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Proceedings Paper

Laser-line scanning speckle reduction based on a one-dimensional beam homogenizer
Author(s): B. Nelsen; P. Jacobs; P. Hartmann
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Paper Abstract

Laser-line scanners have become ubiquitous in many forms of automation and measurement systems. Despite this fact, these systems are still susceptible to speckle or interference on rough scattering surfaces. Many scanning systems must be calibrated to the material being analyzed to obtain their full potential. In general, post-processing algorithms are used in most modern line-scanning devices in order to smooth out speckle and enhance the resolution through sub-pixel interpolation. However, these post-processing techniques come at a cost of increased CPU time and a subsequent decrease in bandwidth and resolution. in this paper, a low-cost, high-resolution solution to generating speckle-free sharply focused laser lines is presented. The key to this technique relies on only removing the spatial coherence in one dimension using a 1-D cylindrical lens array as a beam homogenizer. This beam homogenizer is then wrapped around and rotated about a central axis in order to remove the temporal component on the laser's coherence. Since the plane-wave-like behavior is maintained along one dimension, this beam can still be sharply focused to a line. however, the spatial coherence and temporal coherence are reduced to the point that speckle is minimally visible.

Paper Details

Date Published: 26 June 2017
PDF: 6 pages
Proc. SPIE 10329, Optical Measurement Systems for Industrial Inspection X, 103292I (26 June 2017); doi: 10.1117/12.2270264
Show Author Affiliations
B. Nelsen, Westsächsische Hochschule Zwickau (Germany)
Fraunhofer-Institut für Werkstoff und Strahltechnik (Germany)
P. Jacobs, Westsächsische Hochschule Zwickau (Germany)
Fraunhofer-Institut für Werkstoff und Strahltechnik (Germany)
P. Hartmann, Westsächsische Hochschule Zwickau (Germany)
Fraunhofer-Institut für Werkstoff und Strahltechnik (Germany)


Published in SPIE Proceedings Vol. 10329:
Optical Measurement Systems for Industrial Inspection X
Peter Lehmann; Wolfgang Osten; Armando Albertazzi Gonçalves Jr., Editor(s)

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