Acquiring the Reflectance Field of a Human Face
- Slides: 38
Acquiring the Reflectance Field of a Human Face Paul Debevec, Tim Hawkins, Chris Tchou, H. P. Duiker, Westley Sarokin, and Mark Sagar UC Berkeley / USC Institute for Creative Technologies / Life. F/X www. debevec. org
Related Work Hanrahan and Krueger. Reflection from Layered Surfaces due to Subsurface Scattering. SIGGRAPH 93 Bregler et al. Video Rewrite. SIGGRAPH 97 Guenter et al. Making Faces. SIGGRAPH 98 Pighin et al. Synthesizing Realistic Facial Expressions from Photographs. SIGGRAPH 98 Sagar et al. The Jester. SIGGRAPH 99 ET Marschner et al. Reflectance Measurements of Human Skin.
The Reflectance Field
The Reflectance Field
The Reflectance Field
The Reflectance Field Ri( ui , vi , qi , fi ) incident light field
The Reflectance Field Ri( ui , vi , qi , fi ) Rr ( ur , vr , qr , fr ) incident light field radiant light field
The Reflectance Field Ri( ui , vi , qi , fi ; ur , vr , qr , fr ) 8 D reflectance field
4 D Slices of the 8 D Reflectance Field Ri( ui , vi , qi , fi ; ur , vr , qr , fr )
The Light Stage
The Light Stage: 60 -second exposure
Light Stage Data Original Resolution: 64 32 Lighting through image recombination: Haeberli ‘ 92, Nimeroff ‘ 94, Wong ‘ 97
Light Stage Results Environments from the Light Probe Image Gallery www. debevec. org
Reflectance Functions
Lighting Reflectance Functions 1 normalized light map reflectance function lighting product rendered pixel 1 DCT Basis Smith and Rowe. Compressed domain processing of JPEG-encoded images. 1996
Interactive Lighting Demo SIGGRAPH 2000 Creative Applications Laboratory
Interactive Lighting Demo SIGGRAPH 2000 Creative Applications Laboratory
Changing the Viewpoint
Reflection of Light from Skin After Hanrahan ‘ 93 Specular Component: Color of light, shiny, brighter near grazing, maintains polarization Subsurface Component: Color of skin, diffuse, desaturated near grazing, scrambles polarization
Separating Reflectance Components using Crossed Polarizers Normal Image Subsurface Component Colorspace techniques - Sato ‘ 94, Nayar ‘ 97 Specular Component
Original RF Transforming a Reflectance Function Specular Component => Torrance. Sparrow microfacet distribution Shifted and Scaled Specular Subsurface Component Surface Normal Estimate Final RF Comparison RF
Point-Source Comparison Original Image Novel Viewpoint
Spatially-Varying Reflectance Parameters Surface Normals n Diffuse Albedo rd Specular Intensity ks Specular Roughness a
Compositing Test Original Image Light Probe Rendered Face Composite
4. Ongoing Work • Animate the faces • Capture more spectral samples • Use high-speed cameras to achieve real-time capture
5. Conclusion We have presented: · The light stage apparatus for capturing slices of the reflectance field of the human face · A technique for correctly relighting faces and objects with arbitrary illumination · A technique for extrapolating human reflectance to novel viewpoints
Thanks Digital Media Innovation Program Interactive Pictures Corporation Alias|Wavefront UCB Digital Media/New Genre Program ONR/BMDO Cornell Program of Computer Graphics Berkeley Millennium Project and Shawn Brixey, Bill Buxton, Larry Rowe, Jessica Vallot, Patrick Wilson, Melanie Levine, Eric Paulos, Christine Waggoner, Holly Cim, Eliza Ra, Bryan Musson, David Altenau, Marc Levoy, Maryann Simmons, Henrik Wann Jensen, Don Greenberg, Pat Hanrahan, Randal Kleiser, Chris Bregler, Michael Naimark, Dan Maas, Steve Marschner, and Kevin Binkert.
In-plane Reflectometry Measurements · Subsurface exhibits chromaticity falloff · Specular is monochromatic with Torrance. Sparrow microfacet behavior qi qr Subsurface + Specular qi
Reflectometry Experiment
The Jester SIGGRAPH 99 Electronic Theater Mark Sagar et al. - Life. F/X, Inc. Performance and Text: Jessica Vallot
Changing the Viewpoint Model from Structured Lighting
Traditional Approach · Derive reflectance parameters for each point on the face’s surface · Map the parameters onto a geometric model of the face · Render using traditional methods
Reflectance Function Mosaic
Acquiring the reflectance field of a human face
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Reflectance photometry principle
Reflectance spectroscopy
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