Challenges in Acoustic Signal Enhancement for Human-Robot Communication

The construction of a humanoid robot, which can communicate with humans in a natural manner, is a worthwhile and challenging task alike. This paper discusses some major difficulties encountered in acoustic signal acquisition by the widely used humanoid robot NAO and the implications for the design of the signal enhancement algorithms that are needed for human-robot communication. Measurements with this low-cost robot, whose microphones and loudspeakers are mounted in the head, show the challenges for the noise reduction and acoustic echo control (AEC) due to ego-noise and nonlinear loudspeaker characteristics. It is also discussed how peripheral microphones at the limbs of the robot can mitigate these problems and offer new prospects for multi-channel signal enhancement.