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Motion, e.g., due to patient movement or improper device calibration, is inevitable in many imaging modalities such as photoacoustic tomography (PAT) by a rotating system and can lead to undesirable motion artifacts in image…

Numerical Analysis · Mathematics 2016-09-28 Julianne Chung , Linh Nguyen

This paper deals with a numerical analysis of plastic deformation under various conditions, utilizing Radial Basis Function (RBF) approximation. The focus is on the elasto-plastic von Mises problem under plane-strain assumption. Elastic…

Numerical Analysis · Mathematics 2024-05-09 Filip Strniša , Mitja Jančič , Gregor Kosec

We consider the problem of reconstruction of Cauchy data for the wave equation in $\mathbb{R}^1$ by the measurements of its solution on the boundary of the finite interval. This is a one-dimensional model for the multidimensional problem of…

Analysis of PDEs · Mathematics 2025-05-26 D. Langemann , A. S. Mikhaylov , V. S. Mikhaylov

We propose a new variational model for joint image reconstruction and motion estimation in spatiotemporal imaging, which is investigated along a general framework that we present with shape theory. This model consists of two components, one…

Numerical Analysis · Mathematics 2019-11-06 Chong Chen , Barbara Gris , Ozan Öktem

Current state-of-the-art motion-based dynamic computed tomography reconstruction techniques estimate the deformation by considering motion models in the entire object volume although occasionally the proper change is local. In this article,…

Optimization and Control · Mathematics 2023-09-06 Anh-Tuan Nguyen , Jens Renders , Jan Sijbers , Jan De Beenhouwer

The aim of this paper is to establish a nonlinear variational approach to the reconstruction of moving density images from indirect dynamic measurements. Our approach is to model the dynamics as a hyperelastic deformation of an initial…

Numerical Analysis · Mathematics 2015-12-01 Martin Burger , Jan Modersitzki , Sebastian Suhr

Reconstructing a dynamic object with affine motion in computerized tomography (CT) leads to motion artifacts if the motion is not taken into account. In most cases, the actual motion is neither known nor can be determined easily. As a…

Numerical Analysis · Mathematics 2024-03-14 Gesa Sarnighausen , Anne Wald , Alexander Meaney

In this paper, we propose a global method for estimating the motion of a camera which films a static scene. Our approach is direct, fast and robust, and deals with adjacent frames of a sequence. It is based on a quadratic approximation of…

Computer Vision and Pattern Recognition · Computer Science 2008-09-29 Claire Jonchery , Françoise Dibos , Georges Koepfler

The paper surveys variational approaches for image reconstruction in dynamic inverse problems. Emphasis is on methods that rely on parametrised temporal models. These are here encoded as diffeomorphic deformations with time dependent…

Image and Video Processing · Electrical Eng. & Systems 2020-07-21 Andreas Hauptmann , Ozan Öktem , Carola Schönlieb

In this paper, we investigate image reconstruction for dynamic Computed Tomography. The motion of the target with respect to the measurement acquisition rate leads to highly resolved in time but highly undersampled in space measurements.…

Image and Video Processing · Electrical Eng. & Systems 2025-06-27 Pablo Arratia , Matthias Ehrhardt , Lisa Kreusser

Motion free reconstruction of compressively sampled cardiac perfusion MR images is a challenging problem. It is due to the aliasing artifacts and the rapid contrast changes in the reconstructed perfusion images. In addition to the…

Image and Video Processing · Electrical Eng. & Systems 2019-04-11 Abdul Haseeb Ahmed , Ijaz M. Qureshi

We consider an inverse problem for the elastic wave of simultaneously reconstructing the impedance and the geometric information of the bounded body that is occupied by a homogeneous and isotropic elastic medium from the measured Cauchy…

Numerical Analysis · Mathematics 2025-06-26 Yao Sun , Yan Chang , Yukun Guo

Modeling of respiratory motion is important for a more accurate understanding and accounting of its effect on dose to cancers in the thorax and abdomen by radiotherapy. We have developed a model of respiration-induced organ motion in the…

Motion correction aims to prevent motion artefacts which may be caused by respiration, heartbeat, or head movements for example. In a preliminary step, the measured data is divided in gates corresponding to motion states, and displacement…

Optimization and Control · Mathematics 2024-10-15 Claire Delplancke , Kris Thielemans , Matthias J. Ehrhardt

In this article, we consider the frame hydrodynamics of biaxial nematic phases, a coupled system between the evolution of the orthonormal frame and the Navier--Stokes equation, which is derived from a molecular-theory-based dynamical tensor…

Analysis of PDEs · Mathematics 2025-08-11 Minjiang Feng , Sirui Li , Qi Zeng

A numerical method is developed to efficiently calculate the stress (and displacement) field in finite 2D rectangular media. The solution is expanded on a function basis with elements that satisfy the Navier-Cauchy equation. The obtained…

Materials Science · Physics 2020-04-22 Denes Berta , Istvan Groma , Peter Dusan Ispanovity

Accurate three-dimensional (3D) reconstruction of cardiac chamber motion from time-resolved medical imaging modalities is of growing interest in both the clinical and biomechanical fields. Despite recent advancement, the cardiac motion…

Medical Physics · Physics 2025-04-18 Francesco Capuano , Yue-Hin Loke , Ibrahim Yildiran , Laura Olivieri , Elias Balaras

Solution of the Navier-Stokes equations with initial conditions (Cauchy problem) for 2D and 3D cases was obtained in the convergence series form by iterative method using Fourier and Laplace transforms in paper $\cite{TT02}$. For several…

Analysis of PDEs · Mathematics 2011-01-18 A. Tsionskiy , M. Tsionskiy

In this paper we study the reconstruction of moving object densities from undersampled dynamic X-ray tomography in two dimensions. A particular motivation of this study is to use realistic measurement protocols for practical applications,…

Numerical Analysis · Mathematics 2018-03-28 Martin Burger , Hendrik Dirks , Lena Frerking , Andreas Hauptmann , Tapio Helin , Samuli Siltanen

Stable computational algorithms for the approximate solution of the Cauchy problem for nonstationary problems are based on implicit time approximations. Computational costs for boundary value problems for systems of coupled multidimensional…

Numerical Analysis · Mathematics 2024-03-28 P. N. Vabishchevich
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