English
Related papers

Related papers: Swarm intelligence for full Stokes dynamic imaging…

200 papers

In Very Long Baseline Interferometry (VLBI), signals from multiple antennas combine to create a sparsely sampled virtual aperture, its effective diameter determined by the largest antenna separation. The inherent sparsity makes VLBI imaging…

Instrumentation and Methods for Astrophysics · Physics 2024-01-25 Alejandro Mus , Hendrik Müller , Ivan Martí-Vidal , Andrei Lobanov

Imaging reconstruction of interferometric data is a hard ill-posed inverse problem. Its difficulty is increased when observing the Galactic Center, which is obscured by a scattering screen. This is because the scattering breaks the…

Instrumentation and Methods for Astrophysics · Physics 2025-06-25 Alejandro Mus , Teresa Toscano , Hendrik Müller , Guang-Yao Zhao , Andrei Lobanov , Ciriaco Goddi

Very long baseline interferometry (VLBI) is a technique for imaging celestial radio emissions by simultaneously observing a source from telescopes distributed across Earth. The challenges in reconstructing images from fine angular…

Instrumentation and Methods for Astrophysics · Physics 2016-11-08 Katherine L. Bouman , Michael D. Johnson , Daniel Zoran , Vincent L. Fish , Sheperd S. Doeleman , William T. Freeman

Optical interferometers provide multiple wavelength measurements. In order to fully exploit the spectral and spatial resolution of these instruments, new algorithms for image reconstruction have to be developed. Early attempts to deal with…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 Éric Thiébaut , Ferréol Soulez , Loïc Denis

Very long baseline interferometry (VLBI) makes it possible to recover images of astronomical sources with extremely high angular resolution. Most recently, the Event Horizon Telescope (EHT) has extended VLBI to short millimeter wavelengths…

Instrumentation and Methods for Astrophysics · Physics 2018-02-05 Katherine L. Bouman , Michael D. Johnson , Adrian V. Dalca , Andrew A. Chael , Freek Roelofs , Sheperd S. Doeleman , William T. Freeman

Recently multiscale imaging approaches such as DoG-HiT were developed to solve the VLBI imaging problem and showed a promising performance: they are fast, accurate, unbiased and automatic. We extend the multiscalar imaging approach to…

Instrumentation and Methods for Astrophysics · Physics 2023-05-24 Hendrik Müller , Andrei Lobanov

Reconstructing an image from sparsely sampled Fourier data is an ill-posed inverse problem that occurs in a variety of subjects within science, including the data analysis for Very Long Baseline Interferometry (VLBI) and the…

Instrumentation and Methods for Astrophysics · Physics 2024-01-22 Hendrik Müller , Paolo Massa , Alejandro Mus , Jong-Seo Kim , Emma Perracchione

Context. The current algorithms used for the calibration and analysis of very long baseline interferometry (VLBI) networks that only use linear polarizers (as is the case of the VLBI Global Observing System, VGOS) do not properly account…

Instrumentation and Methods for Astrophysics · Physics 2024-06-19 V. Pérez-Díez , I. Martí-Vidal , E. Albentosa-Ruiz , J. González-García , F. Jaron , T. Savolainen , M. H. Xu , R. Bachiller

Imaging interferometric data in radio astronomy requires the use of non-linear algorithms that rely on different assumptions on the source structure and may produce non-unique results. This is especially true for Very Long Baseline…

Instrumentation and Methods for Astrophysics · Physics 2024-01-19 A. Mus , I. Martí-Vidal

This paper proposes a new image thresholding segmentation approach using the heuristic method, Convergent Heterogeneous Particle Swarm Optimization algorithm. The proposed algorithm incorporates a new strategy of searching the problem space…

Computer Vision and Pattern Recognition · Computer Science 2016-05-17 Mohammad Hamed Mozaffari , Won-Sook Lee

The calibration and analysis of polarization observations in Very Long Baseline Interferometry (VLBI) requires the use of specific algorithms that suffer from several limitations, closely related to assumptions in the data properties that…

Instrumentation and Methods for Astrophysics · Physics 2021-02-10 Ivan Marti-Vidal , Alejandro Mus , Michael Janssen , Pablo de Vicente , Javier Gonzalez

Sparsity is one of the key concepts that allows the recovery of signals that are subsampled at a rate significantly lower than required by the Nyquist-Shannon sampling theorem. Our proposed framework uses arbitrary multiscale transforms,…

Optimization and Control · Mathematics 2017-05-31 Jackie Ma , Maximilian März

A new multi-frequency synthesis algorithm for reconstructing images from multi-frequency VLBI data is proposed. The algorithm is based on a generalized maximum-entropy method, and makes it possible to derive an effective spectral correction…

Astrophysics · Physics 2011-08-31 Anisa T. Bajkova

Iterative reweighted algorithms, as a class of algorithms for sparse signal recovery, have been found to have better performance than their non-reweighted counterparts. However, for solving the problem of multiple measurement vectors…

Machine Learning · Statistics 2011-04-29 Zhilin Zhang , Bhaskar D. Rao

Multi objective (MO) optimization is an emerging field which is increasingly being implemented in many industries globally. In this work, the MO optimization of the extraction process of bioactive compounds from the Gardenia Jasminoides…

Neural and Evolutionary Computing · Computer Science 2016-11-21 T. Ganesan , I. Elamvazuthi , P. Vasant

Self-calibration methods with the CLEAN algorithm have been widely employed in Very Long Baseline Interferometry (VLBI) data processing in order to correct antenna-based amplitude and phase corruptions present in the data. However, human…

Instrumentation and Methods for Astrophysics · Physics 2024-10-02 Jong-Seo Kim , Aleksei S. Nikonov , Jakob Roth , Torsten A. Ensslin , Michael Janssen , Philipp Arras , Hendrik Mueller , Andrei P. Lobanov

We address the problem of sparse recovery in an online setting, where random linear measurements of a sparse signal are revealed sequentially and the objective is to recover the underlying signal. We propose a reweighted least squares (RLS)…

Machine Learning · Computer Science 2017-06-30 Subhadip Mukherjee , Deepak R. , Huaijin Chen , Ashok Veeraraghavan , Chandra Sekhar Seelamantula

A robust algorithm is proposed to reconstruct the spatial support and the Lam\'e parameters of multiple inclusions in a homogeneous background elastic material using a few measurements of the displacement field over a finite collection of…

Numerical Analysis · Mathematics 2017-02-27 Jaejun Yoo , Younghoon Jung , Mikyoung Lim , Jong Chul Ye , Abdul Wahab

For many practical applications in wireless communications, we need to recover a structured sparse signal from a linear observation model with dynamic grid parameters in the sensing matrix. Conventional expectation maximization (EM)-based…

Signal Processing · Electrical Eng. & Systems 2023-11-14 Wenkang Xu , An Liu , Bingpeng Zhou , Minjian Zhao

We propose a new technique for radio interferometry to obtain super-resolution full polarization images in all four Stokes parameters using sparse modeling. The proposed technique reconstructs the image in each Stokes parameter from the…

‹ Prev 1 2 3 10 Next ›