Results 341 to 350 of about 744,050 (371)

Properties of the fractionalization of a Fourier transform

Optics Communications, 1997
Abstract The new fractional Fourier transform, proposed by Shih [Optics Comm. 118 (1995) 495], is shown to differ from the conventional fractional Fourier transform by its four periodic eigenvalues with respect to the order of Hermite-Gaussian functions. Simulations demonstrate that the Hermite-Gaussian superposition algorithm is still valid for this
Yan Zhang, Jingde Zhang, Shutian Liu
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Fractional Fourier transformers through reflection

Journal of the Optical Society of America A, 2002
We show that an arbitrary paraxial optical system, compounded with its reflection in an appropriately warped mirror, is a pure fractional Fourier transformer between coincident input and output planes. The geometric action of reflection on optical systems is introduced axiomatically and is developed in the paraxial regime. The correction of aberrations
Guillermo Krötzsch, Kurt Bernardo Wolf
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Detection of R-peaks using fractional Fourier transform and principal component analysis

Journal of Ambient Intelligence and Humanized Computing, 2021
Varun Gupta, M. Mittal, Vikas Mittal, Y. Chaturvedi   +3 more
semanticscholar   +1 more source

On Namias's Fractional Fourier Transforms

IMA Journal of Applied Mathematics, 1987
Pour lever toute ambiguite, on montre qu'il est necessaire de modifier les operateurs fractionnaires de Namia.
A. C. McBRIDE, F. H. Kerr
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Multiple color image fusion, compression, and encryption using compressive sensing, chaotic-biometric keys, and optical fractional Fourier transform

Optics & Laser Technology, 2022
M. Abuturab, A. Alfalou
semanticscholar   +1 more source

Continued fractions and Fourier transforms

Mathematika, 1980
Let FN be the set of real numbers x whose continued fraction expansion x = [a0; a1, a2,…, an,…] contains only elements ai = 1,2,…, N. Here N ≥ 2. Considerable effort, [1,3], has centred on metrical properties of FN and certain measures carried by FN. A classification of sets of measure zero, as venerable as the dimensional theory, depends on Fourier ...
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Fractional Fourier transform: Time-frequency representation and structural instantaneous frequency identification

Mechanical systems and signal processing, 2022
Lian-Wei Lu, W. Ren, Shi-Dong Wang
semanticscholar   +1 more source

Adaptive harmonic fractional Fourier transform

IEEE Signal Processing Letters, 1999
A novel adaptive harmonic fractional Fourier transform is proposed for analysis of voiced speech signals. It provides a higher concentration than STFT and avoids the cross interference components produced by the Wigner-Ville distribution and other bilinear representation. The proposed method rotates the base tone and harmonics in time-frequency domain.
Yan Qiu Chen, Guoan Bi, Feng Zhang
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Discrete and finite fractional Fourier transforms

Frontiers in Optics, 2003
Finite models for oscillator or waveguide systems provide corresponding fractional Fourier-type transforms between finite arrays of ‘sensor’ points. The kernel matrices are unitary and are well-known in group theory; they involve the discrete polynomials of Kravchuk, q-Kravchuk, Meixner and Hahn.
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Double-encrypted watermarking algorithm based on cosine transform and fractional Fourier transform in invariant wavelet domain

Information Sciences, 2021
Yuanmin Li, Deyun Wei, Lina Zhang
semanticscholar   +1 more source