Identification of sound source position or direction based on the statistical independecy in an actual sound environment

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Sound source localization problem has been important in various actual fields of acoustics and many approaches have been developed e.g., MUSIC, etc. Most of them utilize only the lower order statistics of observations such as a covariance matrix and the orthogonality (or uncorrelation) between the objective signal and noise. Recently , Independent Component Analysis (ICA) becomes popular to solve a blind signal separation problem where independent sources are mixed and then measured by multiple sensors. The ICA of complex signals has been also proposed for a case when observations have time differences between source signals or are affected by system (room etc.).In this research, some trials of estimating the sound source positions or directions are proposed from various viewpoints. In particular, most of them are based on the statistical independency between source signals or between the source signal and an additional noise. The results we obtained in 2001 and 2002 are listed below.[ … More 2001 year]: As the first step of research, the correlation method is introduced to calculate the delay time between observations at each microphone and then to estimate the sound direction. In the second approach, MUSIC method and Kalman filter are employed, respectively, to estimate the direction of source and to detect the amplitude information for sound source localization.The third method is a trial of estimating the time delays or the distances between receivers and sound sources based on the complex ICA, especially for the mixed observations with time delays. Further, we can easily construct an inverse filter to separate the (over-all) real mixed signals using the parameters estimated by ICA, while the usual complex ICA required synthesizing all frequency components. Finally, through fundamental simulation, we demonstrate the high-quality blind separation as well as the validity for the estimation of the source parameters.[2002 year]: Following to the fundamental consideration on the sound source localization problem in 2001, the extensive simulation makes it clear that the proposed method also enables us to find the directions of arrival. These results have been presented in domestic or international conferences. Less