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The interest of compressive sampling in ultrasound imaging has been recently extensively evaluated by several research teams. Following the different application setups, it has been shown that the RF data may be reconstructed from a small…

Computer Vision and Pattern Recognition · Computer Science 2015-12-07 Zhouye Chen , Adrian Basarab , Denis Kouamé

Defect detection by ultrasonic method is limited by the pulse width. Resolution can be improved through a deconvolution process with a priori information of the pulse or by its estimation. In this paper a regularization of the Wiener filter…

Information Theory · Computer Science 2012-05-17 Roberto H. Herrera , Eduardo Moreno , Héctor Calas , Rubén Orozco

A new method for improving the resolution of astronomical images is presented. It is based on the principle that sampled data cannot be fully deconvolved without violating the sampling theorem. Thus, the sampled image should not be…

Astrophysics · Physics 2009-10-30 P. Magain , F. Courbin , S. Sohy

The turbulent ionized interstellar medium diffracts radio waves and makes them propagate in multiple paths. The pulse-broadening observed at low frequencies results from the scattering effect of interstellar clouds of ionized gas. During…

High Energy Astrophysical Phenomena · Physics 2025-06-18 W. C. Jing , J. L. Han , C. Wang , P. F. Wang , T. Wang , N. N. Cai , J. Xu , Z. L. Yang , D. J. Zhou , Yi Yan , W. Q. Su , X. Y. Gao , L. Xie

Radio-astronomical observations are increasingly contaminated by interference, and suppression techniques become essential. A powerful candidate for interference mitigation is adaptive spatial filtering. We study the effect of spatial…

Astrophysics · Physics 2014-10-13 Amir Leshem , Alle-Jan van der Veen

Radio interferometry enables high-resolution imaging of astronomical radio sources by synthesizing a large effective aperture from an array of antennas and solving a deconvolution problem to reconstruct the image. Deep learning has emerged…

Instrumentation and Methods for Astrophysics · Physics 2026-03-11 Zihui Wu , Liam Connor , Samuel McCarty , Katherine L. Bouman

Deconvolution is the most commonly used image processing method to remove the blur caused by the point-spread-function (PSF) in optical imaging systems. While this method has been successful in deblurring, it suffers from several…

Image and Video Processing · Electrical Eng. & Systems 2019-10-10 Huangxuan Zhao , Ziwen Ke , Ningbo Chen , Ke Li , Lidai Wang , Xiaojing Gong , Wei Zheng , Liang Song , Zhicheng Liu , Dong Liang , Chengbo Liu

In order to produce high dynamic range images in radio interferometry, bright extended sources need to be removed with minimal error. However, this is not a trivial task because the Fourier plane is sampled only at a finite number of…

Instrumentation and Methods for Astrophysics · Physics 2011-01-17 Sarod Yatawatta

A pulsar's pulse profile gets broadened at low frequencies due to dispersion along the line of sight or due to multi-path propagation. The dynamic nature of the interstellar medium makes both of these effects time-dependent and introduces…

Radio interferometry allows astronomers to probe small spatial scales that are often inaccessible with single-dish instruments. However, recovering the radio sky from an interferometer is an ill-posed deconvolution problem that astronomers…

Instrumentation and Methods for Astrophysics · Physics 2022-05-25 Liam Connor , Katherine L. Bouman , Vikram Ravi , Gregg Hallinan

Birefringence in ionized, magnetized media is usually measured as Faraday rotation of linearly polarized radiation. However, pulses propagating through regions with very large Faraday rotation measures (RMs) can split into circularly…

High Energy Astrophysical Phenomena · Physics 2019-01-23 Akshay Suresh , James M. Cordes

We present a robust approach to incorporating models for the time-variable broadening of the pulse profile due to scattering in the ionized interstellar medium into profile-domain pulsar timing analysis. We use this approach to…

Instrumentation and Methods for Astrophysics · Physics 2017-04-12 L. Lentati , M. Kerr , S. Dai , R. M. Shannon , G. Hobbs , S. Oslowski

The pulse widths of fast radio bursts are always broadened due to the scattering of the plasma medium through which the electromagnetic wave passes. The recorded pulse width will be further affected by the radio telescopes since the…

High Energy Astrophysical Phenomena · Physics 2025-01-24 Jia-Peng Wei , Yong-Feng Huang , Lang Cui , Xiang Liu , Jin-Jun Geng , Xue-Feng Wu

We study optical pulse propagation through a hollow-core fiber filled with a radially inhomogeneous cloud of cold atoms. A co-propagating control field establishes electromagnetically induced transparency. In analogy to a graded index…

Atomic Physics · Physics 2019-07-31 Roman Sulzbach , Thorsten Peters , Reinhold Walser

Ultrasound is widely used in medical diagnostics allowing for accessible and powerful imaging but suffers from resolution limitations due to diffraction and the finite aperture of the imaging system, which restricts diagnostic use. The…

Computer Vision and Pattern Recognition · Computer Science 2024-08-08 Felix Duelmer , Walter Simson , Mohammad Farid Azampour , Magdalena Wysocki , Angelos Karlas , Nassir Navab

This paper considers scattering screens that have arbitrary spatial variations of scattering strength transverse to the line of sight, including screens that are spatially well confined, such as disks and filaments. We calculate the…

Astrophysics · Physics 2009-10-31 J. M. Cordes , T. Joseph W. Lazio

Cyclic spectroscopy is a signal processing technique that was originally developed for engineering applications and has recently been introduced into the field of pulsar astronomy. It is a powerful technique with many attractive features,…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Mark A. Walker , Paul B. Demorest , Willem van Straten

We explore novel methods of recovering the original spectral line profiles from data obtained by instruments that sample those profiles with an extended or multipeaked spectral transmission profile. The techniques are tested on data…

Solar and Stellar Astrophysics · Physics 2020-05-13 Momchil Molnar , Kevin Reardon , Christopher Osborne , Ivan Milić

The CLEAN deconvolution algorithm has well-known limitations due to the restriction of locating point source model components on a discretized grid. In this letter we demonstrate that these limitations are even more pronounced when applying…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 M. R. Bell , N. Oppermann , A. Crai , T. A. Enßlin

Dispersion in the interstellar medium is a well known phenomenon that follows a simple relationship, which has been used to predict the time delay of dispersed radio pulses since the late 1960s. We performed wide-band simultaneous…