Full waveform inversion for bore reconstruction of woodwind-like instruments

The internal geometry of a wind instrument can be estimated from acoustic measurements. For woodwind instruments, this involves characterizing the inner shape (bore) but also side holes (dimensions and location). In study, geometric parameters are recovered by gradient-based optimization process, which minimizes deviation between simulated measured linear responses resonator for several fingerings through an observable function. fields computed solving system resulting 1D spectral finite elements spatial discretization wave propagation equations (including thermo-viscous effects, radiation holes). “full waveform inversion” (FWI) technique exploits fact that gradient cost function same as direct problem with different source term. is better accuracy less additional than finite-difference. dependence on choice observed quantity, frequency range used, first analyzed. Then, FWI used to reconstruct, impedances, elementary 14 design variables. results, obtained in about 1 minute laptop, excellent agreement