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Speckle noise is a fundamental challenge in coherent imaging systems, significantly degrading image quality. Over the past decades, numerous despeckling algorithms have been developed for applications such as Synthetic Aperture Radar (SAR)…

Information Theory · Computer Science 2025-01-31 Ali Zafari , Shirin Jalali

We examine the Seidel aberrations of thin spherical lenses composed of media with refractive index not restricted to be positive. We find that consideration of this expanded parameter space allows reduction or elimination of more…

Optics · Physics 2009-11-10 D. Schurig , D. R. Smith

In this paper, we propose a reduced-dimensional smoothed particle hydrodynamics (SPH) formulation for quasi-static and dynamic analyses of plate and shell structures undergoing finite deformation and large rotation. By exploiting…

Numerical Analysis · Mathematics 2023-09-07 Dong Wu , Chi Zhang , Xiangyu Hu

A new anode support structure for the spherical proportional counter is presented that incorporates a resistive correction electrode made of glass. This electrode improves the electric field homogeneity versus angle while suppressing the…

Instrumentation and Detectors · Physics 2018-12-05 I. Katsioulas , I. Giomataris , P. Knights , M. Gros , X. F. Navick , K. Nikolopoulos , I. Savvidis

Many adaptive optics systems operate by measuring the distortion of the wavefront in one wavelength range and performing the scientific observations in a second, different wavelength range. One common technique is to measure wavefront…

Astrophysics · Physics 2009-11-07 Henry G. Roe

Band-trellis enumerative sphere shaping is proposed to decrease the energy variations in channel input sequences. Against sphere shaping, 0.74 dB SNR gain and up to 9% increase in data rates are demonstrated for single-span systems.

Signal Processing · Electrical Eng. & Systems 2022-01-11 Yunus Can Gültekin , Alex Alvarado , Olga Vassilieva , Inwoong Kim , Paparao Palacharla , Chigo Okonkwo , Frans M. J. Willems

In this paper, we first derive a theoretical basis for spherical conformal parameterizations between a simply connected closed surface $\mathcal{S}$ and a unit sphere $\mathbb{S}^2$ by minimizing the Dirichlet energy on…

Numerical Analysis · Mathematics 2022-07-01 Wei-Hung Liao , Tsung-Ming Huang , Wen-Wei Lin , Mei-Heng Yueh

Using the phenomena of linear and circular birefringence we propose a device that can alter general elliptical polarization of a beam by a predetermined amount, thereby allowing conversion between linearly-polarized light and circularly…

Optics · Physics 2015-05-28 A. A. Rangelov

This paper presents Taylor expansions for the imaging and timing characteristics of spherical optical systems with infinitesimal mirror facets, sometimes referred to as ''modified Davies-Cotton'' telescopes. Such a system comprises a…

Instrumentation and Methods for Astrophysics · Physics 2024-11-26 S. Fegan

The wavelet shrinkage denoising approach is able to maintain local regularity of a signal while suppressing noise. However, the conventional wavelet shrinkage based methods are not time-scale adaptive to track the local time-scale…

Computer Vision and Pattern Recognition · Computer Science 2016-08-03 Mario Mastriani , Alberto E. Giraldez

The tangential shear signal receives contributions from physical scales in the galaxy-matter correlation function well below the transverse scale at which it is measured. Since small scales are difficult to model, this non-locality has…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-23 Niall MacCrann , Jonathan Blazek , Bhuvnesh Jain , Elisabeth Krause

In this short paper we introduce a variant of the approach to inverting the X-ray transform that originated in the author's work with Uhlmann. The new method is based on semiclassical analysis and eliminates the need for using sufficiently…

Differential Geometry · Mathematics 2020-12-29 András Vasy

This comment corrects some errors which appeared in the calculation of an elastic sphere eigenenergies. As a result, the symmetry of the mode having the lowest frequency is changed. Also a direction for calculating the damping of these…

Materials Science · Physics 2007-05-23 Lucien Saviot , Daniel B Murray , Alain Mermet , Eugene Duval

A solution to the inversion problem of scattering would offer aberration-free diffraction-limited 3D images without the resolution and depth-of-field limitations of lens-based tomographic systems. Powerful algorithms are increasingly being…

We introduce a novel technique to mitigate the adverse effects of atmospheric turbulence on astronomical imaging. Utilizing a video-to-image neural network trained on simulated data, our method processes a sliding sequence of short-exposure…

Instrumentation and Methods for Astrophysics · Physics 2024-05-09 Spencer Bialek , Emmanuel Bertin , Sébastien Fabbro , Hervé Bouy , Jean-Pierre Rivet , Olivier Lai , Jean-Charles Cuillandre

The aim of this paper is to introduce several new particle representations for \textit{ergodic} McKean-Vlasov SDEs. We construct new algorithms by leveraging recent progress in weak convergence analysis of interacting particle system. We…

Probability · Mathematics 2019-01-18 H. AlRachid , Mireille Bossy , Cristiano Ricci , Lukasz Szpruch

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

The scattering cancellation technique is a powerful tool to reduce the scattered field from electrically small objects in a specific frequency window. The technique relies on covering the object of interest with a shell that scatters light…

Aberration-corrected scanning transmission electron microscopes (STEM) provide sub-angstrom lateral resolution; however, the large convergence angle greatly reduces the depth of field. For microscopes with a small depth of field,…

Materials Science · Physics 2011-12-15 Robert Hovden , Huolin L. Xin , David A. Muller

In this work, we derive particle schemes, based on micro-macro decomposition, for linear kinetic equations in the diffusion limit. Due to the particle approximation of the micro part, a splitting between the transport and the collision part…

Numerical Analysis · Mathematics 2017-01-19 Anaïs Crestetto , Nicolas Crouseilles , Mohammed Lemou