Estimation of the Number of Signal Sources in Compound Signals Using Activity Index Variance

This work addresses the problem of estimating the number of signal sources in convolutive signal mixtures. Our approach is based on the blind source separation. The first step builds a measure of the global activity of all active sources. This measure is known as activity index, and is based on the inverse of correlation matrix of the observed signals. The next step analyses the activity index variance. Our experiments have shown that the number of sources can be estimated from the activity index variance. A set of multi-channel synthetic signal mixtures with different number of active sources was generated for the evaluation. The preliminary results using synthetic signals show that our approach is robust and effectively estimates the number of signal sources.