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Related papers: LOFAR Sparse Image Reconstruction

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The LOw Frequency ARray (LOFAR) is capable of imaging spectroscopy of the Sun in the 10-240 MHz frequency range, with high spectral, temporal, and spatial resolution. However, the complex and rapidly varying nature of solar radio emission -…

Solar and Stellar Astrophysics · Physics 2025-08-15 Soham Dey , Divya Oberoi , Pietro Zucca , Mattia Mancini , Deepan Patra , Devojyoti Kansabanik

The Low Frequency Array (LOFAR) is the only existing radio interferometer able to observe at ultra-low frequencies (<100 MHz) with high resolution (<15") and high sensitivity (<1 mJy/beam). To exploit these capabilities, the LOFAR Surveys…

We present a fast and accurate method for dense depth reconstruction from sparsely sampled light fields obtained using a synchronized camera array. In our method, the source images are over-segmented into non-overlapping compact superpixels…

Image and Video Processing · Electrical Eng. & Systems 2018-12-18 Aleksandra Chuchvara , Attila Barsi , Atanas Gotchev

We present the experimental reconstruction of sub-wavelength features from the far-field of sparse optical objects. We show that it is sufficient to know that the object is sparse, and only that, and recover 100 nm features with the…

We present a new approach for image reconstruction and weak lensing measurements with interferometers. Based on the shapelet formalism presented in Refregier (2001), object images are decomposed into orthonormal Hermite basis functions. The…

Astrophysics · Physics 2009-11-06 Tzu-Ching Chang , Alexandre Refregier

To avoid decorrelation, conventional synthetic aperture radar interferometry (InSAR) requires that interferometric images should have a common spectral band and the same resolution after proper preprocessing. For a high-resolution (HR)…

Signal Processing · Electrical Eng. & Systems 2020-10-15 Huizhang Yang , Chengzhi Chen , Shengyao Chen , Feng Xi , Zhong Liu

Light rays incident on a transparent object of uniform refractive index undergo deflections, which uniquely characterize the surface geometry of the object. Associated with each point on the surface is a deflection map (or spectrum) which…

Computer Vision and Pattern Recognition · Computer Science 2015-07-15 Prasad Sudhakar , Laurent Jacques , Xavier Dubois , Philippe Antoine , Luc Joannes

Phase retrieval refers to a classical nonconvex problem of recovering a signal from its Fourier magnitude measurements. Inspired by the compressed sensing technique, signal sparsity is exploited in recent studies of phase retrieval to…

Computational Physics · Physics 2013-02-04 Zai Yang , Cishen Zhang , Lihua Xie

Radio maps reflect the spatial distribution of signal strength and are essential for applications like smart cities, IoT, and wireless network planning. However, reconstructing accurate radio maps from sparse measurements remains…

Computer Vision and Pattern Recognition · Computer Science 2025-07-09 Chuyun Deng , Na Liu , Wei Xie , Lianming Xu , Li Wang

We propose a novel algorithm for image reconstruction in radio interferometry. The ill-posed inverse problem associated with the incomplete Fourier sampling identified by the visibility measurements is regularized by the assumption of…

Instrumentation and Methods for Astrophysics · Physics 2012-10-12 R. E. Carrillo , J. D. McEwen , Y. Wiaux

We describe a "spatio-spectral" deconvolution algorithm for wide-band imaging in radio interferometry. In contrast with the existing multi-frequency reconstruction algorithms, the proposed method does not rely on a model of the…

Instrumentation and Methods for Astrophysics · Physics 2016-03-01 André Ferrari , Jérémy Deguignet , Chiara Ferrari , David Mary , Antony Schutz , Oleg Smirnov

We use compressed sensing to demonstrate theoretically the reconstruction of sub-wavelength features from measured far-field, and provide experimental proof-of-concept. The methods can be applied to non-optical microscopes, provided the…

Optics · Physics 2015-05-14 Snir Gazit , Alexander Szameit , Yonina C. Eldar , Mordechai Segev

The calibration of modern radio interferometers is a significant challenge, specifically at low frequencies. In this perspective, we propose a novel iterative calibration algorithm, which employs the popular sparse representation framework,…

Instrumentation and Methods for Astrophysics · Physics 2016-06-06 Martin Brossard , Mohamed Nabil El Korso , Marius Pesavento , Rémy Boyer , Pascal Larzabal

Magnetic Resonance Imaging (MRI) is a crucial medical imaging technology for the screening and diagnosis of frequently occurring cancers. However image quality may suffer by long acquisition times for MRIs due to patient motion, as well as…

Computer Vision and Pattern Recognition · Computer Science 2015-12-29 Edward Li , Farzad Khalvati , Mohammad Javad Shafiee , Masoom A. Haider , Alexander Wong

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

In a recent article series, the authors have promoted convex optimization algorithms for radio-interferometric imaging in the framework of compressed sensing, which leverages sparsity regularization priors for the associated inverse problem…

Instrumentation and Methods for Astrophysics · Physics 2014-04-01 Rafael E. Carrillo , Jason D. McEwen , Yves Wiaux

An appealing requirement from the well-known diffraction tomography (DT) exists for success reconstruction from few-view and limited-angle data. Inspired by the well-known compressive sensing (CS), the accurate super-resolution…

Computational Engineering, Finance, and Science · Computer Science 2009-04-20 Lianlin Li , Wenji Zhang , Fang Li

The Low Frequency Array (LOFAR) radio telescope is an international aperture synthesis radio telescope used to study the Universe at low frequencies. One of the goals of the LOFAR telescope is to conduct deep wide-field surveys. Here we…

Instrumentation and Methods for Astrophysics · Physics 2018-04-11 A. P. Mechev , J. B. R. Oonk , A. Danezi , T. W. Shimwell , C. Schrijvers , H. T. Intema , A. Plaat , H. J. A. Röttgering

Synthetic aperture radar (SAR) can measure the phase with antenna and microwave, which cannot be directly extended to visible light imaging due to phase lost. In this letter, we reported an active remote sensing with visible light via…

Optics · Physics 2022-04-26 Meng Xiang , An Pan , Yiyi Zhao , Xuewu Fan , Hui Zhao , Chuang Li , Baoli Yao

Radio interferometry probes astrophysical signals through incomplete and noisy Fourier measurements. The theory of compressed sensing demonstrates that such measurements may actually suffice for accurate reconstruction of sparse or…

Astrophysics · Physics 2009-07-09 Y. Wiaux , L. Jacques , G. Puy , A. M. M. Scaife , P. Vandergheynst