10 Spectral Distance Analysis for Quality Estimation of In-Car Communication Systems
Anne Theiß, Anton Namenas, Tobias Hübschen, Gerhard Schmidt · 2020
The communication inside a vehicle can be impaired by background noise while driving at medium or higher velocities and by the unusual orientation of the passengers as they are not facing each other. As a consequence, the passengers often start to raise their voices and to change their positions by leaning forward or, in case of the front passengers, turning backwards to improve this situation. These adaptations to the communication situation may be uncomfortable, exhausting, and might result in an increased risk for accidents if the driver turns around (and does not look on the street). An in-car communication system (ICC system) can improve the communication by recording the speech signals and reproducing the enhanced signals over the loudspeakers inside the compartment, which are close to the listening passengers. After and during the design and the development of such systems, the achieved quality is of great interest. Therefore, a spectral distance approach is presented in this chapter. Even if spectral distance measures are well established and often used for quality evaluation in speech communication systems, we face here a special challenge, which is the creation of an appropriate reference signal. In addition, an investigation of the reliability of the proposed quality estimate by means of a subjective listening test was performed and the results are presented.