The effect of reverberation on a new binaural noise cancellation algorithm for hearing aids
Marc Goueygou, Michael E. Lockwood, Mark E. Elledge, Robert C. Bilger, Douglas L. Jones, Charissa R. Lansing, Chen Liu, William D. O’Brien, Bruce C. Wheeler · The Journal of the Acoustical Society of America · 1999
A new algorithm was developed to emulate the ‘‘cocktail party effect’’ in hearing aids [Liu et al., ASA Symposium (1997)]. Speech signals are received binaurally; the interferers and the desired source are localized; and the signal from the strongest interferer is cancelled by frequency and time selective beamforming. Here we evaluate the algorithm’s performance in real conditions including reverberation. Binaural recordings of speech uttered simultaneously by three different speakers around the receivers were made in three different rooms (an anechoic room, a mildly and a highly reverberant room). Noise cancellation was evaluated by the intelligibility weighted SNR (IWSNR) gain between processed and unprocessed signals [Link and Buckley, J. Acoust. Soc. Am. 91]. Algorithm performance is severely degraded as the reverberation time increases: the IWSNR gain falls from 8–9 dB in the anechoic room to 1–2 dB in the highly reverberant room. Also, knowing of the exact location of the sources does not add significant improvement. The results suggest that the room impulse response be deconvolved from the received signals to suppress the multiple reflections of sound. We suggest a new strategy combining noise cancellation with blind identification of the room impulse response. [Research supported by the Beckman Institute.]