Rapid Acquisition of Specular and Diffuse Normal Maps from Polarized Spherical Gradient Illumination
Eurographics Symposium on Rendering 2007
Wan-Chun Ma    Tim Hawkins    Pieter Peers    Charles-Felix Chabert    Malte Weiss    Paul Debevec   
USC Institute for Creative Technologies

We estimate surface normal maps of an object from either its diffuse or specular reflectance using four spherical gradient illumination patterns. In contrast to traditional photometric stereo, the spherical patterns allow normals to be estimated simultaneously from any number of viewpoints. We present two polarized lighting techniques that allow the diffuse and specular normal maps of an object to be measured independently. For scattering materials, we show that the specular normal maps yield the best record of detailed surface shape while the diffuse normals deviate from the true surface normal due to subsurface scattering, and that this effect is dependent on wavelength. We show several applications of this acquisition technique. First, we capture normal maps of a facial performance simultaneously from several viewing positions using time-multiplexed illumination. Second, we show that highresolution normal maps based on the specular component can be used with structured light 3D scanning to quickly acquire high-resolution facial surface geometry using off-the-shelf digital still cameras. Finally, we present a realtime shading model that uses independently estimated normal maps for the specular and diffuse color channels to reproduce some of the perceptually important effects of subsurface scattering.

(a) High-Res face geometry obtained by embossing a specular normal map (estimated from polarized gradient illumination) onto a structured light 3D scan. All information was acquired in 13 photographs from two digital still cameras.

(b) Real-time rendering of low-res face geometry with hybrid normal mapping for diffuse and specular reflectance.

(c) Offline GI&SSS rendering using the high-resolution geometry and recovered diffuse and specular intensity maps.


ESGR 2007 Paper
EGSR2007_SGI_high.pdf, (4.9MB)
EGSR2007_SGI_low.pdf, (500KB)

ESGR 2007 Video
EGSR2007_SGI_Hires.mp4,864x480, (69.3MB)
EGSR2007_SGI_Lores.mp4,432x240 (36.3MB)


Face Data Set, (164MB)

Face Data Set, (164MB)

Related Projects

Light Stage 1
Acquiring the Reflectance Field of a Human Face, SIGGRAPH 2000
Facial Reflectance Field Demo, SIGGRAPH 2000 Creative Applications Laboratory
Realistic Human Face Scanning and Rendering, ICT Graphics Lab 2001

Light Stage 2
A Photometric Approach to Digitizing Cultural Artifacts, VAST 2001
Animatable Facial Reflectance Fields, EGSR 2004
Reflectance Field Rendering of Human Faces for "Spider-Man 2", SIGGRAPH 2004 Sketch

Light Stage 3
A Lighting Reproduction Approach to Live-Action Compositing, SIGGRAPH 2002
Optimizing Color Matching in a Lighting Reproduction System for Complex Subject and Illuminant Spectra, EGSR 2003

Light Stage 5
Postproduction Re-Illumination of Live Action Using Interleaved Lighting, SIGGRAPH 2004 Poster
Performance Geometry Capture for Spatially Varying Relighting, SIGGRAPH 2005 Sketch

Light Stage 6
Relighting Human Locomotion with Flowed Reflectance Fields, EGSR 2006 Paper
Relighting Human Locomotion with Flowed Reflectance Fields, SIGGRAPH 2006 Sketch
Light Stage Data Gallery.