Simulation of nonlinear ultrasound wave propagation in Fourier domain
Résumé
The nonlinear ultrasound field distortion occurs in all biological media and reminds of great interest in all nonlinear imaging strategies as harmonic or contrast agent imaging. From the various set of methods that compute this propagation, the angular spectrum one is the fastest in term of computation time but the harmonics calculation is less accurate compared to other strategies. In this work, a new formulation based on a slowly varying envelope approximation is proposed to evaluate the full nonlinear spectrum distortion during the propagation. This tool is compared to a previous published angular method and the resulting pressure fields are very close which validate the proposed strategy, with a maximal error inferior to 2 dB. In term of computation time, the proposed tools is as fast as the previous one, but compute the full spectrum in once.