نتایج جستجو برای: wavelet transform and s
تعداد نتایج: 16932503 فیلتر نتایج به سال:
this paper illustrates the application of s-transform and continuous wavelet transform (cwt) for fault location in combined overhead line and cable distribution networks. the high frequency transient signals originated by faults are analyzed using s-transform and cwt. the s-transform is found to be applicable in transient based fault location in distribution networks. this technique is an expan...
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...
this paper presents a new coding method for image compression based on jpeg2000 and contourlet transform. jpeg2000 standard is a common standard that uses discrete wavelet transform (dwt) in the compression process. the main problems of dwt are failure to detect curved edges in image and its shortage representation of the ridge and furrow patterns which cause deficiency and block artifacts rema...
introduction in recent years methods based on radio frequency waves have been used for detecting breast cancer. using theses waves leads to better results in early detection of breast cancer comparing with conventional mammography which has been used during several years. materials and methods in this paper, a new method is introduced for detection of backscattered signals which are received by...
in this paper, we present an edge detection method based on wavelet transform and hessian matrix of image at each pixel. many methods which based on wavelet transform, use wavelet transform to approximate the gradient of image and detect edges by searching the modulus maximum of gradient vectors. in our scheme, we use wavelet transform to approximate hessian matrix of image at each pixel, too. ...
Wavelet transformation is one of the most practical mathematical transformations in the field of image processing, especially image and signal processing. Depending on the nature of the multiresolution analysis, Wavelet transformation become more accessible and powerful tools. In this paper, we refer to the mathematical foundations of this transformation. Introduction: The...
The main objective of this paper is to study the composition continuous Kontorovich-Lebedev wavelet transform (KL-wavelet transform) and wave packet (WPT) based on (KL-transform). Estimates for KL-wavelet are obtained, Plancherel?s relation WPT-transform derived. Reconstruction formula WPT associated KL-transform also deduced at end Calderon?s related using its convolution property obtained.
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...
In this research wavelet coherence measure is implemented for evaluating the relations and effect of rainfall parameters over many years on runoff fluctuations that is for testing proposed linkages between two time series. In this way, monthly Hydro climatological as 3 rainfall stations, one runoff in the outlet of Ardabil plain were used. The results illustrate that 8-12 and 8-16 month modes o...
In 1983 L. G. Brown introduced a spectral distribution measure for non-normal elements in a nite von Neumann algebra M with respect to a xed normal faithful tracial state. In this paper we compute Brown's spectral distribution measure in case T has a polar decomposition T = UH where U is a Haar unitary and U and H are-free. (When Ker T = f0g this is equivalent to that (T; T) is an R-diagonal pa...
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