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The number of gravitational arcs systems detected is increasing quickly and should even increase at a faster rate in the near future. This wealth of new gravitational arcs requires the development of a purely automated method to reconstruct…

Instrumentation and Methods for Astrophysics · Physics 2025-02-03 Christophe Alard

The cosmic horseshoe gravitational lens is analyzed using the perturbative approach. The two first order perturbative fields are expanded in Fourier series. The source is reconstructed using a fine adaptive grid. The expansion of the fields…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-01 C. Alard

This paper introduces the first minimal solvers that jointly estimate lens distortion and affine rectification from the image of rigidly-transformed coplanar features. The solvers work on scenes without straight lines and, in general, relax…

Computer Vision and Pattern Recognition · Computer Science 2020-04-13 James Pritts , Zuzana Kukelova , Viktor Larsson , Yaroslava Lochman , Ondřej Chum

In the perturbative approach, substructures in the lens can be reduced to their effect on the two perturbative fields $f_1$ and $\frac{d f_0}{d\theta}$. A simple generic model of elliptical lens with a substructure situated near the…

Astrophysics · Physics 2009-11-13 C. Alard

The celebrated minimum residual method (MINRES), proposed in the seminal paper of Paige and Saunders, has seen great success and widespread use in solving Hermitian (and complex-symmetric) linear systems. Unless the system is consistent,…

Numerical Analysis · Mathematics 2025-05-22 Yang Liu , Andre Milzarek , Fred Roosta

For singular perturbation problems in dynamical systems, various appropriate singular perturbation methods have been proposed to eliminate secular terms appearing in the naive expansion. For example, the method of multiple time scales, the…

Chaotic Dynamics · Physics 2009-11-13 Masatomo Iwasa

This work deals with a regularization method enforcing solution sparsity of linear ill-posed problems by appropriate discretization in the image space. Namely, we formulate the so called least error method in an $\ell^1$ setting and perform…

Numerical Analysis · Mathematics 2016-08-03 Kristian Bredies , Barbara Kaltenbacher , Elena Resmerita

Several recent works have developed a new, probabilistic interpretation for numerical algorithms solving linear systems in which the solution is inferred in a Bayesian framework, either directly or by inferring the unknown action of the…

Computation · Statistics 2018-10-18 Simon Bartels , Jon Cockayne , Ilse C. F. Ipsen , Philipp Hennig

This paper introduces the first minimal solvers that jointly estimate lens distortion and affine rectification from repetitions of rigidly transformed coplanar local features. The proposed solvers incorporate lens distortion into the camera…

Computer Vision and Pattern Recognition · Computer Science 2018-12-03 James Pritts , Zuzana Kukelova , Viktor Larsson , Ondrej Chum

Blended light is an important source of degeneracy in the characterization of microlensing events, particularly in binary-lens and high magnification events. We show how the techniques of image subtraction can be applied to form an image of…

Astrophysics · Physics 2007-05-23 Andrew Gould , Jin H. An

Strong gravitational lensing offers a wealth of astrophysical information on the background source it affects, provided the lensed source can be reconstructed as if it was seen in the absence of lensing. In the present work, we illustrate…

Instrumentation and Methods for Astrophysics · Physics 2019-02-27 R. Joseph , F. Courbin , J. -L. Starck , S. Birrer

This paper introduces the first minimal solvers that jointly solve for affine-rectification and radial lens distortion from coplanar repeated patterns. Even with imagery from moderately distorted lenses, plane rectification using the…

Computer Vision and Pattern Recognition · Computer Science 2018-06-22 James Pritts , Zuzana Kukelova , Viktor Larsson , Ondrej Chum

The structure and potential of a complex gravitational lens is reconstructed using the perturbative method presented in Alard 2007, MNRAS, 382L, 58; Alard 2008, MNRAS, 388, 375. This lens is composed of 6 galaxies belonging to a small…

Astrophysics of Galaxies · Physics 2015-05-13 C. Alard

Reconstructing lens potentials and lensed sources can easily become an underconstrained problem, even when the degrees of freedom are low, due to degeneracies, particularly when potential perturbations superimposed on a smooth lens are…

Astrophysics of Galaxies · Physics 2022-07-27 Georgios Vernardos , Leon V. E. Koopmans

This paper presents a reconstruction of the gravitational lens SL2S02176-0513 using the singular perturbative method presented in Alard 2007, MNRAS Letters, 382, 58 and Alard, C., 2008, MNRAS, 388, 375. The ability of the perturbative…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 C. Alard

We consider the global minimization of a particular type of minimum structured optimization problems wherein the variables must belong to some basic set, the feasible domain is described by the intersection of a large number of functional…

Optimization and Control · Mathematics 2024-12-09 Guillaume Van Dessel , François Glineur

We present a statistical study of the effects induced by substructures on the deflection potential of dark matter halos in the strong lensing regime. This investigation is based on the pertubative solution around the Einstein radius (Alard…

Compositional minimisation can be an effective technique to reduce the state space explosion problem. This technique considers a parallel composition of several processes. In its simplest form, each sequential process is replaced by an…

Logic in Computer Science · Computer Science 2020-12-14 Maurice Laveaux , Tim A. C. Willemse

This paper introduces minimal solvers that jointly solve for radial lens undistortion and affine-rectification using local features extracted from the image of coplanar translated and reflected scene texture, which is common in man-made…

Computer Vision and Pattern Recognition · Computer Science 2020-11-24 James Pritts , Zuzana Kukelova , Viktor Larsson , Yaroslava Lochman , Ondřej Chum

Super-resolution is generally referred to as the task of recovering fine details from coarse information. Motivated by applications such as single-molecule imaging, radar imaging, etc., we consider parameter estimation of complex…

Information Theory · Computer Science 2016-08-10 Dehui Yang , Gongguo Tang , Michael B. Wakin
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