Reconstructing effective ultrasound transducer models via distributed source inversion

TL;DR

This paper introduces a distributed source inversion method to accurately reconstruct ultrasound transducer models, capturing aperture effects without detailed structural knowledge, thereby enhancing simulation and imaging accuracy.

Contribution

It presents a novel inversion strategy that reconstructs effective transducer source models from measurements, improving ultrasound wavefield simulations without requiring detailed transducer design data.

Findings

Reconstructed models closely match experimental directivity patterns.

Simulation results show improved waveform accuracy.

Enhanced imaging quality in synthetic studies.

Abstract

Accurate modeling of ultrasound wave propagation is essential for high-fidelity simulation and imaging in ultrasonic testing. A primary challenge lies in characterizing the excitation source, particularly for transducers with large apertures relative to the acoustic wavelengths. In such cases, non-uniform excitation and spatial interference significantly affect the resulting radiation patterns. This paper proposes a distributed source inversion strategy to reconstruct an effective spatio-temporal transducer model that reproduces experimentally measured wavefields. The reconstructed source model captures aperture-dependent phase and amplitude variations without the need for detailed knowledge of the transducer structure. The approach is validated using directivity measurements on an aluminum half-cylinder, where simulations incorporating the reconstructed source model show close agreement with experimental directivity patterns and waveform shapes. Finally, synthetic studies on reverse time migration and full-waveform inversion demonstrate that accurate transducer modeling is critical for the success of simulation-based imaging and inversion workflows and significantly improves reconstruction quality.