To estimate the direction of arrival (DOA) of multiple speakers with methods that use prototype transfer functions, frequency-dependent spatial spectra (SPS) are usually constructed. To make the DOA estimation robust, SPS from different frequencies can be combined. According to how the SPS are combined, frequency fusion mechanisms are categorized into narrowband, broadband, or speaker-grouped, where the latter mechanism requires a speaker-wise grouping of frequencies. For a binaural hearing aid setup, in this paper we propose an interaural time difference (ITD)-based speaker-grouped frequency fusion mechanism. By exploiting the DOA dependence of ITDs, frequencies can be grouped according to a common ITD and be used for DOA estimation of the respective speaker. We apply the proposed ITD-based speaker-grouped frequency fusion mechanism for different DOA estimation methods, namely the multiple signal classification, steered response power and a recently published method based on relative transfer function (RTF) vectors. In our experiments, we compare DOA estimation with different fusion mechanisms. For all considered DOA estimation methods, the proposed ITD-based speaker-grouped frequency fusion mechanism results in a higher DOA estimation accuracy compared with the narrowband and broadband fusion mechanisms.

翻译：采用原型传递函数估计多说话人到达方向时，通常需构建频率相关的空间谱。为提升到达方向估计的鲁棒性，可融合不同频率的空间谱信息。根据融合方式的不同，频率融合机制可分为窄带、宽带及说话人分组三类，其中后者需按说话人进行频率分组。针对双耳助听器场景，本文提出一种基于耳间时间差（ITD）的说话人分组频率融合机制。通过利用ITD对到达方向的依赖性，可将具有相同ITD的频率分组，并用于对应说话人的到达方向估计。我们将该基于ITD的说话人分组频率融合机制应用于多种到达方向估计方法，包括多重信号分类、可控响应功率以及近期提出的基于相对传递函数（RTF）向量的方法。实验中，我们比较了不同融合机制的到达方向估计性能。结果表明，在所有考察的估计方法中，本文提出的基于ITD的说话人分组频率融合机制相较于窄带和宽带融合机制，均取得了更高的到达方向估计精度。