New insights into the role of the head radius in model-based binaural speaker localization

In this work we evaluate the effects of the head radius on binaural localization algorithms. We employ a spherical head model and the null-steering beamforming localization method. The model characterizes the binaural cues in the form of HRTFs. One of the main parameters in this model is the head radius. We propose to optimize jointly for both the source location and the head radius. In contrast to the free-field configuration where it is difficult to estimate the source location and microphone distance simultaneously, the binaural algorithm yields a unique solution to the head radius. Moreover, for real recordings we show that the commonly-assumed size of the head achieves a fairly reliable performance. For applications with non-typical size of the head, e.g., hearing-impaired children the adaptation of the head radius using the proposed algorithm would improve the accuracy of the binaural localization algorithm.