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We present a block lower triangular (BLT) preconditioner to accelerate the convergence of nthe Krylov subspace iterative methods, such as generalized minimal residual (GMRES), for solving a broad class of complex symmetric system of linear…

Numerical Analysis · Mathematics 2016-11-14 Davod Khojasteh Salkuyeh , Tahereh Salimi Siahkalaei

Fourier domain structured low-rank matrix priors are emerging as powerful alternatives to traditional image recovery methods such as total variation and wavelet regularization. These priors specify that a convolutional structured matrix,…

Numerical Analysis · Computer Science 2017-06-27 Greg Ongie , Mathews Jacob

This paper introduces inexact versions of several block-splitting preconditioners for solving the three-by-three block linear systems arising from a special class of indefinite least squares problems. We first establish the convergence…

Numerical Analysis · Mathematics 2026-05-26 Mohaddese Kaveh Shaldehi , Davod Khojasteh Salkuyeh

This paper proposes a novel approach to regularize the \textit{ill-posed} and \textit{non-linear} blind image deconvolution (blind deblurring) using deep generative networks as priors. We employ two separate generative models --- one…

Computer Vision and Pattern Recognition · Computer Science 2019-02-28 Muhammad Asim , Fahad Shamshad , Ali Ahmed

Computational imaging through scatter generally is accomplished by first characterizing the scattering medium so that its forward operator is obtained; and then imposing additional priors in the form of regularizers on the reconstruction…

Optics · Physics 2017-11-21 Shuai Li , Mo Deng , Justin Lee , Ayan Sinha , George Barbastathis

We study strategies for increasing the precision in the blurring models by maintaining a complexity in the related numerical linear algebra procedures (matrix-vector product, linear system solution, computation of eigenvalues etc.) of the…

Numerical Analysis · Mathematics 2009-06-16 Marco Donatelli

This paper proposes a novel approach to regularize the ill-posed blind image deconvolution (blind image deblurring) problem using deep generative networks. We employ two separate deep generative models - one trained to produce sharp images…

Computer Vision and Pattern Recognition · Computer Science 2019-08-21 Muhammad Asim , Fahad Shamshad , Ali Ahmed

Block-sparse regularization is already well-known in active thermal imaging and is used for multiple measurement based inverse problems. The main bottleneck of this method is the choice of regularization parameters which differs for each…

Computer Vision and Pattern Recognition · Computer Science 2024-10-30 Samim Ahmadi , Jan Christian Hauffen , Linh Kästner , Peter Jung , Giuseppe Caire , Mathias Ziegler

Bilinear models that decompose dynamic data to spatial and temporal factors are powerful and memory-efficient tools for the recovery of dynamic MRI data. These methods rely on sparsity and energy compaction priors on the factors to…

Image and Video Processing · Electrical Eng. & Systems 2021-07-01 Abdul Haseeb Ahmed , Prashant Nagpal , Mathews Jacob

A linearly implicit conservative difference scheme is applied to discretize the attractive coupled nonlinear Schr\"odinger equations with fractional Laplacian. Complex symmetric linear systems can be obtained, and the system matrices are…

Numerical Analysis · Mathematics 2023-10-19 Yan Cheng , Xi Yang

Image deblurring has advanced rapidly with deep learning, yet most methods exhibit poor generalization beyond their training datasets, with performance dropping significantly in real-world scenarios. Our analysis shows this limitation stems…

Computer Vision and Pattern Recognition · Computer Science 2026-01-13 Yuanting Gao , Shuo Cao , Xiaohui Li , Yuandong Pu , Yihao Liu , Kai Zhang

Recent efforts in applying implicit networks to solve inverse problems in imaging have achieved competitive or even superior results when compared to feedforward networks. These implicit networks only require constant memory during…

Machine Learning · Computer Science 2024-02-06 Linghai Liu , Shuaicheng Tong , Lisa Zhao

Variational regularization models are one of the popular and efficient approaches for image restoration. The regularization functional in the model carries prior knowledge about the image to be restored. The prior knowledge, in particular…

Optimization and Control · Mathematics 2021-02-09 Yan-ran Li , Raymond H. F. Chan , Lixin Shen , Xiaosheng Zhuang

This paper studies the subspace clustering problem. Given some data points approximately drawn from a union of subspaces, the goal is to group these data points into their underlying subspaces. Many subspace clustering methods have been…

Computer Vision and Pattern Recognition · Computer Science 2018-05-24 Canyi Lu , Jiashi Feng , Zhouchen Lin , Tao Mei , Shuicheng Yan

We consider the estimation of the regularization parameter for the simultaneous deblurring of multiple noisy images via Tikhonov regularization. We approach the problem in three ways. We first reduce the problem to a single-image deblurring…

Astrophysics · Physics 2009-11-10 R. Vio , P. Ma , W. Zhong , J. Nagy , L. Tenorio , W. Wamsteker

In this paper, we consider the problem in defocus image deblurring. Previous classical methods follow two-steps approaches, i.e., first defocus map estimation and then the non-blind deblurring. In the era of deep learning, some researchers…

Computer Vision and Pattern Recognition · Computer Science 2022-07-08 Qian Ye , Masanori Suganuma , Takayuki Okatani

Pre-trained representation is one of the key elements in the success of modern deep learning. However, existing works on continual learning methods have mostly focused on learning models incrementally from scratch. In this paper, we explore…

Machine Learning · Computer Science 2022-08-18 Hyounguk Shon , Janghyeon Lee , Seung Hwan Kim , Junmo Kim

We introduce Back to Basics (BTB), a fast iterative algorithm for noise reduction. Our method is computationally efficient, does not require training or ground truth data, and can be applied in the presence of independent noise, as well as…

Image and Video Processing · Electrical Eng. & Systems 2024-04-19 Deborah Pereg

A Bayesian hierarchical model for total variation regularisation is presented in this paper. All the parameters of an inverse problem, including the "regularisation parameter", are estimated simultaneously from the data in the model. The…

Numerical Analysis · Mathematics 2014-12-16 Marko Järvenpää , Robert Piché

In the context of image processing, given a $k$-th order, homogeneous and linear differential operator with constant coefficients, we study a class of variational problems whose regularizing terms depend on the operator. Precisely, the…

Numerical Analysis · Mathematics 2022-11-15 Valerio Pagliari , Kostas Papafitsoros , Bogdan Raiţă , Andreas Vikelis