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Direct imaging of exoplanets is limited by bright quasi-static speckles in the point spread function (PSF) of the central star. This limitation can be reduced by subtraction of reference PSF images. We have developed an algorithm to…

Astrophysics · Physics 2011-02-11 David Lafreniere , Christian Marois , Rene Doyon , Daniel Nadeau , Etienne Artigau

We apply the vectorized Non-negative Matrix Factorization (NMF) method to post-processing of direct imaging data for exoplanetary systems such as circumstellar disks. NMF is an iterative approach, which first creates a non-orthogonal and…

Instrumentation and Methods for Astrophysics · Physics 2018-03-20 Bīn Rén , Laurent Pueyo , Guangtun Ben Zhu , John Debes , Gaspard Duchêne

High-contrast imaging of exoplanets hinges on powerful post-processing methods to denoise the data and separate the signal of a companion from its host star, which is typically orders of magnitude brighter. Existing post-processing…

Instrumentation and Methods for Astrophysics · Physics 2022-10-05 Timothy D. Gebhard , Markus J. Bonse , Sascha P. Quanz , Bernhard Schölkopf

Scanning Kelvin probe microscopy (SKPM) is a powerful technique for investigating the electrostatic properties of material surfaces, enabling the imaging of variations in work function, topology, surface charge density, or combinations…

Applied Physics · Physics 2024-07-26 Isaac C. D. Lenton , Felix Pertl , Lubuna Shafeek , Scott R. Waitukaitis

Direct imaging of exoplanets is usually limited by quasi-static speckles. These uncorrected aberrations in a star's point spread function (PSF) obscure faint companions and limit the sensitivity of high-contrast imaging instruments. Most…

Instrumentation and Methods for Astrophysics · Physics 2021-05-05 William Thompson , Christian Marois

Mixed pixels are presented in hyperspectral images due to low spatial resolution of hyperspectral sensors. Spectral unmixing decomposes mixed pixels spectra into endmembers spectra and abundance fractions. In this paper using of robust…

Computer Vision and Pattern Recognition · Computer Science 2012-12-06 Roozbeh Rajabi , Hassan Ghassemian

Nonnegative matrix factorization (NMF) is a linear dimensionality reduction technique for nonnegative data, with applications such as hyperspectral unmixing and topic modeling. NMF is a difficult problem in general (NP-hard), and its…

Numerical Analysis · Mathematics 2025-11-11 Junjun Pan , Valentin Leplat , Michael Ng , Nicolas Gillis

We present the development of a data-driven, AI-based model of the Point Spread Function (PSF) that achieves higher accuracy than the current state-of-the-art approach, "PSF in the Full Field-of-View'' (PIFF). PIFF is widely used in leading…

Instrumentation and Methods for Astrophysics · Physics 2026-02-18 Dayana Andrea Henao Arbeláez , Pierre-François Léget , Andrés Alejandro Plazas Malagón

We propose a new variant of nonnegative matrix factorization (NMF), combining separability and sparsity assumptions. Separability requires that the columns of the first NMF factor are equal to columns of the input matrix, while sparsity…

Machine Learning · Computer Science 2020-06-16 Nicolas Nadisic , Arnaud Vandaele , Jeremy E. Cohen , Nicolas Gillis

We present a method to self-consistently propagate M$_{*}$ and SFR ($\Psi$) uncertainties onto intercept, slope and intrinsic scatter estimates for a simple model of the main sequence of star forming galaxies where $\Psi = \alpha +…

Astrophysics of Galaxies · Physics 2021-05-10 E. Curtis-Lake , J. Chevallard , S. Charlot , L. Sandles

High-contrast imaging (HCI) is one of the most challenging techniques for exoplanet detection. It relies on sophisticated data processing to reach high contrasts at small angular separations. Most data processing techniques of this type are…

Instrumentation and Methods for Astrophysics · Physics 2021-02-10 Carl-Henrik Dahlqvist , Olivier Absil

We present a general framework for matching the point-spread function (PSF), photometric scaling, and sky background between two images, a subject which is commonly referred to as difference image analysis (DIA). We introduce the new…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 D. M. Bramich , Keith Horne , M. D. Albrow , Y. Tsapras , C. Snodgrass , R. A. Street , M. Hundertmark , Noe Kains , A. Arellano Ferro , R. Figuera Jaimes , Sunetra Giridhar

The first step toward doing high-precision astrometry is the measurement of individual stars in individual images, a step that is fraught with dangers when the images are undersampled. The key to avoiding systematic positional error in…

Astrophysics · Physics 2009-10-05 Jay Anderson , Ivan R. King

Hyperspectral unmixing has been an important technique that estimates a set of endmembers and their corresponding abundances from a hyperspectral image (HSI). Nonnegative matrix factorization (NMF) plays an increasingly significant role in…

Computer Vision and Pattern Recognition · Computer Science 2022-05-23 Xin-Ru Feng , Heng-Chao Li , Rui Wang , Qian Du , Xiuping Jia , Antonio Plaza

Point-spread function (PSF) estimation in spatially undersampled images is challenging because large pixels average fine-scale spatial information. This is problematic when fine-resolution details are necessary, as in optimal photometry…

Instrumentation and Methods for Astrophysics · Physics 2021-02-03 Teresa Symons , Michael Zemcov , James Bock , Yun-Ting Cheng , Brendan Crill , Christopher Hirata , Stephanie Venuto

Diffusion models are extensively used for modeling image priors for inverse problems. We introduce \emph{Diff-Unfolding}, a principled framework for learning posterior score functions of \emph{conditional diffusion models} by explicitly…

Image and Video Processing · Electrical Eng. & Systems 2025-05-22 Yuanhao Wang , Shirin Shoushtari , Ulugbek S. Kamilov

[Abridged] An increasing number of astronomical instruments (on Earth and space-based) provide hyperspectral images, that is three-dimensional data cubes with two spatial dimensions and one spectral dimension. The intrinsic limitation in…

Instrumentation and Methods for Astrophysics · Physics 2021-03-17 Axel Boulais , Olivier Berné , Guillaume Faury , Yannick Deville

Spectral unmixing (SU) is a data processing problem in hyperspectral remote sensing. The significant challenge in the SU problem is how to identify endmembers and their weights, accurately. For estimation of signature and fractional…

Computer Vision and Pattern Recognition · Computer Science 2017-11-06 Sara Khoshsokhan , Roozbeh Rajabi , Hadi Zayyani
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