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Related papers: An Improved Method for 21cm Foreground Removal

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Fourier ptychography (FP) imaging, drawing on the idea of synthetic aperture, has been demonstrated as a potential approach for remote sub-diffraction-limited imaging. Nevertheless, the farthest imaging distance is still limited around 10 m…

Tomography of redshifted 21 cm transition from neutral Hydrogen using Fourier synthesis telescopes is a promising tool to study the Epoch of Reionization (EoR). Limiting the confusion from Galactic and Extragalactic foregrounds is critical…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 Harish Vedantham , N. Udaya Shankar , Ravi Subrahmanyan

High fidelity separation of astrophysical foreground contributions from the cosmic microwave background (CMB) signal has been recognized as one of the main challenges of modern CMB data analysis, and one which needs to be addressed in a…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-19 Magdy Morshed , Arianna Rizzieri , Clément Leloup , Josquin Errard , Radek Stompor

In this work, we propose using camera arrays coupled with coherent illumination as an effective method of improving spatial resolution in long distance images by a factor of ten and beyond. Recent advances in ptychography have demonstrated…

Computer Vision and Pattern Recognition · Computer Science 2015-11-29 Jason Holloway , M. Salman Asif , Manoj Kumar Sharma , Nathan Matsuda , Roarke Horstmeyer , Oliver Cossairt , Ashok Veeraraghavan

Measurement of the global 21-cm signal during Cosmic Dawn (CD) and the Epoch of Reionization (EoR) is made difficult by bright foreground emission which is 2-5 orders of magnitude larger than the expected signal. Fitting for a…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-20 Michael Pagano , Peter Sims , Adrian Liu , Dominic Anstey , Will Handley , Eloy De Lera Acedo

Fourier ptychography (FP) is a recently proposed computational imaging technique for high space-bandwidth product imaging. In real setups such as endoscope and transmission electron microscope, the common sample motion largely degrades the…

Fourier ptychographic microscopy (FPM) is a recently proposed computational imaging technique with both high resolution and wide field-of-view. In current FP experimental setup, the dark-field images with high-angle illuminations are easily…

Computer Vision and Pattern Recognition · Computer Science 2017-12-19 Yan Zhang , An Pan , Ming Lei , Baoli Yao

This paper proposes a novel approach to create an automated visual surveillance system which is very efficient in detecting and tracking moving objects in a video captured by moving camera without any apriori information about the captured…

Computer Vision and Pattern Recognition · Computer Science 2017-06-09 Kumar S. Ray , Soma Chakraborty

Deep learning (DL) has recently been proposed as a novel approach for 21cm foreground removal. Before applying DL to real observations, it is essential to assess its consistency with established methods, its performance across various…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-02 T. Chen , M. Bianco , E. Tolley , M. Spinelli , D. Forero-Sanchez , J. P. Kneib

Observations of the EoR with the 21-cm hyperfine emission of neutral hydrogen (HI) promise to open an entirely new window onto the formation of the first stars, galaxies and accreting black holes. In order to characterize the weak 21-cm…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-06 Abhik Ghosh , L. V. E. Koopmans , Emma Chapman , Vibor Jelic

We develop and demonstrate an acceleration of the Liu & Tegmark quadratic estimator formalism for inverse variance foreground subtraction and power spectrum estimation in 21 cm tomography from O(N^3) to O(N log N), where N is the number of…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-22 Joshua S. Dillon , Adrian Liu , Max Tegmark

Radio interferometers designed to probe the 21cm signal from Cosmic Dawn and the Epoch of Reionisation must contend with systematic effects that make it difficult to achieve sufficient dynamic range to separate the 21cm signal from…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-24 Fraser Kennedy , Philip Bull , Michael Wilensky , Jacob Burba , Samir Choudhuri

We apply the Correlated Component Analysis (CCA) method on simulated data of the Square Kilometre Array, with the aim of accurately cleaning the 21 cm reionization signal from diffuse foreground contamination. The CCA has been developed for…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Anna Bonaldi , Michael L. Brown

Face recognition is a popular application of pat- tern recognition methods, and it faces challenging problems including illumination, expression, and pose. The most popular way is to learn the subspaces of the face images so that it could…

Computer Vision and Pattern Recognition · Computer Science 2014-02-25 Huanguo Zhang , Sha Lv , Wei Li , Xun Qu

Analyses of the cosmic 21-cm signal are hampered by astrophysical foregrounds that are far stronger than the signal itself. These foregrounds, typically confined to a wedge-shaped region in Fourier space, often necessitate the removal of a…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-02 Nashwan Sabti , Ram Reddy , Julian B. Muñoz , Siddharth Mishra-Sharma , Taewook Youn

Image retargeting aims at altering an image size while preserving important content and minimizing noticeable distortions. However, previous image retargeting methods create outputs that suffer from artifacts and distortions. Besides, most…

Computer Vision and Pattern Recognition · Computer Science 2022-09-13 Mohammad Reza Naderi , Mohammad Hossein Givkashi , Nader Karimi , Shahram Shirani , Shadrokh Samavi

Cross-correlation between the redshifted 21 cm signal and Lyman-{\alpha} emitters (LAEs) is powerful tool to probe the Epoch of Reionization (EoR). Although the cross-power spectrum (PS) has an advantage of not correlating with foregrounds…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-25 S. Yoshiura , J. L. B. Line , K. Kubota , K. Hasegawa , K. Takahashi

The development of large-scale 3D scene reconstruction and novel view synthesis methods mostly rely on datasets comprising perspective images with narrow fields of view (FoV). While effective for small-scale scenes, these datasets require…

Computer Vision and Pattern Recognition · Computer Science 2025-04-10 Ulas Gunes , Matias Turkulainen , Xuqian Ren , Arno Solin , Juho Kannala , Esa Rahtu

In the beginning stage, face verification is done using easy method of geometric algorithm models, but the verification route has now developed into a scientific progress of complicated geometric representation and identical procedure. In…

Computer Vision and Pattern Recognition · Computer Science 2014-03-24 V. Karthikeyan , K. Vijayalakshmi , P. Jeyakumar

Traditional fine-grained image classification generally requires abundant labeled samples to deal with the low inter-class variance but high intra-class variance problem. However, in many scenarios we may have limited samples for some novel…

Computer Vision and Pattern Recognition · Computer Science 2021-09-14 Chaofei Wang , Shiji Song , Qisen Yang , Xiang Li , Gao Huang