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Related papers: Sampling Visible GGX Normals with Spherical Caps

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This paper deals with Gibbs samplers that include high dimensional conditional Gaussian distributions. It proposes an efficient algorithm that avoids the high dimensional Gaussian sampling and relies on a random excursion along a small set…

Computation · Statistics 2016-04-20 Olivier Féron , François Orieux , Jean-François Giovannelli

We introduce efficient algorithms for approximate sampling from symmetric Gibbs distributions on the sparse random (hyper)graph. The examples we consider include (but are not restricted to) important distributions on spin systems and…

Discrete Mathematics · Computer Science 2024-03-20 Charilaos Efthymiou

In this paper we show that the spherical cap discrepancy of the point set given by centers of pixels in the HEALPix tessellation (short for Hierarchical, Equal Area and iso-Latitude Pixelation) of unit $2$-sphere is lower and upper bounded…

Numerical Analysis · Mathematics 2022-03-16 Damir Ferizović , Julian Hofstadler , Michelle Mastrianni

Accurately measuring the geometry and spatially-varying reflectance of real-world objects is a complex task due to their intricate shapes formed by concave features, hollow engravings and diverse surfaces, resulting in inter-reflection and…

Computer Vision and Pattern Recognition · Computer Science 2024-12-16 Jing Yang , Pratusha Bhuvana Prasad , Qing Zhang , Yajie Zhao

We present a new Hybrid Photometry and Extraction Routine: Hyper. It is designed to do compact source photometry allowing for varying spatial resolution and sensitivity in multi-wavelength surveys. Hyper combines multi-Gaussian fitting with…

Instrumentation and Methods for Astrophysics · Physics 2015-02-04 A. Traficante , G. A. Fuller , J. E. Pineda , S. Pezzuto

Galaxies whose images overlap in the focal plane of a telescope, commonly referred to as blends, are often located at different redshifts. Blending introduces a challenge to weak-lensing cosmology probes since such blends are subject to…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-18 Zekang Zhang , Daniel Gruen , Luca Tortorelli , Shun-Sheng Li , Jamie McCullough

The optics of a number of future X-ray telescopes will have very long focal lengths (10 - 20 m), and will consist of a number of nested/stacked thin, grazing-incidence mirrors. The optical quality characterization of a real mirror can be…

Instrumentation and Methods for Astrophysics · Physics 2015-09-09 D. Spiga , S. Basso , M. Bavdaz , V. Burwitz , M. Civitani , O. Citterio , M. Ghigo , G. Hartner , B. Menz , G. Pareschi , L. Proserpio , B. Salmaso , G. Tagliaferri , E. Wille

The breaks and truncations in the luminosity profile of face-on spiral galaxies offer valuable insights in their formation history. The traditional method of deriving the surface photometry profile for face-on galaxies is to use elliptical…

Astrophysics of Galaxies · Physics 2016-11-15 S. P. C. Peters , P. C. van der Kruit , R. S. de Jong

We investigate imaging point sources with a monopole gravitational lens, such as the Solar Gravitational Lens in the geometric optics limit. We compute the light amplification of the lens used in conjunction with a telescope featuring a…

Instrumentation and Methods for Astrophysics · Physics 2023-11-08 Viktor T. Toth

We present a novel automatic adaptive aperture photometry algorithm for measuring the total magnitudes of merging galaxies with irregular shapes. First, we use a morphological pattern recognition routine for identifying the shape of an…

Instrumentation and Methods for Astrophysics · Physics 2017-02-08 Jen-Chao Huang , Chorng-Yuan Hwang

We examine whether a cosmologically significant distribution of dark galaxy group or cluster-sized objects can have an optical depth for multiple imaging of distant background sources which is comparable to that from known galaxies while at…

Astrophysics · Physics 2011-02-11 Yu-Chung N. Cheng , Lawrence M. Krauss

We propose a novel coaxial spherical-lens shaping system to achieve a flat-top focus profile by exploiting the spherical aberration of the lens. The well-known aspherical-lens shaping system is compared to ours, and a comparison of etching…

Optics · Physics 2023-03-01 Wei Yang , Zhen Zhang

Schlieren deflectometry aims at characterizing the deflections undergone by refracted incident light rays at any surface point of a transparent object. For smooth surfaces, each surface location is actually associated with a sparse…

Computer Vision and Pattern Recognition · Computer Science 2012-12-04 Prasad Sudhakar , Laurent Jacques , Xavier Dubois , Philippe Antoine , Luc Joannes

Traditional glass-based optics are typically optimized for narrow spectral bands, such as the visible (400-700nm) or shortwave infrared (1000-1800nm). While the emergence of VIS-SWIR sensors (400-1700nm) offers transformative potential,…

Image and Video Processing · Electrical Eng. & Systems 2026-05-04 Vishwanath Saragadam , Niki Nezakati , Amit Roy-Chowdhury , Vivek Boominathan

In this work we introduced a new proposal to study the gravitational lensing theory by spherical lenses, starting from its surface mass density $\Sigma(x)$ written in terms of a decreasing function $f$ of a dimensionless coordinate $x$ on…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-21 Roger Hurtado , Leonardo Castaneda , Juan M. Tejeiro

Spherical spin glasses are canonical models for smooth random functions in high dimensions. In this review, we survey several interrelated lines of research on their geometric structure. We begin with results concerning critical points and…

Probability · Mathematics 2026-01-23 Eliran Subag

The x-ray polycapillary lens is an optical device with good optic performance. Similar to the traditional X-ray polycapillary lens, square polycapillary slice lens was regulated on X-ray based on the full reflection principle of X-ray in…

We use Monte Carlo simulations to investigate the theory of galaxy-galaxy lensing by non-spherical dark matter haloes. The simulations include a careful accounting of the effects of multiple deflections. In a typical data set where the mean…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Paul J. Howell , Tereasa G. Brainerd

Polar slice sampling (Roberts & Rosenthal, 2002) is a Markov chain approach for approximate sampling of distributions that is difficult, if not impossible, to implement efficiently, but behaves provably well with respect to the dimension.…

Methodology · Statistics 2023-08-10 Philip Schär , Michael Habeck , Daniel Rudolf

The envelope of an elliptical Gaussian complex vector, or equivalently, the amplitude or norm of a bivariate normal random vector has application in many weather and signal processing contexts. We explicitly characterize its distribution in…

Statistics Theory · Mathematics 2026-02-03 Sattwik Ghosal , Ranjan Maitra