Speech enhancement for hearing aids using adaptive beamformers

The author presents two techniques based on adaptive noise canceling to suppress the ambient noise in hearing aids. The first technique uses two microphones and gives very good results in the case of one noise source. If two noise sources are situated at the same side of the head, there is also noise suppression, although less effective than with only one noise source. In the second technique the author creates notches in the directivity pattern of the filter when two uncorrelated noise sources are situated at opposite sides of the head by introducing an adaptive noise canceler using three microphones. The techniques were evaluated in real time using a specially developed board plugged into a personal computer. Preliminary results are presented