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Recovering a function from its spherical Radon transform with centers of spheres of integration restricted to a hypersurface is at the heart of several modern imaging technologies, including SAR, ultrasound imaging, and photo- and…

Numerical Analysis · Mathematics 2016-07-19 Markus Haltmeier , Sunghwan Moon

We consider an inverse problem arising in thermo-/photo- acoustic tomography that amounts to reconstructing a function $f$ from its circular or spherical means with the centers lying on a given measurement surface. (Equivalently, these…

Analysis of PDEs · Mathematics 2015-09-02 Leonid Kunyansky

We consider the proximal gradient method on Riemannian manifolds for functions that are possibly not geodesically convex. Starting from the forward-backward-splitting, we define an intrinsic variant of the proximal gradient method that uses…

Optimization and Control · Mathematics 2025-06-12 Ronny Bergmann , Hajg Jasa , Paula John , Max Pfeffer

Estimating the pose of an object from a monocular image is an inverse problem fundamental in computer vision. The ill-posed nature of this problem requires incorporating deformation priors to solve it. In practice, many materials do not…

Computer Vision and Pattern Recognition · Computer Science 2023-03-20 Oriol Barbany , Adrià Colomé , Carme Torras

Using connections to random matrix theory and orthogonal polynomials, we develop a framework for obtaining explicit closed-form formulae for the number, $\mathscr{N}_{g}(2\nu,j)$, of connected $2\nu$-valent labeled graphs with $j$ vertices…

Combinatorics · Mathematics 2025-09-19 Roozbeh Gharakhloo , Tomas Lasic Latimer

This work gives an expository account of certain applications of microlocal analysis in three geometric inverse problems. We will discuss the geodesic X-ray transform inverse problem, the Gelfand problem for the wave equation on a…

Analysis of PDEs · Mathematics 2023-12-14 Mikko Salo

The intertwining operator constructed in [Sz1,Sz2] does not appear in the right form. It is established there by using only the anticommutators. The correct operator must involve all endomorphisms, which are unified by the Z-Fourier…

Differential Geometry · Mathematics 2008-02-14 Z. I. Szabo

The work develops further the theory of the following inversion problem, which plays the central role in the rapidly developing area of thermoacoustic tomography and has intimate connections with PDEs and integral geometry: {\it Reconstruct…

Classical Analysis and ODEs · Mathematics 2011-08-04 Yuri A. Antipov , Ricardo Estrada , Boris Rubin

We prove the existence of infinitely many low-lying and fundamental closed geodesics on the modular surface which are reciprocal, that is, invariant under time reversal. The method combines ideas from Parts I and II of this series, namely…

Number Theory · Mathematics 2019-12-19 Jean Bourgain , Alex Kontorovich

We give an explicit plane-by-plane filtered back-projection reconstruction algorithm for the transverse ray transform of symmetric second rank tensor fields on Euclidean 3-space, using data from rotation about three orthogonal axes. We show…

Analysis of PDEs · Mathematics 2016-11-03 Naeem M. Desai , William R. B. Lionheart

We consider the inverse problem of recovering a potential from the Dirichlet to Neumann map at a large fixed frequency on certain Riemannian manifolds. We extend the earlier result of [G. Uhlmann and Y. Wang, arXiv:2104.03477] to the case…

Analysis of PDEs · Mathematics 2023-09-01 Shiqi Ma , Suman Kumar Sahoo , Mikko Salo

Refraction is a common physical phenomenon and has long been researched in computer vision. Objects imaged through a refractive object appear distorted in the image as a function of the shape of the interface between the media. This hinders…

Computer Vision and Pattern Recognition · Computer Science 2023-06-01 Antonin Sulc , Imari Sato , Bastian Goldluecke , Tali Treibitz

Let $X$ be a smooth bordered surface in $\real^3$ with smooth boundary and $\hat \sigma$ a smooth anisotropic conductivity on $X$. If the genus of $X$ is given, then starting from the Dirichlet-to-Neumann operator $\Lambda_{\hat \sigma}$ on…

Mathematical Physics · Physics 2012-04-13 Gennadi Henkin , Matteo Santacesaria

We introduce and study a new Radon-like transform that averages projected differential p-forms in R^n over affine (n-k)-planes. We then prove an explicit inversion formula for our transform on the space of rapidly-decaying smooth p-forms.…

Differential Geometry · Mathematics 2009-08-21 Bruce Solomon

Hyperplane is a set of non-injectivity of the spherical Radon transform (SRT) in the space of continuous functions in R^d. In this article, for the reconstruction of an unknown function f from C(R^3) (the support can be non-compact), using…

Classical Analysis and ODEs · Mathematics 2024-04-09 Rafik Aramyan

We investigate the inverse scale space flow as a decomposition method for decomposing data into generalised singular vectors. We show that the inverse scale space flow, based on convex and absolutely one-homogeneous regularisation…

Numerical Analysis · Mathematics 2016-12-30 Marie Foged Schmidt , Martin Benning , Carola-Bibiane Schönlieb

The paper uses a frame-theoretic setting to study the injectivity of a ReLU-layer on the closed ball of $\mathbb{R}^n$ and its non-negative part. In particular, the interplay between the radius of the ball and the bias vector is emphasized.…

Machine Learning · Computer Science 2023-10-24 Daniel Haider , Martin Ehler , Peter Balazs

We are concerned with the inverse scattering problem of extracting the geometric structures of an unknown/inaccessible inhomogeneous medium by using the corresponding acoustic far-field measurement. Using the intrinsic geometric properties…

Analysis of PDEs · Mathematics 2017-06-15 Jingzhi Li , Xiaofei Li , Hongyu Liu

The problem of image reconstruction in thermoacoustic tomography requires inversion of a generalized Radon transform, which integrates the unknown function over circles in 2D or spheres in 3D. The paper investigates implementation of the…

Numerical Analysis · Mathematics 2007-05-23 Gaik Ambartsoumian , Sarah K. Patch

Surface reconstruction is a fundamental problem in 3D graphics. In this paper, we propose a learning-based approach for implicit surface reconstruction from raw point clouds without normals. Our method is inspired by Gauss Lemma in…

Computer Vision and Pattern Recognition · Computer Science 2022-02-22 Dong Xiao , Siyou Lin , Zuoqiang Shi , Bin Wang