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Time reversal, that is prefiltering of transmitted signals with time reversed channel impulse responses, may be used in single user communications in order to move complexity from the receiver to the transmitter, and in multiuser…

Information Theory · Computer Science 2014-05-20 Guido Carlo Ferrante , Jocelyn Fiorina , Maria-Gabriella Di Benedetto

In recent work, redressed warped frames have been introduced for the analysis and synthesis of audio signals with non-uniform frequency and time resolutions. In these frames, the allocation of frequency bands or time intervals of the…

Sound · Computer Science 2018-12-11 Thomas Mejstrik , Gianpaolo Evangelista

This paper applies the Recursive Projection Method (RPM) to the problem of finding the effective mechanical response of a periodic heterogeneous solid. Previous works apply the Fast Fourier Transform (FFT) in combination with various…

Computational Engineering, Finance, and Science · Computer Science 2020-03-18 Xiaoyao Peng , Dhriti Nepal , Kaushik Dayal

The inverse acoustic scattering problems using multi-frequency backscattering far field patterns at isolated directions are studied. The underlying object could be point like scatterers, small scatterers, extended inhomogeneities and…

Analysis of PDEs · Mathematics 2019-10-18 Xia Ji , Xiaodong Liu

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 develop mask iterative hard thresholding algorithms (mask IHT and mask DORE) for sparse image reconstruction of objects with known contour. The measurements follow a noisy underdetermined linear model common in the compressive sampling…

Machine Learning · Statistics 2011-12-05 Aleksandar Dogandzic , Renliang Gu , Kun Qiu

A deep neural network solution for time-scale modification (TSM) focused on large stretching factors is proposed, targeting environmental sounds. Traditional TSM artifacts such as transient smearing, loss of presence, and phasiness are…

Audio and Speech Processing · Electrical Eng. & Systems 2022-12-01 Leonardo Fierro , Alec Wright , Vesa Välimäki , Matti Hämäläinen

Direct imaging methods recover the presence, position, and shape of the unknown obstacles in time-harmonic inverse scattering without a priori knowledge of either the physical properties or the number of disconnected components of the…

Analysis of PDEs · Mathematics 2023-11-29 General Ozochiawaeze

In this paper, we consider two time-harmonic inverse scattering problems of reconstructing penetrable inhomogeneous obstacles from near field measurements. First we appeal to the Born approximation for reconstructing small isotropic…

Analysis of PDEs · Mathematics 2017-01-18 Isaac Harris , Scott Rome

The time reversal method in thermoacoustic tomography is used for approximating the initial pressure inside a biological object using measurements of the pressure wave made on a surface surrounding the object. This article presents error…

Analysis of PDEs · Mathematics 2009-03-18 Yulia Hristova

We consider the inverse source problem of thermo- and photoacoustic tomography, with data registered on an open surface partially surrounding the source of acoustic waves. Under the assumption of constant speed of sound we develop an…

Analysis of PDEs · Mathematics 2020-04-17 Mtthias Eller , Philip Hoskins , Leonid Kunyansky

Magnetic Resonance Imaging (MRI) is a valuable clinical diagnostic modality for spine pathologies with excellent characterization for infection, tumor, degenerations, fractures and herniations. However in surgery, image-guided spinal…

Image and Video Processing · Electrical Eng. & Systems 2021-02-11 Madhu Mithra K K , Sriprabha Ramanarayanan , Keerthi Ram , Mohanasankar Sivaprakasam

This paper is devoted to a novel quantitative imaging scheme of identifying impenetrable obstacles in time-harmonic acoustic scattering from the associated far-field data. The proposed method consists of two phases. In the first phase, we…

Numerical Analysis · Mathematics 2023-07-05 Youzi He , Hongyu Liu , Xianchao Wang

Likelihood-based deep generative models have been widely investigated for Image Anomaly Detection (IAD), particularly Normalizing Flows, yet their strict architectural invertibility needs often constrain scalability, particularly in…

Computer Vision and Pattern Recognition · Computer Science 2026-04-15 Liangwei Li , Lin Liu , Hanzhe Liang , Juanxiu Liu , Jing Zhang , Ruqian Hao , Xiaohui Du , Yong Liu , Pan Li

In this paper, we revisit one-channel time reversal (TR) experiments through multiple scattering media in the framework of the self-consistent multiple scattering theory. The hyper resolution and the self-averaging property are retrieved.…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Julien P De Rosny , Arnaud Tourin , Arnaud Derode , Bart Van Tiggelen , Mathias Fink

Motivated by applications in quantitative photoacoustic imaging, we study inverse problems to a semilinear radiative transport equation (RTE) where we intend to reconstruct absorption coefficients in the equation from single and multiple…

Analysis of PDEs · Mathematics 2020-07-21 Kui Ren , Yimin Zhong

An extended aperture has the potential to greatly improve ultrasound imaging performance. This work extends the effective aperture size by coherently compounding the received radio frequency data from multiple transducers. A framework is…

Medical Physics · Physics 2019-11-12 Laura Peralta , Alberto Gomez , Ying Luan , Baehyung Kim , Joseph V. Hajnal , Robert J. Eckersley

We consider the time-harmonic elastic wave scattering from a general (possibly anisotropic) inhomogeneous medium with an embedded impenetrable obstacle. We show that the impenetrable obstacle can be effectively approximated by an isotropic…

Analysis of PDEs · Mathematics 2021-02-19 Zhengjian Bai , Huaian Diao , Hongyu Liu , Qingle Meng

We study the mathematical model of multiwave tomography including thermo and photoacoustic tomography with a variable speed for a fixed time interval $[0,T]$. We assume that the waves reflect from the boundary of the domain. We propose an…

Analysis of PDEs · Mathematics 2015-06-11 Plamen Stefanov , Yang Yang

This article considers the inverse problem of Magnet resonance electrical impedance tomography (MREIT) in two dimensions. A rigorous mathematical framework for this inverse problem as well as the existing Harmonic $B_z$ Algorithm as a…

Numerical Analysis · Mathematics 2018-04-17 Dominik Garmatter , Bastian Harrach
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