Systems and methods for suppressing audio noise in a communication system

• US 9,532,138 B1
• Filed: 07/16/2014
• Issued: 12/27/2016
• Est. Priority Date: 11/05/2013
• Status: Active Grant

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Allen, Justin Lamar
• Primary Examiner(s): TON, DAVID L
• Application Number:
  US14/333,142
• Time in Patent Office: 895 Days
• Field of Search: 381/92, 381/94.1, 381/122
• US Class Current: 1/1
• CPC Class Codes: H04R 2201/401 2D or 3D arrays of transducers
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

A method may include forming a plurality of beams to receive and spatially filter audible sounds from a first microphone and a second microphone. The plurality of beams may include a first unidirectional beam to receive audible sounds from the first microphone and the second microphone, a second unidirectional beam to receive audible sounds from the first microphone and the second microphone, the second unidirectional beam having a spatial null in a direction different from that of the first unidirectional beam, and an omnidirectional beam to receive audible sounds from the first microphone and the second microphone. The method may also include determining a first energy of audible sounds filtered by the first unidirectional beam and a second energy of audible sounds filtered by the second unidirectional beam and, based on the first energy and the second energy, selecting one of the plurality of beams as a selected beam.

Claims

1. A noise suppression system comprising:

a first microphone input configured to receive a first microphone signal indicative of sounds incident upon a first microphone;

a second microphone input configured to receive a second microphone signal indicative of sounds incident upon a second microphone;

a plurality of beam formers each configured to form a respective one of a plurality of beams to spatially filter audible sounds from the first microphone and the second microphone, the plurality of beam formers comprising;

a first beam former configured to form a first unidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone;

a second beam former configured to form a second unidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone, the second unidirectional beam having a spatial null in a direction different from that of the first unidirectional beam; and

a third beam former configured to form an omnidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone; and

a beam selector configured to;

determine a first energy of audible sounds filtered by the first unidirectional beam and a second energy of audible sounds filtered by the second unidirectional beam; and

based on at least the first energy and the second energy, select one of the plurality of beams as a selected beam to be output as an output signal of the noise suppression system.

2. The noise suppression system of claim 1, wherein:

the plurality of beam formers includes one or more additional beam formers each configured to form a respective additional unidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone, wherein each additional unidirectional beam has a spatial null in a direction different from that of the first unidirectional beam, the second unidirectional beam, and the other additional unidirectional beams; and

the beam selector is further configured to;

determine, for each additional unidirectional beam, an additional energy of audible sounds filtered by such additional unidirectional beam;

based on the first energy, the second energy, and the additional energies, select one of the plurality of beams as the selected beam.

3. The noise suppression system of claim 2, further comprising a third microphone, wherein the first unidirectional beam, the second unidirectional beam, and the one or more additional unidirectional beams are further configured to receive and spatially filter audible sounds from the third microphone.

4. The noise suppression system of claim 2, wherein the beam selector is further configured to:

compare a scaled first energy to the second energy and the additional energies, wherein the scaled first energy is equal to the first energy multiplied by a first tolerance factor between 0 and 1;

compare a scaled second energy to the first energy and the additional energies, wherein the scaled second energy is equal to the second energy multiplied by a second tolerance factor between 0 and 1;

for each additional unidirectional beam, compare a respective scaled additional energy to the first energy, the second energy, and the other additional energies, wherein each scaled additional energy is equal to its respective additional energy multiplied by a respective additional tolerance factor between 0 and 1;

select the first unidirectional beam as the selected beam if the scaled first energy is greater than the second energy and the additional energies;

select the second unidirectional beam as the selected beam if the scaled second energy is greater than the first energy and the additional energies;

select one of the additional unidirectional beams as the selected beam if the respective scaled additional energy for such additional unidirectional beam is greater than the first energy, the second energy, and the other additional energies; and

if none of the first directional beam, the second directional beam, and the additional directional beams are selected as the selected beam, select the omnidirectional beam as the selected beam.

5. The noise suppression system of claim 4, wherein the first tolerance factor, the second tolerance factor, and each additional tolerance factor have the same value.

6. The noise suppression system of claim 4, wherein at least one of the first tolerance factor, the second tolerance factor, and each additional tolerance factor are adjustable by a user of the noise suppression system.

7. The noise suppression system of claim 1, wherein the beam selector is further configured to:

compare the first energy to the second energy; and

select one of the plurality of beams as the selected beam based on the comparison.

8. The noise suppression system of claim 1, wherein the beam selector is further configured to:

compare a scaled first energy to the second energy, wherein the scaled first energy is equal to the first energy multiplied by a first tolerance factor between 0 and 1;

compare a scaled second energy to the first energy, wherein the scaled second energy is equal to the second energy multiplied by a second tolerance factor between 0 and 1;

select the first unidirectional beam as the selected beam if the scaled first energy is greater than the second energy;

select the second unidirectional beam as the selected beam if the scaled second energy is greater than the first energy; and

select the omnidirectional beam as the selected beam if the scaled second energy is lesser than the first energy and the scaled first energy is lesser than the second energy.

9. The noise suppression system of claim 8, wherein the first tolerance factor and the second tolerance factor have the same value.

10. The noise suppression system of claim 8, wherein at least one of the first tolerance factor and the second tolerance factor are adjustable by a user of the noise suppression system.

11. The noise suppression system of claim 10, further comprising a beam mixer subsystem, the beam mixer subsystem configured to, when the beam selector switches selection from a first selected beam to a second selected beam, cross-fade the audio output signal between the first selected beam and the second selected beam.

12. The noise suppression system of claim 1, wherein the audible sounds captured by the selected beam are output to a processing circuit as an audio output signal.

13. A method comprising:

forming a plurality of beams to capture audible sounds from a first microphone and a second microphone, the plurality of beams comprising;

a first unidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone;

a second unidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone, the second unidirectional beam having a spatial null in a direction different from that of the first unidirectional beam; and

an omnidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone; and

determining a first energy of audible sounds filtered by the first unidirectional beam and a second energy of audible sounds filtered by the second unidirectional beam; and

based on at least the first energy and the second energy, selecting one of the plurality of beams as a selected beam select one of the plurality of beams as a selected beam to be output as an output signal.

14. The method of claim 13, further comprising:

forming one or more additional unidirectional beams to receive and spatially filter audible sounds from the first microphone and the second microphone, wherein each additional unidirectional beam has a spatial null in a direction different from that of the first unidirectional beam, the second unidirectional beam, and the other additional unidirectional beams;

determining, for each additional unidirectional beam, an additional energy of audible sounds filtered by such additional unidirectional beam; and

based on the first energy, the second energy, and the additional energies, selecting one of the plurality of beams as the selected beam.

15. The method of claim 14, wherein the first unidirectional beam, the second unidirectional beam, and the one or more additional unidirectional beams are further configured to receive and spatially filter audible sounds from a third microphone.

16. The method of claim 14, further comprising:

comparing a scaled first energy to the second energy and the additional energies, wherein the scaled first energy is equal to the first energy multiplied by a first tolerance factor between 0 and 1;

comparing a scaled second energy to the first energy and the additional energies, wherein the scaled second energy is equal to the second energy multiplied by a second tolerance factor between 0 and 1;

for each additional unidirectional beam, comparing a respective scaled additional energy to the first energy, the second energy, and the other additional energies, wherein each scaled additional energy is equal to its respective additional energy multiplied by a respective additional tolerance factor between 0 and 1;

selecting the first unidirectional beam as the selected beam if the scaled first energy is greater than the second energy and the additional energies;

selecting the second unidirectional beam as the selected beam if the scaled second energy is greater than the first energy and the additional energies;

selecting one of the additional unidirectional beams as the selected beam if the respective scaled additional energy for such additional unidirectional beam is greater than the first energy, the second energy, and the other additional energies; and

if none of the first directional beam, the second directional beam, and the additional directional beams are selected as the selected beam, selecting the omnidirectional beam as the selected beam.

17. The method of claim 16, wherein the first tolerance factor, the second tolerance factor, and each additional tolerance factor have the same value.

18. The method of claim 16, wherein at least one of the first tolerance factor, the second tolerance factor, and each additional tolerance factor are adjustable by a user of a noise suppression system associated with the first microphone and the second microphone.

19. The method of claim 13, further comprising:

comparing the first energy to the second energy; and

selecting one of the plurality of beams as the selected beam based on the comparison.

20. The method of claim 13, further comprising:

comparing a scaled first energy to the second energy, wherein the scaled first energy is equal to the first energy multiplied by a first tolerance factor between 0 and 1;

comparing a scaled second energy to the first energy, wherein the scaled second energy is equal to the second energy multiplied by a second tolerance factor between 0 and 1;

selecting the first unidirectional beam as the selected beam if the scaled first energy is greater than the second energy;

selecting the second unidirectional beam as the selected beam if the scaled second energy is greater than the first energy; and

selecting the omnidirectional beam as the selected beam if the scaled second energy is lesser than the first energy and the scaled first energy is lesser than the second energy.

21. The method of claim 20, wherein the first tolerance factor and the second tolerance factor have the same value.

22. The method of claim 20, wherein at least one of the first tolerance factor and the second tolerance factor are adjustable by a user of the noise suppression system.

23. The method of claim 22, further comprising, when selection is switched from a first selected beam to a second selected beam, cross-fading the audio output signal between the first selected beam and the second selected beam.

24. The method of claim 13, wherein the audible sounds captured by the selected beam are output to a processing circuit as an audio output signal.

25. A noise suppression system comprising:

a first microphone input configured to receive a first microphone signal indicative of sounds incident upon a first microphone;

a second microphone input configured to receive a first microphone signal indicative of sounds incident upon a second microphone;

a plurality of beam formers each configured to form a respective one of a plurality of beams to receive and spatially filter audible sounds from the first microphone and the second microphone, the plurality of beam formers comprising;

a first beam former configured to form a first unidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone; and

a second beam former configured to form a second unidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone, the second unidirectional beam having a spatial null in a direction different from that of the first unidirectional beam;

a beam selector configured to;

determine a first energy of audible sounds filtered by the first unidirectional beam and a second energy of audible sounds filtered by the second unidirectional beam; and

based on at least the first energy and the second energy, select at least one of the plurality of beams as a selected beam; and

a beam mixer subsystem configured to, mix selected beams to create an audio output signal.

26. The noise suppression system of claim 25, the beam mixer subsystem configured to, when the beam selector switches selection from a first selected beam to a second selected beam, cross-fade an audio output signal between the first selected beam and the second selected beam.

27. The noise suppression system of claim 25, wherein a proportion of mixing of the selected beams is based on one or more criteria.

28. The noise suppression system of claim 27, wherein the one or more criteria comprise a volume of speech received by each of the selected beams.

29. A method comprising:

forming a plurality of beams to receive and spatially filter audible sounds from a first microphone and a second microphone, the plurality of beams comprising;

a first unidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone; and

a second unidirectional beam to receive and spatially filter audible sounds from the first microphone and the second microphone, the second unidirectional beam having a spatial null in a direction different from that of the first unidirectional beam;

determining a first energy of audible sounds filtered by the first unidirectional beam and a second energy of audible sounds filtered by the second unidirectional beam;

based on at least the first energy and the second energy, selecting at least one of the plurality of beams as a selected beam; and

mixing selected beams to create an audio output signal.

30. The method of claim 29, further comprising, when the beam selector switches selection from a first selected beam to a second selected beam, cross-fade an audio output signal between the first selected beam and the second selected beam.

31. The method of claim 29, wherein a proportion of mixing of the selected beams is based on one or more criteria.

32. The method of claim 31, wherein the one or more criteria comprise a volume of speech received by each of the selected beams.