| The Fully Networked Car, A Workshop on ICT in Vehicles |
A B S T R A C T |
|
| Speaker: |
Dr. Tim Haulick
TEMIC-SDS GmbH |
| Session 7-II: |
In-Vehicle devices and Human Machine Interface (including Voice Interface) |
| Session Moderator: |
Jean-Yves Monfort, Chairman of ITU-T Study Group 12,France Telecom & Jean-Pierre Cheynet, Chairman of ISOTC-22 "Road vehicles", Bureau de Normalisation de l'Automobile |
| Title of Presentation: |
Speech Enhancement Methods for Vehicle Applications |
|
Since several years hands-free telephony and speech dialog systems have been increasingly used in vehicles. Due to the high background noise, effective speech enhancement methods are needed to ensure speech quality and robust speech recognition, respectively. One suitable method is the so-called beamforming which exploits the different spatial distribution of speech and noise making use of a microphone array.
However, not only the communication with a far end subscriber or with a speech dialog system is impaired by the driving noise, but also the communication between the passengers within the vehicle. Especially the communication path from the front passengers to the passengers sitting on the rear seats is often highly impaired even at moderate speed. In consequence, the passengers have to speak louder than normal, which makes longer conversations very tiring and - if the driver turns around - even road safety is endangered. The communication between the passengers can be improved by means of a car intercom system. In a car intercom the speech signal of each passenger is picked up by one or more hands-free microphones. The speech signal is then played back over those loudspeakers which are located near the listeners. Due to the closed loop operation of such a system, an appropriate signal processing is required to ensure stable operation.
Another application of speech enhancement in vehicles is the improvement of the downlink signal of the telephone by bandwidth extension. Due to the limited frequency range of the telephone network, the quality of the received speech signal is often perceived as insufficient, especially in comparison with other audio sources such as radio or CD. The basic idea of bandwidth extension is to improve the downlink signal of the telephone by restoring missing frequency components from the received speech signal. Even though the speech quality of the extended signal is not as good as the original wideband speech, a significant improvement is possible.
The presentation will give an overview of state-of-the-art speech enhancement methods in the vehicle environment by means of practical applications and audio examples.
|
|
|
|
|
