A microphone position calibration method in a reverberant environment for a randomly distributed array

A microphone position calibration method in a reverberant environment is investigated for randomly distributed large-size array in this paper. The microphone positions need to be known exactly in order to localize sound sources. Time delay estimation (TDE) is an important step in calibrating the microphone positions using a few calibrating sound sources for a randomly distributed array. However, TDE method degrades severely in a reverberant environment which can introduce serious position errors. The microphone position error analysis is made due to misleading estimation of time delay. In this paper, impulsive sound source as a calibrating source is investigated compared with chirp source and white noise. The direct sound from an impulsive sound is isolated to calculate exact time delay in a reverberant environment while early reflection and reverberation sound are cut off. The simulation experiments are carried out to demonstrate that accurate microphone positions can be obtained using the proposed method. The proposed method is also applied in a project to calibrate the microphone positions for a spiral-like ceiling-mounted array with 64 elements and aperture of 3.5m, which proves the effectiveness.