Speech enhancement using fourth-order cumulants and time-domain optimal filters

A new method for speech enhancement based on optimal filtering, subbands, and higher-order cumulants is proposed in this paper. The key idea is to use the 4th cumulant to estimate the parameters required for the enhancement filters: It is shown that the kurtosis of noisy speech may be used to estimate the SNR and the probability of speech presence when speech is divided in narrow bands and modeled as a sinusoidal signal. The resulting algorithm is tested in typical mobile noise conditions and proves effective under such types as street, office and fan noises. Compared to the TIA IS-127 standard for noise reduction, the proposed algorithm is better at preserving the harmonic structure of the speech and results in overall more noise reduction in Gaussian-like conditions. However, this comes at the cost of slightly more noise artifact, mostly at very low SNR and non-Gaussian conditions.