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In his monograph Chebyshev and Fourier Spectral Methods, John Boyd claimed that, regarding Fourier spectral methods for solving differential equations, ``[t]he virtues of the Fast Fourier Transform will continue to improve as the relentless…

Numerical Analysis · Mathematics 2023-02-03 Craig Gross , Mark Iwen

Ptychography is a lensless imaging method that allows for wavefront sensing and phase-sensitive microscopy from a set of diffraction patterns. Recently, it has been shown that the optimization task in ptychography can be achieved via…

Image and Video Processing · Electrical Eng. & Systems 2021-01-13 Jacob Seifert , Dorian Bouchet , Lars Loetgering , Allard P. Mosk

Ptychography is a lensless imaging technique, which considers reconstruction from a set of far-field diffraction patterns obtained by illuminating small overlapping regions of the specimen. In many cases, a distribution of light inside the…

Numerical Analysis · Mathematics 2022-10-05 Frank Filbir , Oleh Melnyk

Non-line-of-Sight (NLOS) imaging systems collect light at a diffuse relay surface and input this measurement into computational algorithms that output a 3D volumetric reconstruction. These algorithms utilize the Fast Fourier Transform (FFT)…

Image and Video Processing · Electrical Eng. & Systems 2025-01-14 Talha Sultan , Alex Bocchieri , Chaoying Gu , Xiaochun Liu , Pavel Polynkin , Andreas Velten

Optoacoustic imaging technologies require fast and accurate signal pre-processing algorithms to enable widespread deployment in clinical and home-care settings. However, they still rely on the Discrete Fourier Transform (DFT) as the default…

An integrated photonic circuit architecture to perform a modified-convolution operation based on the Discrete Fractional Fourier Transform (DFrFT) is introduced. This is accomplished by utilizing two nonuniformly-coupled waveguide lattices…

Optics · Physics 2025-02-25 Kevin Zelaya , Mohammad-Ali Miri

Ptychography is an attractive advance of coherent diffraction imaging (CDI), which can provide high lateral resolution and wide field of view. The theoretical resolution of ptychography is dose-limited, therefore making ptychography…

Biological Physics · Physics 2025-01-09 Huixiang Lin , Fucai Zhang

In this work, we present and investigate the novel blind inverse problem of position-blind ptychography, i.e., ptychographic phase retrieval without any knowledge of scan positions, which then must be recovered jointly with the image. The…

Image and Video Processing · Electrical Eng. & Systems 2026-03-18 Simon Welker , Lorenz Kuger , Tim Roith , Berthy Feng , Martin Burger , Timo Gerkmann , Henry Chapman

In this paper, we study the mathematical imaging problem of diffraction tomography (DT), which is an inverse scattering technique used to find material properties of an object by illuminating it with probing waves and recording the…

Numerical Analysis · Mathematics 2023-05-16 Florian Faucher , Clemens Kirisits , Michael Quellmalz , Otmar Scherzer , Eric Setterqvist

The Fast Fourier Transform (FFT) is one of the most widely used algorithms in high performance computing, with critical applications in spectral analysis for both signal processing and the numerical solution of partial differential…

Numerical Analysis · Mathematics 2025-05-01 Laslo Hunhold , John Gustafson

Texture is an essential information in image representation, capturing patterns and structures. As a result, texture plays a crucial role in the manufacturing industry and is extensively studied in the fields of computer vision and pattern…

Computer Vision and Pattern Recognition · Computer Science 2023-07-11 Jongwook Si , Sungyoung Kim

Joint ptychography and tomography (JPT) is a recently developed framework that enables high-resolution reconstruction of 3D volumes with significantly relaxed constraints on probe overlap at adjacent scan positions. In ptychographic X-ray…

Image and Video Processing · Electrical Eng. & Systems 2020-02-20 Azat M. Slyamov , Viktor Nikitin , Doğa Gürsoy , Rajmund Mokso , Jens W. Andreasen

Reflective ptychography is a promising lensless imaging technique with a wide field of view, offering significant potential for applications in semiconductor manufacturing and detection. However, many semiconductor materials are coated with…

Optics · Physics 2025-01-03 Yun Gao , Qijun You , Peixiang Lu , Wei Cao

Frequency-resolved optical gating (FROG) is probably the most popular technique for complete characterization of ultrashort laser pulses. In FROG, a reconstruction algorithm retrieves the pulse from a measured spectrogram, yet current FROG…

Optics · Physics 2019-06-11 Pavel Sidorenko , Oren Lahav , Zohar Avnat , Oren Cohen

In this paper we explain how to use the Fast Fourier Transform (FFT) to solve partial differential equations (PDEs). We start by defining appropriate discrete domains in coordinate and frequency domains. Then describe the main limitation of…

Numerical Analysis · Mathematics 2025-07-31 Daniela Rodriguez-Lara , Ivan Alvarez-Rios , Francisco S. Guzman

We develop the uniform sparse Fast Fourier Transform (usFFT), an efficient, non-intrusive, adaptive algorithm for the solution of elliptic partial differential equations with random coefficients. The algorithm is an adaption of the sparse…

Numerical Analysis · Mathematics 2022-09-05 Lutz Kämmerer , Daniel Potts , Fabian Taubert

Fast scanning probe microscopy enabled via machine learning allows for a broad range of nanoscale, temporally resolved physics to be uncovered. However, such examples for functional imaging are few in number. Here, using piezoresponse force…

Though Fourier Transforms (FTs) are a common technique for finding correlation functions, they are not typically used in computations of the anisotropy of the two-point correlation function (2PCF) about the line of sight in wide-angle…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-28 Zachary Slepian , Daniel J. Eisenstein

Quantum ptychography is a method for estimating an unknown pure quantum state by subjecting it to overlapping projections, each one followed by a projective measurement on a single prescribed basis. Here, we present a comprehensive study of…

Quantum Physics · Physics 2024-12-04 Warley M. S. Alves , Leonardo Neves

Recent developments in machine learning and signal processing have resulted in many new techniques that are able to effectively capture the intrinsic yet complex properties of hyperspectral imagery. Tasks ranging from anomaly detection to…

Computer Vision and Pattern Recognition · Computer Science 2020-11-24 Ilya Kavalerov , Weilin Li , Wojciech Czaja , Rama Chellappa