Frequency domain method for holographic localization of rotating sound sources

Most of the previous studies employed beamforming techniques for the localization of rotating sources. These methods usually rely on the use of a virtual rotating array (VRA), in which the Doppler effects caused by source rotation can be eliminated. The VRA signal generation can be achieved in both frequency and time domains. In this presentation, compressive sensing (CS) near-field acoustic holography (NAH) has been extended to the reconstruction of rotating sources using the frequency domain (FD) VRA method. This combination can provide an improved resolution of spatial reconstructions at low frequencies compared to beamforming methods. In addition to the direct combination of the FD-VRA method and CS acoustical holography techniques, a more efficient algorithm for FD-VRA was developed to address the shortcomings of the traditional approach, such as higher computational cost and the requirement of a circular array with equally spaced microphones. The proposed FD-VRA method only involves a direct summation of the rotating sidebands of signals measured on a stationary array, which effectively reduces the computational load. Furthermore, an arbitrary array of microphones can be used. It will be shown that the proposed algorithm works for narrowband sources without overlapping frequency components in the rotating sidebands.