Exploiting spatial diversity for increasing the robustness of sound source localization systems against reverberation

•Exploiting spatial diversity improves the localization accuracy under reverberation.•Extensive study of SRP-PHAT performance for a wide range of reverberation times.•Smaller microphone arrays perform better than larger arrays for high reverberation times.•Combining information from several arrays is more advantageous than increasing the number of microphones.•Proposal of a novel technique that combines information from different arrays by the summation of the SRP maps. Acoustic reverberation is one of the most relevant factors that hampers the localization of a sound source inside a room. To date, several approaches have been proposed to deal with it, but have not always been evaluated under realistic conditions. This paper proposes exploiting spatial diversity as an alternative approach to achieve robustness against reverberation. The theoretical arguments supporting this approach are first presented and later confirmed by means of simulation results and real measurements. Simulations are run for reverberation times up to 2 s, thus providing results with a wider range of validity than in other previous research works. It is concluded that the use of systems consisting of several, sufficiently separated, small arrays leads to the best results in reverberant environments. Some recommendations are given regarding the choice of the array sizes, the separation among them, and the way to combine SRP-PHAT maps obtained from diverse arrays.