Show Reference: "Binaural sound source localization using the frequency diversity of the head-related transfer function"

Binaural sound source localization using the frequency diversity of the head-related transfer function The Journal of the Acoustical Society of America, Vol. 135, No. 3. (01 March 2014), pp. 1207-1217, doi:10.1121/1.4864304 by Dumidu S. Talagala, Wen Zhang, Thushara D. Abhayapala, Abhilash Kamineni
    abstract = {The spectral localization cues contained in the head-related transfer function are known to play a contributory role in the sound source localization abilities of humans. However, existing localization techniques are unable to fully exploit this diversity to accurately localize a sound source. The availability of just two measured signals complicates matters further, and results in front to back confusions and poor performance distinguishing between the source locations in a vertical plane. This study evaluates the performance of a source location estimator that retains the frequency domain diversity of the head-related transfer function. First, a method for extracting the directional information in the subbands of a broadband signal is described, and a composite estimator based on signal subspace decomposition is introduced. The localization performance is experimentally evaluated for single and multiple source scenarios in the horizontal and vertical planes. The proposed estimator's ability to successfully localize a sound source and resolve the ambiguities in the vertical plane is demonstrated, and the impact of the source location, knowledge of the source and the effect of reverberation is discussed.},
    author = {Talagala, Dumidu S. and Zhang, Wen and Abhayapala, Thushara D. and Kamineni, Abhilash},
    citeulike-article-id = {13444170},
    citeulike-linkout-0 = {},
    day = {01},
    doi = {10.1121/1.4864304},
    issn = {0001-4966},
    journal = {The Journal of the Acoustical Society of America},
    keywords = {auditory, localization},
    month = mar,
    number = {3},
    pages = {1207--1217},
    posted-at = {2014-11-24 16:15:47},
    priority = {2},
    title = {Binaural sound source localization using the frequency diversity of the head-related transfer function},
    url = {},
    volume = {135},
    year = {2014}

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The way sound is shaped by the head and body before reaching the ears of a listener is described by a head-related transfer function (HRTF). There is a different HRTF for every angle of incidence.

A head-related transfer function summarizes ITD, ILD, and spectral cues for sound-source localization.

Sound source localization based only on binaural cues (like ITD or ILD) suffer from the ambiguity due to the approximate point symmetry of the head: ITD and ILD identify only a `cone of confusion', ie. a virtual cone whose tip is at the center of the head and whose axis is the interaural axis, not strictly a single angle of incidence.

Spectral cues provide disambiguation: due to the asymmetry of the head, the sound is shaped differently depending on where on a cone of confusion a sound source is.

Talagala et al. measured the head-related transfer function (HRTF) of a dummy head and body in a semi-anechoc chamber and used this HRTF for sound source localization experiments.

Talagala et al.'s system can reliably localize sounds in all directions around the dummy head.