Journal ArticleDOI
Real Discrete Fractional Fourier, Hartley, Generalized Fourier and Generalized Hartley Transforms With Many Parameters
Wen-Liang Hsue,Wei-Ching Chang +1 more
TLDR
This paper proposes reality-preserving fractional versions of the discrete Fourier, Hartley, generalized Fouriers, and generalized Hartley transforms, which have random outputs and many parameters and thus are very flexible.Abstract:
Real transforms require less complexity for computations and less memory for storages than complex transforms. However, discrete fractional Fourier and Hartley transforms are complex transforms. In this paper, we propose reality-preserving fractional versions of the discrete Fourier, Hartley, generalized Fourier, and generalized Hartley transforms. All of the proposed real discrete fractional transforms have as many as $O(N^{2})$ parameters and thus are very flexible. The proposed real discrete fractional transforms have random eigenvectors and they have only two distinct eigenvalues 1 and $-$ 1. Properties and relationships of the proposed real discrete fractional transforms are investigated. Besides, for the real conventional discrete Hartley and generalized discrete Hartley transforms, we propose their alternative reality-preserving fractionalizations based on diagonal-like matrices to further increase their flexibility. The proposed real transforms have all of the required good properties to be discrete fractional transforms. Finally, since the proposed new transforms have random outputs and many parameters, they are all suitable for data security applications such as image encryption and watermarking.read more
Citations
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Journal ArticleDOI
Phase image encryption in the fractional Hartley domain using Arnold transform and singular value decomposition
TL;DR: A novel scheme for image encryption of phase images is proposed, using fractional Hartley transform followed by Arnold transform and singular value decomposition in the frequency domain, and the mask used in the spatial domain is a random amplitude mask.
Journal ArticleDOI
An innovative fractional order LMS based on variable initial value and gradient order
TL;DR: A variable initial value scheme is proposed to attenuate the non-locality of fractional order calculus and to ensure the convergence of the proposed FOLMS algorithm to remove the contradiction between rapidity and accuracy.
Journal ArticleDOI
Discrete Fractional Fourier Transforms Based on Closed-Form Hermite–Gaussian-Like DFT Eigenvectors
TL;DR: This paper constructs discrete fractional Fourier transforms (DFrFT) using recently introduced closed-form Hermite–Gaussian-like (HGL) eigenvectors, and gives new procedures for obtaining orthonormal bases of HGL eigenivectors, which are used to fractionalize the discrete Fourier transform.
Journal ArticleDOI
Optimized sparse fractional Fourier transform: Principle and performance analysis
TL;DR: The proposed algorithm, termed optimized sparse fractional Fourier transform (OSFrFT), can reduce the computational complexity while guarantee sufficient robustness and estimation accuracy and a successful application of OSFrFT to continuous wave radar signal processing.
Journal ArticleDOI
Random discrete linear canonical transform.
TL;DR: The RDLCT inherits excellent mathematical properties from the DLCT along with some fantastic features of its own and has a greater degree of randomness because of the randomization in terms of both eigenvectors and eigenvalues.
References
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Journal ArticleDOI
Optical image encryption based on input plane and Fourier plane random encoding.
Philippe Réfrégier,Bahram Javidi +1 more
TL;DR: A new optical encoding method of images for security applications is proposed and it is shown that the encoding converts the input signal to stationary white noise and that the reconstruction method is robust.
Book
The Fractional Fourier Transform: with Applications in Optics and Signal Processing
TL;DR: The fractional Fourier transform (FFT) as discussed by the authors has been used in a variety of applications, such as matching filtering, detection, and pattern recognition, as well as signal recovery.
Journal ArticleDOI
Fast algorithms for the discrete W transform and for the discrete Fourier transform
TL;DR: A systematic method of sparse matrix factorization is developed for all four versions of the discrete W transform, the discrete cosine transform, and the discrete sine transform as well as for the discrete Fourier transform, which makes new algorithms more efficient than conventional algorithms.
Journal ArticleDOI
Eigenvectors and functions of the discrete Fourier transform
TL;DR: A method is presented for computing an orthonormal set of eigenvectors for the discrete Fourier transform (DFT) based on a detailed analysis of the eigenstructure of a special matrix which commutes with the DFT.
Journal ArticleDOI
Eigenvalue and eigenvector decomposition of the discrete Fourier transform
J. McClellan,T. Parks +1 more
TL;DR: The eigenvalues of a suitably normalized version of the discrete Fourier transform (DFT) are {1, -1,j, -j} and an eigenvector basis is constructed for the DFT.
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Optical image encryption based on input plane and Fourier plane random encoding.
Philippe Réfrégier,Bahram Javidi +1 more