  Beamforming is a signal processing technique. It has been studied in many
areas such as radar, sonar, seismology and wireless communications, to name but
a few. It can be used for a myriad of purposes, such as detecting the presence
of a signal, estimating the direction of arrival, and enhancing a desired
signal from its measurements corrupted by noise, competing sources and
reverberation. Actually, Beamforming has been adopted by the audio research
society, mostly to separate or extract speech for noisy environment.
Beamforming techniques basically approach the problem from a spatial point of
view. A microphone array is used to form a spatial filter which can extract a
signal from a specific direction and reduce the contamination of signals from
other directions. In this paper we survey some Beamforming techniques used for
multichannel audio signal separation.
