نتایج جستجو برای: wavelet

تعداد نتایج: 38198  

2011
Yong-hong He Peng-wei Jin

With wavelet technology used more widely in deformation analysis, the paper will talk multi-wavelet (the second generation wavelet) theory used for deformation monitoring data analysis. The paper studies signal adopting different preprocessing method, makes a study of the selection problem in optima multi-wavelet preprocessing method. The deformation monitoring signal is disposed using differen...

2000
I. De Moortel

The usefulness of wavelet analysis is demonstrated by considering analytical expressions for phase mixed Alfvén waves in different physical circumstances. The wavelet analysis is briefly introduced, using the complex-valued Morlet wavelet, consisting of a plane wave modulated by a Gaussian, as the basic wavelet. The time and scale resolution of the wavelet transform are then discussed in more d...

2011
Priyanka Singh Priti Singh Rakesh Kumar Sharma

The objective of this paper is to evaluate a set of wavelets for image compression. Image compression using wavelet transforms results in an improved compression ratio. Wavelet transformation is the technique that provides both spatial and frequency domain information. These properties of wavelet transform greatly help in identification and selection of significant and non-significant coefficie...

2013
Tanuja Sarode Prachi Natu

In this paper, image compression using orthogonal wavelet transforms of Walsh, Cosine, Haar, Kekre, Slant and Sine is studied. Wavelet transform of size N 2 xN 2 is generated using its corresponding orthogonal transform of size NxN. These wavelet transforms are applied on R, G, and B planes of 256x256x3 size colour images separately. In each transformed plane rows/columns are sorted in their de...

2007
Ivan W. Selesnick

transforms to compress digitally scanned fingerprints. NASA’s Mars rovers use them to compress images acquired by their 18 cameras. The new JPEG 2000 format is based on wavelet transforms; the smaller files allow one to store images using less memory and to transmit those images faster and more reliably. Researchers also use wavelet transforms to clean signals and images—that is, to reduce unwa...

2003
Jong C. Ye Mihaela van der Schaar

ABSTRACT In this paper, we present a fully scalable 3-D overcomplete wavelet video coder that employs a new and highly efficient 3D lifting structure for adaptive motion compensated temporal filtering (MCTF). Unlike the conventional interframe wavelet video techniques that apply MCTF on the spatial domain video data and then encode the resulting temporally filtered frames using critical sampled...

2010
Arun Dixit Poonam Sharma

Image denoising using wavelet transform has been successful as wavelet transform generates a large number of small coefficients and a small number of large coefficients. Basic denoising algorithm that using the wavelet transform consists of three steps – first computing the wavelet transform of the noisy image, thresholding is performed on the detail coefficients in order to remove noise and fi...

2002
Felix Abramovich Panagiotis Besbeas Theofanis Sapatinas

Wavelet methods have demonstrated considerable success in function estimation through term-by-term thresholding of the empirical wavelet coefficients. However, it has been shown that grouping the empirical wavelet coefficients into blocks and making simultaneous threshold decisions about all the coefficients in each block has a number of advantages over term-by-term wavelet thresholding, includ...

2016
Zitong Zhang Qawi K. Telesford Chad Giusti Kelvin O. Lim Danielle S. Bassett

Wavelet methods are widely used to decompose fMRI, EEG, or MEG signals into time series representing neurophysiological activity in fixed frequency bands. Using these time series, one can estimate frequency-band specific functional connectivity between sensors or regions of interest, and thereby construct functional brain networks that can be examined from a graph theoretic perspective. Despite...

2009
BIN HAN

In this paper, we study nonhomogeneous wavelet systems which have close relations to the fast wavelet transform and homogeneous wavelet systems. We introduce and characterize a pair of frequency-based nonhomogeneous dual wavelet frames in the distribution space; the proposed notion enables us to completely separate the perfect reconstruction property of a wavelet system from its stability prope...

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