نتایج جستجو برای: wavelet transform, non stationary, analog gussian wavelet filter, rms

تعداد نتایج: 1635603  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - پژوهشکده فنی و مهندسی 1390

تبدیل موجک به عنوان ابزار پردازش سیگنال در دوبعد زمان/فرکانس، قادر به استخراج دقیق اطلاعات سیگنال های ناایستا است. این تبدیل در زمینه ی پردازش سیگنال ناایستا، جای خود را به عنوان ابزاری توانمند باز کرده است؛ از این رو امروزه در پردازش سیگنال های بیومدیکال که عموما ناایستا هستند، بسیار مورد توجه و استفاده قرار گرفته است، و اطلاعات دقیق و جامع حاصل از آن، در تشخیص و درمان بسیاری از بیماری ها مورد...

Journal: :journal of advances in computer research 2010
s.m. anisheh

in analyzing a signal, especially a non-stationary signal, it is often necessarythe desired signal to be segmented into small epochs. segmentation can beperformed by splitting the signal at time instances where signal amplitude orfrequency change. in this paper, the signal is initially decomposed into signals withdifferent frequency bands using wavelet transform. then, fractal dimension of thed...

Extended Abstract. Forecasting is one of the most important purposes of time series analysis. For many years, classical methods were used for this aim. But these methods do not give good performance results for real time series due to non-linearity and non-stationarity of these data sets. On one hand, most of real world time series data display a time-varying second order structure. On th...

2011
D. U. Shah C. H. Vithlani

Recently the Wavelet Transform has gained a lot of popularity in the field of signal and image processing. This is due to its capability of providing both time and frequency information simultaneously, hence giving a timefrequency representation of the signal. The traditional Fourier Transform can only provide spectral information about a signal. Moreover, the Fourier method only works for stat...

2012
Ana SOVIĆ Damir SERŠIĆ

Besides many advantages of wavelet transform, it has several drawbacks, e.g. ringing, shift variance, aliasing and lack of directionality. Some of them can be eliminated by using wavelet packet transform, stationary wavelet transform, complex wavelet transform, adaptive directional lifting-based wavelet transform, or adaptive wavelet filter banks that use either L2 or L1 norm. This paper contai...

2014
Jin ZHANG Chang-Cheng SHI Ying-Xuan LI Hong-Liang CUI

Fourier transform is applied to detect the direction of stripe noise before de-noising, which is advantageous for selecting the corresponding detail coefficients for threshold quantization after stationary wavelet transform. Depending on the direction of stripe noise, the corresponding detail coefficients contain stripe noise need to be removed, while retaining the approximate coefficients and ...

2013
Jeena Joy Neetha John

This paper presents a comparative study of different wavelet denoising techniques and the results obtained were examined. The denoising process rejects noise by thresholding in the wavelet domain. It is observed that „rigrsure„ method gives optimum performance. Discrete wavelet transform has the benefit of giving a joint timefrequency representation of the signal. Also it is suitable for both s...

H. Saeedi, M. Modarres-Hashemi and S. Sadri,

With progress in radar systems, a number of methods have been developed for signal processing and detection in radars. A number of modern radar signal processing methods use time-frequency transforms, especially the wavelet transform (WT) which is a well-known linear transform. The interference canceling is one of the most important applications of the wavelet transform. In Ad-hoc detection met...

2013
VIOREL APETREI CONSTANTIN FILOTE CALIN CIUFUDEAN

The process of calculating the effective values of voltage and current root mean square (RMS) using Fourier transform (FT) suffers a high computational effort. Since it provides only an amplitude-frequency spectrum, looses time-related information, and is unable to deal with no stationary waveforms, standard definitions are reformulated in the time-frequency domain using the wavelet transform (...

H. Saeedi, M. Modarres-Hashemi and S. Sadri,

With progress in radar systems, a number of methods have been developed for signal processing and detection in radars. A number of modern radar signal processing methods use time-frequency transforms, especially the wavelet transform (WT) which is a well-known linear transform. The interference canceling is one of the most important applications of the wavelet transform. In Ad-hoc detection met...

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