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The Quaternion Fourier transform (QFT) is one of the key tools in studying color image processing. Indeed, a deep understanding of the QFT has created the color images to be transformed as whole, rather than as color separated component. In…

Classical Analysis and ODEs · Mathematics 2016-07-19 Xiao Xiao Hu , Kit Ian Kou

The quaternion Fourier transform (QFT), a generalization of the classical 2D Fourier transform, plays an increasingly active role in particular signal and colour image processing. There tends to be an inordinate degree of interest placed on…

Classical Analysis and ODEs · Mathematics 2019-03-04 Dong Cheng , Kit Ian Kou

Fourier transform (FT) plays a crucial role in a broad range of applications, from enhancement, restoration and analysis through to security, compression and manipulation. The Fourier transform (FT) is a process that converts a function…

Numerical Analysis · Mathematics 2023-05-05 Benjamin Kenwright

The quadratic phase Fourier transform (QPFT) is a generalization of several well-known integral transforms, including the linear canonical transform (LCT), fractional Fourier transform (FrFT), and Fourier transform (FT). This paper…

Functional Analysis · Mathematics 2025-05-06 Sarga Varghese , Gita Rani Mahato , Manab Kundu

The windowed quadratic phase Fourier transform (WQPFT) combines the localization capabilities of windowed transforms with the phase modulation structure of the quadratic phase Fourier transform (QPFT). This paper investigates fundamental…

Functional Analysis · Mathematics 2025-07-09 Sarga Varghese , Manab Kundu

Discrete Fourier transform (DFT) is the base of modern signal or information processing. 1-Dimensional fast Fourier transform (1D FFT) and 2D FFT have time complexity O(NlogN) and O(N^2logN) respectively. Quantum 1D and 2D DFT algorithms…

Quantum Physics · Physics 2007-06-19 Chao-Yang Pang , Ben-Qiong Hu

We treat the quaternionic Fourier transform (QFT) applied to quaternion fields and investigate QFT properties useful for applications. Different forms of the QFT lead us to different Plancherel theorems. We relate the QFT computation for…

Rings and Algebras · Mathematics 2013-06-06 Eckhard Hitzer

The quadratic phase Fourier transform QPFT is a neoteric addition to the class of Fourier transforms and embodies a variety of signal processing tools including the Fourier, fractional Fourier, linear canonical, and special affine Fourier…

Functional Analysis · Mathematics 2022-07-21 Aamir H. Dar , M. Younus Bhat

Quaternion-valued signals along with quaternion Fourier transforms (QFT)provide an effective framework for vector-valued signal and image processing. However, the sampling theory of quaternion valued signals has not been well developed. In…

Functional Analysis · Mathematics 2019-03-04 Dong Cheng , Kit Ian Kou

The linear canonical transform (LCT) serves as a powerful generalization of the Fourier transform (FT), encapsulating various integral transforms within a unified framework. This versatility has made it a cornerstone in fields such as…

Functional Analysis · Mathematics 2024-10-28 Muhammad Adnan Samad , Yuanqing Xia , Saima Siddiqui , Muhammad Younus Bhat

The notion of fractional Fourier transform (FrFT) has been used and investigated for many years by various research communities, which finds widespread applications in many diverse fields of research study. The potential applications…

Signal Processing · Electrical Eng. & Systems 2018-03-21 Sanjay Kumar

Novel types of convolution operators for quaternion linear canonical transform (QLCT) are proposed. Type one and two are defined in the spatial and QLCT spectral domains, respectively. They are distinct in the quaternion space and are…

Classical Analysis and ODEs · Mathematics 2022-12-13 Xiaoxiao Hu , Dong Cheng , Kit Ian Kou

A novel addition to the family of integral transforms, the quadratic phase Fourier transform (QPFT) embodies a variety of signal processing tools, including the Fourier transform (FT), fractional Fourier transform (FRFT), linear canonical…

Functional Analysis · Mathematics 2024-02-20 Aamir Hamid Dar

Circular convolutions and the corresponding frequency domain formula are fundamentally important in image restoration; however, in this paper, we'll prove that the usual computing method of circular convolutions violates the physical…

Image and Video Processing · Electrical Eng. & Systems 2019-10-09 Changcun Huang

The free metaplectic transformation (FMT) is widely used in many fields such as filter design, pattern recognition, image processing and optics. In order to obtain a more concise and intuitive convolution form, this paper studies two kinds…

General Mathematics · Mathematics 2022-06-28 Hui Zhao , Bing-Zhao Li

We study matrix forms of quaternionic versions of the Fourier Transform and Convolution operations. Quaternions offer a powerful representation unit, however they are related to difficulties in their use that stem foremost from…

Computer Vision and Pattern Recognition · Computer Science 2024-07-23 Giorgos Sfikas , George Retsinas

Fourier transforms are ubiquitous mathematical tools in basic and applied sciences. We here report classical and quantum optical realizations of the discrete fractional Fourier transform, a generalization of the Fourier transform. In the…

This note shows how to align a periodic signal with its the Fourier transform by means of frequency or time scaling. This may be useful in developing new algorithms, e.g. for pitch estimation. This note also convolves the signals and the…

Signal Processing · Electrical Eng. & Systems 2023-09-19 Matthew R. Flax , W. Harvey Holmes

The analytic signal is a useful mathematical tool. It separates qualitative and quantitative information of a signal in form of the local phase and local amplitude. The Clifford Fourier transform (CFT) plays a vital role in the…

Complex Variables · Mathematics 2023-07-26 Zhen Feng Cai , Kit Ian Kou

The Special Affine Fourier Transformation or the SAFT generalizes a number of well known unitary transformations as well as signal processing and optics related mathematical operations. Shift-invariant spaces also play an important role in…

Information Theory · Computer Science 2016-01-25 Ayush Bhandari , Ahmed I. Zayed
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