In hearing aid applications, an important objective is to accurately estimate the direction of arrival (DOA) of multiple speakers in noisy and reverberant environments. Recently, we proposed a binaural DOA estimation method, where the DOAs of the speakers are estimated by selecting the directions for which the so-called Hermitian angle spectrum between the estimated relative transfer function (RTF) vector and a database of prototype anechoic RTF vectors is maximized. The RTF vector is estimated using the covariance whitening (CW) method, which requires a computationally complex generalized eigenvalue decomposition. The spatial spectrum is obtained by only considering frequencies where it is likely that one speaker dominates over the other speakers, noise and reverberation. In this contribution, we exploit the availability of an external microphone that is spatially separated from the hearing aid microphones and consider a low-complexity RTF vector estimation method that assumes a low spatial coherence between the undesired components in the external microphone and the hearing aid microphones. Using recordings of two speakers and diffuse-like babble noise in acoustic environments with mild reverberation and low signal-to-noise ratio, simulation results show that the proposed method yields a comparable DOA estimation performance as the CW method at a lower computational complexity.

翻译：在助听器应用中，精确估计嘈杂混响环境下多个说话人的到达方向是一项重要目标。我们近期提出了一种双耳到达角估计方法，通过选择使估计相对传递函数向量与原型消声RTF向量数据库之间的埃尔米特角谱最大化的方向来估计说话人DOA。该RTF向量采用协方差白化方法进行估计，该方法需要进行计算复杂的广义特征值分解。空间谱仅通过考虑单个说话人可能主导其他说话人、噪声和混响的频率来获取。本文利用与助听器麦克风空间分离的外部麦克风，采用一种低复杂度的RTF向量估计方法，该方法假设外部麦克风与助听器麦克风中非期望分量之间具有低空间相干性。使用两个说话人及类扩散背景噪声在轻度混响和低信噪比声学环境中的录音，仿真结果表明，所提方法在较低计算复杂度下可达到与CW方法相当的DOA估计性能。