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Dispersive Fourier transformation is a powerful technique in which spectral information is mapped into the time domain using chromatic dispersion. It replaces a spectrometer with an electronic digitizer, and enables real-time spectroscopy.…

Optics · Physics 2009-11-13 J. Chou , D. R. Solli , B. Jalali

We introduce a new numerical method for solving time-harmonic acoustic scattering problems. The main focus is on plane waves scattered by smoothly varying material inhomogeneities. The proposed method works for any frequency $\omega$, but…

Numerical Analysis · Mathematics 2022-01-14 Anton Arnold , Sjoerd Geevers , Ilaria Perugia , Dmitry Ponomarev

We present a framework for inferring an atmospheric transmission profile from a spectral scene. This framework leverages a lightweight, physics-based simulator that is automatically tuned - by virtue of autodifferentiation and…

Machine Learning · Computer Science 2024-05-01 James Koch , Brenda Forland , Bruce Bernacki , Timothy Doster , Tegan Emerson

Synthetic turbulence models are a useful tool that provide realistic representations of turbulence, necessary to test theoretical results, to serve as background fields in some numerical simulations, and to test analysis tools. Models of 1D…

Fluid Dynamics · Physics 2016-11-15 Francesco Malara , Francesca Di Mare , Giuseppina Nigro , Luca Sorriso-Valvo

Diffusion models are proficient at generating high-quality images. They are however effective only when operating at the resolution used during training. Inference at a scaled resolution leads to repetitive patterns and structural…

Computer Vision and Pattern Recognition · Computer Science 2024-11-28 Haosen Yang , Adrian Bulat , Isma Hadji , Hai X. Pham , Xiatian Zhu , Georgios Tzimiropoulos , Brais Martinez

The free-space transfer of high-fidelity optical signals between remote locations has many applications, including both classical and quantum communication, precision navigation, clock synchronization, etc. The physical processes that…

Quantum Physics · Physics 2017-07-21 D. Vasylyev , A. A. Semenov , W. Vogel

It remains a challenge to simultaneously remove geometric distortion and space-time-varying blur in frames captured through a turbulent atmospheric medium. To solve, or at least reduce these effects, we propose a new scheme to recover a…

Computer Vision and Pattern Recognition · Computer Science 2014-01-20 Yuan Xie , Wensheng Zhang , Dacheng Tao , Wenrui Hu , Yanyun Qu , Hanzi Wang

We present a new methodology, based on the WKB approximation and Fast Fourier Transforms, for the evaluation of wave propagation through inhomogeneous media. This method can accurately resolve fields containing caustics, while still…

Computational Physics · Physics 2024-03-05 Oscar P. Bruno , Martin D. Maas

The ultimate performance of coronagraphic high contrast exoplanet imaging systems such as SPHERE or GPI is limited by quasi-static aberrations. These aberrations produce speckles that can be mistaken for planets in the image. In order to…

Instrumentation and Methods for Astrophysics · Physics 2017-01-31 Olivier Herscovici-Schiller , Laurent M. Mugnier , Jean-François Sauvage

Correlated imaging through atmospheric turbulence is studied, and the analytical expressions describing turbulence effects on image resolution are derived. Compared with direct imaging, correlated imaging can reduce the influence of…

Optics · Physics 2015-05-19 Pengli Zhang , Wenlin Gong , Xia Shen , Shensheng Han

The effects of turbulence intensity and turbulence region on the distribution of femtosecond laser filaments are experimentally elaborated. Through the ultrasonic signals emitted by the filaments, and it is observed that increasing…

Recently, Rodenburg et al (2014 New J. Phys. 16 033020) presented an approach for simulating propagation over a long path of uniformly distributed Kolmogorov-spectrum turbulence by means of a compact laboratory arrangement that used two…

Optics · Physics 2014-06-11 Jeffrey H. Shapiro

Lagrangian turbulence lies at the core of numerous applied and fundamental problems related to the physics of dispersion and mixing in engineering, bio-fluids, atmosphere, oceans, and astrophysics. Despite exceptional theoretical,…

The paper presents an alternative way to classical stereocorrelation. First, 2D image processing of random patterns is described. Sub-pixel displacements are determined using phase analysis. Then distortion evaluation is presented. The…

Classical Physics · Physics 2013-11-18 Jérôme Molimard , Gaetan Boyer , Hassan Zahouani

We present a novel generative modeling framework,Wavelet-Fourier-Diffusion, which adapts the diffusion paradigm to hybrid frequency representations in order to synthesize high-quality, high-fidelity images with improved spatial…

Computer Vision and Pattern Recognition · Computer Science 2025-04-08 Andrew Kiruluta , Andreas Lemos

We numerically examine the spatial evolution of the structure of coherent and partially coherent laser beams, including the optical vortices, propagating in turbulent atmospheres. The influence of beam fragmentation and wandering relative…

Optics · Physics 2015-05-19 G. P. Berman , V. N. Gorshkov , S. V. Torous

Here we propose an optical method that use phase data of a laser beam obtained from Shack-Hartmann sensor to estimate both inner and outer scales of turbulence. The method is based on the sequential analysis of normalized correlation…

Atmospheric and Oceanic Physics · Physics 2015-06-03 V. A. Kulikov , M. S. Andreeva , A. V. Koryabin , V. I. Shmalhausen

We recently developed a new approach to get a stabilized image from a sequence of frames acquired through atmospheric turbulence. The goal of this algorihtm is to remove the geometric distortions due by the atmosphere movements. This method…

Computer Vision and Pattern Recognition · Computer Science 2024-11-06 Yu Mao , Jerome Gilles

In view of recently demonstrated joint use of novel Fourier-transform techniques and effective high-accuracy frequency domain solvers related to the Method of Moments, it is argued that a set of transformative innovations could be developed…

Computational Physics · Physics 2024-11-11 Thomas G. Anderson , Mark Lyon , Tao Yin , Oscar P. Bruno

This paper describes a novel deep learning-based method for mitigating the effects of atmospheric distortion. We have built an end-to-end supervised convolutional neural network (CNN) to reconstruct turbulence-corrupted video sequence. Our…

Image and Video Processing · Electrical Eng. & Systems 2019-12-25 Jing Gao , N. Anantrasirichai , David Bull