Application of the complex cepstrum to locate acoustic sources near reflective surfaces

The complex cepstrum is used to correct bearing estimations of acoustic sources in the presence of a reflective surface. The echo time delay, given by the complex cepstrum, then is used in conjunction with the bearing estimation and measurement array height to determine the distance to the source. Consequently, the location of the acoustic source is determined with one detection array. An automated liftering procedure is used that zeros out a block portion of the cepstrum including the echo information. The problem of the resulting distortion is alleviated by applying a coherence criterion to the recovered direct signals at each microphone. Thus, to a large degree, the operator interactive nature of cepstral processing is overcome for this application. For the test signals and geometries considered, the cepstrum is shown to accurately correct for bearing errors in acoustic signals contaminated with reflections from nearby surfaces as well as provide the necessary information to determine the source location.