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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

Authors

Faisal Azhar

Dr Khemraj Emrith Khemraj.Emrith@uwe.ac.uk
Associate Head of Departmemt Business Engagement and Partnerships

Stephen Pollard

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Melvyn Smith Melvyn.Smith@uwe.ac.uk
Research Centre Director Vision Lab/Prof

Guy Adams

Steven Simske



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.

Citation

Azhar, F., Emrith, K., Pollard, S., Smith, M., Adams, G., & Simske, S. (2015, March). Testing the validity of Lambert's law for micro-scale photometric stereo applied to paper substrates. Paper presented at 10th International Conference on Computer Vision Theory and Applications (VISIGRAPP 2015), Berlin, Germany

Presentation Conference Type Conference Paper (unpublished)
Conference Name 10th International Conference on Computer Vision Theory and Applications (VISIGRAPP 2015)
Conference Location Berlin, Germany
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