Abstract: A single channel speech enhancement method for noisy speech signals is proposed based on the subspace method. Conditional subspace based enhancement methods require that the noise covariance matrix is full-ranked. Unfortunately this is not satisfied in case of narrowband noise or tonal noise. The proposed method directly deals with rank-deficient noise using a subspace whitening method. Experimental results demonstrate the effectiveness of the proposed algorithms.

Key words: speech enhancement, subspace, rank-deficient