Binaural localization of speech sources in the median plane using cepstral hrtf extraction

In binaural systems, source localization in the median plane is challenging due to the difficulty of exploring the spectral cues of the head-related transfer function (HRTF) independently of the source spectra. This paper presents a method of extracting the HRTF spectral cues using cepstral analysis for speech source localization in the median plane. Binaural signals are preprocessed in the cepstral domain so that the fine spectral structure of speech and the HRTF spectral envelope can be easily separated. We introduce (i) a truncated cepstral transformation to extract the relevant localization cues, and (ii) a mechanism to normalize the effects of the time varying speech spectra. The proposed method is evaluated and compared with a convolution based localization method using a speech corpus of multiple speakers. The results suggest that the proposed method fully exploits the available spectral cues for robust speaker independent binaural source localization in the median plane.