Characterization of a moving surface roughness by backscatterer ultrasound performed with time-frequency analysis and high order statistics
Résumé
The determination of a calibrated surface roughness with translation velocity of v=15 ms-1 was investigated with ultrasonic backscattered technique based on Doppler effect. The difficulty of the Fourier analysis to detect with accuracy the instantaneous changes of roughness induces a time-frequency analysis. The need to analyze both frequency and temporal nature of data is due to the non stationarity of measured signals. The theoretical study demonstrates that the Doppler spectrum is the product of the spatial spectrum of the surface roughness and the velocity of the surface. An accurate detection of roughness has been derived thanks to the spectrogram representation.
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