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The ability to efficiently and accurately construct an inverse frame operator is critical for establishing the utility of numerical frame approximations. Recently, the admissible frame method was developed to approximate inverse frame…

Numerical Analysis · Mathematics 2015-11-11 Guohui Song , Jacqueline Davis , Anne Gelb

Optimization-based filtering smoothes an image by minimizing a fidelity function and simultaneously preserves edges by exploiting a sparse norm penalty over gradients. It has obtained promising performance in practical problems, such as…

Graphics · Computer Science 2013-05-20 Chengxi Ye , Dacheng Tao , Mingli Song , David W. Jacobs , Min Wu

Many inverse problems can be described by a PDE model with unknown parameters that need to be calibrated based on measurements related to its solution. This can be seen as a constrained minimization problem where one wishes to minimize the…

Numerical Analysis · Mathematics 2018-09-06 Nick Schenkels , Wim Vanroose

We study linear inverse problems under the premise that the forward operator is not at hand but given indirectly through some input-output training pairs. We demonstrate that regularization by projection and variational regularization can…

Numerical Analysis · Mathematics 2020-12-30 Andrea Aspri , Yury Korolev , Otmar Scherzer

In many practical applications such as direction-of-arrival (DOA) estimation and line spectral estimation, the sparsifying dictionary is usually characterized by a set of unknown parameters in a continuous domain. To apply the conventional…

Information Theory · Computer Science 2015-06-18 Jun Fang , Jing Li , Yanning Shen , Hongbin Li , Shaoqian Li

Compressed Sensing using $\ell_1$ regularization is among the most powerful and popular sparsification technique in many applications, but why has it not been used to obtain sparse deep learning model such as convolutional neural network…

Machine Learning · Computer Science 2021-10-06 Juncai He , Xiaodong Jia , Jinchao Xu , Lian Zhang , Liang Zhao

The earlier works in the context of low-rank-sparse-decomposition (LRSD)-driven stationary synthetic aperture radar (SAR) imaging have shown significant improvement in the reconstruction-decomposition process. Neither of the proposed…

Image and Video Processing · Electrical Eng. & Systems 2025-12-12 Hamid Reza Hashempour , Majid Moradikia , Hamed Bastami , Ahmed Abdelhadi , Mojtaba Soltanalian

We consider the problem of discretizing evolution operators of linear delay equations with the aim of approximating their spectra, which is useful in investigating the stability properties of (nonlinear) equations via the principle of…

Numerical Analysis · Mathematics 2026-01-01 Alessia andò , Giusy Bosco , Dimitri Breda , Davide Liessi

A supervised learning approach is proposed for regularization of large inverse problems where the main operator is built from noisy data. This is germane to superresolution imaging via the sampling indicators of the inverse scattering…

Numerical Analysis · Mathematics 2025-08-22 Fatemeh Pourahmadian , Yang Xu

Excessive computational cost for learning large data and streaming data can be alleviated by using stochastic algorithms, such as stochastic gradient descent and its variants. Recent advances improve stochastic algorithms on convergence…

Machine Learning · Statistics 2019-09-24 Shih-Kang Chao , Guang Cheng

In this paper we develop adaptive numerical schemes for certain nonlinear variational problems. The discretization of the variational problems is done by representing the solution as a suitable frame decomposition, i.e., a complete, stable,…

Numerical Analysis · Mathematics 2007-05-23 M. Charina , C. Conti , M. Fornasier

Many imaging science tasks can be modeled as a discrete linear inverse problem. Solving linear inverse problems is often challenging, with ill-conditioned operators and potentially non-unique solutions. Embedding prior knowledge, such as…

Numerical Analysis · Mathematics 2023-12-07 Elizabeth Newman , Jack Michael Solomon , Matthias Chung

Diverse inverse problems in imaging can be cast as variational problems composed of a task-specific data fidelity term and a regularization term. In this paper, we propose a novel learnable general-purpose regularizer exploiting recent…

Optimization and Control · Mathematics 2020-02-19 Erich Kobler , Alexander Effland , Karl Kunisch , Thomas Pock

Machine Learning (ML) methods and tools have gained great success in many data, signal, image and video processing tasks, such as classification, clustering, object detection, semantic segmentation, language processing, Human-Machine…

Machine Learning · Computer Science 2023-09-06 Ali Mohammad-Djafari , Ning Chu , Li Wang , Liang Yu

We investigate implicit regularization schemes for gradient descent methods applied to unpenalized least squares regression to solve the problem of reconstructing a sparse signal from an underdetermined system of linear measurements under…

Machine Learning · Statistics 2019-09-12 Tomas Vaškevičius , Varun Kanade , Patrick Rebeschini

We present and analyze a novel sparse polynomial technique for approximating high-dimensional Hilbert-valued functions, with application to parameterized partial differential equations (PDEs) with deterministic and stochastic inputs. Our…

Numerical Analysis · Mathematics 2020-01-22 Nick Dexter , Hoang Tran , Clayton Webster

Recursive adaptive filtering methods are often used for solving the problem of simultaneous state and parameters estimation arising in many areas of research. The gradient-based schemes for adaptive Kalman filtering (KF) require the…

Systems and Control · Computer Science 2017-09-12 Julia V. Tsyganova , Maria V. Kulikova

In this paper, we present an advanced approach to solving the inverse rig problem in blendshape animation, using high-quality corrective blendshapes. Our algorithm introduces novel enhancements in three key areas: ensuring high data…

Graphics · Computer Science 2024-01-31 Stevo Racković , Cláudia Soares , Dušan Jakovetić

Regularization plays an important role in solving ill-posed problems by adding extra information about the desired solution, such as sparsity. Many regularization terms usually involve some vector norm, e.g., $L_1$ and $L_2$ norms. In this…

Numerical Analysis · Mathematics 2021-03-10 Weihong Guo , Yifei Lou , Jing Qin , Ming Yan

3D volumetric reconstruction from incomplete or noisy measurements is a fundamental problem in medical imaging and computational tomography. Deep image prior (DIP)-based methods have recently shown strong capability for solving inverse…

Computational Engineering, Finance, and Science · Computer Science 2026-05-29 Haijie Yuan , Chaoyan Huang , Srijita Bandopadhyay , Liyue Shen , Saiprasad Ravishankar