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In this paper, we derive explicit reconstruction formulas for two common measurement geometries: a plane and a sphere. The problem is formulated as inverting the forward operator $R^a$, which maps the initial source to the measured wave…

Analysis of PDEs · Mathematics 2025-08-27 Cong Shi

In this study, we deal with the local structure of curves and surfaces immersed in a pseudo-isotropic space I_{p}^{3} that is a particular Cayley-Klein space. We provide the formulas of curvature, torsion and Frenet trihedron in order for…

Differential Geometry · Mathematics 2018-11-13 Muhittin Evren Aydin

We study integral transforms mapping a function on the Euclidean plane to the family of its integration on plane curves, that is, a function of plane curves. The plane curves we consider in the present paper are given by the graphs of…

Classical Analysis and ODEs · Mathematics 2020-05-26 Hiroyuki Chihara

Single-view 3D object reconstruction is a challenging fundamental problem in computer vision, largely due to the morphological diversity of objects in the natural world. In particular, high curvature regions are not always captured…

Computer Vision and Pattern Recognition · Computer Science 2020-06-16 Ziyun Wang , Eric A. Mitchell , Volkan Isler , Daniel D. Lee

We study the geodesic X-ray transform on Cartan-Hadamard manifolds, and prove solenoidal injectivity of this transform acting on functions and tensor fields of any order. The functions are assumed to be exponentially decaying if the…

Differential Geometry · Mathematics 2019-09-06 Jere Lehtonen , Jesse Railo , Mikko Salo

We present two theorems describing analytic left-inverses of partial X-ray transforms. The first theorem concerns X-ray data collected with an arbitrary distribution of parallel projections; it contains a convolution-backprojection formula…

Medical Physics · Physics 2025-07-01 Murdock G. Grewar

X-ray tomography has applications in various industrial fields such as sawmill industry, oil and gas industry, chemical engineering, and geotechnical engineering. In this article, we study Bayesian methods for the X-ray tomography…

Computational Engineering, Finance, and Science · Computer Science 2020-03-26 Jarkko Suuronen , Muhammad Emzir , Sari Lasanen , Simo Särkkä , Lassi Roininen

The area of inverse problems in mathematics is highly interdisciplinary. In various fields of science, engineering, medicine, and industry, there arises a need to reconstruct information about unknown entities that cannot be directly…

Numerical Analysis · Mathematics 2024-09-17 Manabu Machida

The paper is devoted to the numerical solution of elastoplastic constitutive initial value problems. An improved form of the implicit return-mapping scheme for nonsmooth yield surfaces is proposed that systematically builds on a…

Computational Engineering, Finance, and Science · Computer Science 2018-01-08 Stanislav Sysala , Martin Cermak , Tomas Koudelka , Jaroslav Kruis , Jan Zeman , Radim Blaheta

Creating virtual models of real spaces and objects is cumbersome and time consuming. This paper focuses on the problem of geometric reconstruction from sparse data obtained from certain image-based modeling approaches. A number of elegant…

Computational Geometry · Computer Science 2010-03-19 Eleanor G. Rieffel , Don Kimber , Jim Vaughan

A brief history of the investigation of the Weil-Petersson curvature and a summary of Teichm\"{u}ller theory are provided. A report is presented on the program to describe an intrinsic geometry with the Weil-Petersson metric and…

Differential Geometry · Mathematics 2008-09-23 Scott A. Wolpert

Let $X$ be a smooth complex projective variety. Using a construction devised to Gathmann, we present a recursive formula for some of the Gromov-Witten invariants of $X$. We prove that, when $X$ is homogeneous, this formula gives the number…

Algebraic Geometry · Mathematics 2024-08-05 Giosuè Muratore

Mechanically reconfigurable reflectors can modify their geometries to realize large angle beam scanning. This paper studies a method for reconfiguring a reflector geometry from a standard parabolic shape to offset parabolic shapes with…

Materials Science · Physics 2021-11-02 Bin Xu , Houfei Fang , Shuidong Jiang , Yangqing Hou , Lan Lan

Imaging systems are represented as linear operators, and their singular value spectra describe the structure recoverable at the operator level. Building on an operator-based information-theoretic framework, this paper introduces a minimal…

Information Theory · Computer Science 2026-01-06 Charles Wood

Iterative Fast Fourier Transform methods are useful for calculating the fields in composite materials and their macroscopic response. By iterating back and forth until convergence, the differential constraints are satisfied in Fourier…

Numerical Analysis · Mathematics 2018-01-25 Hervé Moulinec , Pierre Suquet , Graeme W. Milton

The article suggests a new approach what is called a consistency method for the inversion of the spherical Radon transform in 2D with detectors on a line. It is known that there is not an exact inversion formula in 2D. By means of the…

Numerical Analysis · Mathematics 2017-05-31 Rafik Aramyan

We describe all pseudo-Riemannian metrics on closed surfaces whose geodesic flows admit nontrivial integrals quadratic in momenta. As an application, we solve the Beltrami problem on closed surfaces and prove the nonexistence of…

Differential Geometry · Mathematics 2010-10-25 Vladimir S. Matveev

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

We introduce a novel approach to calculating three-dimensional freeform reflectors with a scattering surface. Our method is based on optimal transport and utilizes a Fredholm integral equation to express scattering. By solving this integral…

The X-ray transform on a compact symmetric space M is here inverted by means of an explicit inversion formula. The proof uses the conjugacy of the minimal closed geodesics in M and of the maximally curved totally geodesic spheres in M,…

Representation Theory · Mathematics 2007-05-23 Sigurdur Helgason