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In Fourier ptychography, multiple low resolution images are captured and subsequently combined computationally into a high-resolution, large-field of view micrograph. A theoretical image-formation model based on the assumption of plane-wave…

Optics · Physics 2022-06-22 Tomas Aidukas , Lars Loetgering , Andrew Robert Harvey

We study the volatility functional inference by Fourier transforms. This spectral framework is advantageous in that it harnesses the power of harmonic analysis to handle missing data and asynchronous observations without any artificial time…

Statistics Theory · Mathematics 2019-11-07 Richard Y. Chen

The Fourier theorem states that any time-series can be decomposed into a set of sinusoidal frequencies, each with its own phase and amplitude. The literature suggests that some frequencies are important to reproduce key qualities of…

Human-Computer Interaction · Computer Science 2024-03-14 Mehedi H. Raju , Lee Friedman , Troy M. Bouman , Oleg V. Komogortsev

Preprocessing the input patterns seems the simplest approach to invariant pattern recognition by neural networks. The Fourier transform has been proposed as an appropriate and elegant preprocessor. Nevertheless, we show in this work that…

Condensed Matter · Physics 2015-06-25 C. G. Carvalhaes , A. T. Costa , T. J. P. Penna

We introduce a robust numerical technique to verify the causality of sampled scattering parameters given on a finite bandwidth. The method is based on a filtered Fourier transform and includes a rigorous estimation of the errors caused by…

Computational Engineering, Finance, and Science · Computer Science 2016-06-29 Piero Triverio

The realm of classical phase retrieval concerns itself with the arduous task of recovering a signal from its Fourier magnitude measurements, which are fraught with inherent ambiguities. A single-exposure intensity measurement is commonly…

Computer Vision and Pattern Recognition · Computer Science 2023-11-21 Yixiao Yang , Ran Tao , Kaixuan Wei , Jun Shi

The Fast Fourier Transform (FFT) is a fundamental tool for signal analysis, widely used across various fields. However, traditional FFT methods encounter challenges in adjusting the frequency bin interval, which may impede accurate spectral…

Data Structures and Algorithms · Computer Science 2024-03-27 Haichao Xu

The problem of recovering a pair of signals from their blind phaseless short-time Fourier transform measurements arises in several important phase retrieval applications, including ptychography and ultra-short pulse characterization. In…

Information Theory · Computer Science 2019-04-11 Tamir Bendory , Dan Edidin , Yonina C. Eldar

Finite-rate-of-innovation (FRI) signals are ubiquitous in applications such as radar, ultrasound, and time of flight imaging. Due to their finite degrees of freedom, FRI signals can be sampled at sub-Nyquist rates using appropriate sampling…

Signal Processing · Electrical Eng. & Systems 2021-07-02 Satish Mulleti , Haiyang Zhang , Yonina C. Eldar

We are investigating to what extent one can use a P(D) analysis to extract number counts of unclustered sources from maps of the far infrared background. Currently available such maps, and those expected to emerge in near future are…

Astrophysics · Physics 2009-11-10 Yasmin Friedmann , Francois Bouchet

In this paper, we consider multiple signals sharing same instantaneous frequencies. This kind of data is very common in scientific and engineering problems. To take advantage of this special structure, we modify our data-driven…

Information Theory · Computer Science 2015-07-09 Thomas Y. Hou , Zuoqiang Shi

The fundamental frequency is one of the parameters that define power quality. Correctly determining this parameter under the conditions that prevail in modern power grids is crucial. Diagnostic purposes often require an efficient estimation…

Signal Processing · Electrical Eng. & Systems 2026-01-26 Antonio Bracale , Pasquale De Falco , Piotr Kuwałek , Grzegorz Wiczyński

In this paper, a new variant to fractional signal processing is proposed known as the Reduced Order Fractional Fourier Transform. Various properties satisfied by its transformation kernel is derived. The properties associated with the…

Signal Processing · Electrical Eng. & Systems 2018-04-18 Sanjay Kumar

This correspondence presents an efficient method for reconstructing a band-limited signal in the discrete domain from its crossings with a sine wave. The method makes it possible to design A/D converters that only deliver the crossing…

Information Theory · Computer Science 2016-11-17 J. Selva

This paper describes a method of calculating the transforms, currently obtained via Fourier and reverse Fourier transforms. The method allows calculating efficiently the transforms of a signal having an arbitrary dimension of the digital…

Numerical Analysis · Mathematics 2025-10-20 Vladimir I Clue

Many real-world time series exhibit strong periodic structures arising from physical laws, human routines, or seasonal cycles. However, modern deep forecasting models often fail to capture these recurring patterns due to spectral bias and a…

Machine Learning · Computer Science 2025-08-05 Menglin Kong , Vincent Zhihao Zheng , Lijun Sun

Gravitational-wave memory is characterized by a signal component that persists after a transient signal has decayed. Treating such signals in the frequency domain is non-trivial, since discrete Fourier transforms assume periodic signals on…

General Relativity and Quantum Cosmology · Physics 2024-12-17 Jorge Valencia , Rodrigo Tenorio , Maria Rosselló-Sastre , Sascha Husa

Sinusoidal parameter estimation is a fundamental task in applications from spectral analysis to time-series forecasting. Estimating the sinusoidal frequency parameter by gradient descent is, however, often impossible as the error function…

Signal Processing · Electrical Eng. & Systems 2022-11-21 Ben Hayes , Charalampos Saitis , György Fazekas

Planck LFI (Low Frequency Instrument) will produce a complete survey of the sky at millimeter wavelengths. Data stream analysis will provide the possibility to reveal unexpected millimeter sources and to study their flux evolution in time…

We propose a two steps fringe analysis method assuming random phase step and changes in the illumination conditions. Our method constructs on a Gabor Filter--Bank (GFB) that independently estimates the phase from the fringe patterns and…

Optics · Physics 2015-08-05 Mariano Rivera , Oscar Dalmau , Adonai Gonzalez , Francisco Hernandez