A closed-form solution to uncalibrated photometric stereo via diffuse maxima

In this paper we propose a novel solution to uncalibrated photometric stereo. Our approach is to eliminate the socalled generalized bas relief (GBR) ambiguity by exploiting points where the Lambertian reflection is maximal. We demonstrate several noteworthy properties of these maxima: 1) Closed-form solution: A single diffuse maximum constrains the GBR ambiguity to a semi-circle in 3D space; 2) Efficiency: As few as two diffuse maxima in different images identify a unique solution; 3) GBR-invariance: The estimation error of the GBR parameters is completely independent of the true parameters. Furthermore, our algorithm is remarkably robust: It can obtain an accurate estimate of the GBR parameters even with extremely high levels of outliers in the detected maxima (up to 80% of the observations). The method is validated on real data and achieves state-of-the-art results.

• Type: Journal
• Year: 2012
• Where: CVPR
• Authors: Paolo Favaro, Thoma Papadhimitri
• Keywords: Bas Relief, Computer Vision, Cvpr 2012, Noteworthy Properties, Semi Circle