Beamforming in a reverberant environment using numerical and experimental steering vector formulations

The effect of acoustic reflections on beamforming maps and their correction is investigated in this paper. By replacing the usual steering vector expression in the beamforming algorithm with an adapted one, the effect of reflections can be reduced. Two formulations of the steering vectors are considered. The first makes use of an experimental Green's function, which is obtained by measuring simultaneously the signal of a speaker and of a 31-channel acoustic array in a hard-walled test-section. The second formulation is based on the assumption that the reflections can be modeled by a set of monopoles located at the image source positions. This numerical model is first validated by comparing the obtained Green's function with the experimental one. Then, the beamforming algorithm is modified by using the different steering vector formulations. In addition, the deconvolution algorithm Clean-SC has been used and implemented with the different formulations. Best results in terms of location and resolution accuracy were generally obtained when using the experimental Green's function formulation