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Modern radio telescopes, such as the Square Kilometre Array (SKA), will probe the radio sky over large fields-of-view, which results in large w-modulations of the sky image. This effect complicates the relationship between the measured…

Instrumentation and Methods for Astrophysics · Physics 2017-07-14 Arwa Dabbech , Laura Wolz , Luke Pratley , Jason D. McEwen , Yves Wiaux

In imaging modalities recording diffraction data, the original image can be reconstructed assuming known phases. When phases are unknown, oversampling and a constraint on the support region in the original object can be used to solve a…

Signal Processing · Electrical Eng. & Systems 2018-10-17 Alberto Pietrini , Carl Nettelblad

Radio interferometric imaging aims to estimate an unknown sky intensity image from degraded observations, acquired through an antenna array. In the theoretical case of a perfectly calibrated array, it has been shown that solving the…

Instrumentation and Methods for Astrophysics · Physics 2017-07-25 Audrey Repetti , Jasleen Birdi , Arwa Dabbech , Yves Wiaux

Interferometric Synthetic Aperture Radar (InSAR) Imaging methods are usually based on algorithms of match-filtering type, without considering the scene's characteristic, which causes limited imaging quality. Besides, post-processing steps…

Signal Processing · Electrical Eng. & Systems 2022-10-07 Xu Zhan , Xiaoling Zhang , Shunjun Wei , Jun Shi

There are a large number of methods for solving under-determined linear inverse problem. Many of them have very high time complexity for large datasets. We propose a new method called Two-Stage Sparse Representation (TSSR) to tackle this…

Computer Vision and Pattern Recognition · Computer Science 2015-12-09 Chengyu Peng , Hong Cheng , Manchor Ko

The concept of a recently proposed small-scale interferometric optical imaging device, an instrument known as the Segmented Planar Imaging Detector for Electro-optical Reconnaissance (SPIDER), is of great interest for its possible…

Instrumentation and Methods for Astrophysics · Physics 2021-03-24 Luke Pratley , Jason D. McEwen

For the next generation of radio interferometric telescopes it is of paramount importance to incorporate wide field-of-view (WFOV) considerations in interferometric imaging, otherwise the fidelity of reconstructed images will suffer…

Instrumentation and Methods for Astrophysics · Physics 2011-05-04 J. D. McEwen , Y. Wiaux

Faraday tomography (or rotation measure synthesis) is a procedure to convert linear polarization spectra into the Faraday dispersion function, which provides us with unique information of magneto-ionic media along the line of sight.…

Instrumentation and Methods for Astrophysics · Physics 2018-12-03 Kazunori Akiyama , Takuya Akahori , Yoshimitsu Miyashita , Shinsuke Ideguchi , Ryosuke Yamaguchi , Shiro Ikeda , Keitaro Takahashi

Ultrasound imaging faces a trade-off between image quality and hardware complexity caused by dense transducers. Sparse arrays are one popular solution to mitigate this challenge. This work proposes an end-to-end optimization framework that…

Image and Video Processing · Electrical Eng. & Systems 2026-04-01 Sergio Urrea , Adrian Basarab , Hervé Liebgott , Henry Arguello

Ultrasound images formed by delay-and-sum beamforming are plagued by artifacts that only clear up after compounding many transmissions. Some prior works pose imaging as an inverse problem. This approach can yield high image quality with few…

Signal Processing · Electrical Eng. & Systems 2024-07-03 Vincent van de Schaft , Oisín Nolan , Ruud J. G. van Sloun

Sparse representations have emerged as a powerful tool in signal and information processing, culminated by the success of new acquisition and processing techniques such as Compressed Sensing (CS). Fusion frames are very rich new signal…

Information Theory · Computer Science 2011-06-20 Petros T. Boufounos , Gitta Kutyniok , Holger Rauhut

Sparse representation using over-complete dictionaries have shown to produce good quality results in various image processing tasks. Dictionary learning algorithms have made it possible to engineer data adaptive dictionaries which have…

Image and Video Processing · Electrical Eng. & Systems 2019-11-11 Nishant Deepak Keni , Amol Mangirish Singbal , Rizwan Ahmed

We propose a deconvolution algorithm for images blurred and degraded by a Poisson noise. The algorithm uses a fast proximal backward-forward splitting iteration. This iteration minimizes an energy which combines a \textit{non-linear} data…

Applications · Statistics 2008-12-18 François-Xavier Dupé , Jalal Fadili , Jean Luc Starck

In this paper, we revisit the class of iterative shrinkage-thresholding algorithms (ISTA) for solving the linear inverse problem with sparse representation, which arises in signal and image processing. It is shown in the numerical…

Optimization and Control · Mathematics 2023-01-18 Bowen Li , Bin Shi , Ya-xiang Yuan

Radiation symmetry evaluation is critical to the laser driven Inertial Confinement Fusion (ICF), which is usually done by solving a view-factor equation model. The model is nonlinear, and the number of equations can be very large when the…

Signal Processing · Electrical Eng. & Systems 2019-08-20 Yanfeng Zhang

As a result of several successful applications in computer vision and image processing, sparse representation (SR) has attracted significant attention in multi-sensor image fusion. Unlike the traditional multiscale transforms (MSTs) that…

Computer Vision and Pattern Recognition · Computer Science 2017-02-14 Qiang Zhang , Yi Liu , Rick S. Blum , Jungong Han , Dacheng Tao

Synthetic aperture sonar (SAS) image resolution is constrained by waveform bandwidth and array geometry. Specifically, the waveform bandwidth determines a point spread function (PSF) that blurs the locations of point scatterers in the…

Computer Vision and Pattern Recognition · Computer Science 2021-12-17 Albert Reed , Thomas Blanford , Daniel C. Brown , Suren Jayasuriya

We propose a new approach within the versatile framework of convex optimization to solve the radio-interferometric wideband imaging problem. Our approach, dubbed HyperSARA, solves a sequence of weighted nuclear norm and l21 minimization…

Image and Video Processing · Electrical Eng. & Systems 2019-09-11 Abdullah Abdulaziz , Arwa Dabbech , Yves Wiaux

A common task in inverse problems and imaging is finding a solution that is sparse, in the sense that most of its components vanish. In the framework of compressed sensing, general results guaranteeing exact recovery have been proven. In…

Numerical Analysis · Mathematics 2021-04-29 Monica Pragliola , Daniela Calvetti , Erkki Somersalo

This paper presents a variational based approach to fusing hyperspectral and multispectral images. The fusion process is formulated as an inverse problem whose solution is the target image assumed to live in a much lower dimensional…

Computer Vision and Pattern Recognition · Computer Science 2023-07-19 Qi Wei , José Bioucas-Dias , Nicolas Dobigeon , Jean-Yves Tourneret