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Limited-angle tomography is a highly ill-posed linear inverse problem. It arises in many applications, such as digital breast tomosynthesis. Reconstructions from limited-angle data typically suffer from severe stretching of features along…

Image and Video Processing · Electrical Eng. & Systems 2022-04-22 Siiri Rautio , Rashmi Murthy , Tatiana A. Bubba , Matti Lassas , Samuli Siltanen

The use of orthogonal projections on high-dimensional input and target data in learning frameworks is studied. First, we investigate the relations between two standard objectives in dimension reduction, preservation of variance and of…

A new approach is proposed for reconstruction of images from Radon projections. Based on Fourier expansions in orthogonal polynomials of two and three variables, instead of Fourier transforms, the approach provides a new algorithm for the…

Classical Analysis and ODEs · Mathematics 2007-05-23 Yuan Xu

Beamforming in ultrasound imaging has significant impact on the quality of the final image, controlling its resolution and contrast. Despite its low spatial resolution and contrast, delay-and-sum is still extensively used nowadays in…

Computer Vision and Pattern Recognition · Computer Science 2016-05-20 Teodora Szasz , Adrian Basarab , Denis Kouamé

We propose a new model-order reduction framework to poorly reducible problems arising from parametric partial differential equations with geometric variability. In such problems, the solution manifold exhibits a slowly decaying Kolmogorov…

Numerical Analysis · Mathematics 2025-10-30 Abbas Kabalan , Fabien Casenave , Felipe Bordeu , Virginie Ehrlacher , Alexandre Ern

We consider algebraic iterative reconstruction methods with applications in image reconstruction. In particular, we are concerned with methods based on an unmatched projector/backprojector pair; i.e., the backprojector is not the exact…

Numerical Analysis · Mathematics 2019-02-14 Yiqiu Dong , Per Christian Hansen , Michiel E. Hochstenbach , Nicolai Andre Brogaard Riis

The need for tomographic reconstruction from sparse measurements arises when the measurement process is potentially harmful, needs to be rapid, or is uneconomical. In such cases, information from previous longitudinal scans of the same…

Image and Video Processing · Electrical Eng. & Systems 2019-09-13 Preeti Gopal , Sharat Chandran , Imants Svalbe , Ajit Rajwade

Biomedical imaging is unequivocally dependent on the ability to reconstruct interpretable and high-quality images from acquired sensor data. This reconstruction process is pivotal across many applications, spanning from magnetic resonance…

Signal Processing · Electrical Eng. & Systems 2019-09-24 Ben Luijten , Regev Cohen , Frederik J. de Bruijn , Harold A. W. Schmeitz , Massimo Mischi , Yonina C. Eldar , Ruud J. G. van Sloun

Image reconstruction based on indirect, noisy, or incomplete data remains an important yet challenging task. While methods such as compressive sensing have demonstrated high-resolution image recovery in various settings, there remain issues…

Numerical Analysis · Mathematics 2023-03-07 Jan Glaubitz , Anne Gelb , Guohui Song

A wide array of image recovery problems can be abstracted into the problem of minimizing a sum of composite convex functions in a Hilbert space. To solve such problems, primal-dual proximal approaches have been developed which provide…

Optimization and Control · Mathematics 2014-06-23 Patrick L. Combettes , Laurent Condat , Jean-Christophe Pesquet , Bang Cong Vu

We introduce backdrop, a flexible and simple-to-implement method, intuitively described as dropout acting only along the backpropagation pipeline. Backdrop is implemented via one or more masking layers which are inserted at specific points…

Machine Learning · Statistics 2018-06-06 Siavash Golkar , Kyle Cranmer

Models with dominant advection always posed a difficult challenge for projection-based reduced order modelling. Many methodologies that have recently been proposed are based on the pre-processing of the full-order solutions to accelerate…

Numerical Analysis · Mathematics 2022-03-02 Davide Papapicco , Nicola Demo , Michele Girfoglio , Giovanni Stabile , Gianluigi Rozza

Electron tomographic reconstruction is a method for obtaining a three-dimensional image of a specimen with a series of two dimensional microscope images taken from different viewing angles. Filtered backprojection, one of the most popular…

Computer Vision and Pattern Recognition · Computer Science 2018-08-01 Chen Mu , Chiwoo Park

We discuss the possibility to learn a data-driven explicit model correction for inverse problems and whether such a model correction can be used within a variational framework to obtain regularised reconstructions. This paper discusses the…

Numerical Analysis · Mathematics 2020-10-22 Sebastian Lunz , Andreas Hauptmann , Tanja Tarvainen , Carola-Bibiane Schönlieb , Simon Arridge

In this paper, the compact linearization approach originally proposed for binary quadratic programs with assignment constraints is generalized to such programs with arbitrary linear equations and inequalities that have positive coefficients…

Optimization and Control · Mathematics 2018-08-28 Sven Mallach

Deep-learning-based nonlinear system identification has shown the ability to produce reliable and highly accurate models in practice. However, these black-box models lack physical interpretability, and a considerable part of the learning…

Machine Learning · Computer Science 2025-07-15 Bendegúz M. Györök , Jan H. Hoekstra , Johan Kon , Tamás Péni , Maarten Schoukens , Roland Tóth

In Bayesian inverse problems sampling the posterior distribution is often a challenging task when the underlying models are computationally intensive. To this end, surrogates or reduced models are often used to accelerate the computation.…

Numerical Analysis · Mathematics 2019-09-04 Qifeng Liao , Jinglai Li

Deep neural networks have been applied successfully to a wide variety of inverse problems arising in computational imaging. These networks are typically trained using a forward model that describes the measurement process to be inverted,…

Image and Video Processing · Electrical Eng. & Systems 2021-04-14 Davis Gilton , Gregory Ongie , Rebecca Willett

In radio astronomy, the science output of a telescope is often limited by computational resources. This is especially true for transient and technosignature surveys that need to search high-resolution data across a large parameter space.…

Instrumentation and Methods for Astrophysics · Physics 2024-04-11 Danny C. Price

Retrieval systems rely on representations learned by increasingly powerful models. However, due to the high training cost and inconsistencies in learned representations, there is significant interest in facilitating communication between…

Machine Learning · Computer Science 2026-05-20 Simone Ricci , Niccolò Biondi , Federico Pernici , Ioannis Patras , Alberto Del Bimbo