s is a time-frequency transform based on the concept of short-time fourier transform and wavelet transform. the main property of this transform that separate it from the discrete short-time fourier transform is variable frequency resolution. but in this transform the change of resolution of high frequencies to low frequencies is very high. so another transform as a modified s transform is intro...

We consider “scale” a physical attribute of a signal and develop its properties. We present an operator which represents scale and study its characteristics and representation. This allows one to define the scale transform and the energy scale density spectrum which is an indication of the intensity of scale values in a signal. We obtain explicit expressions for the mean scale, scale bandwidth,...

$FNQRZOHGJHPHQWV 3 This Master's thesis is the result of my final project at the University of Karlskrona/Ronneby. There are many people whom I'd like to thank for their assistance during the project. First, I would like to thank Jens Augustsson and Erik Pavlica, working at SSPA Maritime Consulting, for their guidance and the possibility to gain knowledge in an exciting field of science. In thi...

A new signal-adaptive joint time-frequency distribution for the analysis of nonstationary signals is proposed. It is based on a fractionalFourier-domain realization of the weighted Wigner distribution producing auto-terms close to the ones in the Wigner distribution itself, but with reduced cross-terms. Improvement over the standard time-frequency representations is achieved when the principal ...

This paper deals with application of Radar (ISAR) image for the safety applications in Intelligent Transport System (ITS).Comparative performance of conventional Fourier transform and joint time-frequency transform for the formation of Radar image is given here, Matlab(version 10) is used as the simulation platform and finally by comparing images obtained by two techniques ,the work is validated.

A new approach has been proposed to reduce the computations involved in the ISAR imaging, which uses Harmonic Wavelet (HW) based Time-Frequency Representation (TFR). Since the HW based TFR falls into a category of non-parametric Time-Frequency (T-F) analysis tool, it is computationally efficient compared to parametric T-F analysis tools such as Adaptive Joint Time-Frequency Transform (AJTFT), A...

in this paper, we propose a new residual analysis method using fourier series transform into fuzzy time series model for improving the forecasting performance. this hybrid model takes advantage of the high predictable power of fuzzy time series model and fourier series transform to fit the estimated residuals into frequency spectra, select the low-frequency terms, filter out high-frequency term...

Coherent image formation in step transform algorithm is realized by overlapped subapertures in both range and cross range direction. Subaperture formation principle is treated as multiplication of target backscatter signature with a set of overlapped and shifted complex, conjugate reference functions and subsequent spectral analysis. A polyphase filter bank interpretation of step transform is p...