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Anisoplanatic effects can cause significant systematic photometric uncertainty in the analysis of dense stellar fields observed with adaptive optics. Program packages have been developed for a spatially variable PSF, but they require that a…

Instrumentation and Methods for Astrophysics · Physics 2009-12-08 R. Schoedel

This paper proposes a novel learning based high-dynamic-range (HDR) reconstruction method using a polarization camera. We utilize a previous observation that polarization filters with different orientations can attenuate natural light…

Image and Video Processing · Electrical Eng. & Systems 2022-03-29 Juiwen Ting , Moein Shakeri , Hong Zhang

Next-generation radio interferometers, such as the Square Kilometre Array (SKA), will revolutionise our understanding of the universe through their unprecedented sensitivity and resolution. However, standard methods in radio interferometry…

Instrumentation and Methods for Astrophysics · Physics 2017-02-23 Luke Pratley , Jason D. McEwen , Mayeul d'Avezac , Rafael E. Carrillo , Alexandru Onose , Yves Wiaux

Angular and spectral differential imaging is an observational technique of choice to investigate the immediate vicinity of stars. The relative angular motion and spectral scaling between on-axis and off-axis sources are exploited by…

Instrumentation and Methods for Astrophysics · Physics 2024-10-04 Olivier Flasseur , Loïc Denis , Éric Thiébaut , Maud Langlois

Recovering images from optical interferometric observations is one of the major challenges in the field. Unlike the case of observations at radio wavelengths, in the optical the atmospheric turbulence changes the phases on a very short time…

We propose a general framework to recover underlying images from noisy phaseless diffraction measurements based on the alternating directional method of multipliers and the plug-and-play technique. The algorithm consists of three-step…

Optimization and Control · Mathematics 2016-11-07 Huibin Chang , Stefano Marchesini

A fruitful approach for solving signal deconvolution problems consists of resorting to a frame-based convex variational formulation. In this context, parallel proximal algorithms and related alternating direction methods of multipliers have…

Other Computer Science · Computer Science 2015-05-28 Nelly Pustelnik , Jean-Christophe Pesquet , Caroline Chaux

X-ray polarization is a powerful tool for unveiling the anisotropic characteristics of high-energy celestial objects. We present a novel imaging reconstruction method designed for hard X-ray polarimeters employing a Si CMOS sensor and coded…

Instrumentation and Methods for Astrophysics · Physics 2024-07-09 Tsubasa Tamba , Hirokazu Odaka , Taihei Watanabe , Toshiya Iwata , Tomoaki Kasuga , Atsushi Tanimoto , Satoshi Takashima , Masahiro Ichihashi , Hiromasa Suzuki , Aya Bamba

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

I start by providing an updated summary of the penalized pixel-fitting (pPXF) method, which is used to extract the stellar and gas kinematics, as well as the stellar population of galaxies, via full spectrum fitting. I then focus on the…

Astrophysics of Galaxies · Physics 2017-01-11 Michele Cappellari

A new generation of wide-field radio interferometers designed for 21-cm surveys is being built as drift scan instruments allowing them to observe large fractions of the sky. With large numbers of antennas and frequency channels the enormous…

Instrumentation and Methods for Astrophysics · Physics 2017-10-10 Philippe Berger , Niels Oppermann , Ue-Li Pen , J. Richard Shaw

In this paper, we consider the highly ill-posed problem of jointly recovering two real-valued signals from the phaseless measurements of their circular convolution. The problem arises in various imaging modalities such as Fourier…

Image and Video Processing · Electrical Eng. & Systems 2020-03-02 Fahad Shamshad , Ali Ahmed

The Gemini Planet Imager (GPI) has been designed for the direct detection and characterization of exoplanets and circumstellar disks. GPI is equipped with a dual channel polarimetry mode designed to take advantage of the inherently…

Deconvolution is a fundamental inverse problem in signal processing and the prototypical model for recovering a signal from its noisy measurement. Nevertheless, the majority of model-based inversion techniques require knowledge on the…

Signal Processing · Electrical Eng. & Systems 2020-07-23 Arttu Arjas , Lassi Roininen , Mikko J. Sillanpää , Andreas Hauptmann

Blind deconvolution is a challenging problem, but in low-light it is even more difficult. Existing algorithms, both classical and deep-learning based, are not designed for this condition. When the photon shot noise is strong, conventional…

Image and Video Processing · Electrical Eng. & Systems 2022-11-21 Yash Sanghvi , Abhiram Gnanasambandam , Zhiyuan Mao , Stanley H. Chan

In single-molecule super-resolution microscopy, engineered point-spread functions (PSFs) are designed to efficiently encode new molecular properties, such as 3D orientation, into complex spatial features captured by a camera. To fully…

Image and Video Processing · Electrical Eng. & Systems 2019-07-16 Hesam Mazidi , Eshan S. King , Oumeng Zhang , Arye Nehorai , Matthew D. Lew

Polarisation Filter Array (PFA) cameras allow the analysis of light polarisation state in a simple and cost-effective manner. Such filter arrays work as the Bayer pattern for colour cameras, sharing similar advantages and drawbacks. Among…

Computer Vision and Pattern Recognition · Computer Science 2022-11-28 Mara Pistellato , Filippo Bergamasco , Tehreem Fatima , Andrea Torsello

Interferometric closure invariants encode calibration-independent details of an object's morphology. Excepting simple cases, a direct backward transformation from closure invariants to morphologies is not well established. We demonstrate…

Instrumentation and Methods for Astrophysics · Physics 2024-08-27 Nithyanandan Thyagarajan , Lucas Hoefs , O. Ivy Wong

Polarization-based vision has gained increasing attention for providing richer physical cues beyond RGB images. While achieving single-shot capture is highly desirable for practical applications, existing Division-of-Focal-Plane (DoFP)…

Computer Vision and Pattern Recognition · Computer Science 2026-04-08 Shuangfan Zhou , Chu Zhou , Heng Guo , Youwei Lyu , Boxin Shi , Zhanyu Ma , Imari Sato

Image restoration in astronomy has been considered a vital step in many ground-based observational programs that often suffer from sub-optimal seeing due to atmospheric turbulence, distortion of stellar shapes due to instrumental…

Instrumentation and Methods for Astrophysics · Physics 2023-09-14 Yash Gondhalekar , Margarita Safonova , Snehanshu Saha
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