. In the power quality analysis non-stationary nature of voltage distortions require some precise and powerful analytical techniques. The time-frequency representation (TFR) provides a powerful method for identification of the non-stationary of the signals. This paper investigates a comparative study on two techniques for analysis and visualization of voltage distortions with time-varying ampli...

This paper proposes a new method of monitoring and analyzing voltage flicker based on wavelet packet transform and virtual instrument, and establishes an arithmetic model of the system. First, through the wavelet package transform, we can extract the amplitude modulation waveform, get the accurate time when the voltage flicker occurs and stops, and count the frequency and amplitude of voltage f...

Several algorithms are reviewed for computing various types of wavelet transforms: the Mallat algorithm, the “a trous” algorithm and their generalizations by Shensa. The goal is 1) to develop guidelines for implementing discrete and continuous wavelet transforms efficiently, 2) to compare the various algorithms obtained and give an idea of possible gains by providing operation counts. The compu...

The multi-scale Hermitian wavelet order envelope spectrum based bearing fault detection and diagnosis method under run-up condition is presented in this paper. This new approach based on the fusion of the computed order tracking, Hermitian wavelet transform and envelope spectrum is used for detection defects in roller element bearings. Firstly, Non-stationary vibration signal under run-up condi...

The implementation of three noise estimation algorithms using two different signal decomposition methods: a second-generation wavelet transform and a perceptual wavelet packet transform are described in this paper. The algorithms, which do not require the use of a speech activity detector or signal statistics learning histograms, are: a smoothing-based adaptive technique, a minimum variance tra...

It is proposed that a new image enhancement scheme using wavelet transform, smooth and sharp approximation of a piecewise non linear filter technique after converting the RGB (Red, Green, and Blue) values of each pixel of the original image to HSV (Hue, Saturation, and Value). Wavelet transform is then applied to the luminance value of V component, it decomposes the input image into the four su...

A efficient VLSI based architecture is proposed in this paper for implementation Discrete Wavelet Transform (DWT) of 5/3 filter. The proposed architecture includes transforms modules, a RAM and bus interfaces. This architecture works in non separable fashion using a serial-parallel filter with distributed control to compute all the DWT (1D-DWT and 2D-DWT) resolution levels. KeywordsDiscrete Wav...

The wavelet transform is a very popular tool for signal processing and analysis. It is widely used for the analysis of non-stationary, non-periodic and transient signals. The popularity of the wavelet transforms is mainly due to their ability to concentrate the energy of the processed signal into a finite number of coefficients. They are capable of providing the time-frequency localization of t...

This paper describes a technique for noise reduction in synthetic aperture radar interferometry. The noisy interferogram is decomposed using undecimated wavelet transform and the coefficients are weighted. A novel method for computing the weights for each subband, based on an estimate of the relative noise content in them, is presented with a median filter used as the noise estimator. The propo...