Results 21 to 30 of about 469,971 (293)

One-dimensional Quaternion Fourier Transform and Some Applications

Bulletin of Computational Applied Mathematics, 2021
The Fourier transform is a very useful tool in many areas. This transform has been defined in many contexts, as complex numbers, quaternions, and Clifford algebras.
Eusebio Ariza García, Claudia Jiménez Heredia, Carlos Chipantiza   +2 more
doaj  

Fingerprint frequency normalisation and enhancement using two‐dimensional short‐time Fourier transform analysis

IET Computer Vision, 2016
A fingerprint image with non‐uniform ridge frequencies can be considered as a two‐dimensional dynamic signal. A non‐uniform stress on the sensing area applied during fingerprint acquisition may result in a non‐linear distortion that disturbs the local ...
Mubeen Ghafoor, Imtiaz Ahmad Taj, Mohammad Noman Jafri   +2 more
doaj   +1 more source

Verification of pattern formation mechanism using voxel model and estimation accuracy for inverse analysis of vibration phenomenon using two-dimensional discrete Fourier transform of end mill chatter mark

Nihon Kikai Gakkai ronbunshu, 2021
The vibration generated at the contact point between a tool blade and a machined surface during cutting significantly influences the generation mechanism of regenerated chatter vibration.
Nobutoshi OZAKI, Haruki MINETAKA, Shota MATSUI, Toshiki HIROGAKI, Eiichi AOYAMA   +4 more
doaj   +1 more source

Two-Dimensional Discrete Coupled Fractional Fourier Transform (DCFrFT)

Fractal and Fractional
The fractional Fourier transform is critical in signal processing and supports many applications. Signal processing is one notable application. Implementing the fractional Fourier transform requires discrete versions.
Asma Elshamy, Zeinab S. I. Mansour, Ahmed Zayed   +2 more
doaj   +1 more source

Application of parallel version two-dimensional fast Fourier transform algorithm, analog of the Cooley-Tukey algorithm, for digital image processing of satellite data

E3S Web of Conferences, 2019
In modern systems of remote sensing two-dimensional fast Fourier transform (FFT) has been widely used for digital processing of satellite images and subsequent image filtering.
Noskov Mikhail, Tutatchikov Valeriy, Lapchik Mikhail, Ragulina Marina, Yamskikh Tatiana   +4 more
doaj   +1 more source

Objective Center-Finding Algorithm for Tropical Cyclones in Numerical Models

Atmosphere, 2019
Precise center-detection of tropical cyclones (TCs) is critical for dynamic analysis in high resolution model data. The existence of both smaller scale perturbations and larger scale circulations could reduce the accuracy of center positioning.
Chengwu Zhao, Junqiang Song, Hongze Leng, Juan Zhao   +3 more
doaj   +1 more source

Application and graphical interpretation of a new two-dimensional quaternion fractional Fourier transform

International Journal of Analysis and Applications, 2021
In this paper, a new two-dimensional quaternion fractional Fourier transform is developed. The properties such as linearity, shifting and derivatives of the quaternion-valued function are studied.
Khinal Parmar, V. R. Lakshmi Gorty
doaj  

Array-Beamspace Mapping for Planar Two-Dimensional Beam-Forming

IEEE Access, 2023
As sixth-generation (6G) communication systems manifest at carrier frequencies well into the millimeter-wave (mmW) spectrum, the ability of conventional digital beamforming techniques to handle the beam-bandwidth product is increasingly stressed ...
William L. Beardell, Janusz Murakowski, Garrett J. Schneider, Dennis W. Prather   +3 more
doaj   +1 more source

Interference suppression in digital holographic images

Компьютерная оптика
This paper presents a digital filtering software module for noise suppression in reconstructed holographic images and in original digital holograms.
N.N. Yudin, G.S. Geimbukh, V.S. Kuznetsov, M.M. Zinoviev, M.M. Kulesh, S.N. Podzyvalov, E.S. Slyunko, H. Baalbaki   +7 more
doaj   +1 more source

Three-dimensional sculpting of laser beams

SciPost Physics, 2023
We demonstrate three-dimensional sculpting of laser beams using two-dimensional holograms. Without relying on initial guesses of the analytic properties or the Fourier transform of the desired light field, we show that an improved numerical phase ...
Tobias Kree, Michael Köhl
doaj   +1 more source