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Computational time reversal imaging can be used to locate the position of multiple scatterers in a known background medium. The current methods for computational time reversal imaging are based on the null subspace projection operator,…

Data Analysis, Statistics and Probability · Physics 2009-06-16 M. Andrecut

We study the mathematical model of thermoacoustic tomography in media with a variable speed for a fixed time interval, greater than the diameter of the domain. In case of measurements on the whole boundary, we give an explicit solution in…

Analysis of PDEs · Mathematics 2010-09-10 Plamen Stefanov , Gunther Uhlmann

In ultrasound tomography, the speed of sound inside an object is estimated based on acoustic measurements carried out by sensors surrounding the object. An accurate forward model is a prominent factor for high-quality image reconstruction,…

Image and Video Processing · Electrical Eng. & Systems 2021-11-24 Janne Koponen , Timo Lähivaara , Jari Kaipio , Marko Vauhkonen

Thermal tomography is an imaging technique for deducing information about the internal structure of a physical body from temperature measurements on its boundary. This work considers time-dependent thermal tomography modeled by a parabolic…

Numerical Analysis · Mathematics 2017-07-25 Nuutti Hyvönen , Lauri Mustonen

We study the mathematical model of thermoacoustic and photoacoustic tomography when the sound speed has a jump across a smooth surface. This models the change of the sound speed in the skull when trying to image the human brain. We derive…

Analysis of PDEs · Mathematics 2015-05-19 Plamen Stefanov , Gunther Uhlmann

We derive an explicit method for reconstructing singularities of the initial data in a thermoacoustic tomography problem, in the case of variable sound speed and limited boundary data. In order to obtain this explicit formula we assume the…

Analysis of PDEs · Mathematics 2009-05-19 Dustin Steinhauer

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

We analyze the mathematical model of multiwave tomography with a variable speed with integrating measurements on planes tangent to a sphere surrounding the source. We prove sharp uniqueness and stability estimates with full and partial data…

Analysis of PDEs · Mathematics 2016-05-04 Plamen Stefanov , Yang Yang

Time reversal of waves has been successfully used in communications, sensing and imaging for decades. The application in underwater acoustic communications is of our special interest, as it puts together a reversible process (allowing a…

Cellular Automata and Lattice Gases · Physics 2018-06-13 Harun Siljak

A novel method to solve inverse problems for the wave equation is introduced. The method is a combination of the boundary control method and an iterative time reversal scheme, leading to adaptive imaging of coefficient functions of the wave…

Analysis of PDEs · Mathematics 2007-05-23 Kenrick Bingham , Yaroslav Kurylev , Matti Lassas , Samuli Siltanen

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

The reverberation time is one of the most important parameters used to characterize the acoustic property of an enclosure. In real-world scenarios, it is much more convenient to estimate the reverberation time blindly from recorded speech…

Sound · Computer Science 2021-12-10 Kaitong Zheng , Chengshi Zheng , Jinqiu Sang , Yulong Zhang , Xiaodong Li

In this paper, we study the photoacoustic tomography problem for which we seek to recover both the initial state of the pressure field and the wave speed of the medium from the knowledge of a single boundary measurement. The goal is to…

Analysis of PDEs · Mathematics 2020-07-01 Sebastian Acosta

In thermoacoustic and photoacoustic tomography an electromagnetic wave is sent through a medium, heating it and therefore generating an elastic expansion that in turns generates an acoustic wave that is measured outside the medium. The…

Analysis of PDEs · Mathematics 2023-02-08 Yavar Kian , Gunther Uhlmann

The aim of this paper is to study the feasibility of time-reversal methods in a non homogeneous elastic medium, from data recorded in an acoustic medium. We aim to determine, from partial aperture boundary measurements, the presence and…

Numerical Analysis · Mathematics 2020-10-28 Franck Assous , Moshe Lin

Time-reversal (TR) refocusing of waves is one of fundamental principles in wave physics. Using the TR approach, "Time-reversal mirrors" can physically create a time-reversed wave that exactly refocus back, in space and time, to its original…

Fluid Dynamics · Physics 2016-09-23 G. Ducrozet , M. Fink , A. Chabchoub

The attenuation of ultrasound waves in photoacoustic and thermoacoustic imaging presents an important drawback in the applicability of these modalities. This issue has been addressed previously in the applied and theoretical literature, and…

Analysis of PDEs · Mathematics 2021-09-15 Benjamin Palacios

We demonstrate that the diffusion coefficient, $D$, for ultrasound propagating in a multiple scattering medium, such as a dense granular suspension, can be measured using a time reversal experiment. This requires an unprecedented…

Soft Condensed Matter · Physics 2025-02-27 Y. Abraham , B. A. van Tiggelen , N. Benech , C. Negreira , X. Jia , A. Tourin

We investigate the inverse source problem for the wave equation, arising in photo- and thermoacoustic tomography. There exist quite a few theoretically exact inversion formulas explicitly expressing solution of this problem in terms of the…

Analysis of PDEs · Mathematics 2018-08-01 Ngoc Do , Leonid Kunyansky

A simple deterministic and time reversal invariant type of thermostat is proposed to be used for computer simulations of classical systems. It acts on collisions with the walls of the container exclusively. It maps the incoming and outgoing…

Statistical Mechanics · Physics 2014-11-13 Henk van Beijeren