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The inverse problem of backward diffusion is known to be ill-posed and highly unstable. Backward diffusion processes appear naturally in image enhancement and deblurring applications. It is therefore greatly desirable to establish a…

Numerical Analysis · Mathematics 2020-06-18 Leif Bergerhoff , Marcelo Cárdenas , Joachim Weickert , Martin Welk

The aim of this paper is to put the problem of vibroacoustic imaging into the mathematical framework of inverse problems (more precisely, coefficient identification in PDEs) and regularization. We present a model in frequency domain, prove…

Analysis of PDEs · Mathematics 2021-09-07 Barbara Kaltenbacher

Diffusion models have recently emerged as powerful priors for solving inverse problems. While computed tomography (CT) is theoretically a linear inverse problem, it poses many practical challenges. These include correlated noise, artifact…

Image and Video Processing · Electrical Eng. & Systems 2026-02-24 Jiayang Shi , Daniel M. Pelt , K. Joost Batenburg

We aim at the solution of inverse problems in imaging, by combining a penalized sparse representation of image patches with an unconstrained smooth one. This allows for a straightforward interpretation of the reconstruction. We formulate…

Image and Video Processing · Electrical Eng. & Systems 2025-03-18 Stanislas Ducotterd , Sebastian Neumayer , Michael Unser

Retraction maps have been generalized to discretization maps in (Barbero Li\~n\'an and and Mart\'{\i}n de Diego, 2022). Discretization maps are used to systematically derive numerical integrators that preserve the symplectic structure, as…

Numerical Analysis · Mathematics 2024-01-29 María Barbero-Liñán , Juan Carlos Marrero , David Martín de Diego

Mathematically representing the shape of an object is a key ingredient for solving inverse rendering problems. Explicit representations like meshes are efficient to render in a differentiable fashion but have difficulties handling topology…

Graphics · Computer Science 2022-07-12 Guangyan Cai , Kai Yan , Zhao Dong , Ioannis Gkioulekas , Shuang Zhao

We consider the problem of approximating a two-dimensional shape contour (or curve segment) using discrete assembly systems, which allow to build geometric structures based on limited sets of node and edge types subject to edge length and…

Computational Geometry · Computer Science 2021-02-03 Andreas M. Tillmann , Leif Kobbelt

The high complexity of various inverse problems poses a significant challenge to model-based reconstruction schemes, which in such situations often reach their limits. At the same time, we witness an exceptional success of data-based…

Computer Vision and Pattern Recognition · Computer Science 2019-09-04 T. A. Bubba , G. Kutyniok , M. Lassas , M. März , W. Samek , S. Siltanen , V. Srinivasan

Discrete tomography focuses on the reconstruction of functions $f: A \to \mathbb{R}$ from their line sums in a finite number $d$ of directions, where $A$ is a finite subset of $\mathbb{Z}^2$. Consequently, the techniques of discrete…

Combinatorics · Mathematics 2026-04-08 M. Ceko , L. Hajdu , R. Tijdeman

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

This paper aims to develop and analyze a numerical scheme for solving the backward problem of semilinear subdiffusion equations. We establish the existence, uniqueness, and conditional stability of the solution to the inverse problem by…

Numerical Analysis · Mathematics 2025-05-07 Xu Wu , Jiang Yang , Zhi Zhou

In this paper, we study a 2D tomography problem for point source models with random unknown view angles. Rather than recovering the projection angles, we reconstruct the model through a set of rotation-invariant features that are estimated…

Signal Processing · Electrical Eng. & Systems 2018-11-27 Mona Zehni , Shuai Huang , Ivan Dokmanić , Zhizhen Zhao

The discrete moment problem is a foundational problem in distribution-free robust optimization, where the goal is to find a worst-case distribution that satisfies a given set of moments. This paper studies the discrete moment problems with…

Optimization and Control · Mathematics 2017-08-08 Xi Chen , Simai He , Bo Jiang , Christopher Thomas Ryan , Teng Zhang

This letter announces and summarizes results obtained in arXiv:1111.5051 and considers several natural extensions. The aforementioned paper proposes a procedure to reconstruct coefficients in a second-order, scalar, elliptic equation from…

Analysis of PDEs · Mathematics 2012-03-07 Guillaume Bal , Gunther Uhlmann

We present a general paradigm for dynamic 3D reconstruction from multiple independent and uncontrolled image sources having arbitrary temporal sampling density and distribution. Our graph-theoretic formulation models the Spatio-temporal…

Computer Vision and Pattern Recognition · Computer Science 2019-08-30 Xiangyu Xu , Enrique Dunn

Various problems in computer vision and medical imaging can be cast as inverse problems. A frequent method for solving inverse problems is the variational approach, which amounts to minimizing an energy composed of a data fidelity term and…

Computer Vision and Pattern Recognition · Computer Science 2020-06-17 Erich Kobler , Alexander Effland , Karl Kunisch , Thomas Pock

The inverse problem of special geometry (Seiberg-Witten geometry of 4d N=2 SCFT) asks for a recursive construction of all such geometries in rank $r$ by assembling together known lower-rank ``strata''. This leads to a program to…

High Energy Physics - Theory · Physics 2023-12-06 Sergio Cecotti

Computed Tomography (CT) is an imaging technique where information about an object are collected at different angles (called projections or scans). Then the cross-sectional image showing the internal structure of the slice is produced by…

Image and Video Processing · Electrical Eng. & Systems 2022-09-07 Zhengchun Liu , Rajkumar Kettimuthu , Ian Foster

We propose a new approach to linear ill-posed inverse problems. Our algorithm alternates between enforcing two constraints: the measurements and the statistical correlation structure in some transformed space. We use a non-linear multiscale…

Computational Engineering, Finance, and Science · Computer Science 2018-12-04 Ivan Dokmanić , Joan Bruna , Stéphane Mallat , Maarten de Hoop

Indirect image registration is a promising technique to improve image reconstruction quality by providing a shape prior for the reconstruction task. In this paper, we propose a novel hybrid method that seeks to reconstruct high quality…

Image and Video Processing · Electrical Eng. & Systems 2019-12-18 Jiulong Liu , Angelica I. Aviles-Rivero , Hui Ji , Carola-Bibiane Schönlieb