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Applied Optics

Applied Optics


  • Editor: Joseph N. Mait
  • Vol. 52, Iss. 3 — Jan. 20, 2013
  • pp: 350–358

Frequency-division multiplexing for multicomponent shearography

Ian A. Bledowski, Thomas O. H. Charrett, Daniel Francis, Stephen W. James, and Ralph P. Tatam  »View Author Affiliations

Applied Optics, Vol. 52, Issue 3, pp. 350-358 (2013)

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A new method of multiplexing the speckle patterns needed in multicomponent digital shearography systems is presented. Frequency-division multiplexing (FDM) of the measurement channels is achieved by recording speckle patterns from objects illuminated by intensity-modulated sources. Each source is modulated at a discrete frequency, which is less than half of the camera frame rate, and a bank of images of the modulated speckle patterns is captured. This allows for pixel-by-pixel Fourier-based extraction of the individual speckle patterns from peaks in the power spectra. The approach is demonstrated with a two-component in-plane shearography instrument.

© 2013 Optical Society of America

OCIS Codes
(120.3940) Instrumentation, measurement, and metrology : Metrology
(120.4290) Instrumentation, measurement, and metrology : Nondestructive testing
(110.4155) Imaging systems : Multiframe image processing
(120.6165) Instrumentation, measurement, and metrology : Speckle interferometry, metrology

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: October 19, 2012
Manuscript Accepted: November 27, 2012
Published: January 11, 2013

Ian A. Bledowski, Thomas O. H. Charrett, Daniel Francis, Stephen W. James, and Ralph P. Tatam, "Frequency-division multiplexing for multicomponent shearography," Appl. Opt. 52, 350-358 (2013)

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