منابع مشابه
Time-varying lapped transforms and wavelet packets
The perfect reconstruction conditions for a timevarying lapped transform (paraunitary filter bank) are developed through the factorization of the transform matrix into sparse factors. A general formulation is presented allowing one to switch between two paraunitary filter banks. However, the extended lapped transform (ELT) is often used as an example. Furthermore, an adaptive wavelet packet is ...
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It is well-known that every two dimensional rotation around the origin in the plane R can be represented by the multiplication of the complex number e = cos θ + i sin θ, 0 ≤ θ < 2π. Similarly, every three dimensional rotation in the space R can be represented by the multiplications of the quaternion q from the left-hand side and its conjugate q̄ from the right-hand side, where q = cos(θ/2) + α s...
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A new method to secure speech communication using the discrete wavelet transforms (DWT) and the fast Fourier transform is presented in this article. In the first phase of the hiding technique, we separate the speech high-frequency components from the low-frequency components using the DWT. In a second phase, we exploit the low-pass spectral proprieties of the speech spectrum to hide another sec...
متن کاملAdaptive transforms for image coding using spatially varying wavelet packets
We introduce a novel, adaptive image representation using spatially varying wavelet packets (WPs), Our adaptive representation uses the fast double-tree algorithm introduced previously (Herley et al., 1993) to optimize an operational rate-distortion (R-D) cost function, as is appropriate for the lossy image compression framework. This involves jointly determining which filter bank tree (WP freq...
متن کاملOn adaptive wavelet packets
An algorithm is presented for fast implementation of time-varying wavelet packets maintaining perfect reconstruction throughout transitions. It is based on filter banks known as the extended lapped transforms in an association following the paths of a binary-tree. Methods for pruning or expanding the branches of the tree are presented and a discussion on adaptation issues is carried. Recently, ...
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ژورنال
عنوان ژورنال: Zeitschrift für Analysis und ihre Anwendungen
سال: 2001
ISSN: 0232-2064
DOI: 10.4171/zaa/1032