Testing the validity of Lambert's law for micro-scale photometric stereo applied to paper substrates

Azhar, Faisal; Emrith, Khemraj; Pollard, Stephen; Smith, Melvyn; Adams, Guy; Simske, Steven

Abstract

This paper presents an empirical study to investigate the use of photometric stereo (PS) for micro-scale 3D measurement of paper samples. PS estimates per-pixel surface orientation from images of a surface captured from the same viewpoint but under different illumination directions. Specifically, we investigate the surface properties of paper to test whether they are sufficiently well approximated by a Lambertian reflectance
model to allow veridical surface reconstruction under PS and explore the range of conditions for which this model is valid. We present an empirical setup that is used to conduct a series of experiments in order to analyse the applicability of PS at the micro-scale. In addition, we determine the best 4, 6, and 8 light source tilt (illumination) angles with respect to multi-source micro-scale PS. Furthermore, an intensity based image
registration method is used to test the accuracy of the recovery of surface normals. The results demonstrate that at the micro-scale: (a) Lambert model represents well the data sets with low root mean square (RMS) error between the original and reconstructed image, (b) increasing the light sources from 4 to 8 reduces RMS error, and (c) PS can be used to extract veridical surface normals.

• Presentation Conference Type: Conference Paper (unpublished)
• Conference Name: 10th International Conference on Computer Vision Theory and Applications (VISIGRAPP 2015)
• Start Date: Mar 11, 2015
• End Date: Mar 14, 2015
• Acceptance Date: Mar 14, 2015
• Publication Date: Mar 14, 2015
• Deposit Date: Aug 23, 2017
• Peer Reviewed: Peer Reviewed
• Pages: 246-253
• Keywords: document imaging in business, feature extraction, image formation, acquisition devices and sensors, image registration,; image-based modeling, 3D reconstruction
• Public URL: https://uwe-repository.worktribe.com/output/837256
• Additional Information: Title of Conference or Conference Proceedings : In Proceedings of the 10th International Conference on Computer Vision Theory and Applications, 246-253, 2015, Berlin, Germany
• Contract Date: Aug 23, 2017