Shape Estimation in Natural Illumination
Computer Vision and Pattern Recognition, 2011
The traditional shape-from-shading problem, with a single light source and Lambertian reflectance, is challenging since the constraints implied by the illumination are not sufficient to specify local orientation. Photometric stereo algorithms, a variant of shape-from-shading, simplify the problem by controlling the illumination to obtain additional constraints. In this paper, we demonstrate that many natural lighting environments already have sufficient variability to constrain local shape. We describe a novel optimization scheme that exploits this variability to estimate surface normals from a single image of a diffuse object in natural illumination. We demonstrate the effectiveness of our method on both simulated and real images.
This work was supported in part by the NSF under Grant No. 0739255, NIH contract 1-R01-EY019292-01, and by a grant from the NTT-MIT Research Collaboration. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.