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I present a method for the fast convolution of a model galaxy profile by a point-spread function (PSF) model represented as a pixel grid. The method relies upon three observations: First, most simple radial galaxy profiles of common…

Instrumentation and Methods for Astrophysics · Physics 2021-01-01 Dustin Lang

Beam displacement measurements are widely used in optical sensing and communications; however, their performance is affected by numerous intrinsic and extrinsic factors including beam profile, propagation loss, and receiver architecture.…

Optics · Physics 2025-03-11 Wenhua He , Christos N. Gagatsos , Dalziel J. Wilson , Saikat Guha

This paper demonstrates a practical method that can correct spatial varying blur from a set of images of the same object. The algorithm jointly estimates the object and local point spread functions~(PSF). The method prioritizes sections…

Image and Video Processing · Electrical Eng. & Systems 2020-11-04 Wouter van de Ketterij , Oleg Soloviev , Michel Verhaegen

Optical astronomical images are strongly affected by the point spread function (PSF) of the optical system and the atmosphere (seeing) which blurs the observed image. The amount of blurring depends both on the observed band, and on the…

Instrumentation and Methods for Astrophysics · Physics 2023-08-31 Hong Wang , Sreevarsha Sreejith , Yuewei Lin , Nesar Ramachandra , Anže Slosar , Shinjae Yoo

The numerical analysis of the diffraction features rendered by transmission electron microscopy (TEM) typically relies either on classical approximations (Monte Carlo simulations) or quantum paraxial tomography (the multislice method and…

Materials Science · Physics 2017-03-20 Samantha Rudinsky , Angel S. Sanz , Raynald Gauvin

Calibrating for direction-dependent ionospheric distortions in visibility data is one of the main technical challenges that must be overcome to advance low-frequency radio astronomy. In this paper, we propose a novel probabilistic,…

Instrumentation and Methods for Astrophysics · Physics 2020-01-15 J. G. Albert , M. S. S. L. Oei , R. J. van Weeren , H. T. Intema , H. J. A. Röttgering

Determination of orientation in the imaged sample/scene has a large application potential when the anisotropy of properties is analysed, usually, under a linearly polarised illumination. This study combined several improvements of…

We investigate possibilities to speed up iterative algorithms for non-blind image deconvolution. We focus on algorithms in which convolution with the point-spread function to be deconvolved is used in each iteration, and aim at accelerating…

Computer Vision and Pattern Recognition · Computer Science 2013-04-29 Martin Welk , Martin Erler

Modern high-resolution microscopes, such as the scanning tunneling microscope, are commonly used to study specimens that have dense and aperiodic spatial structure. Extracting meaningful information from images obtained from such…

Computational Physics · Physics 2018-08-28 Sky C. Cheung , John Y. Shin , Yenson Lau , Zhengyu Chen , Ju Sun , Yuqian Zhang , John N. Wright , Abhay N. Pasupathy

Efficiently solving large-scale optimal power flow (OPF) problems is challenging due to the high dimensionality and interconnectivity of modern power systems. Decomposition methods offer a promising solution via partitioning large problems…

Optimization and Control · Mathematics 2025-12-30 Mohannad Alkhraijah , Devon Sigler , Daniel K. Molzahn

The effects of seeing on Sersic r^{1/n} profile parameters are extensively studied using a Moffat function. This analytical approximation to the point spread function (PSF) is shown to provide the best fit to the PSF predicted from…

Astrophysics · Physics 2009-11-07 I. Trujillo , A. Aguerri , J. Cepa , C. M. Gutierrez

Accurately simulating the atmospheric turbulence behaviour is always challenging. The well-known FFT based method falls short in correctly predicting both the low and high frequency behaviours. Sub-harmonic compensation aids in…

Instrumentation and Methods for Astrophysics · Physics 2022-08-15 Sorabh Chhabra , Jyotirmay Paul , A. N. Ramaprakash , Avinash Surendran

Image computation is a fundamental tool for performance assessment of astronomical instrumentation, usually implemented by Fourier transform techniques. We review the numerical implementation, evaluating a direct implementation of the…

Astrophysics · Physics 2008-11-26 M. Gai , R. Cancelliere

Graph-based diffusion models have shown promising results in terms of generating high-quality solutions to NP-complete (NPC) combinatorial optimization (CO) problems. However, those models are often inefficient in inference, due to the…

Machine Learning · Computer Science 2023-08-24 Junwei Huang , Zhiqing Sun , Yiming Yang

A unified method for three-dimensional reconstruction of objects from transmission images collected at multiple illumination directions is described. The method may be applicable to experimental conditions relevant to absorption-based,…

Medical Physics · Physics 2022-12-07 Timur E. Gureyev , Hamish G. Brown , Harry M. Quiney , Leslie J. Allen

In Optics it is common to split up the formal analysis of diffraction according to two convenient approximations, in the near and far fields (also known as the Fresnel and Fraunhofer regimes, respectively). Within this scenario, geometrical…

Classical Physics · Physics 2022-04-25 Almudena García-Sánchez , Ángel S. Sanz

Partial identification often arises when the joint distribution of the data is known only up to its marginals. We consider the corresponding partially identified GMM model and develop a methodology for identification, estimation, and…

Econometrics · Economics 2025-12-29 Grigory Franguridi , Laura Liu

Diffusion models approximate the denoising distribution as a Gaussian and predict its mean, whereas flow matching models reparameterize the Gaussian mean as flow velocity. However, they underperform in few-step sampling due to…

Machine Learning · Computer Science 2025-09-03 Hansheng Chen , Kai Zhang , Hao Tan , Zexiang Xu , Fujun Luan , Leonidas Guibas , Gordon Wetzstein , Sai Bi

We present a method of Gaussian-beam-mode decomposition to calculate classical diffraction of optical beams by apertures. This method offers a entirely different approach to examine the classic problem. Although our method is based on a…

Phase is a fundamental resource for optical imaging but cannot be directly observed with intensity measurements. The existing methods to quantify a phase distribution rely on complex devices and structures. Here we experimentally…

Optics · Physics 2020-03-25 Tengfeng Zhu , Junyi Huang , Zhichao Ruan
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