Traitement d'échogrammes ultrasonores par déconvolution aveugle

Ultrasonic traces can be supposed to result from the convolution between the propagation wavelet and the reflectivity that represent the inhomogeneihities. The wavelet is often unknown; thus the recovery of the reflectivity requires a blind deconvolution process. In such a case, it is common to estimate a minimum-phase wavelet and then to restore the reflectivity. In fact, there is no reason why the wavelet should have minimal phase. We propose two blind deconvolution methods that enable the recovery of the wavelet’s phase. The first consists in estimating jointly the reflectivity and the wavelet. The second method proposes to refine the knowledge of the convolution kernel by accounting for kernel waveshifts.