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Related papers: A fast and exact $w$-stacking and $w$-projection h…

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I present an exact and explicit solution to the scalar (Stokes flux intensity) radio interferometer imaging equation on a spherical surface which is valid also for non-coplanar interferometer configurations. This imaging equation is…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 T. D. Carozzi

w-Projection is a wide-field imaging technique that is widely used in radio synthesis arrays. Processing the wide-field big data generated by the future Square Kilometre Array (SKA) will require significant updates to current methods to…

Instrumentation and Methods for Astrophysics · Physics 2019-11-11 Baoqiang Lao , Tao An , Ang Yu , Wenhui Zhang , Junyi Wang , Quan Guo , Shaoguang Guo , Xiaocong Wu

We present a new methodology, based on the WKB approximation and Fast Fourier Transforms, for the evaluation of wave propagation through inhomogeneous media. This method can accurately resolve fields containing caustics, while still…

Computational Physics · Physics 2024-03-05 Oscar P. Bruno , Martin D. Maas

Next generation radio interferometric telescopes are entering an era of big data with extremely large data sets. While these telescopes can observe the sky in higher sensitivity and resolution than before, computational challenges in image…

Instrumentation and Methods for Astrophysics · Physics 2019-12-17 Luke Pratley , Jason D. McEwen , Mayeul d'Avezac , Xiaohao Cai , David Perez-Suarez , Ilektra Christidi , Roland Guichard

Deformable medical image registration is an essential task in computer-assisted interventions. This problem is particularly relevant to oncological treatments, where precise image alignment is necessary for tracking tumor growth, assessing…

Computer Vision and Pattern Recognition · Computer Science 2025-06-04 Stefano Fogarollo , Gregor Laimer , Reto Bale , Matthias Harders

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

The desire for wide-field of view, large fractional bandwidth, high sensitivity, high spectral and temporal resolution has driven radio interferometry to the point of big data revolution where the data is represented in at least three…

Instrumentation and Methods for Astrophysics · Physics 2020-09-30 M. Atemkeng , O. Smirnov , C. Tasse , G. Foster , S. Makhathini

Incorporating wide-field considerations in interferometric imaging is of increasing importance for next-generation radio telescopes. Compressed sensing techniques for interferometric imaging have been extended to wide fields recently,…

Instrumentation and Methods for Astrophysics · Physics 2011-08-29 J. D. McEwen , Y. Wiaux

Adaptive stretching, where the post compression signal is iteratively stretched to maximize the correlation between the pre and post compression rf echo frames, has demonstrated superior performance compared to gradient based methods. At…

Tissues and Organs · Quantitative Biology 2022-10-25 Shaiban Ahmed , Rasheed Abid , S. Kaisar Alam

Dealing with land cover classification of the new image sources has also turned to be a complex problem requiring large amount of memory and processing time. In order to cope with these problems, statistical learning has greatly helped in…

Variations of the antenna primary beam (PB) pattern as a function of time, frequency and polarization form one of the dominant direction-dependent effects at most radio frequency bands. These gains may also vary from antenna to antenna. The…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 S. Bhatnagar , U. Rau , K. Golap

In this paper, we develop a quadrature framework for large-scale kernel machines via a numerical integration representation. Considering that the integration domain and measure of typical kernels, e.g., Gaussian kernels, arc-cosine kernels,…

Machine Learning · Computer Science 2021-06-14 Fanghui Liu , Xiaolin Huang , Yudong Chen , Johan A. K. Suykens

Accurate and robust positioning in multipath environments can enable many applications, such as search-and-rescue and asset tracking. For this problem, ultra-wideband (UWB) technology can provide the most accurate range estimates, which are…

Machine Learning · Computer Science 2015-11-13 Vladimir Savic , Erik G. Larsson , Javier Ferrer-Coll , Peter Stenumgaard

In a companion paper, a faceted wideband imaging technique for radio interferometry, dubbed Faceted HyperSARA, has been introduced and validated on synthetic data. Building on the recent HyperSARA approach, Faceted HyperSARA leverages the…

Instrumentation and Methods for Astrophysics · Physics 2023-08-22 Pierre-Antoine Thouvenin , Arwa Dabbech , Ming Jiang , Abdullah Abdulaziz , Jean-Philippe Thiran , Adrian Jackson , Yves Wiaux

Wavefront reconstruction in lateral shearing interferometry typically assumes that the shear amount is an integer multiple of the sampling interval. When the shear is fractional, approximating it with the nearest integer value leads to…

Recently, the use of circle representation has emerged as a method to improve the identification of spherical objects (such as glomeruli, cells, and nuclei) in medical imaging studies. In traditional bounding box-based object detection,…

Computer Vision and Pattern Recognition · Computer Science 2024-12-02 Jialin Yue , Tianyuan Yao , Ruining Deng , Quan Liu , Juming Xiong , Junlin Guo , Haichun Yang , Yuankai Huo

The advent of enhanced technologies in radio interferometry and the perspective of the SKA telescope bring new challenges in image reconstruction. One of these challenges is the spatio-spectral reconstruction of large (Terabytes) data cubes…

Instrumentation and Methods for Astrophysics · Physics 2016-03-07 Jérémy Deguignet , André Ferrari , David Mary , Chiara Ferrari

The aimed high sensitivities and large fields of view of the new generation of interferometers impose to reach high dynamic range of order $\sim$1:$10^6$ to 1:$10^8$ in the case of the Square Kilometer Array. The main problem is the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 C. Tasse , B. van der Tol , J. van Zwieten , Ger van Diepen , S. Bhatnagar

The fast computation of large kernel sums is a challenging task, which arises as a subproblem in any kernel method. We approach the problem by slicing, which relies on random projections to one-dimensional subspaces and fast Fourier…

Numerical Analysis · Mathematics 2025-02-25 Johannes Hertrich , Tim Jahn , Michael Quellmalz