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We investigate the potential of second generation measurements of redshifted 21 cm radiation from before and during the epoch of reionization (EOR) to reconstruct the matter density fluctuations along the line of sight. To do so we…

Astrophysics · Physics 2008-11-26 Oliver Zahn , Matias Zaldarriaga

Twenty-one centimeter tomography is emerging as a powerful tool to explore the end of the cosmic dark ages and the reionization epoch, but it will only be as good as our ability to accurately model and remove astrophysical foreground…

Astrophysics · Physics 2008-11-26 Xiaomin Wang , Max Tegmark , Mario Santos , Lloyd Knox

Due to the energy-dependent nature of the attenuation coefficient and the polychromaticity of the X-ray source, beam hardening effect occurs when X-ray photons penetrate through an object, causing a nonlinear projection data. When a linear…

Medical Physics · Physics 2018-12-07 Wei Zhao , Dengwang Li , Kai Niu , Wenjian Qin , Hao Peng , Tianye Niu

The wavelength calibration of spectrographs is an essential but challenging task in many disciplines. Calibration is traditionally accomplished by imaging the spectrum of a light source containing features that are known to appear at…

Instrumentation and Methods for Astrophysics · Physics 2018-04-04 Neil Thomas

This presentation describes the Bayesian Block algorithm in the context of its application to analysis of time series data from the Fermi Gamma Ray Space Telescope. More generally this algorithm performs optimal segmentation analysis on…

Instrumentation and Methods for Astrophysics · Physics 2013-05-28 Jeffrey D. Scargle , Jay P. Norris , Brad Jackson , James Chiang

This paper describes the Bayesian Technique for Multi-image Analysis (BaTMAn), a novel image-segmentation technique based on Bayesian statistics that characterizes any astronomical dataset containing spatial information and performs a…

Instrumentation and Methods for Astrophysics · Physics 2017-01-18 J. Casado , Y. Ascasibar , R. García-Benito , G. Guidi , O. S. Choudhury , E. Bellocchi , S. F. Sánchez , A. I. Díaz

Disease subtype identification (clustering) is an important problem in biomedical research. Gene expression profiles are commonly utilized to infer disease subtypes, which often lead to biologically meaningful insights into disease. Despite…

Methodology · Statistics 2016-09-27 Jiehuan Sun , Joshua L. Warren , Hongyu Zhao

We propose a new method, {\it binary fused compressive sensing} (BFCS), to recover sparse piece-wise smooth signals from 1-bit compressive measurements. The proposed algorithm is a modification of the previous {\it binary iterative hard…

Computer Vision and Pattern Recognition · Computer Science 2014-02-21 Xiangrong Zeng , Mário A. T. Figueiredo

With the development of computed tomography (CT) imaging technology, it is possible to acquire multi-energy data by spectral CT. Being different from conventional CT, the X-ray energy spectrum of spectral CT is cutting into several narrow…

Medical Physics · Physics 2023-01-25 Yuanwei He , Li Zeng , Qiong Xu , Zhe Wang , Haijun Yu , Zhaoqiang Shen , Zhaojun Yang , Rifeng Zhou

It is an ill-posed problem to recover the true scene colors from a color biased image by discounting the effects of scene illuminant and camera spectral sensitivity (CSS) at the same time. Most color constancy (CC) models have been designed…

Computer Vision and Pattern Recognition · Computer Science 2017-10-11 Shao-Bing Gao , Ming Zhang , Chao-Yi Li , Yong-Jie Li

Photon counting detectors (PCDs) offer promising advancements in computed tomography (CT) imaging by enabling the quantification and 3D imaging of contrast agents and tissue types through multi-energy projections. However, the accuracy of…

Medical Physics · Physics 2023-10-18 Juan C. R. Luna , Mini Das

Function-Correcting Codes (FCCs) enable reliable computation of a function of a $k$-bit message over noisy channels without requiring full message recovery. In this work, we study optimal single-error correcting FCCs (SEFCCs) for…

Information Theory · Computer Science 2026-01-16 Rajlaxmi Pandey , Shiven Bajpai , Anjana A Mahesh , B. Sundar Rajan

Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and…

Blind source separation (BSS) algorithms are unsupervised methods, which are the cornerstone of hyperspectral data analysis by allowing for physically meaningful data decompositions. BSS problems being ill-posed, the resolution requires…

Signal Processing · Electrical Eng. & Systems 2022-09-28 Rémi Carloni Gertosio , Jérôme Bobin , Fabio Acero

Star-galaxy classification is one of the most fundamental data-processing tasks in survey astronomy, and a critical starting point for the scientific exploitation of survey data. For bright sources this classification can be done with…

Instrumentation and Methods for Astrophysics · Physics 2013-07-30 Marc Henrion , Daniel J. Mortlock , David J. Hand , Axel Gandy

The analysis of high spectral resolution spectroscopic and spectropolarimetric observations constitute a very powerful way of inferring the dynamical, thermodynamical, and magnetic properties of distant objects. However, these techniques…

Solar and Stellar Astrophysics · Physics 2015-06-11 A. Asensio Ramos , R. Manso Sainz

We present an end-to-end simulation and data-processing framework for digital beamforming experiments conducted with four stations of the 21 Centimeter Array (21CMA). Motivated by the need to characterize instrumental systematics, such as…

Instrumentation and Methods for Astrophysics · Physics 2026-03-04 Feiyu Zhao , Quan Guo , Junhua Gu , Qian Zheng , Yan Huang , Yun Yu

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

Detection of millikelvin-level signals from the 'Cosmic Dawn' requires an unprecedented level of sensitivity and systematic calibration. We report the theory behind a novel calibration algorithm developed from the formalism introduced by…

Instrumentation and Methods for Astrophysics · Physics 2022-09-15 I. L. V. Roque , W. J. Handley , N. Razavi-Ghods

Photoacoustic imaging (PAI) is a promising medical imaging modality providing the spatial resolution of ultrasound (US) imaging and the contrast of pure optical imaging. For linear-array PAI, a beamformer has to be used as the…

Medical Physics · Physics 2018-02-15 Moein Mozaffarzadeh , Yan Yan , Mohammad Mehrmohammadi , Bahador Makkiabadi