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    Speaker Localization Techniques in Reverberant Acoustic Environments

    TitleSpeaker Localization Techniques in Reverberant Acoustic Environments
    Publication TypeMaster Thesis
    Año de publicación2007
    Thesis Advisor(s)Macias-Guarasa, J
    AutoresCastro-Gonzalez, C
    Idioma de publicaciónEnglish

    Royal Institute of Technology (KTH)

    Academic DepartmentDepartment of Electrical Engineering
    Number of volumes1 vol.
    Fecha de publicación06/2007
    Lugar de publicaciónStockholm (SWEDEN)

    Nowadays, the use of speech technology to operate with electronic and informatic
    systems is getting more and more frequent and its usefulness indisputable. Given that
    speech is the most natural way in which humans interact with their environment, there
    is a clear tendency to make use of this technology as the mean to communicate with
    Automatic speech recognition systems are already able to properly understand reasonably
    complex human commands. Nevertheless, there are certain accoustic conditions
    under which the error rates commited by them are still too high. Particularly, the capture
    of distant speech in reverberant accoustic environments is specially conflictive for
    this type of systemswhich usually show lower performances than expected. At the same
    time, this distant speech acquisition is of high importance since it allows a more natural
    way to interact, without neccesarily having to carry intrusive, close-talk microphones,
    and it is present in multiple and common situations, such as those given in a digital
    home or a conference room.
    This present Master Thesis intends to design, implement and evaluate from scratch
    an accurate and complete tool to estimate the speaker localization in these reverberant
    accoustic environments. This localization application is crucial to improve the results
    of the mentioned recognition systems since it can be used to exploit the spatial filtering
    ability of an array, which allows the speech signal from one talker to be enhanced as the
    signals from other talkers as well as undesired sources and noise are supressed.
    After a detailed theoretical study, a robust localization system was implemented based
    on the Steered Response Power (SRP) of an array when focused at different locations.
    In turn, this scheme lies itself on a more basic localization algorithm able to estimate
    the Direction of Arrival (DOA) of the given speech by computing the Generalized Cross
    Correlation (GCC) between microphone pairs. Finally, an exhaustive evaluation of the
    results obtained by the system was carried out in order to check the validity of its outcomes,
    hint the possible improvement techniques, get some general conclusions about its
    performance and suggest future lines of investigation.

    2007-carloscastro-msthesis.pdf1.69 MB