Onset zone detection using coherent focusing summation over multiple geometric positions

A system comprising:

• data processing hardware;
• and
• memory hardware in communication with the data processing hardware, the memory hardware storing instructions that when executed on the data processing hardware cause the data processing hardware to perform operations comprising:
• receiving a multichannel input signal including a sequence of frames captured in an environment of a vehicle, the environment of the vehicle having at least two zones;
• for each zone of the at least two zones of the environment of the vehicle, performing speech detection by:
• converting each frame in a sequence of frames of the multichannel input signal into a plurality of frequency sub-bands, each frequency sub-band comprising a respective cross-correlation matrix (CCM);
• for each respective frequency sub-band of the plurality of frequency sub-bands:
• applying a focusing matrix to the respective CCM to generate a corrected CCM;
• extracting eigenvalues from the corrected CCM;
• and
• determining an eigenvalue ratio between a highest eigenvalue extracted from the corrected CCM and a second highest eigenvalue extracted from the corrected CCM;
• for each frame in the sequence of frames, calculating a median value of the eigenvalue ratios of the plurality of frequency sub-bands;
• determining a difference between respective median values of the at least two zones of the environment of the vehicle;
• and
• when an absolute value of the difference between the respective median values of the at least two zones of the environment of the vehicle is greater than a threshold, generating an initial detection of speech indication.