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An inverse nonequispaced fast Fourier transform (iNFFT) is a fast algorithm to compute the Fourier coefficients of a trigonometric polynomial from nonequispaced sampling data. However, various applications such as magnetic resonance imaging…

Numerical Analysis · Mathematics 2025-06-09 Melanie Kircheis , Daniel Potts

Vertex-frequency analysis, particularly the windowed graph Fourier transform (WGFT), is a significant challenge in graph signal processing. Tight frame theories is known for its low computational complexity in signal reconstruction, while…

Signal Processing · Electrical Eng. & Systems 2024-12-31 Linbo Shang , Zhichao Zhang

Recent progress in synthetic aperture sonar (SAS) technology and processing has led to significant advances in underwater imaging, outperforming previously common approaches in both accuracy and efficiency. There are, however, inherent…

Numerical Analysis · Mathematics 2017-06-28 John McKay , Anne Gelb , Vishal Monga , Raghu Raj

Even though image signals are typically defined on a regular two-dimensional grid, there also exist many scenarios where this is not the case and the amplitude of the image signal only is available for a non-regular subset of pixel…

Image and Video Processing · Electrical Eng. & Systems 2022-04-28 Jürgen Seiler , Markus Jonscher , Michael Schöberl , André Kaup

By using unsupervised domain adaptation (UDA), knowledge can be transferred from a label-rich source domain to a target domain that contains relevant information but lacks labels. Many existing UDA algorithms suffer from directly using raw…

Computer Vision and Pattern Recognition · Computer Science 2024-03-22 Le Luo , Bingrong Xu , Qingyong Zhang , Cheng Lian , Jie Luo

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

Sampling theory in fractional Fourier Transform (FrFT) domain has been studied extensively in the last decades. This interest stems from the ability of the FrFT to generalize the traditional Fourier Transform, broadening the traditional…

Information Theory · Computer Science 2024-04-30 Václav Pavlíček , Ayush Bhandari

Recovering a sparse signal from its low-pass projections in the Fourier domain is a problem of broad interest in science and engineering and is commonly referred to as super-resolution. In many cases, however, Fourier domain may not be the…

Information Theory · Computer Science 2019-02-20 Ayush Bhandari , Yonina C. Eldar

We introduce a method to recover a continuous domain representation of a piecewise constant two-dimensional image from few low-pass Fourier samples. Assuming the edge set of the image is localized to the zero set of a trigonometric…

Computer Vision and Pattern Recognition · Computer Science 2016-04-25 Greg Ongie , Mathews Jacob

With Fourier sensing, it is commonly the case that the field-of-view (FOV), the area of space to be imaged, is known prior to reconstruction. To date, reconstruction algorithms have focused on FOVs with simple geometries: a rectangle or a…

Image and Video Processing · Electrical Eng. & Systems 2024-06-25 Nicholas Dwork , Erin K. Englund , Alex J. Barker

Algorithms for processing data in short-time batches are critical for both online and offline processing of streamed and large data respectively due to the quadratic relation between signal length and computational cost of convolution-based…

Quantum Physics · Physics 2025-04-30 Sreeraj Rajindran Nair , Benjamin Southwell , Christopher Ferrie

We present theoretical formulation and experimental demonstration of a novel technique for the fast compression-less terahertz imaging based on the broadband Fourier optics. The technique exploits k-vector/frequency duality in Fourier…

Optics · Physics 2017-08-28 Hichem Guerboukha , Kathirvel Nallappan , Maksim Skorobogatiy

We present several domain decomposition algorithms for sequential and parallel minimization of functionals formed by a discrepancy term with respect to data and total variation constraints. The convergence properties of the algorithms are…

Numerical Analysis · Mathematics 2009-02-03 Massimo Fornasier , Andreas Langer , Carola-Bibiane Schönlieb

In this paper, we consider the problem of reconstructing piece-wise smooth functions from their non-uniform Fourier data. We first extend the filter method for uniform Fourier data to the non-uniform setting by using the techniques of…

Numerical Analysis · Mathematics 2026-01-23 Guohui Song , Congzhi Xia

The rapid and accurate evaluation of convolutions with singular kernels plays crucial roles in a wide range of scientific and engineering applications. Building on the recently introduced Truncated Fourier Filtering method for smooth…

Numerical Analysis · Mathematics 2025-11-27 Oscar Bruno , Jinghao Cao

This article is written to serve as an introduction and survey of imaging with synthetic aperture radar (SAR). The reader will benefit from having some familiarity with harmonic analysis, electromagnetic radiation, and inverse problems.…

Numerical Analysis · Mathematics 2019-10-24 Toby Sanders , Christian Dwyer , Rodrigo B. Platte

Existing convolutional neural networks widely adopt spatial down-/up-sampling for multi-scale modeling. However, spatial up-sampling operators (\emph{e.g.}, interpolation, transposed convolution, and un-pooling) heavily depend on local…

Computer Vision and Pattern Recognition · Computer Science 2022-10-12 Man Zhou , Hu Yu , Jie Huang , Feng Zhao , Jinwei Gu , Chen Change Loy , Deyu Meng , Chongyi Li

To increase the flexibility and scalability of deep neural networks for image reconstruction, a framework is proposed based on bandpass filtering. For many applications, sensing measurements are performed indirectly. For example, in…

Computer Vision and Pattern Recognition · Computer Science 2018-11-27 Joseph Y. Cheng , Feiyu Chen , Marcus T. Alley , John M. Pauly , Shreyas S. Vasanawala

We present a computationally efficient algorithm for stable numerical differentiation from noisy, uniformly-sampled data on a bounded interval. The method combines multi-interval Fourier extension approximations with an adaptive domain…

Numerical Analysis · Mathematics 2025-08-29 Zhenyu Zhao , Yanfei Wang , Xinran Liu

We introduce two efficient algorithms for computing the partial Fourier transforms in one and two dimensions. Our study is motivated by the wave extrapolation procedure in reflection seismology. In both algorithms, the main idea is to…

Numerical Analysis · Mathematics 2008-02-13 Lexing Ying , Sergey Fomel