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Proceedings Paper

Recording and analysis of (high-frequency) sinusoidal vibrations using computerized TV-holography
Author(s): Svein Ellingsrud; Ole Johan Lokberg; Hans Magne Pedersen
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Paper Abstract

The RETRA 1000 TV-holography system has been further developed for analysis of high frequency vibrations, using automatic data acquisition. Special phase shift algorithms are executed by means of a PC-based image processing system. The phase shifts are effected by a built in electro-optic modulator, controlled by a two channel high-resolution digital frequency synthesizer. The optical (speckle) and electronic noise is reduced, using an automatic speckle averaging technique. Amplitude and phase distributions can be calculated and presented for frequencies up to 10 MHz. The lower limit for amplitude detection is below 1 nm (for HeNe laser), while the relative phase distribution is given with less than 3° accuracy under stable conditions. We show results where the technique has been used to analyze various vibrating test objects like a ceramic "crystal", a high frequency loudspeaker and finally an underwater acoustic transducer. The crystal had resonant modes from 3,8 to 7,8 MHz

Paper Details

Date Published: 1 March 1991
PDF: 12 pages
Proc. SPIE 1399, Optical Systems in Adverse Environments, (1 March 1991); doi: 10.1117/12.26092
Show Author Affiliations
Svein Ellingsrud, Norwegian Institute of Technology (Norway)
Ole Johan Lokberg, Norwegian Institute of Technology (Norway)
Hans Magne Pedersen, Norwegian Institute of Technology (Norway)

Published in SPIE Proceedings Vol. 1399:
Optical Systems in Adverse Environments
Soon Fatt Yoon; M. H. Kuok; Donald E. Silva, Editor(s)

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