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The advent of large aperture arrays, such as the currently under construction Square Kilometer Array (SKA), allows for observing the universe in the radio-spectrum at unprecedented resolution and sensitivity. However, these telescopes…

Instrumentation and Methods for Astrophysics · Physics 2024-12-04 S. Wang , S. Prunet , S. Mignot , A. Ferrari

By use of window functions, time-frequency analysis tools like Short Time Fourier Transform overcome a shortcoming of the Fourier Transform and enable us to study the time- frequency characteristics of signals which exhibit transient os-…

Information Theory · Computer Science 2013-07-25 Sangnam Nam

Recent advances in deep learning have markedly improved the quality of visual-attention modelling. In this work we apply these advances to video compression. We propose a compression method that uses a saliency model to adaptively compress…

Computer Vision and Pattern Recognition · Computer Science 2019-07-25 Vitaliy Lyudvichenko , Mikhail Erofeev , Alexander Ploshkin , Dmitriy Vatolin

We advocate a compressed sensing strategy that consists of multiplying the signal of interest by a wide bandwidth modulation before projection onto randomly selected vectors of an orthonormal basis. Firstly, in a digital setting with random…

Information Theory · Computer Science 2012-03-13 Gilles Puy , Pierre Vandergheynst , Rémi Gribonval , Yves Wiaux

Perceptive mobile networks (PMN) have been widely recognized as a pivotal pillar for the sixth generation (6G) mobile communication systems. However, the asynchronicity between transmitters and receivers results in velocity and range…

Signal Processing · Electrical Eng. & Systems 2024-09-04 Xiao-Yang Wang , Shaoshi Yang , Hou-Yu Zhai , Christos Masouros , J. Andrew Zhang

Aperture array interferometers, such as that proposed for the Square Kilometre Array (SKA), will see the entire sky, hence the standard approach to simulating visibilities will not be applicable since it relies on a tangent plane…

Astrophysics · Physics 2008-09-11 J. D. McEwen , A. M. M. Scaife

Learning-based lossy image compression usually involves the joint optimization of rate-distortion performance. Most existing methods adopt spatially invariant bit length allocation and incorporate discrete entropy approximation to constrain…

Computer Vision and Pattern Recognition · Computer Science 2019-04-02 Mu Li , Wangmeng Zuo , Shuhang Gu , Jane You , David Zhang

The joint detection and classification of RF signals has been a critical problem in the field of wideband RF spectrum sensing. Recent advancements in deep learning models have revolutionized this field, remarkably through the application of…

Signal Processing · Electrical Eng. & Systems 2024-08-14 Xiwen Kang , Hua-mei Chen , Genshe Chen , Kuo-Chu Chang , Thomas M. Clemons

Synthetic aperture radar is a high-resolution two-dimensional imaging radar, however, during the imaging process, SAR is susceptible to intentional and unintentional interference, with radio frequency interference (RFI) being the most…

Signal Processing · Electrical Eng. & Systems 2024-03-06 Fuping Fang , Wenhao Lv , Dahai Dai

We consider the semantic rate-distortion problem motivated by task-oriented video compression. The semantic information corresponding to the task, which is not observable to the encoder, shows impacts on the observations through a joint…

Information Theory · Computer Science 2022-08-15 Tao Guo , Yizhu Wang , Jie Han , Huihui Wu , Bo Bai , Wei Han

Antenna layout is an important design consideration for radio interferometers because it determines the quality of the snapshot point spread function (PSF, or array beam). This is particularly true for experiments targeting the 21 cm Epoch…

Radio interferometers suffer from the problem of missing information in their data, due to the gaps between the antennas. This results in artifacts, such as bright rings around sources, in the images obtained. Multiple deconvolution…

Instrumentation and Methods for Astrophysics · Physics 2021-03-24 Michelle Lochner , Bruce A. Bassett , Martin Kunz , Iniyan Natarajan , Nadeem Oozeer , Oleg Smirnov , Jon Zwart

Optical interferometers increasingly use single-mode fibers as spatial filters to convert varying wavefront distortion into intensity fluctuations which can be monitored for accurate calibration of fringe amplitudes. Here I propose using an…

Astrophysics · Physics 2009-11-06 J. D. Monnier

In this paper, we propose a new interactive compression scheme for omnidirectional images. This requires two characteristics: efficient compression of data, to lower the storage cost, and random access ability to extract part of the…

Multimedia · Computer Science 2020-08-24 Navid Mahmoudian Bidgoli , Thomas Maugey , Aline Roumy

Passive radar has key advantages over its active counterpart in terms of cost and stealth. In this paper, we address passive radar imaging problem by interferometric inversion using a spectral estimation method with a priori information…

Signal Processing · Electrical Eng. & Systems 2022-12-06 Samia Kazemi , Bariscan Yonel , Birsen Yazici

Over the next decade, improvements in cosmological parameter constraints will be driven by surveys of large-scale structure. Its inherent non-linearity suggests that significant information will be embedded in higher correlations beyond the…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-19 Joyce Byun , Alexander Eggemeier , Donough Regan , David Seery , Robert E. Smith

Performing likelihood ratio based detection with high dimensional multimodal data is a challenging problem since the computation of the joint probability density functions (pdfs) in the presence of inter-modal dependence is difficult. While…

Information Theory · Computer Science 2016-09-19 Thakshila Wimalajeewa , Pramod K. Varshney

We discuss the technique of Wide-field imaging as it applies to Very Long Baseline Interferometry (VLBI). In the past VLBI data sets were usually averaged so severely that the field-of-view was typically restricted to regions extending a…

Astrophysics · Physics 2009-10-31 M. A. Garrett , R. W. Porcas , A. Pedlar , T. W. B. Muxlow , S. T. Garrington

High-resolution astronomical imaging at sub-GHz radio frequencies has been available for more than 15 years, with the VLA at 74 and 330 MHz, and the GMRT at 150, 240, 330 and 610 MHz. Recent developments include wide-bandwidth upgrades for…

Instrumentation and Methods for Astrophysics · Physics 2014-02-21 H. T. Intema

Detection with high dimensional multimodal data is a challenging problem when there are complex inter- and intra- modal dependencies. While several approaches have been proposed for dependent data fusion (e.g., based on copula theory),…

Applications · Statistics 2018-02-14 Thakshila Wimalajeewa , Pramod K. Varshney