Overcoming shadows in 3-source photometric stereo


Light occlusions are one of the most significant difficulties of photometric stereo methods. When three or more images are available without occlusion, the local surface orientation is overdetermined so that shape can be computed and the shadowed pixels can be discarded. In this paper, we look at the challenging case when only two images are available without occlusion, leading to a one degree of freedom ambiguity per pixel in the local orientation. We show that, in the presence of noise, integrability alone cannot resolve this ambiguity and reconstruct the geometry in the shadowed regions. As the problem is ill-posed in the presence of noise, we describe two regularization schemes that improve the numerical performance of the algorithm while preserving the data. Finally, the paper describes how this theory applies in the framework of color photometric stereo where one is restricted to only three images and light occlusions are common. Experiments on synthetic and real image sequences are presented.

Publication DOI: https://doi.org/10.1109/TPAMI.2010.181
Divisions: Engineering & Applied Sciences > Computer Science
Additional Information: © 2011 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Uncontrolled Keywords: color photometric stereo,ill-posed problem,image sequence,light occlusions,noise,regularization scheme,shadow,Artificial Intelligence,Computer Vision and Pattern Recognition,Software,Computational Theory and Mathematics,Applied Mathematics
Full Text Link: http://ieeexplo ... rnumber=5601736
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2011-02
Authors: Hernández, Carlos
Vogiatzis, George ( 0000-0002-3226-0603)
Cipolla, Roberto


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