Laura Perichon

Control parameters inversion using genetic algorithms applied to numerical impedance synthesis for woodwinds

Woodwind sound synthesis in real time has been achieved using different computational techniques, especially the so‐called numerical impedance model based only on acoustical variables. The impedances of the excitation mechanism and of the resonator are approximated by IIR filters and related by a nonlinear coupling. The control parameters can be reduced to a number of three including the length of the resonator, the mouth pressure, and a mask parameter. In this paper we present preliminary inversion results for the latter two parameters in the case of a clarinet. The inversion algorithm is based on differential evolution metaheuristics with a number of prior conditions on the correlated parameters. A cost function based on time‐domain correlation has been implemented, allowing us to obtain better results in terms of signal matching than with conventional descriptors extraction. The technique has proved its effectiveness on the sustained part of synthesized sounds and a regularization method is presented t...

Characterization of sediment dynamics in an estuary environment using acoustic techniques

In recent years, acoustic‐based methods have been developed to characterize the dynamical behavior of loose sediments and bed deposits in very shallow water environments. In this paper, we present preliminary results on the estimation of the dynamic changes in an estuarine environment using data from dual‐frequency echosounding at high resolution and contemporaneous hydrological measurements including suspended matter concentration, density subbottom profiling, and data assimilation based on a sediment transport model. Those measurements are being conducted in the lower estuary of the Scheldt (Belgium) at the Sint Anna site where strong tide and season‐dependent phenomena can be observed. This allows us to construct a ground‐truthed, time‐dependent geoacoustic model of the environment, i.e., a characterization of sound speed, density, and attenuation in function of time and depth. Synthetic acoustic data generated by that model will then be used to test inversion methods for monitoring sediment dynamics i...