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Bispectrum phase, closure phase and their generalisation to kernel-phase are all independent of pupil-plane phase errors to first-order. This property, when used with Sparse Aperture Masking (SAM) behind adaptive optics, has been used…

Instrumentation and Methods for Astrophysics · Physics 2013-06-25 Michael J. Ireland

Stacking polarized radio emission in SKA surveys provides statistical information on large samples that is not accessible otherwise due to limitations in sensitivity, source statistics in small fields, and averaging over frequency…

Instrumentation and Methods for Astrophysics · Physics 2015-01-05 J. M. Stil , B. W. Keller

Rotating Synthetic Aperture Radar (ROSAR) can generate a 360$^\circ$ image of its surrounding environment using the collected data from a single moving track. Due to its non-linear track, the Back-Projection Algorithm (BPA) is commonly used…

Signal Processing · Electrical Eng. & Systems 2023-09-18 Wei Zhao , Cai Wen , Quan Yuan , Rong Zheng

We focus on developing an effective Direction Of Arrival (DOA) estimation method for wideband sources based on the gridless sparse concept. Previous coherent methods have been designed by dividing wideband frequencies into a few subbands…

Signal Processing · Electrical Eng. & Systems 2021-03-05 Milad Javadzadeh Jirhandeh , Mohammad Hossein Kahae

Next generation radio telescope arrays are being designed and commissioned to accurately measure polarized intensity and rotation measures across the entire sky through deep, wide-field radio interferometric surveys. Radio interferometer…

Instrumentation and Methods for Astrophysics · Physics 2017-08-02 P. Jagannathan , S. Bhatnagar , U. Rau , A. R. Taylor

A mathematical framework is presented for use in the experimental determination of the polarimetric response of observatory instrumentation. Elementary principles of linear algebra are applied to model the full matrix description of the…

Astrophysics · Physics 2009-11-10 W. van Straten

Interferometric radio astronomy data require the effects of limited coverage in the Fourier plane to be accounted for via a deconvolution process. For the last 40 years this process, known as `cleaning', has been performed almost…

Instrumentation and Methods for Astrophysics · Physics 2016-06-15 Luke Pratley , Melanie Johnston-Hollitt

We introduce a new technique for imaging the polarized radio sky using interferometric data. The new approach, which we call Faraday synthesis, combines aperture and rotation measure synthesis imaging and deconvolution into a single…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 M. R. Bell , T. A. Enßlin

Polarimetric imaging aims to recover polarimetric parameters, including Total Intensity (TI), Degree of Polarization (DoP), and Angle of Polarization (AoP), from captured polarized measurements. In real-world scenarios, these measurements…

Image and Video Processing · Electrical Eng. & Systems 2026-03-09 Chu Zhou , Yufei Han , Junda Liao , Linrui Dai , Wangze Xu , Art Subpa-Asa , Heng Guo , Boxin Shi , Imari Sato

In this third paper of a series on radio weak lensing for cosmology with the Square Kilometre Array, we scrutinise synergies between cosmic shear measurements in the radio and optical/near-IR bands for mitigating systematic effects. We…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 Stefano Camera , Ian Harrison , Anna Bonaldi , Michael L. Brown

We consider the problem of direction finding using partly calibrated arrays, a distributed subarray with position errors between subarrays. The key challenge is to enhance angular resolution in the presence of position errors. To achieve…

Signal Processing · Electrical Eng. & Systems 2022-12-12 Guangbin Zhang , Tianyao Huang , Yimin Liu , Xiqin Wang , Yonina C. Eldar

A new method of matrix template matching is presented in the context of pulsar timing analysis. Pulse arrival times are typically measured using only the observed total intensity light curve. The new technique exploits the additional timing…

Astrophysics · Physics 2017-08-02 W. van Straten

Polarimetric phased arrays (PPAs) enhance radar target detection and anti-jamming capabilities, but their conventional dual transmit/receive (T/R) channel architecture leads to high cost and system complexity. To address these limitations,…

Systems and Control · Electrical Eng. & Systems 2026-01-07 Yiqing Wang , Jian Zhou , Chen Pang , Wenyang Man , Zixiang Xiong , Ke Meng , Zhanling Wang , Yongzhen Li

We describe techniques concerning wavelength calibration and sky subtraction to maximise the scientific utility of data from tunable filter instruments. While we specifically address data from the Optical System for Imaging and low…

Instrumentation and Methods for Astrophysics · Physics 2015-10-14 Tim Weinzirl , Alfonso Aragon-Salamanca , Steven P. Bamford , Bruno Rodriguez del Pino , Meghan E. Gray , Ana L. Chies-Santos

Context: Polarimetry is a very powerful tool to uncover various properties of astronomical objects that remain otherwise hidden in standard imaging or spectroscopic observations. However, the reliable measurement of the low polarization…

Instrumentation and Methods for Astrophysics · Physics 2020-02-12 S. González-Gaitán , A. M. Mourão , F. Patat , J. P. Anderson , A. Cikota , K. Wiersema , A. B. Higgins , K. Silva

Mueller matrices provide a complete description of a medium's response to excitation by polarized light, and their characterization is important across a broad range of applications from ellipsometry in material science to polarimetry in…

In this paper we develop a new approach to the calibration of polarimetric radar data based on two key ideas. The first is the use of in-scene trihedral corner reflectors not only for radiometric and geometric calibration but also to…

Signal Processing · Electrical Eng. & Systems 2021-11-09 Shane R. Cloude

New and upcoming radio interferometers will produce unprecedented amounts of data that demand extremely powerful computers for processing. This is a limiting factor due to the large computational power and energy costs involved. Such…

Instrumentation and Methods for Astrophysics · Physics 2018-01-31 Sarod Yatawatta , Faruk Diblen , Hanno Spreeuw , L. V. E. Koopmans

A deep neural networks based method is proposed to convert single polarization grayscale SAR image to fully polarimetric. It consists of two components: a feature extractor network to extract hierarchical multi-scale spatial features of…

Computer Vision and Pattern Recognition · Computer Science 2017-07-25 Qian Song , Feng Xu , Ya-Qiu Jin

Many circumstellar dust scattering regions have been detected and investigated with polarimetric imaging. However, the quantitative determination of the intrinsic polarization and of dust properties is difficult because of complex…

Solar and Stellar Astrophysics · Physics 2026-02-11 H. M. Schmid , J. Ma