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This paper presents five different statistical methods for ground scene prediction (GSP) in wavelength-resolution synthetic aperture radar (SAR) images. The GSP image can be used as a reference image in a change detection algorithm yielding…

Image and Video Processing · Electrical Eng. & Systems 2022-07-26 B. G. Palm , D. I. Alves , M. I. Pettersson , V. T. Vu , R. Machado , R. J. Cintra , F. M. Bayer , P. Dammert , H. Hellsten

Delay-and-sum (DAS) algorithms are widely used for beamforming in linear array photoacoustic imaging systems and are characterized by fast execution. However, these algorithms suffer from various drawbacks like low resolution, low contrast,…

Medical Physics · Physics 2021-07-29 Souradip Paul , Subhamoy Mandal , Mayanglambam Suheshkumar Singh

An expression is obtained on the basis of phase perturbation theory for the contribution to the mean differential reflection coefficient from the in-plane co-polarized component of the light scattered diffusely from a two-dimensional…

Inversion of gravity data is an important method for investigating subsurface density variations relevant to mineral exploration, geothermal assessment, carbon storage, natural hydrogen, groundwater resources, and tectonic evolution. Here…

Geophysics · Physics 2026-04-07 Pankaj K Mishra , Sanni Laaksonen , Jochen Kamm , Anand Singh

We focus on an alignment-free method to estimate the underlying signal from a large number of noisy randomly shifted observations. Specifically, we estimate the mean, power spectrum, and bispectrum of the signal from the observations. Since…

Signal Processing · Electrical Eng. & Systems 2018-07-04 Hua Chen , Mona Zehni , Zhizhen Zhao

In exploration seismology, seismic inversion refers to the process of inferring physical properties of the subsurface from seismic data. Knowledge of physical properties can prove helpful in identifying key structures in the subsurface for…

Signal Processing · Electrical Eng. & Systems 2019-06-07 Ahmad Mustafa , Motaz Alfarraj , Ghassan AlRegib

We present a calculation of the spectral properties of a single charge doped at a Cu($3d$) site of the Cu-F plane in KCuF$_{3}$. The problem is treated by generating the equations of motion for the Green's function by means of subsequent…

Strongly Correlated Electrons · Physics 2016-12-26 Krzysztof Bieniasz , Mona Berciu , Andrzej M. Oleś

During the past three years, Wapenaar, Snieder, Broggini and others have developed an algorithm to compute the Green's function for any point inside a medium to points on the surface from measurements on that surface only. Their algorithm…

Geophysics · Physics 2012-12-18 Harun Omer

Atmospheric lidar observations provide a unique capability to directly observe the vertical column of cloud and aerosol scattering properties. Detector and solar background noise, however, hinder the ability of lidar systems to provide…

Optimization and Control · Mathematics 2016-06-21 Willem J. Marais , Robert E. Holz , Yu Hen Hu , Ralph E. Kuehn , Edwin E. Eloranta , Rebecca M. Willett

An important application of next-generation wide-field radio interferometers is making high dynamic range maps of radio emission. Traditional deconvolution methods like CLEAN can give poor recovery of diffuse structure, prompting the…

Instrumentation and Methods for Astrophysics · Physics 2024-10-23 Katrine A. Glasscock , Philip Bull , Jacob Burba , Hugh Garsden , Michael J. Wilensky

In this article we derive the average and the variance of the cross-correlation of a noise wavefield. The noise cross-correlation function (NCF) is widely used to passively estimate the Green's function between two probes and is…

Disordered Systems and Neural Networks · Physics 2015-06-17 Julien de Rosny , Matthieu Davy

Computing resonance and anti-resonance backbone curves in complex nonlinear mechanical systems is of high engineering relevance but remains computationally challenging, especially for large finite-element (FE) models. Existing…

Classical Physics · Physics 2026-02-09 Wei Wen , Weikai Qi , Weidong Wen

Results of forward modelling of acoustic wave propagation in a realistic solar sub-photosphere with two cases of steady horizontal flows are presented and analysed by the means of local helioseismology. The simulations are based on fully…

Astrophysics · Physics 2009-11-13 S. Shelyag , R. Erdelyi , M. J. Thompson

Instrumental aberrations strongly limit high-contrast imaging of exoplanets, especially when they produce quasistatic speckles in the science images. With the help of recent advances in deep learning, we have developed in previous works an…

Instrumentation and Methods for Astrophysics · Physics 2022-11-14 Maxime Quesnel , Gilles Orban de Xivry , Olivier Absil , Gilles Louppe

Helioseismic holography is a useful method to detect active regions on the Sun's far side and improve space weather forecasts. We aim to improve helioseismic holography by using a clear formulation of the problem, an accurate forward solver…

Solar and Stellar Astrophysics · Physics 2023-01-18 Dan Yang , Laurent Gizon , Hélène Barucq

Empirical Green's functions (EGFs) extracted from seismic ambient noise have been widely used to image Earth's interior structures, and the resolution of EGF-based tomography depends on the spatial density of seismic stations. However, due…

Geophysics · Physics 2026-01-12 Guoyi Chen , Junlun Li , Bao Deng

The main goal of this paper is to estimate the regional acoustic and geoacoustic shallow-water environment from data collected by a vertical hydrophone array and transmitted by distant time-harmonic point sources. We aim at estimating the…

Analysis of PDEs · Mathematics 2019-09-04 Laure Dumaz , Josselin Garnier , Guilhem Lepoultier

Hyperspectral unmixing is an important remote sensing task with applications including material identification and analysis. Characteristic spectral features make many pure materials identifiable from their visible-to-infrared spectra, but…

Computer Vision and Pattern Recognition · Computer Science 2020-07-14 John Janiczek , Parth Thaker , Gautam Dasarathy , Christopher S. Edwards , Philip Christensen , Suren Jayasuriya

In order to predict future performance of subsurface fluid reservoirs under possible operating scenarios, a dynamic, porous-medium flow simulation model must be tuned to include representative properties of the reservoir. Estimating…

Geophysics · Physics 2026-02-04 Zhen Zhang , Xuebin Zhao , Andrew Curtis

We introduce a novel diffusion-based spectral algorithm to tackle regression analysis on high-dimensional data, particularly data embedded within lower-dimensional manifolds. Traditional spectral algorithms often fall short in such…

Machine Learning · Statistics 2024-10-21 Weichun Xia , Jiaxin Jiang , Lei Shi