Matched representations and filters for guided waves
Résumé
We propose time-frequency methods to filter dispersive guided wave signals. Guided waves occur in acoustical propagation (oceanic waveguides), geophysics (layered medium), or optics (dielectric optical waveguides). In waveguides, signals can be decomposed into normal modes which contain information on environmental parameters and source localization. As modes present nonlinear time-frequency evolution, modal filtering is not possible with conventional tools. To overcome the difficulty presented by these nonlinearties, we have developed matched tools: matched frequency and time-frequency representations and the modal filterings associated with these representations. The tools developed are based on unitary equivalence principle. Performance and robustness of different proposed modal filters are evaluated and compared. All of these tools can be used for both source localization and environmental inversion.