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Related papers: Symmetrization Techniques in Image Deblurring

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This paper addresses the problem of inverse rendering from photometric images. Existing approaches for this problem suffer from the effects of self-shadows, inter-reflections, and lack of constraints on the surface reflectance, leading to…

Computer Vision and Pattern Recognition · Computer Science 2025-04-09 Jingzhi Bao , Guanying Chen , Shuguang Cui

We introduce a new general purpose multiresolution preconditioner for symmetric linear systems. Most existing multiresolution preconditioners use some standard wavelet basis that relies on knowledge of the geometry of the underlying domain.…

Numerical Analysis · Mathematics 2017-07-10 Pramod Kaushik Mudrakarta , Risi Kondor

Image prior modeling is the key issue in image recovery, computational imaging, compresses sensing, and other inverse problems. Recent algorithms combining multiple effective priors such as the sparse or low-rank models, have demonstrated…

Image and Video Processing · Electrical Eng. & Systems 2020-03-31 Bihan Wen , Yanjun Li , Yuqi Li , Yoram Bresler

High-quality reconstructions of signals and images with sharp edges are needed in a wide range of applications. To overcome the large dimensionality of the parameter space and the complexity of the regularization functional,…

Numerical Analysis · Mathematics 2025-05-06 Jonathan Lindbloom , Mirjeta Pasha , Jan Glaubitz , Youssef Marzouk

Stationary iterative methods with a symmetric splitting matrix are performed as inner-iteration preconditioning for Krylov subspace methods. We give conditions such that the inner-iteration preconditioning matrix is definite, and show that…

Numerical Analysis · Mathematics 2019-05-20 Keiichi Morikuni

Preconditioned Krylov subspace (KSP) methods are widely used for solving large-scale sparse linear systems arising from numerical solutions of partial differential equations (PDEs). These linear systems are often nonsymmetric due to the…

Numerical Analysis · Mathematics 2018-09-05 Aditi Ghai , Cao Lu , Xiangmin Jiao

Real world image super-resolution (Real-ISR) often leverages the powerful generative priors of text-to-image diffusion models by regularizing the output to lie on their learned manifold. However, existing methods often overlook the…

Computer Vision and Pattern Recognition · Computer Science 2026-04-03 Junoh Kang , Donghun Ryou , Bohyung Han

The conventional methods for estimating camera poses and scene structures from severely blurry or low resolution images often result in failure. The off-the-shelf deblurring or super-resolution methods may show visually pleasing results.…

Computer Vision and Pattern Recognition · Computer Science 2017-09-19 Haesol Park , Kyoung Mu Lee

Detection of inconsistencies of double JPEG artefacts across different image regions is often used to detect local image manipulations, like image splicing, and to localize them. In this paper, we move one step further, proposing an…

Image and Video Processing · Electrical Eng. & Systems 2022-01-20 Yakun Niu , Benedetta Tondi , Yao Zhao , Rongrong Ni , Mauro Barni

Neural Radiance Fields (NeRF) can be optimized to obtain high-fidelity 3D scene reconstructions of objects and large-scale scenes. However, NeRFs require accurate camera parameters as input -- inaccurate camera parameters result in blurry…

Computer Vision and Pattern Recognition · Computer Science 2023-09-01 Keunhong Park , Philipp Henzler , Ben Mildenhall , Jonathan T. Barron , Ricardo Martin-Brualla

Adaptive regularization methods pre-multiply a descent direction by a preconditioning matrix. Due to the large number of parameters of machine learning problems, full-matrix preconditioning methods are prohibitively expensive. We show how…

Machine Learning · Computer Science 2020-11-19 Naman Agarwal , Brian Bullins , Xinyi Chen , Elad Hazan , Karan Singh , Cyril Zhang , Yi Zhang

Image deblurring is a notoriously challenging ill-posed inverse problem. In recent years, a wide variety of approaches have been proposed based upon regularization at the level of the image or on techniques from machine learning. We propose…

Computer Vision and Pattern Recognition · Computer Science 2020-10-22 Gabriel Rioux , Rustum Choksi , Tim Hoheisel , Pierre Marechal , Christopher Scarvelis

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

This paper introduces a new preconditioning technique that is suitable for matrices arising from the discretization of a system of PDEs on unstructured grids. The preconditioner satisfies a so-called filtering property, which ensures that…

Numerical Analysis · Computer Science 2011-03-17 Laura Grigori , Frédéric Nataf

In this paper we present general-purpose preconditioners for regularized augmented systems arising from optimization problems, and their corresponding normal equations. We discuss positive definite preconditioners, suitable for CG and…

Optimization and Control · Mathematics 2022-04-01 Jacek Gondzio , Spyridon Pougkakiotis , John W. Pearson

Several important classes of images such as text, barcode and pattern images have the property that pixels can only take a distinct subset of values. This knowledge can benefit the restoration of such images, but it has not been widely…

Computer Vision and Pattern Recognition · Computer Science 2015-08-21 Xing Mei , Honggang Qi , Bao-Gang Hu , Siwei Lyu

Incomplete LU factorizations of sparse matrices are widely used as preconditioners in Krylov subspace methods to speed up solving linear systems. Unfortunately, computing the preconditioner itself can be time-consuming and sensitive to…

Machine Learning · Computer Science 2024-12-12 Paul Häusner , Aleix Nieto Juscafresa , Jens Sjölund

We consider the problem of minimizing an objective function that is the sum of a convex function and a group sparsity-inducing regularizer. Problems that integrate such regularizers arise in modern machine learning applications, often for…

Optimization and Control · Mathematics 2020-07-30 Frank E. Curtis , Yutong Dai , Daniel P. Robinson

Group sparse representation has shown promising results in image debulrring and image inpainting in GSR [3] , the main reason that lead to the success is by exploiting Sparsity and Nonlocal self-similarity (NSS) between patches on natural…

Computer Vision and Pattern Recognition · Computer Science 2022-12-23 Luoyu Chen , Fei Wu

Synthetic images created by image editing operations are prevalent, but the color or illumination inconsistency between the manipulated region and background may make it unrealistic. Thus, it is important yet challenging to localize the…

Computer Vision and Pattern Recognition · Computer Science 2022-10-06 Penghao Wu , Li Niu , Jing Liang , Liqing Zhang