Paper
3 October 2008 A simple method to estimate surface reflectance parameters for three light photometric stereo
Mohammad A. Younes, M. A. Al-Nady
Author Affiliations +
Proceedings Volume 7155, Ninth International Symposium on Laser Metrology; 715516 (2008) https://doi.org/10.1117/12.814542
Event: Ninth International Symposium on Laser Metrology, 2008, Singapore, Singapore
Abstract
A complete procedure to reconstruct part shape using a 3-light photometric stereo technique is investigated and experimentally verified. The part reflectance parameters are initially estimated and then the photometric stereo technique is applied at selected illumination directions. Finally, the recovered surface normals are integrated to reconstruct the part shape. The light sources are placed at 120° azimuth angle spacing while the slant angle is optimized according to the range of slopes found in the part surface. For a free form surface with small radii of curvature, a 45° light source slant angle is found to give better results on the global scale, with relatively lower accuracy. For a near-flat surface, a light source slant angle of 25° may be used to attain more accurate results. For surfaces having slopes less than 40° the mean surface normal recovery error is experimentally found to be less than 5°.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mohammad A. Younes and M. A. Al-Nady "A simple method to estimate surface reflectance parameters for three light photometric stereo", Proc. SPIE 7155, Ninth International Symposium on Laser Metrology, 715516 (3 October 2008); https://doi.org/10.1117/12.814542
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KEYWORDS
Light sources

Reflectivity

Optical spheres

Reticles

Error analysis

Algorithm development

Image processing

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