Iterative Modified SRP-PHAT with Adaptive Search Space for Acoustic Source Localization

The Steered Response Power with Phase Transform (SRP-PHAT) is one of the leading methods for sound source localization because of its proven robustness in a noisy and reverberant environment. However, for the higher accuracy, the maximum power location needs to be searched over a dense grid, making the computational cost a real issue for large-scale microphone arrays. Modified SRP-PHAT introduced an effective strategy that computes the SRP functional at each discrete location, also considering the volume surrounding it. Subsequently, it explores the entire search space and achieves improved robustness over a coarse spatial grid. To accomplish higher spatial resolution with minimal computations, the Modified SRP-PHAT was further extended by employing an iterative grid decomposition search strategy. However, in challenging environments, the performance of the method deteriorates considerably with the iterative approach. In this paper, we suggest furtherance to iterative modified SRP-PHAT by employing adaptive search space in each iteration. The performance of the proposed method is extensively tested and compared to the state-of-the-art techniques on a simulated dataset and SMARD database to validate its reliability. The results exhibited that the proposed method achieves higher accuracy with only a marginal increase in computation expense than that of iterative modified SRP-PHAT.