In this paper, we present an algorithm for seismic source wavelet estimation that is based on seismic time frequency spectral decomposition with matching pursuit technique. The main assumption of this algorithm is that the source wavelet is stationary for single wavelet estimation in a selected time window and that the source wavelet has normalized energy to avoid scale ambiguity between reflec...

We present a general framework for the design of a mother wavelet best adapted to a specific signal or to a class of signals. The filter’s coefficients are obtained via optimization of a smooth objective function. We develop an unconstrained gradient-based optimization algorithm for a discrete wavelet transform. The algorithm is extended to the joint optimization of the mother wavelet and of th...

The aim of this paper is to study wavelet frame packets in which there are many frames. It is a generalization of wavelet packets. We derive few results on wavelet frame packets and have obtained the corresponding frame bounds.

In wavelet-based image coding the choice of wavelets is crucial and determines the coding performance. Current techniques use computationally intensive search procedures to find the optimal basis (type, order and tree). In this paper, we show that searching for optimal wavelet does not always offer a substantial improvement in coding performance over "good" standard wavelets. We propose some gu...

The proposed contribution describes a method for the detection and classification of harmonic transients, as they occur in electrical networks. The method uses, as bases, a special class of wavelet-packets, i. e. smooth biorthogonal sine and cosine-packets in order to find the best ’’Shannon-basis“. The algorithm is based on the minimization of Shannon‘s function for the decomposed wanted signa...

An adaptive multilevel wavelet collocation method for solving multi-dimensional elliptic problems with localized structures is described. The method is based on multi-dimensional second generation wavelets, and is an extension of the dynamically adaptive second generation wavelet collocation method for evolution problems [Int. J. Comp. Fluid Dyn. 17 (2003) 151]. Wavelet decomposition is used fo...

The spectral distribution of energy varies between normal ECGs and those from patients post infarct or with ventricular hypertrophies. This suggests that discriminating between normal and abnormal conditions may be possible on the basis of differences in the distribution of spectral energy. We compare a reduced Discrete Wavelet Transform characterisation of an ECG QRS complex using three differ...

This paper presents a new approach for human cataract automatical detection based on ultrasound signal processing. Two signal decomposition techniques, empirical mode decomposition and discrete wavelet transform are used in the presented method. Performance comparison of these two decomposition methods when applied to this specific ultrasound signal is given. Described method includes ultrasoni...

Accuracy and efficiency are two important issues in designing content-based image retrieval system. In this paper we present an approach on a wavelet transform called tree-structured transform or wavelet packets for texture analysis. A simple texture classification algorithm having excellent performance for dominant channels decomposition tree structured is proposed here. The performance of our...

The rapid expansion of the Internet and the wide use of digital data have increased the need for both efficient image database creation and retrieval procedure. The challenge in image retrieval is to develop methods that can capture the important characteristics of an image, which makes it unique, and allow its accurate identification. The focus of this paper is on the image processing aspects ...