulating wave effects using geometric optics • Constructed the Wave BSDF • Minimal changes to current render software • Valid in near- and far-field • Efficient rendering

  28. This slide has a 16:9 media window

More Related