Evaluation of In-Car Communication Systems - Digital Signal Processing for In-Vehicle Systems and Safety - page 101

of these subjective methods have been suggested for describing the quality
improvement or degradation for the listening passenger. Similar evaluations can
be carried out for the talking passenger.
Since subjective tests are rather time-consuming, the aim is to develop an
automatic system evaluation based on objective criteria. Examples for these
measures are the SNR and the STI, which also proved to be capable of reproducing
the results of some of the subjective tests. However, in some cases, it is difficult to
find appropriate indicators, e.g. for judging on localization effects. An approach for
the design of an automatic evaluation scheme has been presented by pointing out
which questions should be answered by such a system. Even though some mean-
ingful objective measures have been found, further research in this particular field is
necessary to obtain more indicators that are correlated to the auditory perception of
humans.
Since ICC systems are starting to enter the market, the demand for
standardization of quality evaluation procedures arises. Evaluation systems could
not only help to compare different ICC systems but also assist during the design and
parameterization process.
References
1. Cifani S, Montesi LC, Rotili R, Principi E, Squartini S, Piazza F (2009) A PEM based
algorithm for acoustic feedback control in automotive speech reinforcement systems.
In: Proceedings of ISPA 2009, Chengdu, China, pp 656-661
2. Freudenberger J, Pittermann J (2008) Noise and feedback suppression for in-car communica-
tion systems. ITG Fachtagung Sprachkommunikation, Aachen
3. Haulick T, Schmidt G (2006) Signal processing for in-car communication systems. Signal
Process 86(6):1307-1326
4. Ortega A, Lleida E, Masgrau E (2001) Acoustic echo control and noise reduction for cabin car
communication. Proc EUROSPEECH 2001 3:1585-1588
5. Ortega Gimenez A, Lleida Solano E, Masgrau G ´ mez EJ, Buera Rodr ´ guez L, Miguel Artiaga
A (2006) Acoustic echo reduction in a two-channel speech reinforcement system for vehicles.
In: Abut H, Hansen JHL, Takeda K (eds) Digital signal processing for in-vehicle and mobile
systems 2. Springer, New York
6. Schmidt G, Haulick T (2006) Signal processing for in-car communication systems. In: Hansler
E, Schmidt G (eds) Topics in acoustic echo and noise control. Springer, Berlin, pp 553-605
7. Haulick T, Schmidt G, Wolf A (2009) Evaluation of in-car communication systems.
In: Proceedings of DSP workshop for in-vehicle systems and safety, Dallas, USA
8. Kuttruff H (2000) Room acoustics, 4th edn. Spon Press, London
9. Lombard E (1911) Le signe de l'elevation de la voix. Ann Maladies Oreille, Larynx, Nez
Pharynx 37:101-119, In French
10. Hanson JHL (1994) Morphological constrained feature enhancement With adaptive cepstral
compensation (MCE-ACC) for speech recognition in noise and lombard effect. IEEE Trans
Speech Audio Process T-SA-2(4):598-614
11. Haas H (1972) The influence of a single echo on the audibility of speech. J Audio Eng
Soc 20:145-159