Arrays in Motion - Localization Techniques for Compensation of Relative Motion between Microphone Arrays and Sources 2013-01-1966
With the exact knowledge of the current positions of the microphones in an array and the potential noise sources, it is possible to compensate a relative motion between them. In the past, techniques exploiting this knowledge have been used successfully, e.g., for the measurement of wind turbines and airplane flyover measurement. In this paper, these ideas are applied and modified for the development of a traffic flow observation system.
The main purpose of a vehicle pass by measurement is to extract the continuous noise levels of the dominant sources. With the use of advanced video processing or additional sensor information (radar, light barrier) it is possible to create a continuous tracking model of the vehicle. The scan grid in the beam forming algorithm is then recalculated to compensate the movement. In the resulting acoustic video, the vehicle is fixed and the evolution of the sound sources can be observed and auralized for psychoacoustic evaluations.
To characterize the acoustic emissions of a vehicle passing by a large number of single measurements under various running conditions have to be made. Thereby it is often not possible to acquire the exact same set of running conditions for different tire/road combinations. With the technique called Acoustical Fingerprint the whole set of measurements is synthesized and interpolated leading to a single level function that can then directly be evaluated and compared