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Fourier phase retrieval is a classical problem of restoring a signal only from the measured magnitude of its Fourier transform. Although Fienup-type algorithms, which use prior knowledge in both spatial and Fourier domains, have been widely…

Computer Vision and Pattern Recognition · Computer Science 2020-11-23 Eunju Cha , Chanseok Lee , Mooseok Jang , Jong Chul Ye

We study the problem of recovering an unknown compactly-supported multivariate function from samples of its Fourier transform that are acquired nonuniformly, i.e. not necessarily on a uniform Cartesian grid. Reconstruction problems of this…

Numerical Analysis · Mathematics 2022-05-04 Ben Adcock , Milana Gataric , José Luis Romero

This study introduces a short-time Fourier transform-based method for reconstructing signals encoded using modulo analog-to-digital converters with 1-bit folding information. In contrast to existing Fourier-based reconstruction approaches…

Signal Processing · Electrical Eng. & Systems 2026-01-14 Neil Irwin Bernardo

We present an approach for improving spatial frequency sampling in active incoherent millimeter-wave (AIM) imaging systems using frequency diversity. AIM imaging relies on active transmission of spatio-temporally incoherent signals to…

Signal Processing · Electrical Eng. & Systems 2025-03-12 Jorge R. Colon-Berrios , Jeffrey A. Nanzer

Deep learning-based methods deliver state-of-the-art performance for solving inverse problems that arise in computational imaging. These methods can be broadly divided into two groups: (1) learn a network to map measurements to the signal…

Image and Video Processing · Electrical Eng. & Systems 2023-10-11 Nebiyou Yismaw , Ulugbek S. Kamilov , M. Salman Asif

We proposed a novel approach to coherent imaging of dynamic samples. The inter-frame similarity of the sample's local structures is found to be a powerful constraint in phasing a sequence of diffraction patterns. We devised a new image…

Optics · Physics 2024-07-11 Pengju Sheng , Fucai Zhang

Recently Fourier Ptychography (FP) has attracted great attention, due to its marked effectiveness in leveraging snapshot numbers for spatial resolution in large field-of-view imaging. To acquire high signal-to-noise-ratio (SNR) images under…

Optics · Physics 2015-02-19 Liheng Bian , Jinli Suo , Guoan Zheng , KaiKai Guo , Feng Chen , Qionghai Dai

The novel camera architecture facilitates the development of machine vision. Instead of capturing frame sequences in the temporal domain as traditional video cameras, FourierCam directly measures the pixel-wise temporal spectrum of the…

Image and Video Processing · Electrical Eng. & Systems 2020-11-02 Chengyang Hu , Honghao Huang , Minghua Chen , Sigang Yang , Hongwei Chen

Compressed Sensing (CS) significantly speeds up Magnetic Resonance Image (MRI) processing and achieves accurate MRI reconstruction from under-sampled k-space data. According to the current research, there are still several problems with…

Image and Video Processing · Electrical Eng. & Systems 2023-10-24 Junpeng Tan , Chunmei Qing , Xiangmin Xu

Information about microscopic objects with features smaller than the diffraction limit is almost entirely lost in a far-field diffraction image but could be partly recovered with data completition techniques. Any such approach critically…

Optics · Physics 2020-11-17 Maria Bancerek , Krzysztof M. Czajkowski , Rafal Kotynski

We present a new deterministic algorithm for the sparse Fourier transform problem, in which we seek to identify k << N significant Fourier coefficients from a signal of bandwidth N. Previous deterministic algorithms exhibit quadratic…

Numerical Analysis · Mathematics 2012-07-27 David Lawlor , Yang Wang , Andrew Christlieb

This paper discusses different approaches used for millimeter wave imaging of two-dimensional objects. Imaging of a two dimensional object requires reflected wave data to be collected across two distinct dimensions. In this paper, we…

Computer Vision and Pattern Recognition · Computer Science 2014-04-21 Sujeet Patole , Murat Torlak

In this paper, we present a frequency domain neural network for image super-resolution. The network employs the convolution theorem so as to cast convolutions in the spatial domain as products in the frequency domain. Moreover, the…

Computer Vision and Pattern Recognition · Computer Science 2017-12-11 Junxuan Li , Shaodi You , Antonio Robles-Kelly

The Fourier spectrum at a fractional period is often examined when extracting features from biological sequences and time series. It reflects the inner information structure of the sequences. A fractional period is not uncommon in time…

Spectral Theory · Mathematics 2017-11-03 Jiasong Wang , Changchuan Yin

The Gridding algorithm has shown great utility for reconstructing images from non-uniformly spaced samples in the Fourier domain in several imaging modalities. Due to the non-uniform spacing, some correction for the variable density of the…

Image and Video Processing · Electrical Eng. & Systems 2021-06-17 Nicholas Dwork , Daniel O'Connor , Ethan M. I. Johnson , Corey A. Baron , Jeremy W. Gordon , John M. Pauly , Peder E. Z. Larson

For reconstructing large tomographic datasets fast, filtered backprojection-type or Fourier-based algorithms are still the method of choice, as they have been for decades. These robust and computationally efficient algorithms have been…

Numerical Analysis · Mathematics 2021-08-31 Poulami Somanya Ganguly , Daniël M. Pelt , Doga Gürsoy , Francesco de Carlo , K. Joost Batenburg

The pre-trained transformer demonstrates remarkable generalization ability in natural image processing. However, directly transferring it to magnetic resonance images faces two key challenges: the inability to adapt to the specificity of…

Computer Vision and Pattern Recognition · Computer Science 2026-01-21 Jingkai Li , Xiaoze Tian , Yuhang Shen , Jia Wang , Dianjie Lu , Guijuan Zhang , Zhuoran Zheng

Fourier methods have a long and proven track record as an excellent tool in data processing. As memory and computational constraints gain importance in embedded and mobile applications, we propose to combine Fourier methods and recurrent…

Machine Learning · Computer Science 2020-08-17 Moritz Wolter , Juergen Gall , Angela Yao

In many practical applications, spatial data are often collected at areal levels (i.e., block data) and the inferences and predictions about the variable at points or blocks different from those at which it has been observed typically…

Computation · Statistics 2020-01-10 Peter Simonson , Douglas Nychka , Soutir Bandyopadhyay

We present a closed-form image reconstruction method for single pixel imaging based on the generalized inverse of the measurement matrix. Its numerical cost scales linearly with the number of measured samples. Regularization is obtained by…

Image and Video Processing · Electrical Eng. & Systems 2018-07-26 Krzysztof M. Czajkowski , Anna Pastuszczak , Rafal Kotynski