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Optical turbulence modelling and simulation are crucial for developing astronomical ground-based instruments, laser communication, laser metrology, or any application where light propagates through a turbulent medium. In the context of…

Instrumentation and Methods for Astrophysics · Physics 2024-04-05 A. Berdja , M. Hadjara , M. Carbillet , R. L. Bernardi , R. G. Petrov

Phase aberration is one of the primary sources of image quality degradation in ultrasound, which is induced by spatial variations in sound speed across the heterogeneous medium. This effect disrupts transmitted waves and prevents coherent…

Image and Video Processing · Electrical Eng. & Systems 2023-05-18 Mostafa Sharifzadeh , Habib Benali , Hassan Rivaz

Fourier ptychographic microscopy (FPM) is a recently developed imaging modality that uses angularly varying illumination to extend a system performance beyond the limit defined by its optical elements. The FPM technique applies a novel…

Optics · Physics 2014-05-02 Xiaoze Ou , Roarke Horstmeyer , Changhuei Yang , Guoan Zheng

One of the primary sources of suboptimal image quality in ultrasound imaging is phase aberration. It is caused by spatial changes in sound speed over a heterogeneous medium, which disturbs the transmitted waves and prevents coherent…

Image and Video Processing · Electrical Eng. & Systems 2024-07-03 Mostafa Sharifzadeh , Sobhan Goudarzi , An Tang , Habib Benali , Hassan Rivaz

Fourier ptychographic microscopy (FPM) is a novel computational coherent imaging technique for high space-bandwidth product imaging. Mathematically, Fourier ptychographic (FP) reconstruction can be implemented as a phase retrieval…

Computer Vision and Pattern Recognition · Computer Science 2016-07-19 Liheng Bian , Jinli Suo , Jaebum Chung , Xiaoze Ou , Changhuei Yang , Feng Chen , Qionghai Dai

Tomography is an imaging technique that works by reconstructing a scene from acquired data in the form of line integrals of the imaging domain. A fundamental underlying assumption in the reconstruction procedure is the precise alignment of…

Numerical Analysis · Mathematics 2018-07-13 Toby Sanders

We present a method to calibrate wavefront distortion of the spatial light modulator setup by registering far field images of several Gaussian beams diffracted off the modulator. The Fourier transform of resulting interference images…

Optics · Physics 2016-03-22 Adam Leszczyński , Wojciech Wasilewski

In pulse-echo ultrasound, aberration often degrades image quality when beamforming does not account for wavefront distortions. To address this issue, local sound speed estimators have been developed in the past decade for distributed…

Medical Physics · Physics 2026-05-08 Louise Zhuang , Samuel Beuret , Ben Frey , Saachi Munot , Walter Simson , Dongwoon Hyun , Jeremy J. Dahl

Time series forecasting is a long-standing challenge due to the real-world information is in various scenario (e.g., energy, weather, traffic, economics, earthquake warning). However some mainstream forecasting model forecasting result is…

Artificial Intelligence · Computer Science 2022-12-05 Maowei Jiang , Pengyu Zeng , Kai Wang , Huan Liu , Wenbo Chen , Haoran Liu

Given a time series vector, how can we efficiently compute a specified part of Fourier coefficients? Fast Fourier transform (FFT) is a widely used algorithm that computes the discrete Fourier transform in many machine learning applications.…

Machine Learning · Computer Science 2020-08-31 Yong-chan Park , Jun-Gi Jang , U Kang

We present a modified model order reduction (MOR) technique for the FFT-based simulation of composite microstructures. It utilizes the earlier introduced MOR technique (Kochmann et al. [2019]), which is based on solving the…

Computational Engineering, Finance, and Science · Computer Science 2021-03-19 Christian Gierden , Johanna Waimann , Bob Svendsen , Stefanie Reese

Reflection seismic imaging usually suffers from a loss of resolution and contrast because of the fluctuations of the wave velocities in the Earth's crust. In the literature, phase distortion issues are generally circumvented by means of a…

Geophysics · Physics 2021-05-13 Rita Touma , Thibaud Blondel , Arnaud Derode , Michel Campillo , Alexandre Aubry

It is recently shown that discrete $N\times N$ linear unitary operators can be represented by interlacing $N+1$ phase shift layers with a fixed intervening operator such as Discrete Fractional Fourier Transform (DFrFT). Here, we show that…

Emerging Technologies · Computer Science 2025-02-25 Matthew Markowitz , Kevin Zelaya , Mohammad-Ali Miri

In this paper phase of a signal has been viewed from a different angle. According to this view a signal can have countably infinitely many phases, one associated with each Fourier component. In other words each frequency has a phase…

Neurons and Cognition · Quantitative Biology 2008-04-25 Kaushik Majumdar

The problem of recovering a signal from the magnitude of its short-time Fourier transform (STFT) is a longstanding one in audio signal processing. Existing approaches rely on heuristics that often perform poorly because of the nonconvexity…

Applications · Statistics 2012-09-11 Dennis L. Sun , Julius O. Smith

Pseudo-spectral method is one of the most accurate techniques for simulating turbulent flows. Fast Fourier transform (FFT) is an integral part of this method. In this paper, we present a new procedure to compute FFT in which we save…

Mathematical Software · Computer Science 2014-06-24 A. G. Chatterjee , M. K. Verma , M. Chaudhuri

This paper introduces a novel technique to preserve spectral features in lossy compression based on a novel fast Fourier correction algorithm\added{ for regular-grid data}. Preserving both spatial and frequency representations of data is…

Distributed, Parallel, and Cluster Computing · Computer Science 2026-01-06 Congrong Ren , Robert Underwood , Sheng Di , Emrecan Kutay , Zarija Lukic , Aylin Yener , Franck Cappello , Hanqi Guo

The diffraction contrast modalities accessible by X-ray grating interferometers are not imaged directly but have to be inferred from sine like signal variations occurring in a series of images acquired at varying relative positions of the…

Instrumentation and Detectors · Physics 2021-02-01 Jonas Dittmann , Andreas Balles , Simon Zabler

Quantitative helio- and asteroseismology require very precise measurements of the frequencies, amplitudes, and lifetimes of the global modes of stellar oscillation. It is common knowledge that the precision of these measurements depends on…

Astrophysics · Physics 2009-11-13 Thorsten Stahn , Laurent Gizon

The graph Fourier transform (GFT) is an important tool for graph signal processing, with applications ranging from graph-based image processing to spectral clustering. However, unlike the discrete Fourier transform, the GFT typically does…

Signal Processing · Electrical Eng. & Systems 2019-10-02 Keng-Shih Lu , Antonio Ortega