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A numerically exact path integral treatment of the absorption and emission spectra of open quantum systems is presented that requires only the straightforward solution of a stochastic differential equation. The approach converges rapidly…

Chemical Physics · Physics 2015-05-05 Jeremy Moix , Jian Ma , Jianshu Cao

Accurate detection of arterial input function is a crucial step in obtaining perfusion hemodynamic parameters using dynamic susceptibility contrast-enhanced magnetic resonance imaging. It is required as input for perfusion quantification…

Image and Video Processing · Electrical Eng. & Systems 2023-03-07 Svitlana Alkhimova , Kateryna Sazonova

Fourier ptychography microscopy (FPM), sharing its roots with synthetic aperture technique and phase retrieval method, is a recently developed computational microscopic super-resolution technique. By turning on the light-emitting diode…

Optics · Physics 2021-05-07 G. Zhou , S. Zhang , C. Zheng , T. Li , Y. Hu , Q. Hao

The quadratic phase Fourier transform (QPFT) is a generalization of several well-known integral transforms, including the linear canonical transform (LCT), fractional Fourier transform (FrFT), and Fourier transform (FT). This paper…

Functional Analysis · Mathematics 2025-05-06 Sarga Varghese , Gita Rani Mahato , Manab Kundu

This work deals with uncertainty quantification for a generic input distribution to some resource-intensive simulation, e.g., requiring the solution of a partial differential equation. While efficient numerical methods exist to compute…

Numerical Analysis · Mathematics 2025-06-16 Oliver G. Ernst , Hanno Gottschalk , Toni Kowalewitz , Patrick Krüger

A new method is proposed to get image features' geometric information. Using Gaussian as an input signal, a theoretical optimal solution to calculate feature's affine shape is proposed. Based on analytic result of a feature model, the…

Computer Vision and Pattern Recognition · Computer Science 2015-03-19 Xiaopeng Xu , Xiaochun Zhang

Here we show how to design phase-shifting algorithms (PSAs) for nonuniform phase-shifted fringe patterns using their frequency transfer function (FTF). Assuming that the nonuniform/nonlinear (NL) phase-steps are known, we introduce the…

Signal Processing · Electrical Eng. & Systems 2019-02-20 Manuel Servin , Moises Padilla , Guillermo Garnica , Gonzalo Paez

Recently, the joint design of optical systems and downstream algorithms is showing significant potential. However, existing rays-described methods are limited to optimizing geometric degradation, making it difficult to fully represent the…

Computer Vision and Pattern Recognition · Computer Science 2024-12-24 Zheng Ren , Jingwen Zhou , Wenguan Zhang , Jiapu Yan , Bingkun Chen , Huajun Feng , Shiqi Chen

When using an electron microscope for imaging of particles embedded in vitreous ice, the objective lens will inevitably corrupt the projection images. This corruption manifests as a band-pass filter on the micrograph. In addition, it causes…

Image and Video Processing · Electrical Eng. & Systems 2020-01-29 Ayelet Heimowitz , Joakim Andén , Amit Singer

In this paper, a novel objective evaluation metric for image fusion is presented. Remarkable and attractive points of the proposed metric are that it has no parameter, the result is probability in the range of [0, 1] and it is free from…

Image and Video Processing · Electrical Eng. & Systems 2019-05-28 Ali A. Kiaei , Hassan Khotanlou , Mahdi Abbasi , Paniz Kiaei , Yasin Bhrouzi

The differential Optical Transfer Function (dOTF) is a focal plane wavefront sensing method that uses a diversity in the pupil plane to generate two different focal plane images. The difference of their Fourier transforms recovers the…

Instrumentation and Methods for Astrophysics · Physics 2016-08-17 Keira J. Brooks , Laure Catala , Matthew A. Kenworthy , Steven M. Crawford , Johanan L. Codona

We provide an analytical solution of the heat equation in the half-space subject to a moving Gaussian heat flux with piecewise constant parameters. The solution is of interest in powder bed fusion applications where these parameters can be…

Numerical Analysis · Mathematics 2019-01-31 Robert Forslund , Anders Snis , Stig Larsson

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

Diffusion tensor imaging (DTI) holds significant importance in clinical diagnosis and neuroscience research. However, conventional model-based fitting methods often suffer from sensitivity to noise, leading to decreased accuracy in…

Computer Vision and Pattern Recognition · Computer Science 2024-09-05 Jialong Li , Zhicheng Zhang , Yunwei Chen , Qiqi Lu , Ye Wu , Xiaoming Liu , QianJin Feng , Yanqiu Feng , Xinyuan Zhang

We describe a rapid and direct method for regularizing, post-facto, the point-spread function (PSF) of a telescope or other imaging instrument, across its entire field of view. Imaging instruments in general blur point sources of light by…

Instrumentation and Methods for Astrophysics · Physics 2023-03-20 J. M. Hughes , C. E. DeForest , D. B. Seaton

Computed tomography (CT) reconstructs volumetric images using X-ray projection data acquired from multiple angles around an object. For low-dose or sparse-view CT scans, the classic image reconstruction algorithms often produce severe noise…

Medical Physics · Physics 2024-03-04 Wenxiang Cong , Wenjun Xia , Ge Wang

In this work we derive analytic expressions and numerical recipes for finding the effective observed position of sources close enough on sky that their Point Spread Functions (PSF), modelled as Gaussian profiles, overlap. In particularly we…

Solar and Stellar Astrophysics · Physics 2026-03-24 Zephyr Penoyre

A high accuracy photometric reduction method is needed to take full advantage of the potential of the transit method for the detection and characterization of exoplanets, especially in deep crowded fields. In this context, we present…

Astrophysics · Physics 2007-05-23 M. Gillon , P. Magain , V. Chantry , G. Letawe , S. Sohy , F. Courbin , F. Pont , C. Moutou

Ideal photon-number-resolving detectors form a class of important optical components in quantum optics and quantum information theory. In this article, we theoretically investigate the potential of multiport devices having reconstruction…

I start by providing an updated summary of the penalized pixel-fitting (pPXF) method, which is used to extract the stellar and gas kinematics, as well as the stellar population of galaxies, via full spectrum fitting. I then focus on the…

Astrophysics of Galaxies · Physics 2017-01-11 Michele Cappellari