A Theory of Shape by Space Carving
International Journal of Computer Vision - Special issue on Genomic Signal Processing
International Journal of Computer Vision
Photometric Stereo with General, Unknown Lighting
International Journal of Computer Vision
Journal of Mathematical Imaging and Vision
Digital inspection: an interactive stage for viewing surface details
Proceedings of the 2008 symposium on Interactive 3D graphics and games
Median Photometric Stereo as Applied to the Segonko Tumulus and Museum Objects
International Journal of Computer Vision
DECHO—a framework for the digital exploration of cultural heritage objects
Journal on Computing and Cultural Heritage (JOCCH)
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This paper reconsiders the familiar case of photometric stereo under the assumption of Lambertian surface reflectance and three distant point sources of illumination. Here, it is assumed that the directions to and the relative strengths of the three light sources are not known {\it a priori}. Rather, estimation of these parameters becomes part of the problem formulation. \nEach light source is represented by a 3-D vector that points in the direction of the light source and has magnitude proportional to the strength of the light source. Thus, nine parameters are required to characterize the three light sources. It is shown that, regardless of object shape, triples of measured intensity values are constrained to lie on a quadratic surface having six degrees of freedom. Estimation of the six parameters of the quadratic surface allows the determination of the nine parameters of the light sources up to an unknown rotation. \nThis is sufficient to determine object shape, although attitude with respect to the world-based or the camera-based coordinate system can not be simultaneously recovered without additional information.