Automatic heterodyning of fiber-optic speckle pattern interferometry

Jesus D. Valera, David Harvey, Julian D. Jones

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)


The operational advantages of the complementary techniques of electronic speckle pattern interferometry (ESPI) and laser Doppler velocimetry (LDV) are combined for out-of-plane vibrational analysis. A cw laser was used in a fiberoptic system to generate time-averaged ESPI fringes. By mutual phase-locking of the ESPI and LDV signals, automatic heterodyning of the ESPI signal was achieved, together with compensation for unwanted nondeterministic out-of-plane whole body motion of the object under study. Automatic heterodyning extends the operating range of time-averaged ESPI systems to higher vibrational amplitudes, and reveals phase relationships in the object vibration. A practical demonstration of this new technique is described.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Number of pages10
Publication statusPublished - 1991
EventIndustrial Applications of Holographic and Speckle Measuring Techniques - Hague, Neth
Duration: 12 Mar 199113 Mar 1991


ConferenceIndustrial Applications of Holographic and Speckle Measuring Techniques
CityHague, Neth


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