Thanks to their capability to cover large areas, in all weather conditions, during the day as well as during the night, spaceborne Synthetic Aperture Radar (SAR) techniques constitute an extremely promising alternative to traditional surveillance methods. Nevertheless, in order to assure further usability of SAR images, specific data mining methods are still to be developed to provide an effici...

Yan Zhao 1,2,*, Zhimin Li 1 and Yonghui Nie 3 1 Department of Electrical Engineering, Harbin Institute of Technology, Harbin 150001, China; [email protected] 2 Department of Power Transmission and Transformation Technology College, Northeast Dianli University, Jilin 132012, China 3 Academic Administration Office, Northeast Dianli University, Jilin 132012, China; [email protected] * Corresp...

This is a very brief introduction on the basic concepts of wavelet transform and its applications. It is certainly not possible to present comprehensive details for wavelets in a short time, only an attempt to interject some underlying features to engineers who are not yet familiarize with wavelet transform on what makes wavelet one of the most exciting useful tools as well as research areas to...

Traditional modal analysis methods use either time domain or frequency domain approaches. Because vibration signals are generally non-stationary, time and frequency information is needed simultaneously in many cases. This paper presents an overview of the applications of joint time-frequency methods for modal analysis. Since a joint time-frequency analysis can decouple vibration modes, it has a...

Distortion in the ISAR image of a target is a result of nonuniform rotational motion of the target during the imaging period. In many of the measured ISAR images from moving targets, such as those from in-flight aircraft, the distortion can be quite severe. Often, the image integration time is only a few seconds in duration and the target’s rotational displacement is only a few degrees. The con...

Establishing measures for local stationarity is an open problem in the field of time-frequency analysis. One promising theoretical measure, known as the spread, provides a means for quantizing potential correlation between signal elements. In this paper we undertake the issue of generalizing techniques developed by the Authors to better estimate the spread of a signal. Existing techniques estim...

The objective of this paper is to demonstrate the importance of position of the analysis time window in time-frequency analysis of speech signals. Speech signals contain information about the time varying characteristics of the excitation source and the vocal tract system. Resolution in both the temporal and spectral domains is essential for extracting the source and system characteristics from...

This paper proposes time-frequency analysis of EEG spectrum and wavelet analysis in EEG de-noising. In this paper, the basic idea is to use the characteristics of multi-scale multi-resolution, using four different thresholds to wipe off interference and noise after decomposition of the EEG signals. By analyzing the results, understanding the effects of four different methods, it comes to a conc...

This paper describes how a signal can be written as a weighted sum of certain "elementary" synthesizing functions, which are the dilated and translated versions of a single parent function. The weighting constants in this sum define a transform of the signal. This is much like Fourier analysis except that a wide choice is permitted in the selection of a set of synthesizing functions. Moreover, ...

Context. Photometry of Procyon obtained by the MOST satellite in 2004 has been searched for p modes by several groups, with sometimes contradictory interpretations. Aims. We explore two possible factors that complicate the analysis and may lead to erroneous reports of p modes in these data. Methods. Two methods are used to illustrate the role of subtle instrumental effects in the photometry: ti...