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Ocular biometric systems working in unconstrained environments usually face the problem of small within-class compactness caused by the multiple factors that jointly degrade the quality of the obtained data. In this work, we propose an…

Computer Vision and Pattern Recognition · Computer Science 2020-02-11 Luiz A. Zanlorensi , Hugo Proença , David Menotti

Local perturbations around contours strongly disturb the final result of computer vision tasks. It is common to introduce a priori information in the estimation process. Improvement can be achieved via a deformable model such as the snake…

Computer Vision and Pattern Recognition · Computer Science 2016-04-01 R. L. B. Breder , Vania V. Estrela , J. T. de Assis

Strong-lensing images provide a wealth of information both about the magnified source and about the dark matter distribution in the lens. Precision analyses of these images can be used to constrain the nature of dark matter. However, this…

Instrumentation and Methods for Astrophysics · Physics 2022-05-25 Konstantin Karchev , Adam Coogan , Christoph Weniger

(abridged) Using the particularly long gravitational microlensing event OGLE-2014-BLG-1186 with a time-scale $t_\mathrm{E}$ ~ 300 d, we present a methodology for identifying the nature of localised deviations from single-lens point-source…

Gravitational lensing is potentially able to observe mass-selected halos, and to measure the projected cluster mass function. An optimal mass-selection requires a quantitative understanding of the noise behavior in mass maps. This paper is…

Astrophysics · Physics 2015-06-24 L. Van Waerbeke

Lens magnification by galaxy clusters induces characteristic spatial variations in the number counts of background sources, amplifying their observed fluxes and expanding the area of sky, the net effect of which, known as magnification…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Keiichi Umetsu

In this work, we address the solution of both linear and nonlinear ill-posed inverse problems by developing a novel graph-based regularization framework, where the regularization term is formulated through an iteratively updated graph…

Numerical Analysis · Mathematics 2026-01-21 Harshit Bajpai , Ankik Kumar Giri

Gridless methods show great superiority in line spectral estimation. These methods need to solve an atomic $l_0$ norm (i.e., the continuous analog of $l_0$ norm) minimization problem to estimate frequencies and model order. Since this…

Optimization and Control · Mathematics 2024-10-28 Bai Yan , Qi Zhao , Jin Zhang , J. Andrew Zhang , Xin Yao

Measuring weak lensing cosmic magnification signal is very challenging due to the overwhelming intrinsic clustering in the observed galaxy distribution. In this paper, we modify the Internal Linear Combination (ILC) method to reconstruct…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-13 Shutong Hou , Yu Yu , Pengjie Zhang

The inversion of a gravitational lens system is, as is well known, plagued by the so-called mass-sheet degeneracy: one can always rescale the density distribution of the lens and add a constant-density mass-sheet such that the, also…

Astrophysics · Physics 2009-11-13 J. Liesenborgs , S. De Rijcke , H. Dejonghe , P. Bekaert

In recent years, gravitational lensing has been used as a means to detect substructure in galaxy-sized halos, via anomalous flux ratios in quadruply-imaged lenses. In addition to causing anomalous flux ratios, substructure may also perturb…

Astrophysics · Physics 2011-02-11 Jacqueline Chen , Eduardo Rozo , Neal Dalal , James E. Taylor

When traveling from their source to the observer, gravitational waves can get deflected by massive objects along their travel path. When the lens is massive enough and the source aligns closely with the line-of-sight to the lens, the wave…

General Relativity and Quantum Cosmology · Physics 2022-12-28 Justin Janquart , Anupreeta More , Chris Van Den Broeck

Multiplicative noise (also known as speckle noise) models are central to the study of coherent imaging systems, such as synthetic aperture radar and sonar, and ultrasound and laser imaging. These models introduce two additional layers of…

Optimization and Control · Mathematics 2015-05-14 José M. Bioucas-Dias , Mário A. T. Figueiredo

Astronomical instruments generally possess spatially variant point-spread functions, which determine the amount by which an image pixel is blurred as a function of position. Several techniques have been devised to handle this variability in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Adam Rogers , Jason D. Fiege

In this work, we investigate the regularized solutions and their finite element solutions to the inverse source problems governed by partial differential equations, and establish the stochastic convergence and optimal finite element…

Numerical Analysis · Mathematics 2021-10-25 Zhiming Chen , Wenlong Zhang , Jun Zou

The reconstruction of images from measured data is an increasing field of research. For highly under-determined problems, template-based image reconstruction provides a way of compensating for the lack of sufficient data. A caveat of this…

Optimization and Control · Mathematics 2023-05-29 Sebastian Neumayer , Antonia Topalovic

Gravitational lensing of the cosmic microwave background (CMB) polarization field has been recognized as a potentially valuable probe of the cosmological density field. We apply likelihood-based techniques to the problem of lensing of CMB…

Astrophysics · Physics 2011-06-21 Christopher M. Hirata , Uros Seljak

We present a framework for analyzing weak gravitational lensing survey data, including lensing and source-density observables, plus spectroscopic redshift calibration data. All two-point observables are predicted in terms of parameters of a…

Astrophysics · Physics 2014-11-18 Gary M. Bernstein

Weak gravitational lensing has the potential to constrain cosmological parameters to high precision. However, as shown by the Shear TEsting Programmes (STEP) and GRavitational lEnsing Accuracy Testing (GREAT) Challenges, measuring galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Tomasz Kacprzak , Joe Zuntz , Barnaby Rowe , Sarah Bridle , Alexandre Refregier , Adam Amara , Lisa Voigt , Michael Hirsch

Source localization and spectral estimation are among the most fundamental problems in statistical and array signal processing. Methods which rely on the orthogonality of the signal and noise subspaces, such as Pisarenko's method, MUSIC,…

Information Theory · Computer Science 2019-04-16 Matthew W. Morency , Sergiy A. Vorobyov , Geert Leus