Spatial audio array processing system and method
摘要
說明書
Multiple channels of audio can be combined to create patterns of constructive and destructive interference across the frequency band of interest that will discriminate between sound waves arriving from different directions. This approach is commonly referred to as “beamforming” due to the shape of the constructive interference pattern of an array of transducer channels arranged in a 2D planar configuration. Conventional, or delay-sum, beamforming (also called “acoustic focus” beamforming) combines the channels, with or without amounts of time delay being applied to the channels before combining for steering the “beam,” in a direction with a bearing and/or elevation relative to a conceptual 2D plane, as drawn through the array configuration. In the case of speech enhancement, conventional beamformers increase the SNR of the target source by reducing sound energy that comes of directions other than the steered direction. They are effective at reducing the energy of reverberation but also reduce energy from the target source that arrives at the array via an indirect path (i.e., the “early reflections” that do not arrive in the beam). Conventional beamforming requires prior knowledge of the array configuration to accomplish the design of the interference pattern, the range of frequencies the interference pattern (beamforming) will be effective over, and any steering direction, including understanding the required steering delays to steer toward the target source. Individual channels may also have additional channel-combining or other filtering applied on a per-channel basis to modify the behavior of the beamformer, such as the shape of the pattern.
