The human ear not only hears sound but also distinguishes the type and direction of the sound source. A microphone array mimics the human ear, enhancing the ability to identify sound sources and filter out noise, ensuring effective human-machine interaction. While the human ear has a complex structure, especially in consumer-grade microphone arrays, it is difficult to replicate its discerning and adjusting capabilities fully.
1. Noise Suppression
Noise primarily includes environmental sounds and voice interference. These noises usually don't mask normal speech but do impact clarity. The microphone array uses beamforming technology to suppress unwanted sounds outside the main direction, effectively reducing noise.
2. Source Localization
More accurately, microphone arrays achieve sound direction finding rather than precise location tracking. The primary function is to detect the direction of the sound source, aiding in subsequent beamforming. Source localization is typically performed during the voice wake-up phase.
3. Gain Adjustment
As the distance in far-field interactions varies, and sound intensity fluctuates, gain adjustment amplifies or attenuates the human voice, improving the signal-to-noise ratio (SNR) and enhancing speech recognition accuracy.
4. Echo Cancellation
Echo refers to sounds produced by the voice interaction device itself, such as music playing when a user issues a command. The microphone array's echo cancellation aims to eliminate the music and retain the user's voice.
Additional Features
Microphone arrays can also perform "electronic scanning" (electric sweeping), altering the direction of the array through signal delay without changing its physical position.
Applications
Speech enhancement and source localization have become essential components of array technology. These capabilities are crucial in fields like video conferencing, intelligent robots, hearing aids, smart home devices, telecommunications, smart toys, and automotive systems.
Microphone array technology is rapidly evolving in areas like source localization, speech enhancement, sound field visualization, and target tracking. Due to these advantages, it finds applications in defense, industrial production, biomedical fields, and consumer electronics.
