Abstract:
Since time precision in finding delays between channels is one of the most important issues in estimating direction of arrival (DOA) from multichannel signals, a zero-crossing analysis is proposed as a fine and robust time-domain preprocessing for the DOA finding. As for the preliminary evaluation of noise robustness using zero-crossing information, how the zero-crossing points are affected is investigated, i.e., how far the zero-crossing points move from the original points, under the presence of noise. For test speech, a 48-kHz sampling of a male voice (upsampled from an 8-kHz signal) is used after an adding machine generated white noise so that the SNR of the signal becomes 0 to 20 dB. The robustness of the zero-crossing analysis can be concluded from the summarized results: (1) the mean value of the distance is less than 100 (mu)s throughout the SNR; and (2) the standard deviation of the distribution becomes large as the SNR decreases; the standard deviation is less than 0.125 even under the condition of 0 dB SNR.