Removal of non-Gaussian, broadband interferers using blind source separation and spatial processing
Elizabeth A. Hoppe, Michael J. Roan · The Journal of the Acoustical Society of America · 2007
A method is introduced where blind source separation of acoustical sources is combined with spatial processing to remove non-Gaussian, broadband interferers from space-time displays such as bearing track recorder (BTR displays). This is quite different from the standard technique of placing nulls in the direction of interferers. The algorithm is implemented and tested against standard adaptive beamforming techniques, such as minimum variance distortionless response beamforming. In order to illustrate the utility of the approach, experiments were carried out in an anechoic chamber using two acoustic sources. The interferer source remained stationary at boresight, while the signal source moved, in steps of two deg, from negative to positive 20 deg. At each step, one second of data was recorded using a 64-element microphone array that had been calibrated at each subband frequency. All 64 channels of the array were sampled simultaneously at a rate of 22,050 Hz. Spatial processing is implemented using a broadband beamformer. The broadband beamforming algorithm first divides the signals into subbands, basebands, resamples, and finally low-passes the subbands, so that they can be processed using standard frequency domain narrowband beamformers.