Anne Theiß: Instrumentelle Evaluierung von Innenraum-Kommunikationssystemen

Pdf-based submission (available freely via the MACAU system), 2017



  • Prof. Dr.-Ing. Gerhard Schmidt
    (first reviewer)
  • Prof. Dr.-Ing. Sebastian Möller
    (second reviewer)
  • Prof. Dr.-Ing. habil. Ludger Klinkenbusch
  • Prof. Dr.-Ing. Jeffrey McCord
    (head of the examination board)



The communication between the occupants of a speeding vehicle can be impaired. In particular, the conversation between the passengers of the front row and those of the rear seats is due to the occuring background noise and the arrangement of the passengers difficult. Usually the passengers change their position and their voice in order to compensate for this impairment. Another method to improve the communication situation is a so-called in-car communication system (ICC system). Such systems take the speech signal of a talking person using the already installed microphones, process and play back the amplified desired signal inside the passenger compartment through the loudspeakers nearby the listening passengers. Thus, the power of the desired signal inside the compartment increases as well as the intelligibility.

Following the successful implementation and development of such systems, the question arises to the quality of the ICC system. To answer this question, in this work, first, the term ”quality” referring to an ICC system is defined. Subsequently, an evaluation strategy, which consists of a variety of individual instrumental methods, is presented. For a plausible classification of the methods and a transparent investigation of the overall quality, these methods are divided into three different evaluation groups. These evaluation groups examine the characteristics of the vehicle, the behavior of the ICC system itself, as well as the quality of the communication. Within each of these groups first instrumental methods are described and validated. Subsequently, the individual results of the instrumental methods are weighted by previously calculated attributes and combined into an overall result. The attributes of the vehicle and the ICC system are determined based on the determined characteristics of the vehicle. For the development of the instrumental methods a quality reference which reflects the subjective perception of passengers is required. For this purpose, some auditory evaluation methods are introduced in addition to the instrumental methods and the results analyzed. Therefore, not only listening tests, but also psychoacoustic perception experiments have been carried out and analyzed. The evaluation strategy implemented into a real-time framework is finally tested on a specific ICC system and an overall view of the quality of all its results is proposed.

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Prof. Dr.-Ing. Gerhard Schmidt


Christian-Albrechts-Universität zu Kiel
Faculty of Engineering
Institute for Electrical Engineering and Information Engineering
Digital Signal Processing and System Theory

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24143 Kiel, Germany

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