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3 June 1997 Photometric stereo without multiple images
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Proceedings Volume 3016, Human Vision and Electronic Imaging II; (1997)
Event: Electronic Imaging '97, 1997, San Jose, CA, United States
Photometric stereo (PMS) recovers orientation vectors from a set of graylevel images. Under orthography, when the lights are unknown, and for a single uniform Lambertian surface, one can recover surface normals up to an unknown overall orthogonal transformation. The same situation obtains if, instead of three graylevel images, one uses a single RGB image taken with at least three point or extended colored lights impinging on the surface at once. Then using a robust technique and the constraints among the resulting three effective lighting vectors one can recover effective lights as well as normals, with no unknown rotation. However, in the case of a non-Lambertian object, PMS reduces to the idea of using a lookup table (LUT) based on a calibration sphere. Here, we show that a LUT can also be used in the many-colored- lights paradigm, eliminating the need for three separate images as in standard PMS. As well, we show how to transform a calibration sphere made of a particular material into a theoretical sphere for a cognate material similar in its specular properties but of a different color. In particular, we postulate that a LUT developed from one human's skin can be used for any other person; problems arising from shadows, hair, eyes, etc. are automatically eliminated using robust statistics. Results are shown using both synthetic and real images.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mark S. Drew "Photometric stereo without multiple images", Proc. SPIE 3016, Human Vision and Electronic Imaging II, (3 June 1997);

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