SPEECH ENHANCEMENT USING ARRAY SIGNAL-PROCESSING BASED ON THE COHERENT-SUBSPACE METHOD

A method for recovering the LPC spectrum from a microphone array input signal corrupted by less directional ambient noise is proposed. This method is based on the subspace method, in which directional signal an d non-directional noise is classified in the subspace domain using eig envalue analysis of the spatial correlation matrix. In this paper, the coherent subspace (CSS) method, a broadband extension of the subspace method, is employed. The advantage of this method is that it requires a much smaller number of averages in the time domain for estimating s ubspace, suitable feature for frame processing such as speech recognit ion. To enhance the performance of noise reduction, elimination of noi se-dominant subspace using projection is further proposed, which is ef fective when the SNR is low and classification of noise and signals us ing eigenvalue analysis is difficult.