1 June 1998 Real-time measurement of in-plane vibration by double-aperture laser speckle interferometry
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Proceedings Volume 3411, Third International Conference on Vibration Measurements by Laser Techniques: Advances and Applications; (1998) https://doi.org/10.1117/12.307717
Event: Third International Conference on Vibration Measurements by Laser Techniques: Advances and Applications, 1998, Ancona, Italy
Abstract
This paper describes the real-time measurement of in-plane vibration using an improved double-aperture laser speckle interferometer. To detect the in-plane vibration in real- time, a new signal processing system which can detect the phase angle of the frequency component of the interference fringes in real-time by calculating Fourier coefficients is proposed. The proposed real-time signal processing system is composed of a pulse generator, a sin/cos generator and an A/D converter controlled by a personal computer, and of an analog electronic circuit made of analog IC's. The linearity of the output signal of the prototype due to a number of the detected fringes and noises is experimentally examined. In- plane static displacement and vibration displacements of a specimen driven by a piezostack are measured with a new laser speckle interferometer equipped with the proposed signal processing system and are calibrated with a gap sensor. The measured static in-plane displacements varied in proportion to the given displacement with reproductive error variation with the maximum value of 0.5 micrometers . The vibration displacements measured with the laser speckle interferometer were detected with the maximum sampling frequency of 470Hz. This new laser speckle interferometer thus achieved the measurement of in-plane vibration in real-time.
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Nobuyuki Iwatsuki, Nobuyuki Iwatsuki, Kouichi Morikawa, Kouichi Morikawa, Iwao Hayashi, Iwao Hayashi, } "Real-time measurement of in-plane vibration by double-aperture laser speckle interferometry", Proc. SPIE 3411, Third International Conference on Vibration Measurements by Laser Techniques: Advances and Applications, (1 June 1998); doi: 10.1117/12.307717; https://doi.org/10.1117/12.307717
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