Improved Direct-path Dominance Test for Speaker Localization in Reverberant Environments

Speaker localization in real environments is a fundamental task for many audio signal processing applications. Many localization methods fail when the environment imposes challenging conditions, such as reverberation. Recently, a method for direction of arrival (DOA) estimation of speakers in reverberant environments was developed, which utilizes spherical arrays. This method uses the direct-path dominance (DPD) test to select time-frequency bins that contain spatial information on the direct sound. In this work, it is shown that when the threshold of the DPD test is lowered to select more bins for the estimation process, it falsely identifies bins dominated by reverberant sound, reducing DOA estimation accuracy. In this paper, a new DPD test is developed, which evaluates the extent to which the measured plane-wave density can be represented by a single plane-wave. While being more computationally expensive than the original test, it is more robust to reverberation, and leads to an improved DOA estimation. The latter is demonstrated by simulations of a speaker in a reverberant room.