In this paper, it is shown that the higher compression performance of biorthogonal wavelet filters over orthogonal wavelet filters is the combined effect from (1) the asymmetry of the frequency responses of the biorthogonal wavelet filters and (2) the non-flat spectra of the signals to be decomposed. Based upon this observation, an improved wavelet packet decomposition method for natural images...

Cognitive LTE system, such as LTE-U, has received tremendous interest from almost all research disciplines in wireless communications. In Cognitive LTE systems, spectrum sensing is the key enabling technology to realize dynamic spectrum access. In this paper, an error decision probability is proposed to solve the trade-off problem between detection and false alarm probability with the constrain...

In this paper we describe the implementation, use and applications of WaveThresh, a real time Fourier\wavelet spectral expander. Expansion and reverse-expansion of spectral components is offered. In order that analysis methods can be better adapted to the signal we offer a combined wavelet\Fourier mode. This mode separates sinusoids from the rest of the signal (residual) and applies Fourier ana...

The wavelet de-noising technique with wavelet based function has been used in this paper for bearing fault detection. The applications of the wavelet de-noising show that the fault pulses in time-domain of the de-noised signals are easily to be detected as a result of removing the covering noise, which is not possible through the time-domain analysis of the original signal. Furthermore, the rec...

In this article, the continuous wavelet transform is introduced as a signal processing tool for investigating time-varying frequency spectrum characteristics of nonstationary signals. The transform is discussed within the context of Fourier methods and the general problem of time-frequency representation and is compared with the more traditional Gabor method of windowed Fourier transforms. To t...

We discuss wavelet filter parametrization as a means to add security to wavelet based watermarking schemes. It turns out that our proposed scheme is resistant to unauthorized detection and unauthorized removal attacks and is equally robust as compared to the use of standard wavelet filters in case the underlying watermarking scheme is spread-spectrum based. Quantization-based watermarking techn...