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For several decades, image restoration remains an active research topic in low-level computer vision and hence new approaches are constantly emerging. However, many recently proposed algorithms achieve state-of-the-art performance only at…

Computer Vision and Pattern Recognition · Computer Science 2015-03-26 Yunjin Chen , Wei Yu , Thomas Pock

Diffusion models have emerged as powerful priors for solving inverse problems in computed tomography (CT). In certain applications, such as neutron CT, it can be expensive to collect large amounts of measurements even for a single scan,…

Computer Vision and Pattern Recognition · Computer Science 2026-03-03 Timofey Efimov , Singanallur Venkatakrishnan , Maliha Hossain , Haley Duba-Sullivan , Amirkoushyar Ziabari

Many practical imaging systems suffer from uncertainty in acquisition geometry -- such as projection angles in computed tomography or sensor positions in photoacoustic tomography -- leading to nonlinear inverse problems that require joint…

Numerical Analysis · Mathematics 2026-05-08 Toluwani Okunola , Mirjeta Pasha , Misha E. Kilmer , James G. Nagy , Eric de Sturler

The advanced magnetic resonance (MR) image reconstructions such as the compressed sensing and subspace-based imaging are considered as large-scale, iterative, optimization problems. Given the large number of reconstructions required by the…

Computational Engineering, Finance, and Science · Computer Science 2020-06-26 Tianjian Lu , Thibault Marin , Yue Zhuo , Yi-Fan Chen , Chao Ma

Accelerating magnetic resonance image (MRI) reconstruction process is a challenging ill-posed inverse problem due to the excessive under-sampling operation in k-space. In this paper, we propose a recurrent transformer model, namely…

Image and Video Processing · Electrical Eng. & Systems 2022-01-31 Pengfei Guo , Yiqun Mei , Jinyuan Zhou , Shanshan Jiang , Vishal M. Patel

3D scene reconstruction from 2D images has been a long-standing task. Instead of estimating per-frame depth maps and fusing them in 3D, recent research leverages the neural implicit surface as a unified representation for 3D reconstruction.…

Computer Vision and Pattern Recognition · Computer Science 2023-09-19 Xinyi Yu , Liqin Lu , Jintao Rong , Guangkai Xu , Linlin Ou

Since convolutional neural networks (CNNs) perform well at learning generalizable image priors from large-scale data, these models have been extensively applied to image restoration and related tasks. Recently, another class of neural…

Computer Vision and Pattern Recognition · Computer Science 2022-03-14 Syed Waqas Zamir , Aditya Arora , Salman Khan , Munawar Hayat , Fahad Shahbaz Khan , Ming-Hsuan Yang

We describe an algorithm that, given any full-rank matrix A having fewer rows than columns, can rapidly compute the orthogonal projection of any vector onto the null space of A, as well as the orthogonal projection onto the row space of A,…

Numerical Analysis · Computer Science 2011-05-26 Vladimir Rokhlin , Mark Tygert

In this paper we present a fast and efficient method for the reconstruction of Magnetic Resonance Images (MRI) from severely under-sampled data. From the Compressed Sensing theory we have mathematically modeled the problem as a constrained…

Numerical Analysis · Computer Science 2017-12-01 Damiana Lazzaro , Elena Loli Piccolomini , Fabiana Zama

In this paper we consider the problem of acoustic inversion in the context of the optoacoustic tomography image reconstruction problem. By leveraging the ability of the recently proposed diffusion models for image generative tasks among…

Image and Video Processing · Electrical Eng. & Systems 2024-04-17 M. G. González , M. Vera , A. Dreszman , L. J. Rey Vega

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 many applications of tomography, the acquired projections are either limited in number or contain a significant amount of noise. In these cases, standard reconstruction methods tend to produce artifacts that can make further analysis…

Numerical Analysis · Mathematics 2016-04-11 D. M. Pelt , K. J. Batenburg

Neural preconditioners for real-time physics simulation offer promising data-driven priors, but they often fail to capture long-range couplings efficiently because they inherit local message passing or sparse-operator access patterns. We…

Graphics · Computer Science 2026-05-15 Carl Osborne , Minghao Guo , Crystal Owens , Wojciech Matusik

Iterative sketching and sketch-and-precondition are randomized algorithms used for solving overdetermined linear least-squares problems. When implemented in exact arithmetic, these algorithms produce high-accuracy solutions to least-squares…

Numerical Analysis · Mathematics 2024-04-15 Ethan N. Epperly

In this paper, we revisit the large-scale constrained linear regression problem and propose faster methods based on some recent developments in sketching and optimization. Our algorithms combine (accelerated) mini-batch SGD with a new…

Machine Learning · Computer Science 2018-02-12 Di Wang , Jinhui Xu

Image reconstruction under multiple light scattering is crucial in a number of applications such as diffraction tomography. The reconstruction problem is often formulated as a nonconvex optimization, where a nonlinear measurement model is…

Computer Vision and Pattern Recognition · Computer Science 2018-07-04 Yu Sun , Zhihao Xia , Ulugbek S. Kamilov

Kernel Ridge Regression (KRR) is a simple yet powerful technique for non-parametric regression whose computation amounts to solving a linear system. This system is usually dense and highly ill-conditioned. In addition, the dimensions of the…

Numerical Analysis · Computer Science 2017-07-18 Haim Avron , Kenneth L. Clarkson , David P. Woodruff

We consider solving ill-posed imaging inverse problems without access to an explicit image prior or ground-truth examples. An overarching challenge in inverse problems is that there are many undesired images that fit to the observed…

Image and Video Processing · Electrical Eng. & Systems 2023-03-23 Angela F. Gao , Oscar Leong , He Sun , Katherine L. Bouman

Recent advancements in text-guided diffusion models have unlocked powerful image manipulation capabilities. However, applying these methods to real images necessitates the inversion of the images into the domain of the pretrained diffusion…

Computer Vision and Pattern Recognition · Computer Science 2024-03-22 Daniel Garibi , Or Patashnik , Andrey Voynov , Hadar Averbuch-Elor , Daniel Cohen-Or

A challenge in high-dimensional inverse problems is developing iterative solvers to find the accurate solution of regularized optimization problems with low computational cost. An important example is computed tomography (CT) where both…

Numerical Analysis · Mathematics 2024-12-16 Alessandro Perelli , Carola-Bibiane Schonlieb , Matthias J. Ehrhardt