Common-acoustical-pole preprocessing for source localization in reverberant rooms

Localization of acoustic sources has become an important task in many practical applications. Typically the position of a source is determined from preliminary estimation of a set of relative time delays between couples of sensors, followed by triangulation. Unfortunately the presence of reverberation degrades the performance of most time delay estimators, thus leading to grossly incorrect location estimates. Algorithms based on the Generalized Cross Correlation are commonly used, but show clear limitations even in the presence of low reverberation levels. More complex approaches are possible, but they require a higher computational cost. In this paper the common-acoustical-pole modeling of room transfer functions is exploited to get improved time delay estimates with respect to generalized cross-correlation approaches, with reduced computational cost. Experimental tests are described to demonstrate the effectiveness of the proposed solution in combating reverberation, while maintaining the simplicity requirements needed in many practical situations.