Blindly mixing matrix estimation of speech source signals using short time-wavelet packet analysis by Laplacian model in over-complete cases

Wavelet packets decompose signals in to broader components using linear spectral bisecting. Mixing matrix is the key issue in the Blind Source Separation (BSS) literature especially in under-determined cases. In this paper, we propose a simple and novel method in short time wavelet packet analysis to estimate blindly the mixing matrix of speech signals from noise free linear mixtures in over-complete cases. In this paper, the Laplacian model is considered in short time-wavelet packets and is applied to each histogram of packets. Expectation Maximization (EM) algorithm is used to train the model and calculate the model parameters. It is shown that complexity of computation of model is decreased and consequently the speed of convergence is increased.