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Longtime monitoring of gravitational lens systems is often done using telescopes and recording equipment with modest resolution. Still, it would be interesting to get as much information as possible from the measured lightcurves. From high…

Astrophysics · Physics 2015-06-24 A. Hirv , T. Eenmäe , T. Liimets , L. J. Liivamägi , J. Pelt

We introduce a deep machine learning approach to studying quasar microlensing light curves for the first time by analyzing hundreds of thousands of simulated light curves with respect to the accretion disc size and temperature profile. Our…

Instrumentation and Methods for Astrophysics · Physics 2019-04-24 Georgios Vernardos , Grigorios Tsagkatakis

Robust modelling of strong lensing systems is fundamental to exploit the information they contain about the distribution of matter in galaxies and clusters. In this work, we present Lensed, a new code which performs forward parametric…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-15 Nicolas Tessore , Fabio Bellagamba , R. Benton Metcalf

The strong galaxy-galaxy lensing produces highly magnified and distorted images of background galaxies in the form of arcs and Einstein rings. Statistically, these effects are quantified, for example, in the number counts of highly luminous…

Astrophysics of Galaxies · Physics 2019-03-08 Vanessa P. de Freitas , Martin Makler , Habib S. Dúmet-Montoya

I present a new algorithm, CALCLENS, for efficiently computing weak gravitational lensing shear signals from large N-body light cone simulations over a curved sky. This new algorithm properly accounts for the sky curvature and boundary…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-15 Matthew R. Becker

Computational color constancy refers to the problem of computing the illuminant color so that the images of a scene under varying illumination can be normalized to an image under the canonical illumination. In this paper, we adopt a deep…

Computer Vision and Pattern Recognition · Computer Science 2016-08-30 Seoung Wug Oh , Seon Joo Kim

We present an effective and efficient approach for low-light image enhancement, named Lookup Table Global Curve Estimation (LUT-GCE). In contrast to existing curve-based methods with pixel-wise adjustment, we propose to estimate a global…

Computer Vision and Pattern Recognition · Computer Science 2023-07-03 Changguang Wu , Jiangxin Dong , Jinhui Tang

We present a new method for directly determining accurate, self-consistent cluster lens mass and shear maps in the strong lensing regime from the magnification bias of background galaxies. The method relies upon pixellisation of the surface…

Astrophysics · Physics 2009-10-30 S. Dye , A. Taylor

At present, microlensing light curves from different telescopes and filters are photometrically aligned by fitting them to a common model. We present a second method based on photometry of common field stars. If two spectral responses are…

Earth and Planetary Astrophysics · Physics 2014-11-20 Andrew Gould , Subo Dong , David P. Bennett , Ian A. Bond , Andrzej Udalski , Szymon Kozlowski

Weak gravitational lensing induces flux dependent fluctuations in the observed galaxy number density distribution. This cosmic magnification (magnification bias) effect in principle enables lensing reconstruction alternative to cosmic shear…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-04 Ruijie Ma , Pengjie Zhang , Yu Yu , Jian Qin

When a luminous source is extended, its distortions by weak gravitational lensing are richer than a mere combination of magnification and shear. In a recent work, we proposed an elegant formalism based on complex analysis to describe and…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-29 Pierre Fleury , Julien Larena , Jean-Philippe Uzan

A computer code is described for the simulation of gravitational lensing data. The code incorporates adaptive mesh refinement in choosing which rays to shoot based on the requirements of the source size, location and surface brightness…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-29 R. Benton Metcalf , Margarita Petkova

We formulate a simple algorithm for computing global exact symmetries of closed discrete curves in plane. The method is based on a suitable trigonometric interpolation of vertices of the given polyline and consequent computation of the…

Computational Geometry · Computer Science 2021-08-11 Michal Bizzarri , Miroslav Lávička , Jan Vršek

Nonlinear lens distortion rectification is a common first step in image processing applications where the assumption of a linear camera model is essential. For rectifying the lens distortion, forward distortion model needs to be known.…

Computer Vision and Pattern Recognition · Computer Science 2017-07-05 Burak Benligiray , Cihan Topal

Recent discussion of the effects of finite source size on high magnification microlensing events due to MACHOs motivates a study into the feasibility of observing such effects and extracting the source radius. Simulated observations are…

Astrophysics · Physics 2009-10-28 Eric Peng

We introduce a novel method to measure the masses of galaxy clusters at high redshift selected from optical and IR Spitzer data via the red-sequence technique. Lyman-break galaxies are used as a well understood, high-redshift background…

We present an image classification algorithm using deep learning convolutional neural network architecture, which classifies the morphologies of eclipsing binary systems based on their light curves. The algorithm trains the machine with…

Solar and Stellar Astrophysics · Physics 2023-06-06 Burak Ulas

We propose a novel method for adjusting luminance for multi-exposure image fusion. For the adjustment, two novel scene segmentation approaches based on luminance distribution are also proposed. Multi-exposure image fusion is a method for…

Multimedia · Computer Science 2019-04-23 Yuma Kinoshita , Hitoshi Kiya

Illumination estimation is often used in mixed reality to re-render a scene from another point of view, to change the color/texture of an object, or to insert a virtual object consistently lit into a real video or photograph. Specifically,…

Computer Vision and Pattern Recognition · Computer Science 2018-12-13 Grégoire Nieto , Salma Jiddi , Philippe Robert

Computational color constancy is a preprocessing step used in many camera systems. The main aim is to discount the effect of the illumination on the colors in the scene and restore the original colors of the objects. Recently, several deep…

Computer Vision and Pattern Recognition · Computer Science 2020-07-21 Firas Laakom , Jenni Raitoharju , Alexandros Iosifidis , Jarno Nikkanen , Moncef Gabbouj