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Modeling the Point Spread Function (PSF) of wide-field surveys is vital for many astrophysical applications and cosmological probes including weak gravitational lensing. The PSF smears the image of any recorded object and therefore needs to…

Instrumentation and Methods for Astrophysics · Physics 2018-07-26 Jörg Herbel , Tomasz Kacprzak , Adam Amara , Alexandre Refregier , Aurelien Lucchi

Deblurring is a fundamental inverse problem in bioimaging. It requires modelling the point spread function (PSF), which captures the optical distortions entailed by the image formation process. The PSF limits the spatial resolution…

Image and Video Processing · Electrical Eng. & Systems 2019-03-04 Denis K. Samuylov , Prateek Purwar , Gábor Székely , Grégory Paul

In an iterative approach for solving linear systems with ill-conditioned, symmetric positive definite (SPD) kernel matrices, both fast matrix-vector products and fast preconditioning operations are required. Fast (linear-scaling)…

Numerical Analysis · Mathematics 2021-01-13 Xin Xing , Hua Huang , Edmond Chow

Gaussian processes (GPs) are crucial in machine learning for quantifying uncertainty in predictions. However, their associated covariance matrices, defined by kernel functions, are typically dense and large-scale, posing significant…

Machine Learning · Computer Science 2025-04-02 Theresa Wagner , Tianshi Xu , Franziska Nestler , Yuanzhe Xi , Martin Stoll

We introduce a broad class of models called semiparametric spatial point process for making inference between spatial point patterns and spatial covariates. These models feature an intensity function with both parametric and nonparametric…

Methodology · Statistics 2025-09-24 Xindi Lin , Bumjun Park , Christopher Zahasky , Hyunseung Kang

A point spread function (PSF) describes the distribution of light for a pure point source in an astronomical image due to the optics of the instrument. An accurate PSF is key for deconvolution, point source photometry and source removal.…

Instrumentation and Methods for Astrophysics · Physics 2025-07-28 Ava Polzin

We propose a compressive spectral collocation method for the numerical approximation of Partial Differential Equations (PDEs). The approach is based on a spectral Sturm-Liouville approximation of the solution and on the collocation of the…

Numerical Analysis · Mathematics 2018-10-18 Simone Brugiapaglia

Approximate inference in probability models is a fundamental task in machine learning. Approximate inference provides powerful tools to Bayesian reasoning, decision making, and Bayesian deep learning. The main goal is to estimate the…

Machine Learning · Computer Science 2020-03-10 Jun Han

Interferometric scattering (iSCAT) microscopy is an emerging label-free technique optimized for the sensitive detection of nano-matter. Previous iSCAT studies have approximated the point spread function in iSCAT by a Gaussian intensity…

The knowledge of the exact structure of the optical system PSF enables a high-quality image reconstruction in fluorescence microscopy. Accurate PSF models account for the vector nature of light and the phase and amplitude modifications.…

We make the in-orbit calibration to the point-spread functions (PSFs) of the collimators of the Hard X-ray Modulation Telescope with the scanning observation of the Crab. We construct the empirical adjustments to the theoretically…

Instrumentation and Methods for Astrophysics · Physics 2020-02-05 Yi Nang , Jin-Yuan Liao , Na Sai , Chen Wang , Ju Guan , Cheng-Kui Li , Cheng-Cheng Guo , Yuan Liu , Jing Jin , Xiao-Bo Li , Shu Zhang , Shuang-Nan Zhang

This paper considers the problem of approximating the inverse of the wave-equation Hessian, also called normal operator, in seismology and other types of wave-based imaging. An expansion scheme for the pseudodifferential symbol of the…

Numerical Analysis · Mathematics 2015-03-17 Laurent Demanet , Pierre-David Létourneau , Nicolas Boumal , Henri Calandra , Jiawei Chiu , Stanley Snelson

We introduce a fast algorithm for Gaussian process regression in low dimensions, applicable to a widely-used family of non-stationary kernels. The non-stationarity of these kernels is induced by arbitrary spatially-varying vertical and…

Numerical Analysis · Mathematics 2025-03-28 P. Michael Kielstra , Michael Lindsey

Given the joint distribution of two random variables $X,Y$ on some second countable locally compact Hausdorff space, we investigate the statistical approximation of the $L^2$-operator defined by $[Pf](x) := \mathbb{E}[ f(Y) \mid X = x ]$…

Statistics Theory · Mathematics 2023-08-08 Mattes Mollenhauer , Péter Koltai

We present extended point spread function (PSF) models for the Hyper Suprime-Cam Subaru Strategic Program Public Data Release 3 (HSC-SSP PDR3) in all $\textit{g,r,i,Z}$ and $\textit{Y}$-bands. Due to its 8.2m primary mirror and long…

Astrophysics of Galaxies · Physics 2024-05-17 L. P. Garate-Nuñez , A. S. G. Robotham , S. Bellstedt , L. J. M. Davies , C. Martínez-Lombilla

Second-order methods are widely adopted to improve the convergence rate of learning algorithms. In federated learning (FL), these methods require the clients to share their local Hessian matrices with the parameter server (PS), which comes…

Machine Learning · Computer Science 2024-12-06 Shayan Mohajer Hamidi , Ali Bereyhi , Saba Asaad , H. Vincent Poor

We study nonparametric estimation of an unknown density function $f$ based on the ranked-based observations obtained from a partially rank-ordered set (PROS) sampling design. PROS sampling design has many applications in environmental,…

Statistics Theory · Mathematics 2014-01-07 Sahar Nazari , Mohammad Jafari Jozani , Mahmood Kharrati-Kopaei

Point spread function (PSF) engineering of the emitter can code higher spatial frequency information of an image to break diffraction limit but suffer from the complexed optical systems. Here we present a robust strategy to simultaneously…

Optics · Physics 2021-02-23 Chaohao Chen , Baolei Liu , Yongtao Liu , Jiayan Liao , Xuchen Shan , Fan Wang , Dayong Jin

In this work, we develop a high-order collocation method using radial basis function (RBF) for the incompressible Navier-Stokes equation (NSE) on the rotating sphere. The method is based on solving the projection of the NSE on the space of…

Numerical Analysis · Mathematics 2022-04-27 Tino Franz

Precise knowledge of the point spread function (PSF) underpins many data analysis steps in astronomy, from photometry and astrometry to source de-blending and deconvolution. In adaptive optics (AO) observations, however, the PSF is highly…

Instrumentation and Methods for Astrophysics · Physics 2026-04-02 Arseniy Kuznetsov , Benoit Neichel , Sylvain Oberti , Thierry Fusco