Analysis of two-sensors forward BSS structure with post-filters in the presence of coherent and incoherent noise

• We propose a post-filter technique analysis on the presence of coherent noise.
• New criteria are proposed to quantify the post-filter behaviour in noisy condition.
• The new first proposed parameter is the speech to coherent noise ratio (SCR).
• The second proposed parameter is the coherent to diffuse noise ratio (CDR).
• A perfect agreement between the proposed theory and the experimentation is shown.

We consider the speech enhancement problem in a moving car through a blind source separation BSS scheme involving two sensors. To correct the distortion brought by this structure we have proposed in previous work (Djendi et al., 2007) two frequency-domain methods to compute the post-filters placed at the output of the forward BSS structure (FBSS). In this work, we consider the case where the noises at the sensor inputs contain coherent and non-coherent components. We provide an analysis of the performance (output SNR and the distortion criterion) of the FBSS structure with post-filters as a function of two new parameters: the coherent to diffuse ratio (CDR) and the speech to coherent ratio (SCR). Simulation results show perfect agreement between theoretical and experimental results.