Subjective and objective quality assessment of noise reduced speech signals

Summary form only given. Recently, hands-free speech communication is becoming increasingly necessary for teleconferences, in-car telephones, and PC-based IP telephony. Since speech signals acquired by a distant microphone are generally corrupted by ambient noise, noise reduction is indispensable for ensuring speech quality. To investigate the effect of noise reduction on speech quality, the subjective quality assessment of noisy speech signals and noise reduced speech signals was performed. This result confirmed that the difference of noise types gives little effect on the subjective quality and the subjective quality is more sensitive to the speech distortion than the residual noise. This paper also investigated the applicability of the PESQ to the objective quality assessment of noise reduction algorithms. The experimental result showed that the objective quality correlates well with the subjective quality. However, there was the case that the objective quality is lower than the subjective quality in the specific noise reduction algorithms.