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2008

A photometric approach for estimating normals and tangents

8 years 11 months ago
A photometric approach for estimating normals and tangents
This paper presents a technique for acquiring the shape of realworld objects with complex isotropic and anisotropic reflectance. Our method estimates the local normal and tangent vectors at each pixel in a reference view from a sequence of images taken under varying point lighting. We show that for many real-world materials and a restricted set of light positions, the 2D slice of the BRDF obtained by fixing the local view direction is symmetric under reflections of the halfway vector across the normal-tangent and normal-binormal planes. Based on this analysis, we develop an optimization that estimates the local surface frame by identifying these planes of symmetry in the measured BRDF. As with other photometric methods, a key benefit of our approach is that the input is easy to acquire and is less sensitive to calibration errors than stereo or multi-view techniques. Unlike prior work, our approach allows estimating the surface tangent in the case of anisotropic reflectance. We confirm...
Michael Holroyd, Jason Lawrence, Greg Humphreys, T
Added 15 Dec 2010
Updated 15 Dec 2010
Type Journal
Year 2008
Where TOG
Authors Michael Holroyd, Jason Lawrence, Greg Humphreys, Todd Zickler
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