Coordination of beamformers for noise estimation and noise suppression

An audio system, comprising:

• a housing having integrated therein a plurality of microphones having a fixed geometrical relationship to each other;
• a processor to access a plurality of microphone signals produced by the plurality of microphones, respectively;
• and
• memory having stored therein instructions that when executed by the processor (a)
• produce a plurality of acoustic pickup beams based on groups of the plurality of microphones,
• wherein the groups are determined based on an estimation of voice activity, and an estimation of noise characteristics in the microphone signals, and (b) select two or more beams, including a voice beam and a noise beam, from among the plurality of acoustic pickup beams based on thresholds for voice separation and thresholds for noise-matching,
• wherein selecting the voice beam and the noise beam, comprises,
• during a period where a desired voice is deemed active, indicating a presence of speech, difference between a strength of a component of the noise beam and a strength of a component of the voice beam are compared to a threshold for voice separation to determine whether there is sufficiently large voice separation between the two or more beams, and
• during a period where the desired voice is deemed inactive, indicating non-speech, difference between a strength of a component of the noise beam and a strength of a component of the voice beam are compared to a threshold for noise-matching to determine whether there is sufficient noise matching between the two or more beams, and
• wherein the voice beam is selected and used to pick up a voice signal and the noise beam is selected and used to provide information to estimate a noise signal, and wherein
• it is determined whether the two or more beams meet the threshold for noise-matching by a) obtaining ratios between the strength of a component of the noise beam in the noise beam and a strength of a component of the voice beam over a time interval, b) comparing the ratios to the threshold for noise-matching, and c) if the threshold for noise-matching is met, setting a correction factor for noise-matching;
• and
• it is determined whether the two or more beams meet the threshold for voice separation by calculating adjusted ratios by applying the correction factor to initial ratios between the strength of a component of the noise beam and the strength of a component of the voice beam.