Simultaneous solution for sparsity and filter responses for a microphone network

1. A method to place microphones and design filters in a microphone network, the method comprising:

determining possible locations for the microphones of an array of the microphone network in a region;

assigning two or more sub-channels for each of the possible locations and a filter for each of the sub-channels;

for a target source in the region, solving for a sub-set of the possible locations and filter responses for the filters of the sub-channels of the sub-set, the solving for the sub-set of the possible locations and the filter responses for the sub-set being simultaneous; and

linking the filter responses for the sub-set to the microphones at the possible locations of the sub-set.

2. The method of claim 1 wherein determining comprises determining the possible locations as locations of the microphones as existing in the region.

3. The method of claim 1 wherein determining comprises determining the possible locations as design locations for the microphones.

4. The method of claim 1 wherein assigning comprises assigning the filter as an analysis filter local to the microphone and a synthesis filter remote from the microphone.

5. The method of claim 1 wherein assigning the filter comprises assigning a FIR filter with a plurality of taps in a multirate filterbank, and wherein solving comprise solving for values of the taps of the FIR filter.

6. The method of claim 1 wherein assigning the two or more sub-channels comprises assigning the two or more as frequency divisions of a spectrum, the frequency divisions of each of the possible locations being the same.

7. The method of claim 1 wherein solving comprises solving as a convex optimization.

8. The method of claim 1 wherein solving comprises solving as a function a first term that is a p-norm of a gain of interferences from interference sources and a second term that is a penalty for the sub-channels.

9. The method of claim 8 wherein solving as a function of the first term comprises solving with the interferences modeled as white noise.

10. The method of claim 8 wherein solving simultaneously comprises solving as a function of the first and second terms, and further comprising solving for the filter responses again with the penalty set to zero.

11. The method of claim 8 wherein solving comprises solving with the first and second terms each being a function of the filter responses.

12. The method of claim 8 wherein solving as a function of the second term comprises iterating with different values of a constant until a number of sub-channels in the sub-set matches with a user input of a number of the sub-channels for the microphone network.

13. The method of claim 8 wherein solving as the function of the second term comprises solving with the penalty term comprising a count of the sub-channels with the respective frequency responses above a threshold, the sub-channels with the respective frequency response above the threshold being in the sub-set and the sub-channels with the respective frequency response below the threshold not being in the sub-set.

14. The method of claim 8 wherein solving as the function of the second term comprises solving as a function of a maximum of an absolute value of an infinity norm with discrete frequencies.

15. The method of claim 8 wherein solving comprises minimizing an objective function with the first and second terms subject to a constraint of target source perfect reconstruction.

16. The method of claim 1 wherein linking comprises linking the filter responses to the sub-channels at the possible locations of the sub-set.

17. The method of claim 1 further comprising repeating the solving for different target source locations.

18. The method of claim 1 further comprising filtering with filters configured by the filter responses signals from the microphones at the possible locations.

19. A system for placing microphones and designing filters, the system comprising:

a processor configured to:

determine possible locations for microphones of a microphone array in a region,

assign two or more sub-channels for each of the possible locations and a filter for each of the sub-channels, and

for a target source in the region, solve for a sub-set of the possible locations and filter responses for the filters of the sub-channels of the sub-set, the solution for the sub-set of the possible locations and the filter responses for the sub-set being simultaneous; and

a memory configured to store the filter responses for the sub-set and the possible locations of the sub-set.

20. A system to filter microphone signals for a target source, the system comprising:

an acoustic beamformer, comprising:

a plurality of beamformer channels;

a plurality of microphones, each microphone assigned to a corresponding beamformer channel, each microphone having a location within an array of the plurality of microphones in a region;

a plurality of first filters, wherein each of the first filters is coupled to one of the plurality of microphones, each first filter having a frequency response based at least in part on the type of the respective microphone, and each first filter generating a filtered sub-channel;

a plurality of second filters, each of the second filters configured to filter a corresponding filtered sub-channel from a respective first filter, wherein second filter responses of the second filters are based on from a simultaneous solution of a respective microphone location and a corresponding second filter response, wherein the simultaneous solution comprises solving as a function a first term that is a p-norm of a gain of interferences from interference sources and a second term that is a penalty for the sub-channels; and

a summer configured to sum outputs from the second filters.