The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Fourier domain deblurring methods are not fit for space variant degradation due to time invariant property of the Fourier transform (FT). Filtering in the fractional Fourier transform (FRFT) domain can deblur space variant degradation effectively, but hardly denoise substantially in the meantime. We propose a fractional Fourier-contourlet restoration algorithm to remove the space variant blur and...
The time delay estimation between two signals in the passive system has been an important issue. In this paper, we propose a new time delay estimator based on the delay property of the fractional Fourier transform (FRFT). It is suitable for chirp signals in the passive system. The time delay is evaluated in the fractional Fourier domain by measuring the time differential between the time delays obtained...
In this paper, Shih's weighted fractional Fourier transform is generalized to contain two 4D vector parameters IfrRfr, Rfr isin Zopf4, which is denoted by generalized weighted fractional Fourier transform (GWFRFT). The proposed GWFRFT is shown to possess all of the desired properties for Shih's FRFT. In fact, the GWFRFT will reduce to Shih's FRFT when both IfrRfr, Rfr are zero vectors. The eigenvalue...
In this paper, we introduce the fractional Fourier transform (FrFT), which is a potent tool for linear frequency modulated (LFM) signal processing, and its applications to synthetic aperture radar (SAR) moving target detection and parameter estimation. A new method based on the FrFT for range cell migration correction (RCMC) is also presented. Both the analytic properties and the advantages are shown...
A novel image encryption technique is proposed associated with the generalized Hilbert transform in this paper. Two schemes of this technique are presented in generating real encrypted image and recovering the original image. The encrypted image is real-valued without data expanding, which can benefit the digital processing of images by electronic computers where speed of computation is important...
In engineering applications, piezoelectric materials are usually bonded to elastic substrates to form so-called smart materials and structures. Such materials and structures can respond to external electromechanical environments. This article studies a piezoelectric layer bonded to an elastic substrate subjected to static electromechanical loads, both of which are of finite length. A system of differential...
In this paper, we present a novel algorithm for FRFT with zooming-in ability, which is preferable to previous algorithms because it can freely choose computational resolution and zoom in on any interested portion of the fractional spectra, meanwhile, retains the advantage of the Ozaktas algorithm in computational speed. Its advantages in scrutinizing the fine structure of the partial spectra and improving...
The uniform sampling theorem and the reconstruction formulae associated with the fractional Fourier transform (FrFT) have been deduced in the literature, but the nonuniform sampling is yet to receive attention in the fractional Fourier domain. This paper focus on a special kind of non-uniform sampling process associated with the fractional Fourier transform. A nonuniform sampling model is first introduced...
The sampling theorem associated with the fractional Fourier transform can be looked as the convolution of the sinc kernel with infinite sequence of signal points and chirp signal modulations. But in most practical applications we only have finite number of samples, which makes a perfect reconstruction of the original signal impossible. To solve this problem, we obtain a new formula for perfect reconstruction...
A novel method of digital image encryption is presented. Image encryption and decryption are performed based on the continuously increasing decorrelation property and the real-valuedness of the reality-preserving fractional Fourier transform. The input and encrypted data are respectively in the spatial domain and the reality-preserving fractional Fourier transformed domain determined by encryption...
Linear canonical transform play an important role in many fields of optics and signal processing society. Well known transforms in these fields such as the Fourier transform, the fractional Fourier transform, and the Fresnel transform can be looked at as special cases of the linear canonical transform. In this paper we obtain new sampling formulae for reconstructing signals that are band-limited or...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.