Multichannel noise reduction wiener filter in the Karhunen-Loève expansion domain

This paper explores the noise reduction problem in the Karhunen-Loève expansion (KLE) domain from a multichannel perspective. Based on formulations proposed for the design of optimal single-channel noise reduction in the KLE domain, we formulate the multichannel noise reduction in the KLE domain. Two different performance measures are presented: the noise reduction and speech distortion. The optimal multichannel Wiener filter is derived and its performance in terms of noise reduction and speech distortion is compared with the performance of the optimal single-channel Wiener filter. Experimental results show that a significant improvement in performance is obtained when using multiple microphone signals. The multichannel Wiener filter results also in better noise reduction in the presence of coherent noise sources.