Maximum likelihood approach to “informed” Sound Source Localization for Hearing Aid applications

Most state-of-the-art Sound Source Localization (SSL) algorithms have been proposed for applications which are "uninformed'' about the target sound content; however, utilizing a wireless microphone worn by a target talker, enables recent Hearing Aid Systems (HASs) to access to an almost noise-free sound signal of the target talker at the HAS via the wireless connection. Therefore, in this paper, we propose a maximum likelihood (ML) approach, which we call MLSSL, to estimate the Direction of Arrival (DoA) of the target signal given access to the target signal content. Compared with other "informed'' SSL algorithms which use binaural microphones for localization, MLSSL performs better using signals of one or more microphones placed on just one ear, thereby reducing the wireless transmission overhead of binaural hearing aids. More specifically, when the target location confined to the front-horizontal plane, MLSSL shows an average absolute DoA estimation error of 5 degrees at SNR of -5dB in a large-crowd noise and non-reverberant situation. Moreover, MLSSL suffers less from front-back confusions compared with the recent approaches.