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We study active array imaging of small but strong scatterers in homogeneous media when multiple scattering between them is important. We use the Foldy-Lax equations to model wave propagation with multiple scattering when the scatterers are…

Mathematical Physics · Physics 2015-12-15 Anwei Chai , Miguel Moscoso , George Papanicolaou

It is one typical and general topic of learning a good embedding model to efficiently learn the representation coefficients between two spaces/subspaces. To solve this task, $L_{1}$ regularization is widely used for the pursuit of feature…

Computer Vision and Pattern Recognition · Computer Science 2021-03-09 Bo Zhao , Xinwei Sun , Yanwei Fu , Yuan Yao , Yizhou Wang

Single molecule localization microscopy (SMLM) techniques enable imaging biological samples well beyond the diffraction limit of light, but they vary significantly in their spatial and temporal resolutions. High-order statistical analysis…

Biological Physics · Physics 2016-03-15 Shachar Schidorsky , Xiyu Yi , Yair Razvag , Yonatan Golan , Shimon Weiss , Eilon Sherman

Assessing the quality of aperture synthesis maps is relevant for benchmarking image reconstruction algorithms, for the scientific exploitation of data from optical long-baseline interferometers, and for the design/upgrade of new/existing…

Instrumentation and Methods for Astrophysics · Physics 2017-02-22 Nuno Gomes , Paulo J. V. Garcia , Éric Thiébaut

The problem of phaseless aperture synthesis is of current interest in phase-unstable VLBI with a small number of elements when either the use of closure phases is not possible (a two-element interferometer) or their quality and number are…

Astrophysics · Physics 2009-11-10 Anisa T. Bajkova

Current trends in scientific imaging are challenged by the emerging need of integrating sophisticated machine learning with Big Data analytics platforms. This work proposes an in-memory distributed learning architecture for enabling…

Distributed, Parallel, and Cluster Computing · Computer Science 2018-10-01 A. Panousopoulou , S. Farrens , K. Fotiadou , A. Woiselle , G. Tsagkatakis , J-L. Starck , P. Tsakalides

Since its observation in 2019, the first image of a super-massive black hole using Very Long Baseline Interferometry (VLBI) with an Earth-scale baseline has generated much scientific and public interest, including the possible extension of…

Instrumentation and Methods for Astrophysics · Physics 2026-05-08 Eric Burt , Todd Ely , Geoff Bower , Joe Lazio , Marin Anderson , Sonia Hernandez

We demonstrate that at 1.4 GHz the combined response of sources detected serendipitously in deep, wide-field VLBI images is sufficient to permit self-calibration techniques to be employed. This technique of "full-beam" VLBI self-calibration…

Astrophysics · Physics 2007-05-23 M. A. Garrett , J. M. Wrobel , R. Morganti

The Event Horizon Telescope (EHT) recently released the first horizon-scale images of the black hole in M87. Combined with other astronomical data, these images constrain the mass and spin of the hole as well as the accretion rate and…

High Energy Astrophysical Phenomena · Physics 2021-10-15 Joshua Yao-Yu Lin , Dominic W. Pesce , George N. Wong , Ajay Uppili Arasanipalai , Ben S. Prather , Charles F. Gammie

Context: This is the first of a series of papers presenting VLBI observations of the 293 Caltech-Jodrell Bank Flat-Spectrum (hereafter CJF) sources and their analysis. Aims: One of the major goals of the CJF is to make a statistical study…

Shuffled linear regression (SLR) seeks to estimate latent features through a linear transformation, complicated by unknown permutations in the measurement dimensions. This problem extends traditional least-squares (LS) and Least Absolute…

Statistics Theory · Mathematics 2025-04-17 Hang Liu , Anna Scaglione

We present the results of the pilot observations of the Deep Extragalactic VLBI-Optical Survey (DEVOS). Our ultimate aim is to collect information on compact structures in a large sample of extragalactic radio sources (~10000 objects) up to…

Astrophysics · Physics 2009-11-13 L. Mosoni , S. Frey , L. I. Gurvits , M. A. Garrett , S. T. Garrington , Z. I. Tsvetanov

Stacking analysis is a means of detecting faint sources using a priori position information to estimate an aggregate signal from individually undetected objects. Confusion severely limits the effectiveness of stacking in deep surveys with…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Peter Kurczynski , Eric Gawiser

Data acquisition, image processing, and image quality are the long-lasting issues for terahertz (THz) 3D reconstructed imaging. Existing methods are primarily designed for 2D scenarios, given the challenges associated with obtaining…

Optics · Physics 2024-03-28 Yiyao Zhang , Ke Chen , Shang-Hua Yang

Hyperspectral image (HI) analysis approaches have recently become increasingly complex and sophisticated. Recently, the combination of spectral-spatial information and superpixel techniques have addressed some hyperspectral data issues,…

Image and Video Processing · Electrical Eng. & Systems 2024-07-23 Luciano Carvalho Ayres , Sérgio José Melo de Almeida , José Carlos Moreira Bermudez , Ricardo Augusto Borsoi

In this paper we consider iterative methods for stochastic variational inequalities (s.v.i.) with monotone operators. Our basic assumption is that the operator possesses both smooth and nonsmooth components. Further, only noisy observations…

Optimization and Control · Mathematics 2011-06-01 Anatoli Juditsky , Arkadii S. Nemirovskii , Claire Tauvel

The space astrometry mission GAIA will construct a dense optical QSO-based celestial reference frame. For consistency between the optical and radio positions, it will be important to align the GAIA frame and the International Celestial…

Astrophysics · Physics 2009-11-13 Geraldine Bourda , Patrick Charlot , Richard Porcas , Simon Garrington

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

Fourier ptychography is a new computational microscopy technique that provides gigapixel-scale intensity and phase images with both wide field-of-view and high resolution. By capturing a stack of low-resolution images under different…

The aim of the steganography methods is to communicate securely in a completely undetectable manner. LSB Matching and LSB Matching Revisited steganography methods are two general and esiest methods to achieve this aim. Being secured against…

Cryptography and Security · Computer Science 2017-09-21 Kazem Qazanfari , Reza Safabakhsh