Spatially Selective Active Noise Control Systems

Wearable active noise control (ANC) systems are commonly designed to achieve maximal sound reduction regardless of the incident direction of the sound. When desired sound is present, the state-of-the-art methods add a separate system to reconstruct it, often with distortion and latency. In this work, we propose a multi-channel ANC system that only controls the sound from the undesired directions. The system truly preserves the desired sound instead of reproducing it. The proposed algorithm imposes a spatial constraint on the hybrid ANC cost function to achieve spatial selectivity. We simulated the proposed algorithm based on a microphone array on a pair of augmented eye-glasses and compared it with the existing methods in the literature. Not only did the proposed system provide better noise reduction while preserving the physical sound wave from the desired source, but it also consumed much less energy, which is critical for lightweight wearable devices. Overall, the proposed method has demonstrated significant advantages over the state-of-the-art methods.