Modern communication devices, such as mobile phones, teleconferencing
systems, VoIP, etc., are often used in noisy and reverberant
environments. Therefore, signals picked up by the microphones from
telecommunication devices contain not only the desired near-end speech
signal, but also interferences such as the background noise, far-end
echoes produced by the loudspeaker, and reverberations of the desired
source. These interferences degrade the fidelity and intelligibility of
the near-end speech in human-to-human telecommunications and decrease
the performance of human-to-machine interfaces (i.e., automatic speech
recognition systems).
The proposed book deals with the fundamental challenges of speech
processing in modern communication, including speech enhancement,
interference suppression, acoustic echo cancellation, relative transfer
function identification, source localization, dereverberation, and
beamforming in reverberant environments.
Enhancement of speech signals is necessary whenever the source signal is
corrupted by noise. In highly non-stationary noise environments, noise
transients, and interferences may be extremely annoying. Acoustic echo
cancellation is used to eliminate the acoustic coupling between the
loudspeaker and the microphone of a communication device. Identification
of the relative transfer function between sensors in response to a
desired speech signal enables to derive a reference noise signal for
suppressing directional or coherent noise sources. Source localization,
dereverberation, and beamforming in reverberant environments further
enable to increase the intelligibility of the near-end speech signal.
