A restricted impact noise suppressor in zero phase domain

This paper proposes an impact noise suppression method in zero phase (ZP) domain. The signal in ZP domain (ZP signal) is obtained by taking IDFT of the pth power of a spectral amplitude. We previously proposed an impact noise suppressor in ZP domain for reducing impact noise signals, even if they are accompanied with damped oscillation. Unfortunately, the previous method causes speech degradation in non-impact noise segments, because this method performs noise reduction in all the segments. Since an impact noise exists only a short duration, we restrict the noise suppression procedure so that it cannot be applied to the non-impact noise segments. The restriction is achieved by using the ratio of the first to the second peak values of the ZP signal. In non-impact noise segments, this ratio becomes much larger than one. Thus, we can improve speech quality of the extracted signal when the restriction works well. Simulation results show that the proposed method improves about 15dB of SNR for a speech signal mixed with clap noise with SNR= 0dB.