Techniques for selecting a direct path acoustic signal

1. A computer-implemented method, comprising:

receiving, from a first microphone, a first input acoustic signal;

generating a first audio spectrum from at least the first input acoustic signal, wherein the first audio spectrum includes a set of time-frequency bins; and

selecting a first time-frequency bin from the set based on a first local space-domain distance (LSDD) computed for the first time-frequency bin.

2. The computer-implemented method of claim 1 , wherein selecting the first time-frequency bin from the set comprises:

computing a first local spectrum value from the first LSDD, and

selecting the first time-frequency bin when the first local spectrum value exceeds a predetermined threshold.

3. The computer-implemented method of claim 1 , further comprising performing a direction of arrival (DOA) estimation on the first time-frequency bin to determine a first estimated direction of the first input acoustic signal.

4. The computer-implemented method of claim 1 , further comprising selecting a second time-frequency bin in the set based on a second LSDD computed for the second time-frequency bin, wherein the second time-frequency bin is selected when a second local spectrum value computed from the second LSDD exceeds the predetermined threshold.

5. The computer-implemented method of claim 4 , further comprising:

performing a DOA estimation on the second time-frequency bin to generate a second estimated direction of the first input acoustic signal; and

determining a first direction for the first input acoustic signal based at least on the first estimated direction and the second estimated direction.

6. The computer-implemented method of claim 2 , wherein the local spectrum value comprises a direct-to-reverberant ratio (DRR) based on a ratio of a maximum peak value of the first LSDD compared to an average peak value of the first LSDD.

7. The computer-implemented method of claim 2 , wherein the predetermined threshold is equal to a multiple of an average peak value of the first LSDD.

8. The computer-implemented method of claim 1 , wherein generating a first audio spectrum from the first input acoustic signal comprises generating a short-time Fourier transform (STFT) from the first input acoustic signal.

9. The computer-implemented method of claim 1 , wherein the microphone is included in a wearable headset.

10. A wearable device, comprising:

a microphone array that receives a first input acoustic signal; and

a controller that:

generates a first audio spectrum from at least the first input acoustic signal, wherein the first audio spectrum includes a set of time-frequency bins,

selects a first time-frequency bin from the set based on a local space-domain distance (LSDD) computed for the first time-frequency bin, and

performs a direction of arrival (DOA) estimation on the first time-frequency bin to determine a first estimated direction of the first input acoustic signal.

11. The wearable device of claim 10 , wherein the microphone array comprises two or more distinct microphones at different locations on the wearable device.

12. The wearable device of claim 11 , wherein:

the two or more distinct microphones receive at least two or more acoustic signals; and

the controller adds the two or more acoustic signals to generate the first input acoustic signal.

13. The wearable device of claim 10 , wherein selecting the first time-frequency bin from the set comprises:

computing a first local spectrum value from the first LSDD; and

selecting the first time-frequency bin when the first local spectrum value exceeds a predetermined threshold.

14. The wearable device of claim 10 , wherein the controller selects a second time-frequency bin in the set based on a second LSDD computed for the second time-frequency bin, wherein the second time-frequency bin is selected when a second local spectrum value computed from the second LSDD exceeds the predetermined threshold.

15. The wearable device of claim 14 , wherein the controller:

performs a DOA estimation on the second time-frequency bin to generate a second estimated direction of the first input acoustic signal; and

determines a first direction for the first input acoustic signal based at least on the first estimated direction and the second estimated direction.

16. The wearable device of claim 10 , wherein the local spectrum value comprises a direct-to-reverberant ratio (DRR) based on a ratio of a maximum peak value of the first LSDD compared to an average peak value of the first LSDD.

17. The wearable device of claim 11 , wherein the predetermined threshold has a value equal to a multiple of an average peak value of the first LSDD.

18. The wearable device of claim 10 , wherein the controller generates the first audio spectrum from the first input acoustic signal by generating a short-time Fourier transform (STFT) from the first input acoustic signal.

19. A non-transitory computer-readable storage medium storing instructions, which, when executed by a processor, perform a set of operations comprising:

receiving a first input acoustic signal;

generating a first audio spectrum from at least the first input acoustic signal;

wherein the first audio spectrum includes a set of time-frequency bins; and

selecting a first time-frequency bin from the set based on a first local space-domain distance (LSDD) computed within the first time-frequency bin.

20. The non-transitory computer-readable storage medium of claim 19 , wherein selecting the first time-frequency bin from the set comprises:

computing a first local spectrum value from the first LSDD, and

selecting the first time-frequency bin when the first local spectrum value exceeds a predetermined threshold.