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A procedure is described for estimating an optimum kernel for the detection by convolution of signals among Poissonian noise. The technique is applied to the detection of x-ray point sources in XMM-Newton data, and is shown to yield an…

Astrophysics · Physics 2009-11-11 Ian Stewart

It is well-known that the noise associated with the collection of an astronomical image by a CCD camera is, in large part, Poissonian. One would expect, therefore, that computational approaches that incorporate this a priori information…

Astrophysics · Physics 2009-11-10 R. Vio , J. Bardsley , W. Wamsteker

Detection of templates (e.g., sources) embedded in low-number count Poisson noise is a common problem in astrophysics. Examples include source detection in X-ray images, gamma-rays, UV, neutrinos, and search for clusters of galaxies and…

Instrumentation and Methods for Astrophysics · Physics 2018-04-11 Eran O. Ofek , Barak Zackay

Procedures based on current methods to detect sources in X-ray images are applied to simulated XMM images. All significant instrumental effects are taken into account, and two kinds of sources are considered -- unresolved sources…

Astrophysics · Physics 2009-11-06 I. Valtchanov , M. Pierre , R. Gastaud

We present X-sifter, a software package designed for near-optimal detection of sources in X-ray images and other forms of photon images in the Poisson-noise regime. The code is based on the Poisson-noise-matched filter (Ofek & Zackay),…

Instrumentation and Methods for Astrophysics · Physics 2024-12-12 Maayane T. Soumagnac , Eran O. Ofek , Shachar S. Israeli , Guy Nir , Imri A. Dickstein

We have developed a maximum likelihood source detection method capable of detecting ultra-faint streaks with surface brightnesses approximately an order of magnitude fainter than the pixel level noise. Our maximum likelihood detection…

Instrumentation and Methods for Astrophysics · Physics 2016-09-26 William A. Dawson , Michael D. Schneider , Chandrika Kamath

Source separation is one of the signal processing's main emerging domain. Many techniques such as maximum likelihood (ML), Infomax, cumulant matching, estimating function, etc. have been used to address this difficult problem.…

Mathematical Physics · Physics 2009-10-31 Ali Mohammad-Djafari

We consider a set of M images, whose pixel intensities at a common point can be treated as the components of a M-dimensional vector. We are interested in the estimation of the modulus of such a vector associated to a compact source. For…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-05 F. Argueso , J. L. Sanz , D. Herranz

Optical measurements often exhibit mixed Poisson-Gaussian noise statistics, which hampers image quality, particularly under low signal-to-noise ratio (SNR) conditions. Computational imaging falls short in such situations when solely…

Image and Video Processing · Electrical Eng. & Systems 2023-11-16 Jacob Seifert , Yifeng Shao , Rens van Dam , Dorian Bouchet , Tristan van Leeuwen , Allard P. Mosk

In this paper, the problem of determining the number of signal sources impinging on an array of sensors and estimating their directions-of-arrival (DOAs) in the presence of spatially white nonuniform noise is considered. It is known that,…

Signal Processing · Electrical Eng. & Systems 2021-09-10 Mahmood Karimi

Many surveys use maximum-likelihood (ML) methods to fit models when extracting photometry from images. We show these ML estimators systematically overestimate the flux as a function of the signal-to-noise ratio and the number of model…

Instrumentation and Methods for Astrophysics · Physics 2020-03-25 Stephen K. N. Portillo , Joshua S. Speagle , Douglas P. Finkbeiner

We describe an X-ray source detection method entirely based on the maximum likelihood analysis, in application to observations with the ART-XC telescope onboard the Spectrum Roentgen Gamma observatory. The method optimally combines the data…

High Energy Astrophysical Phenomena · Physics 2024-04-03 A. Semena , A. Vikhlinin , I. Mereminskiy , A. Lutovinov , A. Tkachenko , I. Lapshov , R. Burenin

Astrophysical sources are now observed by many different instruments at different wavelengths, from radio to high-energy gamma-rays, with an unprecedented quality. Putting all these data together to form a coherent view, however, is a very…

We present a statistical method based on a maximum likelihood approach to constrain the number counts of extragalactic sources below the nominal flux-density limit of continuum imaging surveys. We extract flux densities from a radio map…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 Ketron Mitchell-Wynne , Mario G. Santos , Jose Afonso , Matt J. Jarvis

Given a set of images, whose pixel values can be considered as the components of a vector, it is interesting to estimate the modulus of such a vector in some localised areas corresponding to a compact signal. For instance, the…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-02 F. Argueso , J. L. Sanz , D. Herranz , M. Lopez-Caniego , J. Gonzalez-Nuevo

We consider filters for the detection and extraction of compact sources on a background. We make a one-dimensional treatment (though a generalization to two or more dimensions is possible) assuming that the sources have a Gaussian profile…

Astrophysics · Physics 2009-11-10 M. Lopez-Caniego , D. Herranz , R. B. Barreiro , J. L. Sanz

In this paper, we address the classical problem of maximum-likelihood (ML) detection of data in the presence of random phase noise. We consider a system, where the random phase noise affecting the received signal is first compensated by a…

Information Theory · Computer Science 2016-11-15 Rajet Krishnan , M. Reza Khanzadi , Thomas Eriksson , Tommy Svensson

(Abridged) We present a new method for detecting and measuring compact sources in conditions of intense, and highly variable, fore/background. While all most commonly used packages carry out the source detection over the signal image, our…

In this paper, symbol-by-symbol maximum likelihood (ML) detection is proposed for a cooperative diffusion-based molecular communication (MC) system. In this system, a fusion center (FC) chooses the transmitter's symbol that is more likely,…

Information Theory · Computer Science 2018-09-06 Yuting Fang , Adam Noel , Nan Yang , Andrew W. Eckford , Rodney A. Kennedy

This letter derives the noncoherent (NC) maximum likelihood (ML) detection rule for LoRa signals under Rician multi-path fading channel. The proposed NC-ML detection only requires the channel statistic, not the actual instantaneous channel…

Signal Processing · Electrical Eng. & Systems 2026-04-16 The Khai Nguyen , Ebrahim Bedeer , Robert Barton
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