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We study the seismic inverse problem for the recovery of subsurface properties in acoustic media. In order to reduce the ill-posedness of the problem, the heterogeneous wave speed parameter to be recovered is represented using a limited…

Analysis of PDEs · Mathematics 2020-09-10 Florian Faucher , Otmar Scherzer , Hélène Barucq

Multi-frequency Electrical Impedance Tomography (mfEIT) is an emerging biomedical imaging modality to reveal frequency-dependent conductivity distributions in biomedical applications. Conventional model-based image reconstruction methods…

Image and Video Processing · Electrical Eng. & Systems 2021-05-27 Zhou Chen , Jinxi Xiang , Pierre Bagnaninchi , Yunjie Yang

The Event Horizon Telescope (EHT) has produced images of the plasma flow around the supermassive black holes in Sgr A* and M87* with a resolution comparable to the projected size of their event horizons. Observations with the…

High Energy Astrophysical Phenomena · Physics 2023-03-15 Andrew Chael , Sara Issaoun , Dominic W. Pesce , Michael D. Johnson , Angelo Ricarte , Christian M. Fromm , Yosuke Mizuno

In this work we develop and analyze an adaptive finite element method for efficiently solving electrical impedance tomography -- a severely ill-posed nonlinear inverse problem for recovering the conductivity from boundary voltage…

Numerical Analysis · Mathematics 2019-05-16 Bangti Jin , Yifeng Xu , Jun Zou

Ultrasound images vary widely across scanners, operators, and anatomical targets, which often causes models trained in one setting to generalize poorly to new hospitals and clinical conditions. The Foundation Model Challenge for Ultrasound…

Computer Vision and Pattern Recognition · Computer Science 2026-03-23 Ufaq Khan , L. D. M. S. Sai Teja , Ayuba Shakiru , Mai A. Shaaban , Yutong Xie , Muhammad Bilal , Muhammad Haris Khan

We introduce and analyze a virtual element method (VEM) for the Helmholtz problem with approximating spaces made of products of low order VEM functions and plane waves. We restrict ourselves to the 2D Helmholtz equation with impedance…

Numerical Analysis · Mathematics 2015-05-20 Ilaria Perugia , Paola Pietra , Alessandro Russo

Achieving high-quality High Dynamic Range (HDR) imaging on resource-constrained edge devices is a critical challenge in computer vision, as its performance directly impacts downstream tasks such as intelligent surveillance and autonomous…

Computer Vision and Pattern Recognition · Computer Science 2025-09-25 Yu-Shen Huang , Tzu-Han Chen , Cheng-Yen Hsiao , Shaou-Gang Miaou

Multiscale and multiphysics problems need novel numerical methods in order for them to be solved correctly and predictively. To that end, we develop a wavelet based technique to solve a coupled system of nonlinear partial differential…

Numerical Analysis · Mathematics 2023-03-22 Cale Harnish , Luke Dalessandro , Karel Matous , Daniel Livescu

We propose the complex-plane generalization of a powerful algebraic sequence acceleration algorithm, the Method of Weighted Averages (MWA), to guarantee exponential-cum-algebraic convergence of Fourier and Fourier-Hankel (F-H) integral…

Computational Physics · Physics 2016-02-17 Kamalesh Sainath , Fernando Teixeira , Burkay Donderici

Bayesian image restoration has had a long history of successful application but one of the limitations that has prevented more widespread use is that the methods are generally computationally intensive. The authors recently addressed this…

Methodology · Statistics 2023-06-02 Karl Young , John Kornak , Eric Friedman

We develop and analyze a new approach for simultaneously computing multiple solutions to the Helmholtz equation for different frequencies and different forcing functions. The new Multi-Frequency WaveHoltz (MFWH) algorithm is an extension of…

The advent of enhanced technologies in radio interferometry and the perspective of the SKA telescope bring new challenges in image reconstruction. One of these challenges is the spatio-spectral reconstruction of large (Terabytes) data cubes…

Instrumentation and Methods for Astrophysics · Physics 2016-03-07 Jérémy Deguignet , André Ferrari , David Mary , Chiara Ferrari

This paper documents package for the particle level fast simulation. The package is designed to complete the AcerMC generator framework with the easy-to-use simulation and reconstruction algorithms. The package provides, starting from list…

High Energy Physics - Phenomenology · Physics 2007-05-23 E. Richter-Was

In tomographic adaptive-optics (AO) systems, errors due to tomographic wave-front reconstruction limit the performance and angular size of the scientific field of view (FoV), where AO correction is effective. We propose a multi time-step…

Instrumentation and Methods for Astrophysics · Physics 2016-04-12 Yoshito H. Ono , Masayuki Akiyama , Shin Oya , Olivier Lardiere , David R. Andersen , Carlos Correia , Kate Jackson , Colin Bradley

The development of efficient and accurate reconstruction methods is an important aspect of tomographic imaging. In this article, we address this issue for photoacoustic tomography. To this aim, we use models for acoustic wave propagation…

Numerical Analysis · Mathematics 2017-11-22 Markus Haltmeier , Richard Kowar , Linh V. Nguyen

Photoacoustic (PA) imaging technology combines the advantages of optical imaging and ultrasound imaging, showing great potential in biomedical applications. Many preclinical studies and clinical applications urgently require fast,…

Image and Video Processing · Electrical Eng. & Systems 2024-08-13 Yuwei Zheng , Zijian Gao , Yuting Shen , Jiadong Zhang , Daohuai Jiang , Fengyu Liu , Feng Gao , Fei Gao

Producing reliable acoustic subsurface velocity models still remains the main bottleneck of the oil and gas industry's traditional imaging sequence. In complex geological settings, the output of conventional ray-based or wave-equation-based…

Geophysics · Physics 2022-06-07 Guillaume Barnier , Ettore Biondi , Robert G. Clapp , Biondo Biondi

The scattering and transmission of harmonic acoustic waves at a penetrable material are commonly modelled by a set of Helmholtz equations. This system of partial differential equations can be rewritten into boundary integral equations…

Numerical Analysis · Mathematics 2022-04-19 Elwin van 't Wout , Seyyed R. Haqshenas , Pierre Gélat , Timo Betcke , Nader Saffari

We consider the application of the WaveHoltz iteration to time-harmonic elastic wave equations with energy conserving boundary conditions. The original WaveHoltz iteration for acoustic Helmholtz problems is a fixed-point iteration that…

Numerical Analysis · Mathematics 2022-09-28 Daniel Appelö , Fortino Garcia , Allen Alvarez Loya , Olof Runborg

Abstract Objective. Cone-beam computed tomography is becoming more and more popular in applications such as 3D dental imaging. Iterative methods compared to the standard Feldkamp algorithm have shown improvements in image quality of…

Signal Processing · Electrical Eng. & Systems 2024-11-15 Louise Friot-Giroux , Françoise Peyrin , Voichita Maxim