English
Related papers

Related papers: Beam squint and Stokes V with off-axis feeds

200 papers

Context. Circumstellar disks and self-luminous giant exoplanets or companion brown dwarfs can be characterized through direct-imaging polarimetry at near-infrared wavelengths. SPHERE/IRDIS at the Very Large Telescope has the capabilities to…

Optical coherence tomography (OCT) suffers from speckle noise, causing the deterioration of image quality, especially in high-resolution modalities like visible light OCT (vis-OCT). The potential of conventional supervised deep learning…

Image and Video Processing · Electrical Eng. & Systems 2024-05-16 Lingyun Wang , Jose A Sahel , Shaohua Pi

High-contrast imaging from space must overcome two major noise sources to successfully detect a terrestrial planet angularly close to its parent star: photon noise from diffracted star light, and speckle noise from star light scattered by…

Astrophysics · Physics 2009-11-13 Pascal J. Borde , Wesley A. Traub

Deconvolution is the most commonly used image processing method to remove the blur caused by the point-spread-function (PSF) in optical imaging systems. While this method has been successful in deblurring, it suffers from several…

Image and Video Processing · Electrical Eng. & Systems 2019-10-10 Huangxuan Zhao , Ziwen Ke , Ningbo Chen , Ke Li , Lidai Wang , Xiaojing Gong , Wei Zheng , Liang Song , Zhicheng Liu , Dong Liang , Chengbo Liu

In Cone-Beam CT (CBCT) imaging systems, the scattering phenomenon has a significant impact on the reconstructed image and is a long-lasting research topic on CBCT. In this paper, we propose a simple, novel and fast approach for mitigating…

Medical Physics · Physics 2016-04-07 Shi-peng Xie , Rui-ju Yan

The process of wide-field synthesis imaging is explored, with the aim of understanding the implications of variable, polarised primary beams for forthcoming Epoch of Reionisation experiments. These experiments seek to detect weak signatures…

Instrumentation and Methods for Astrophysics · Physics 2012-06-05 Daniel A. Mitchell , Randall B. Wayth , Gianni Bernardi , Lincoln J. Greenhill , Stephen M. Ord

Neural recordings, returns from radars and sonars, images in astronomy and single-molecule microscopy can be modeled as a linear superposition of a small number of scaled and delayed copies of a band-limited or diffraction-limited point…

Information Theory · Computer Science 2016-05-25 Yuejie Chi

This work is concerned with optical imaging in strongly diffusive environments. We consider a typical setting in optical coherence tomography where a sample is probed by a collection of wavefields produced by a laser and propagating through…

Optics · Physics 2024-12-10 Randy Bartels , Olivier Pinaud , Maxine Varughese

Vibro-acoustography (VA) is a medical imaging method based on the difference-frequency generation produced by the mixture of two focused ultrasound beams. VA has been applied to different problems in medical imaging such as imaging bones,…

Computer Vision and Pattern Recognition · Computer Science 2012-07-17 Talita Perciano , Matthew Urban , Nelson D. A. Mascarenhas , Mostafa Fatemi , Alejandro C. Frery , Glauber T. Silva

In the case of ground-based telescopes equipped with adaptive optics systems, the point spread function (PSF) is only poorly known or completely unknown. Moreover, an accurate modeling of the PSF is in general not available. Therefore in…

Numerical Analysis · Mathematics 2015-06-09 M. Prato , A. La Camera , S. Bonettini , S. Rebegoldi , M. Bertero , P. Boccacci

The goal of this project is to build a deep-learning solution that deblurs cornea scans, used for medical examination. The spherical shape of the eye prevents ophtamologist from having completely sharp image. Provided with a stack of…

Computer Vision and Pattern Recognition · Computer Science 2020-06-26 Toussain Cardot , Pilar Marxer , Ivan Snozzi

We describe a rapid and direct method for regularizing, post-facto, the point-spread function (PSF) of a telescope or other imaging instrument, across its entire field of view. Imaging instruments in general blur point sources of light by…

Instrumentation and Methods for Astrophysics · Physics 2023-03-20 J. M. Hughes , C. E. DeForest , D. B. Seaton

Deconvolution is essential for radio interferometric imaging to produce scientific quality data because of finite sampling in the Fourier plane. Most deconvolution algorithms are based on CLEAN which uses a grid of image pixels, or clean…

Instrumentation and Methods for Astrophysics · Physics 2016-11-18 Sarod Yatawatta

Measurements of the cosmic microwave background polarization are vulnerable to systematic contamination from beam imperfections. Because the unpolarized CMB T is orders of magnitude larger than the polarized E and B signals, even a tiny…

Instrumentation and Methods for Astrophysics · Physics 2019-11-12 Christopher Sheehy

Ptychography involves a sample being illuminated by a coherent, localised probe of illumination. When the probe interacts with the sample, the light is diffracted and a diffraction pattern is detected. Then the probe or sample is shifted…

Numerical Analysis · Mathematics 2023-05-09 Mark Philip Roach

One of the major limitations of adaptive optics (AO) corrected image post-processing is the lack of knowledge on the system point spread function (PSF). The PSF is not always available as a direct imaging on isolated point like objects such…

Instrumentation and Methods for Astrophysics · Physics 2020-07-22 Romain Fétick , Laurent Mugnier , Thierry Fusco , Benoit Neichel

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

This study introduces {\tt{PI-AstroDeconv}}, a physics-informed semi-supervised learning method specifically designed for removing beam effects in astronomical telescope observation systems. The method utilizes an encoder-decoder network…

Instrumentation and Methods for Astrophysics · Physics 2025-08-15 Shulei Ni , Yisheng Qiu , Yunchuan Chen , Zihao Song , Hao Chen , Xuejian Jiang , Donghui Quan , Huaxi Chen

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

Accurate alignment of the radio and optical celestial reference frames requires detailed understanding of physical factors that may cause offsets between the positions of the same object measured in different spectral bands. Opacity in…

Astrophysics · Physics 2008-07-21 Y. Y. Kovalev , A. P. Lobanov , A. B. Pushkarev , J. A. Zensus