Calibration of distributed sound acquisition systems using TOA measurements from a moving acoustic source

We present a method for calibrating a distributed microphone array using time-of-arrival (TOA) measurements. The calibration encompasses localization and gain equalization of the microphones, which are both important in applications such as beamforming. The availability of accurate TOA measurements between the microphones and a set of spatially distributed acoustic events is pivotal to the calibration task. We propose to use a moving acoustic source emitting a calibration signal at known intervals. We then show that the TOAs and the observed signals can be used to estimate the gain differences between microphones in addition to the more established microphone localization. Finally, we provide experimental results with simulated and real measured data to demonstrate that our approach facilitates accurate TOA measurements and hence, accurate localization and gain equalization, even in reverberant and noisy conditions.