Comparison of the Rotating Source Identifier and the Virtual Rotating Array Method

  • Bence Tóth Department of Fluid Mechanics, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, H-1111 Budapest, Bertalan Lajos u. 4-6, Hungary
  • János Vad Department of Fluid Mechanics, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, H-1111 Budapest, Bertalan Lajos u. 4-6, Hungary
  • Gábor Kotán Department of Fluid Mechanics, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, H-1111 Budapest, Bertalan Lajos u. 4-6, Hungary

Abstract

The aim of this paper is to present two acoustic beamforming methods developed for rotating sources, namely the Rotating Source Identifier (ROSI) and the Virtual Rotating Array method (VRAM). These were applied onto a series of simulated test cases, and their behaviour was analysed. Both methods were able to localise the source reliably. However, the source strength was found to depend on the number or microphones when VRAM was applied. This phenomenon was quantified and an approximate formula was given providing the minimum number of microphones required to reach a certain amplitude error. Beamwidth and side lobe suppression were found to agree between the two methods, meaning that the way rotation is handled does not significantly affect the point spread functions. The computational cost of ROSI was two to three orders of magnitude higher than that of VRAM. The results show that both methods are applicable for the beamforming analysis of rotating sound sources. However, in case of VRAM, the number of microphones has to be chosen carefully to obtain reliable amplitude results.

Keywords: beamforming, rotating sound source, phased array microphone, Rotating Source Identifier, Virtual Rotating Array method
Published online
2018-07-16
How to Cite
Tóth, B., Vad, J. and Kotán, G. (2018) “Comparison of the Rotating Source Identifier and the Virtual Rotating Array Method”, Periodica Polytechnica Mechanical Engineering, 62(4), pp. 261-268. doi: https://doi.org/10.3311/PPme.11194.
Section
Articles