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This paper proposes a precise signal recovery method with multilayered non-convex regularization, enhancing sparsity/low-rankness for high-dimensional signals including images and videos. In optimization-based signal recovery, multilayered…

Signal Processing · Electrical Eng. & Systems 2024-09-24 Akari Katsuma , Seisuke Kyochi , Shunsuke Ono , Ivan Selesnick

We consider the problem of estimating a signal from noisy circularly-translated versions of itself, called multireference alignment (MRA). One natural approach to MRA could be to estimate the shifts of the observations first, and infer the…

Information Theory · Computer Science 2018-02-14 Tamir Bendory , Nicolas Boumal , Chao Ma , Zhizhen Zhao , Amit Singer

Sparse channel estimation for massive multiple-input multiple-output systems has drawn much attention in recent years. The required pilots are substantially reduced when the sparse channel state vectors can be reconstructed from a few…

Information Theory · Computer Science 2021-02-17 Pengxia Wu , Hui Ma , Julian Cheng

This study concentrates on advancing mathematical and computational methodology for radar tomography imaging in which the unknown volumetric velocity distribution of a wave within a bounded domain is to be reconstructed. Our goal is to…

Instrumentation and Methods for Astrophysics · Physics 2018-04-04 Mika Takala , Defne Us , Sampsa Pursiainen

Obtaining conductance spectra for a concentration of disordered impurities distributed over a nanoscale device with sensing capabilities is a well-defined problem. However, to do this inversely, i.e., extracting information about the…

Mesoscale and Nanoscale Physics · Physics 2021-12-01 S. Mukim , J. O'Brien , M. Abarashi , M. S. Ferreira , C. G. Rocha

Compressive sensing is a technique to sample signals well below the Nyquist rate using linear measurement operators. In this paper we present an algorithm for signal reconstruction given such a set of measurements. This algorithm…

Information Theory · Computer Science 2009-06-08 Graeme Pope

Natural signals and images are well-known to be approximately sparse in transform domains such as Wavelets and DCT. This property has been heavily exploited in various applications in image processing and medical imaging. Compressed sensing…

Machine Learning · Computer Science 2015-10-26 Saiprasad Ravishankar , Yoram Bresler

A central theme in classical algorithms for the reconstruction of discontinuous functions from observational data is perimeter regularization via the use of the total variation. On the other hand, sparse or noisy data often demands a…

Optimization and Control · Mathematics 2020-04-13 Oliver R. A. Dunbar , Matthew M. Dunlop , Charles M. Elliott , Viet Ha Hoang , Andrew M. Stuart

During the inversion of discrete linear systems noise in data can be amplified and result in meaningless solutions. To combat this effect, characteristics of solutions that are considered desirable are mathematically implemented during…

Numerical Analysis · Mathematics 2023-02-07 Michael J. Byrne , Rosemary A. Renaut

Full-waveform inversion (FWI) is a powerful geophysical imaging technique that infers high-resolution subsurface physical parameters by solving a non-convex optimization problem. However, due to limitations in observation, e.g., limited…

Numerical Analysis · Mathematics 2023-11-09 Xiong-Bin Yan , Keke Wu , Zhi-Qin John Xu , Zheng Ma

We consider an inverse scattering problem for time-harmonic acoustic or electromagnetic waves. The goal is to localize several small penetrable objects embedded inside an otherwise homogeneous background medium from observations of far…

Numerical Analysis · Mathematics 2017-04-05 Roland Griesmaier , Christian Schmiedecke

The inverse problem of electrical impedance tomography is severely ill-posed, meaning that, only limited information about the conductivity can in practice be recovered from boundary measurements of electric current and voltage. Recently it…

Analysis of PDEs · Mathematics 2018-09-20 Henrik Garde , Stratos Staboulis

Sharpness-aware minimization (SAM) has emerged as a highly effective technique to improve model generalization, but its underlying principles are not fully understood. We investigate m-sharpness, where SAM performance improves monotonically…

Machine Learning · Computer Science 2026-04-03 Haocheng Luo , Mehrtash Harandi , Dinh Phung , Trung Le

In this paper we study the topic of signal restoration using complexity regularization, quantifying the compression bit-cost of the signal estimate. While complexity-regularized restoration is an established concept, solid practical methods…

Information Theory · Computer Science 2018-11-14 Yehuda Dar , Michael Elad , Alfred M. Bruckstein

In this work, we consider the problem of multi-pitch estimation, i.e., identifying super-imposed truncated harmonic series from noisy measurements. We phrase this as recovering a harmonically-structured measure on the unit circle, where the…

Signal Processing · Electrical Eng. & Systems 2025-08-05 Anton Björkman , Filip Elvander

This work considers using reduced basis techniques in connection to (smoothened) total variation regularization in electrical impedance tomography, but analogous ideas can also be used for other inverse elliptic boundary value problems. It…

Numerical Analysis · Mathematics 2026-02-18 A. Hannukainen , N. Hyvönen , V. Toresen

A procedure based on a Mixture Density Model for correcting experimental data for distortions due to finite resolution and limited detector acceptance is presented. Addressing the case that the solution is known to be non-negative, in the…

Data Analysis, Statistics and Probability · Physics 2015-03-09 Nikolai Gagunashvili

Extended formulation of Full Waveform Inversion (FWI), called Wavefield Reconstruction Inversion (WRI), offers potential benefits of decreasing the nonlinearity of the inverse problem by replacing the explicit inverse of the ill-conditioned…

Optimization and Control · Mathematics 2020-05-18 Hossein S. Aghamiry , Ali Gholami , Stéphane Operto

We study imaging with an array of sensors that probes a medium with single frequency electromagnetic waves and records the scattered electric field. The medium is known and homogenous except for some small and penetrable inclusions. The…

Analysis of PDEs · Mathematics 2016-09-21 Liliana Borcea , Josselin Garnier

Electrical Impedance Tomography (EIT) is a widely employed imaging technique in industrial inspection, geophysical prospecting, and medical imaging. However, the inherent nonlinearity and ill-posedness of EIT image reconstruction present…

Image and Video Processing · Electrical Eng. & Systems 2024-05-03 Huihui Wang , Guixian Xu , Qingping Zhou