Design and calibration of large microphone arrays for robotic applications

Hearing is amongst the most important senses a modern robot must exhibit. Perceiving the acoustic world enables capabilities such as natural interaction with humans, interpreting spoken commands or the localization of victims during search and rescue tasks. Real-world robotic operations often take place in noisy, reverberant environments while requiring features such as source separation, accurate direction of arrival estimation or high performance noise suppression. This work presents a methodology to design, calibrate and operate large microphone arrays that enable such features. Recent micro electro-mechanical microphones in conjunction with reconfigurable logic tackle the weight, size, power consumption and cost constraints of robotic systems. A novel, automatic array shape calibration algorithm is developed for 2D and 3D arrays to face common experimental problems such as reverberation and poor signal-to-noise ratio when calibrating the array. The special case of a 2D array calibrated using sources moving in 3D is addressed. No prior information on array geometry is required, the process is fully automated and does not require any specific calibration equipment. The example application of an acoustic camera is presented as a proof of concept. High-quality acoustic images are computed in real-time by generalized inverse beamforming. This demonstrates the effectiveness of the proposed design and illustrates the usefulness of such sensing capabilities for various robotic applications.