نتایج جستجو برای: wavelet transform

تعداد نتایج: 136653  

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...

Journal: :فیزیک زمین و فضا 0
امین روشندل کاهو فرشاد سلاجقه

introduction: wavelet transform is one of the useful and suitable tools for time series and signal analysis. nowadays wavelet transform is frequently used in geophysical data processing and interpretation, especially seismic data. however, the use of this method isn’t widespread in gravity and geomagnetic. fedi and quarta (1998), martelet et al. (2001) and de oliveira lyrio (2004) used the wave...

Power transformers are the most important components of a power system, so their protection is a critical issue. This paper proposes a novel and efficient algorithm based on the high-frequency components of the differential current signal to discriminate between the magnetizing inrush currents and the internal faults. After detecting the over-current in the differential current signals, samples...

Journal: :journal of advances in computer research 0

in this paper a wavelet-based logo watermarking scheme is presented. the logo watermark is embedded into all sub-blocks of the lln sub-band of the transformed host image, using quantization technique. extracted logos from all sub-blocks are merged to make the extracted watermark from distorted watermarked image. knowing the quantization step-size, dimensions of logo and the level of wavelet tra...

Journal: :journal of medical signals and sensors 0

electrocardiogram (ecg) is one of the most common biological signals which plays a significant role in diagnosis of heart diseases. one of the most important parts of ecg signal processing is interpretation of qrs complex and obtaining its characteristics. r wave is one of the most important sections of this complex which has an essential role in diagnosis of heart rhythm irregularities and als...

Journal: :computational methods for differential equations 0
chun-hui hsiao no.101, sec. 2, jhongcheng rd., shihlin district, taipei city 111, taiwan, r.o.c.

this paper presents a rational haar wavelet operational method for solving the inverse laplace transform problemand improves inherent errors from irrational haar wavelet. the approach is thus straightforward, rather simple andsuitable for computer programming. we define that $p$ is the operational matrix for integration of the orthogonalhaar wavelet. simultaneously, simplify the formulaes of li...

Journal: :iranian journal of medical physics 0
ali rastjoo ardakani msc in medical engineering, medical physics and medical engineering dept., faculty of medicine, tehran university of medical sciences, tehran, iran hossein arabalibeik assistant professor, medical physics and medical engineering dept., faculty of medicine, tehran university of medical sciences, tehran, iran

introduction: evoked potentials arisen by stimulating the brain can be utilized as a communication tool  between humans and machines. most brain-computer interface (bci) systems use the p300 component,  which is an evoked potential. in this paper, we evaluate the use of the hidden markov model (hmm) for  detection of p300.  materials and methods: the wavelet transforms, wavelet-enhanced indepen...

Journal: :iranian journal of radiation research 0
p. abdolmaleki department of biophysics, faculty of science, tarbiat modares university, tehran,iran h. abrishami-moghddam m. gity m. mokhtari-dizaji a. mostafa

abstract background: a computer aided diagnosis system was established using the wavelet transform and neural network to differentiate malignant from benign in a   group of patients with histo-pathologically proved breast lesions based on the data derived independ­ently from time-intensity profile.   materials and methods: the per­formance of the artificial neural network (ann) was evaluated us...

2016
Navdeep Goel Gurwinder Singh

The aim of this paper is to examine a set of wavelet functions (wavelets) used in image watermarking system. Several wavelet functions are used to transform the component detail of the image in frequency domain. Discrete wavelet transform (DWT), discrete Fourier transform (DFT) and discrete cosine transform (DCT) are some commonly used transform domain functions out of which discrete wavelet tr...

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