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Most of the seismic inversion techniques currently proposed focus on robustness with respect to the background model choice or inaccurate physical modeling assumptions, but are not apt to large-scale 3D applications. On the other hand,…

Geophysics · Physics 2021-04-22 Gabrio Rizzuti , Mathias Louboutin , Rongrong Wang , Felix J. Herrmann

Full waveform inversion (FWI) is a nonlinear waveform matching procedure, which suffers from cycle skipping when the initial model is not kinematically-accurate enough. To mitigate cycle skipping, wavefield reconstruction inversion (WRI)…

Optimization and Control · Mathematics 2019-10-29 Hossein S. Aghamiry , Ali Gholami , Stéphane Operto

Most existing beamforming methods are frequency-domain methods, and are designed for enhancing a farfield target source over a narrow frequency band. They have found diverse applications and are still under active development. However, they…

Audio and Speech Processing · Electrical Eng. & Systems 2021-05-19 Fei Ma , Thushara D. Abhayapala , Prasanga N. Samarasinghe

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…

Medical Physics · Physics 2026-03-26 Tim Bürchner , Simon Schmid , Ernst Rank , Stefan Kollmannsberger , Andreas Fichtner

Extended formulation of Full Waveform Inversion (FWI), called Wavefield Reconstruction Inversion (WRI), offers potential benefits of decreasing the nonlinearity of the inverse problem by replacing the explicit inverse of the ill-conditioned…

Optimization and Control · Mathematics 2020-05-18 Hossein S. Aghamiry , Ali Gholami , Stéphane Operto

Frequency-domain unsteady lifting-line theory is better developed than its time-domain counterpart. To take advantage of this, this paper transforms time-domain kinematics to the frequency domain, performs a convolution and then returns the…

Fluid Dynamics · Physics 2021-05-13 Hugh J. A. Bird , Kiran Ramesh

Full waveform inversion (FWI) updates the subsurface model from an initial model by comparing observed and synthetic seismograms. Due to high nonlinearity, FWI is easy to be trapped into local minima. Extended domain FWI, including…

Numerical Analysis · Mathematics 2024-08-28 Pengliang Yang , Wei Zhou

The aim of the study is to demonstrate that some methods are more relevant for implementing the Real-Time Nearfield Acoustic Holography than others. First by focusing on the forward propagation problem, different approaches are compared to…

Classical Physics · Physics 2008-10-13 Jean-Hugh Thomas , Vincent Grulier , Sébastien Paillasseur , Jean-Claude Pascal

Extended full-waveform inversion (FWI) has shown promising results for accurate estimation of subsurface parameters when the initial models are not sufficiently accurate. Frequency-domain applications have shown that the augmented…

Numerical Analysis · Mathematics 2021-09-16 Ali Gholami , Hossein S. Aghamiry , Stephane Operto

In this article we study the inverse problem of thermoacoustic tomography (TAT) on a medium with attenuation represented by a time- convolution (or memory) term, and whose consideration is motivated by the modeling of ultrasound waves in…

Analysis of PDEs · Mathematics 2017-03-29 Sebastian Acosta , Benjamin Palacios

We introduce the joint time-frequency scattering transform, a time shift invariant descriptor of time-frequency structure for audio classification. It is obtained by applying a two-dimensional wavelet transform in time and log-frequency to…

Sound · Computer Science 2018-08-06 Joakim Andén , Vincent Lostanlen , Stéphane Mallat

Passive acoustic mapping enables the spatial mapping and temporal monitoring of cavitation activity, playing a crucial role in therapeutic ultrasound applications. Most conventional beamforming methods, whether implemented in the time or…

Signal Processing · Electrical Eng. & Systems 2025-11-26 Tatiana Gelvez-Barrera , Barbara Nicolas , Denis Kouamé , Bruno Gilles , Adrian Basarab

Spatial sound field interpolation relies on suitable models to both conform to available measurements and predict the sound field in the domain of interest. A suitable model can be difficult to determine when the spatial domain of interest…

Audio and Speech Processing · Electrical Eng. & Systems 2022-11-30 Manuel Hahmann , Efren Fernandez-Grande

In this paper, we present a frequency-domain volume integral method to model the microseismic wavefield in heterogeneous anisotropic-elastic media. The elastic wave equation is written as an integral equation of the Lippmann-Schwinger type,…

Geophysics · Physics 2023-01-31 Ujjwal Shekhar , Morten Jakobsen , Einar Iversen , Inga Berre , Florin A. Radu

Wavefield reconstruction inversion (WRI) extends the search space of Full Waveform Inversion (FWI) by allowing for wave equation errors during wavefield reconstruction to match the data from the first iteration. Then, the wavespeeds are…

Optimization and Control · Mathematics 2020-05-18 Hossein S. Aghamiry , Ali Gholami , Stéphane Operto

Inline holographic imaging presents an ill-posed inverse problem of reconstructing objects' complex amplitude from recorded diffraction patterns. Although recent deep learning approaches have shown promise over classical phase retrieval…

Optics · Physics 2025-07-02 Chanseok Lee , Fakhriyya Mammadova , Jiseong Barg , Mooseok Jang

Wavefield focusing is often achieved by Time-Reversal Mirrors, where wavefields emitted by a source located at the focal point are evaluated at a closed boundary and sent back, after Time-Reversal, into the medium from that boundary.…

Classical Physics · Physics 2025-09-12 Giovanni Angelo Meles , Joost van der Neut , Koen W. A. van Dongen , Kees Wapenaar

This study formally adapts the time-domain linear sampling method (TLSM) for ultrasonic imaging of stationary and evolving fractures in safety-critical components. The TLSM indicator is then applied to the laboratory test data of [22, 18]…

Numerical Analysis · Mathematics 2022-09-16 Xiaoli Liu , Jian Song , Fatemeh Pourahmadian , Houssem Haddar

Seismic acoustic impedance plays a crucial role in lithological identification and subsurface structure interpretation. However, due to the inherently ill-posed nature of the inversion problem, directly estimating impedance from post-stack…

Machine Learning · Computer Science 2025-06-17 Jie Chen , Hongling Chen , Jinghuai Gao , Chuangji Meng , Tao Yang , XinXin Liang

In time reversal acoustics experiments, a signal is emitted from a localized source, recorded at an array of receivers-transducers, time reversed, and finally re-emitted into the medium. A celebrated feature of time reversal experiments is…

Chaotic Dynamics · Physics 2007-05-23 Guillaume Bal , Leonid Ryzhik
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