11 October 2010 Application of wavelet analysis in laser Doppler vibration signal denoising
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Large number of experiments show that, due to external disturbances, the measured surface is too rough and other factors make use of laser Doppler technique to detect the vibration signal contained complex information, low SNR, resulting in Doppler frequency shift signals unmeasured, can not be demodulated Doppler phase and so on. This paper first analyzes the laser Doppler signal model and feature in the vibration test, and studies the most commonly used three ways of wavelet denoising techniques: the modulus maxima wavelet denoising method, the spatial correlation denoising method and wavelet threshold denoising method. Here we experiment with the vibration signals and achieve three ways by MATLAB simulation. Processing results show that the wavelet modulus maxima denoising method at low laser Doppler vibration SNR, has an advantage for the signal which mixed with white noise and contained more singularities; the spatial correlation denoising method is more suitable for denoising the laser Doppler vibration signal which noise level is not very high, and has a better edge reconstruction capacity; wavelet threshold denoising method has a wide range of adaptability, computational efficiency, and good denoising effect. Specifically, in the wavelet threshold denoising method, we estimate the original noise variance by spatial correlation method, using an adaptive threshold denoising method, and make some certain amendments in practice. Test can be shown that, compared with conventional threshold denoising, this method is more effective to extract the feature of laser Doppler vibration signal.
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Yu-fei Lan, Hui-feng Xue, Xin-liang Li, Dan Liu, "Application of wavelet analysis in laser Doppler vibration signal denoising", Proc. SPIE 7656, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 765609 (11 October 2010); doi: 10.1117/12.863866; https://doi.org/10.1117/12.863866

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