Noise source identification in transportation systems in Brazil using beamforming technique

• Published in: The Journal of the Acoustical Society of America Vol. 126; no. 4_Supplement; p. 2279
• Main Authors: Gerges, Samir, Fonseca, William, Bento Coelho, Jose, M. Neves, Miguel
• Format: Journal Article
• Language: English
• Published: 01-10-2009
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.3249340

Beamforming with acoustic phased arrays has become a popular technique for locating and quantifying noise sources in complex system such as environmental noise, aircraft noise, internal and external automobile noise, beside other applications. The signal processing performs traditional delay-and-sum beamforming and accounting for the different propagation paths from the source and to the different microphones. The sources may pass the acoustic camera with high speeds, allowing the beam to focus and follow the bypassing source past the microphone array. The signal processing can zoom into any part of the studied objector of any frequency band. Ultimately, image quality depends on the number of microphones and their configuration. When the microphones cover a big surface, the resolution gets higher; however, the image may contain noise at high frequencies. Reducing microphone distances from the source removes the specks but at the same time worsens the resolution. So the best way to guarantee high-quality images is to use as many microphones as possible. This paper presents the results of tests with 32-channel from National Instrument phased array system developed by the UFSC-Brazil. Measurement results are shown for motorcycle, car motor, and external automobile noise during pass-by test.