Geometry calibration of multiple microphone arrays in highly reverberant environments

Microphone arrays can be used for a number of applications such as speaker diarization and tracking. For these, it is necessary to calibrate their geometry with good precision. Manual measurement is cumbersome and impractical for ad hoc configurations as distributed sensor nodes. So an fast automated calibration method that provides sufficient accuracy is required. It is even more convenient if data from the target application itself can be used so that the system can be calibrated online during its use. In this paper, we propose an automated geometry calibration method that outperforms existing state-of-the-art approaches. It does not require speakers at the nodes and works well in high reverberation. It was evaluated with real recordings in a smart room. By simply playing a white noise signal from a mobile phone at a few positions around the arrays, a calibration error of below 2 cm and 2° was achieved. By identification of speech events at different positions, the same method can be applied online; Here an error of 10 cm and 3° was achieved.