An Acoustical Imaging Processing for the Localization of Acoustic Sources inside a Vehicle: Method and Results for Tests on Road

The localization of acoustic sources inside a moving vehicle presents at least two main difficulties. The zone to be explored may be important (such as a door, a window, the toe board): the use of a sound intensity probe may take an expensive time for the context of a moving car. The other difficulty is the presence of a background noise, increasing with the car speed. These two difficulties may be overcome by the use of a robust acoustical imaging method, but the utilization of the system requires a few precautions for the implementation and for the interpretation of the acoustic images. The purpose of this paper is to present the chosen acoustical imaging processing, based on the beamforming method, and the procedure for the set-up and tests. This processing and the procedure are applied for experimental tests on the road and for different configurations: constant and decelerating speed. Acoustic images are presented for the case of sources on a passenger door. To improve the interpretation of the results, acoustic images are obtained for different tape configurations. This study shows a good robustness of the system and reliable results. In addition, the use of beamforming processing allows a reduced time for the set-up and for the measurements.