Using quasi-holographic backpropagation to understand high-frequency scattering from curved elastic objects in water

Area of Science:

• Acoustics
• Underwater acoustics
• Elastic wave scattering

Background:

• High-frequency sound scattering in water involves structural guided waves.
• These waves can appear to originate from virtual sources within elastic objects.

Purpose of the Study:

• To utilize Quasi-Holographic Backpropagation (QHBP) for analyzing backscattered signals from elastic objects.
• To investigate virtual sources and axial focusing in glory scattering using QHBP.

Main Methods:

• Applied QHBP, limited to supersonic wave numbers, to locate virtual sources in space and time.
• Isolated target scatter signals by eliminating interference from tank reflections and anomalies.
• Analyzed bistatic underwater experimental data, including space-time plots from short pulse illumination.

Main Results:

• QHBP successfully identified the location and diameter of virtual ring sources responsible for glory scattering.
• Demonstrated the isolation of specific scatter signals of interest.
• Showcased the ability to extract information about elastic object features from backpropagated data.

Conclusions:

• QHBP is effective for characterizing virtual sources and scattering phenomena like glory scattering.
• The technique provides insights into elastic object properties (size, shape, density) through backscatter analysis.
• QHBP enhances the understanding of complex acoustic scattering in underwater environments.