
Proceedings Paper
Episcopic coaxial illumination device for the simultaneous recording of the speckle signature in the spectrum and in the image of scattering reflective surfacesFormat | Member Price | Non-Member Price |
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Paper Abstract
Inspection of optically rough surfaces in search of defects or other surface features with deterministic reflectance
distributions is a subject well suited to optical techniques. We present a device with episcopic coaxial illumination,
specifically developed for such kind of inspection tasks, which simultaneously renders both a coherent image and the
spatial spectrum of a portion of the surface, precisely defined by the illuminating laser spot. It is based on the wellknown
single-lens coherent image processing system, with beamsplitters added to insert the illuminating laser beam and
to allow simultaneous access to the Fourier transform and the image planes. The device allows inspecting the speckle
signature of surface features in both planes, thus allowing different defect recognition approaches. By selecting the size
of the illuminated area of the object or the lens aperture, different speckle sizes can be obtained. If the speckle size is
made large enough, identification of individual features can be made on the basis of their particular speckle signatures.
Some envisaged applications are the characterization of defects or structures in rough surfaces, the evaluation of speckle
statistics in precisely defined zones of surfaces or the identification of authentication marks.
Paper Details
Date Published: 11 September 2012
PDF: 6 pages
Proc. SPIE 8413, Speckle 2012: V International Conference on Speckle Metrology, 84131O (11 September 2012); doi: 10.1117/12.978075
Published in SPIE Proceedings Vol. 8413:
Speckle 2012: V International Conference on Speckle Metrology
Ángel Fernandez Doval; Cristina Trillo, Editor(s)
PDF: 6 pages
Proc. SPIE 8413, Speckle 2012: V International Conference on Speckle Metrology, 84131O (11 September 2012); doi: 10.1117/12.978075
Show Author Affiliations
Published in SPIE Proceedings Vol. 8413:
Speckle 2012: V International Conference on Speckle Metrology
Ángel Fernandez Doval; Cristina Trillo, Editor(s)
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