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Bayesian hierarchical models can provide efficient algorithms for finding sparse solutions to ill-posed inverse problems. The models typically comprise a conditionally Gaussian prior model for the unknown which is augmented by a generalized…

Numerical Analysis · Mathematics 2025-01-09 Jonathan Lindbloom , Jan Glaubitz , Anne Gelb

The electrical impedance tomography (EIT) problem of estimating the unknown conductivity distribution inside a domain from boundary current or voltage measurements requires the solution of a nonlinear inverse problem. Sparsity promoting…

Numerical Analysis · Mathematics 2024-05-27 Daniela Calvetti , Monica Pragliola , Erkki Somersalo

Bayesian hierarchical models have been demonstrated to provide efficient algorithms for finding sparse solutions to ill-posed inverse problems. The models comprise typically a conditionally Gaussian prior model for the unknown, augmented by…

Numerical Analysis · Mathematics 2023-03-31 Daniela Calvetti , Erkki Somersalo

In ill-posed dynamic inverse problems expected spatial features and temporal correlation between frames can be leveraged to improve the quality of the computed solution, in particular when the available data are limited and the…

The sparse structure of the solution for an inverse problem can be modelled using different sparsity enforcing priors when the Bayesian approach is considered. Analytical expression for the unknowns of the model can be obtained by building…

Applications · Statistics 2017-05-31 Mircea Dumitru

In high-dimensional settings, sparse structures are critical for efficiency in term of memory and computation complexity. For a linear system, to find the sparsest solution provided with an over-complete dictionary of features directly is…

Machine Learning · Statistics 2020-07-09 Yiping Jiang , Tianshi Chen

A general framework for solving image inverse problems is introduced in this paper. The approach is based on Gaussian mixture models, estimated via a computationally efficient MAP-EM algorithm. A dual mathematical interpretation of the…

Computer Vision and Pattern Recognition · Computer Science 2010-06-16 Guoshen Yu , Guillermo Sapiro , Stéphane Mallat

In inverse problems, it is widely recognized that the incorporation of a sparsity prior yields a regularization effect on the solution. This approach is grounded on the a priori assumption that the unknown can be appropriately represented…

Machine Learning · Statistics 2025-06-13 Giovanni S. Alberti , Luca Ratti , Matteo Santacesaria , Silvia Sciutto

We consider a dictionary learning problem whose objective is to design a dictionary such that the signals admits a sparse or an approximate sparse representation over the learned dictionary. Such a problem finds a variety of applications…

Machine Learning · Computer Science 2015-03-10 Linxiao Yang , Jun Fang , Hong Cheng , Hongbin Li

The recovery of sparse generative models from few noisy measurements is an important and challenging problem. Many deterministic algorithms rely on some form of $\ell_1$-$\ell_2$ minimization to combine the computational convenience of the…

Numerical Analysis · Mathematics 2020-03-20 Daniela Calvetti , Monica Pragliola , Erkki Somersalo

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

This paper analyzes hierarchical Bayesian inverse problems using techniques from high-dimensional statistics. Our analysis leverages a property of hierarchical Bayesian regularizers that we call approximate decomposability to obtain…

Statistics Theory · Mathematics 2024-01-09 Daniel Sanz-Alonso , Nathan Waniorek

The present paper proposes a Bayesian framework for inverse problems that seamlessly integrates optimization and inversion to enable rapid surrogate modeling, accurate parameter inference, and rigorous uncertainty quantification. Bayesian…

Computational Engineering, Finance, and Science · Computer Science 2026-02-05 Mihaela Chiappetta , Massimo Carraturo , Alexander Raßloff , Markus Kästner , Ferdinando Auricchio

Sparse representations have proven their efficiency in solving a wide class of inverse problems encountered in signal and image processing. Conversely, enforcing the information to be spread uniformly over representation coefficients…

Machine Learning · Statistics 2017-12-29 Clément Elvira , Pierre Chainais , Nicolas Dobigeon

This paper presents a hierarchical Bayesian model to reconstruct sparse images when the observations are obtained from linear transformations and corrupted by an additive white Gaussian noise. Our hierarchical Bayes model is well suited to…

Data Analysis, Statistics and Probability · Physics 2011-01-19 Nicolas Dobigeon , Alfred O. Hero , Jean-Yves Tourneret

Machine learning methods for computational imaging require uncertainty estimation to be reliable in real settings. While Bayesian models offer a computationally tractable way of recovering uncertainty, they need large data volumes to be…

Machine Learning · Computer Science 2020-08-24 Francesco Tonolini , Jack Radford , Alex Turpin , Daniele Faccio , Roderick Murray-Smith

Models with dimension more than the available sample size are now commonly used in various applications. A sensible inference is possible using a lower-dimensional structure. In regression problems with a large number of predictors, the…

Statistics Theory · Mathematics 2025-11-25 Sayantan Banerjee , Ismaël Castillo , Subhashis Ghosal

Regularization is a common tool in variational inverse problems to impose assumptions on the parameters of the problem. One such assumption is sparsity, which is commonly promoted using lasso and total variation-like regularization.…

Statistics Theory · Mathematics 2023-02-15 Jasper Marijn Everink , Yiqiu Dong , Martin Skovgaard Andersen

This paper addresses the problem of identifying a lower dimensional space where observed data can be sparsely represented. This under-complete dictionary learning task can be formulated as a blind separation problem of sparse sources…

Methodology · Statistics 2010-08-30 Nicolas Dobigeon , Jean-Yves Tourneret

Hierarchical models with gamma hyperpriors provide a flexible, sparse-promoting framework to bridge $L^1$ and $L^2$ regularizations in Bayesian formulations to inverse problems. Despite the Bayesian motivation for these models, existing…

Methodology · Statistics 2021-11-30 Shiv Agrawal , Hwanwoo Kim , Daniel Sanz-Alonso , Alexander Strang
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