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A qualitative comparison of total variation like penalties (total variation, Huber variant of total variation, total generalized variation, ...) is made in the context of global seismic tomography. Both penalized and constrained…

Geophysics · Physics 2012-04-09 Ignace Loris , Caroline Verhoeven

In this paper we study the attenuated $X$-ray transform of 2-tensors supported in strictly convex bounded subsets in the Euclidean plane. We characterize its range and reconstruct all possible 2-tensors yielding identical $X$-ray data. The…

Analysis of PDEs · Mathematics 2015-03-17 Kamran Sadiq , Otmar Scherzer , Alexandru Tamasan

We study the problem of recovering a function on a pseudo-Riemannian manifold from its integrals over all null geodesics in three geometries: pseudo-Riemannian products of Riemannian manifolds, Minkowski spaces and tori. We give proofs of…

Differential Geometry · Mathematics 2016-08-11 Joonas Ilmavirta

High resolution reconstruction of complicated objects from incomplete and noisy data can be achieved by solving modulation equations iteratively under physical constraints. This direct demodulation method is a powerful technique for dealing…

Astrophysics · Physics 2009-11-10 Ti-Pei Li , Mei Wu

In this paper we propose a variational regularization method for denoising and inpainting of diffusion tensor magnetic resonance images. We consider these images as manifold-valued Sobolev functions, i.e. in an infinite dimensional setting,…

Optimization and Control · Mathematics 2021-06-22 Leon Frischauf , Melanie Melching , Otmar Scherzer

We consider the shape reconstruction of a conductivity inclusion in two dimensions. We use the concept of Faber polynomials Polarization Tensors (FPTs) introduced in \cite{choi:2018:GME} to derive an exact shape recovery formula for an…

Numerical Analysis · Mathematics 2024-12-20 Doosung Choi , Junbeom Kim , Mikyoung Lim

In this paper, we study the mathematical imaging problem of diffraction tomography (DT), which is an inverse scattering technique used to find material properties of an object by illuminating it with probing waves and recording the…

Numerical Analysis · Mathematics 2023-05-16 Florian Faucher , Clemens Kirisits , Michael Quellmalz , Otmar Scherzer , Eric Setterqvist

In this article, we introduce and study various V-line transforms (VLTs) defined on symmetric 2-tensor fields in $\mathbb{R}^2$. The operators of interest include the longitudinal, transverse, and mixed VLTs, their integral moments, and the…

Classical Analysis and ODEs · Mathematics 2024-01-23 Gaik Ambartsoumian , Rohit Kumar Mishra , Indrani Zamindar

We present the details for the covariant renormalization of the stress tensor for vacuum tensor perturbations at the level of the effective action, adopting Hadamard regularization techniques to isolate short distance divergences and gauge…

High Energy Physics - Theory · Physics 2024-03-26 Anna Negro , Subodh P. Patil

This paper derives the CS decomposition for orthogonal tensors (T-CSD) and the generalized singular value decomposition for two tensors (T-GSVD) via the T-product. The structures of the two decompositions are analyzed in detail and are…

Numerical Analysis · Mathematics 2021-07-01 Yating Zhang , Xiaoxia Guo , Pengpeng Xie , Zhengbang Cao

Analyzing 3D anisotropic materials presents significant challenges, especially when assessing 3D orientations, material distributions, and anisotropies through scattered light, due to the inherently vectorial nature of light-matter…

Optics · Physics 2024-04-29 ChulMin Oh , Herve Hugonnet , Juheon Lee , YongKeun Park

Multi-energy computed tomography (ME-CT) is an x-ray transmission imaging technique that uses the energy dependence of x-ray photon attenuation to determine the elemental composition of an object of interest. Mathematically, forward ME-CT…

Medical Physics · Physics 2022-02-16 Guillaume Bal , Ruoming Gong , Fatma Terzioglu

Traditional tensor decomposition methods, e.g., two dimensional principal component analysis and two dimensional singular value decomposition, that minimize mean square errors, are sensitive to outliers. To overcome this problem, in this…

Computer Vision and Pattern Recognition · Computer Science 2020-12-30 Miaohua Zhang , Yongsheng Gao , Changming Sun , Michael Blumenstein

We develop a method to reconstruct, from measured displacements of an underlying elastic substrate, the spatially dependent forces that cells or tissues impart on it. Given newly available high-resolution images of substrate displacements,…

Quantitative Methods · Quantitative Biology 2018-01-22 Joshua C. Chang , Yanli Liu , Tom Chou

We present a versatile method for full-field, X-ray scattering tensor tomography that is based on energy conservation and is applicable to data obtained using different wavefront modulators. Using this algorithm, we pave the way for…

Grassmann tensors arise from classical problems of scene reconstruction in computer vision. Trifocal Grassmann tensors, related to three projections from a projective space of dimension k onto view-spaces of varying dimensions are studied…

Algebraic Geometry · Mathematics 2019-07-25 Marina Bertolini , Gian Mario Besana , Gilberto Bini , Cristina Turrini

A numerical approach to compute tensor integrals in one-loop calculations is presented. The algorithm is based on a recursion relation which allows to express high rank tensor integrals as a function of lower rank ones. At each level of…

High Energy Physics - Phenomenology · Physics 2010-02-03 F. del Aguila , R. Pittau

A two-dimensional tomographic problem is studied. The target is assumed to be a homogeneous object bounded by a smooth curve. A Non Uniform Rational Basis Splines (NURBS) curve is used as computational representation of the boundary. This…

Numerical Analysis · Mathematics 2017-08-08 Heikki Haario , Aki Kallonen , Marko Laine , Esa Niemi , Zenith Purisha , Samuli Siltanen

We consider the broken ray transform on Riemann surfaces in the presence of an obstacle, following earlier work of Mukhometov. If the surface has nonpositive curvature and the obstacle is strictly convex, we show that a function is…

Differential Geometry · Mathematics 2016-06-21 Joonas Ilmavirta , Mikko Salo

We propose a novel strategy for the perturbative resummation of transverse momentum-dependent (TMD) observables, using the $q_T$ spectra of gauge bosons ($\gamma^*$, Higgs) in $pp$ collisions in the regime of low (but perturbative)…

High Energy Physics - Phenomenology · Physics 2018-05-23 Daekyoung Kang , Christopher Lee , Varun Vaidya