3 - Utilisation du cepstre d'énergie pour la vélocimétrie par images de particules

While the autocorrelation is often computed in particle image velocimetry (PIV), we propose instead to use the power cepstrum for such a measurement. We discuss different formulations of the power cepstrum which is indeed a Cool well-suited for the detection of the echoes due to multi-exposure . Contrary ta the autocorrelation, the resolution of the power cepstrum is not related to the size of particles . Thence, the use of the power cepstrum has the advantage to allow the measurement of displacements lower than the size of particles . We show that the contribution of the echo in comparison with the contribution of the initial signal in the cepstrum is increased by the use of a window. We verify that such a use also allows to improve the cepstrum over noise ratio .