System and method for feedback control for in-car communications

Patent metadata

Field	Value
Publication number	US-10110997-B2
Application number	US-201715436311-A
Country	US
Kind code	B2
Filing date	Feb 17, 2017
Priority date	Feb 17, 2017
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

A system and method (referred to as the system) that mitigates feedback in an audio system that adjust voice signals in a vehicle. The system generates transfer function estimates from multiple loudspeakers to multiple microphones and generates maximum forward path frequency-dependent gains based on the transfer function estimates and a frequency-dependent tuning factor for each of the loudspeakers to each of the microphones. The system generates forward path frequency-dependent gains independently that are applied to multiple loudspeaker signals, each of the loudspeaker signals drive one of the loudspeakers, respectively. The forward path frequency-dependent gains are adjusted based on the maximum forward path frequency-dependent gains.

First claim

What is claimed is:

1. A method that mitigates feedback in an audio system that adjusts audio signals in a vehicle cabin comprising:
generating maximum forward path frequency-dependent gains for each of the plurality of loudspeakers to each of the plurality of microphones;
generating forward path frequency-dependent gains independently that are applied to a plurality of loudspeaker signals, each of the loud speaker signals drive one of the plurality of loudspeakers, respectively; and
adjusting forward path frequency-dependent gains based on the maximum forward path frequency-dependent gains to prevent the actual forward path frequency-dependent gains from exceeding the maximum forward path frequency-dependent gains;
wherein the maximum forward path frequency-dependent gains are inversely related to an estimated or a measured noise within the vehicle cabin, equalization conditions that modify speech within the vehicle cabin, and an echo reduction within the vehicle cabin.

2. The method of claim 1 where the determination of maximum forward path frequency-dependent gains comprises generating transfer function estimates from each of a plurality of loudspeakers to each of a plurality of microphones in the vehicle, and a frequency-dependent tuning factor.

3. The method of claim 1 where the maximum forward path frequency-dependent gains are inversely proportional to a transfer function estimate.

4. The method of claim 1 further comprising generating and applying the adjusted forward path frequency-dependent gains independently to each signal received from the plurality of microphones prior to combining each of the received signals.

5. The method of claim 4 where each signal received from the plurality of microphones comprises a voice signal.

6. The method of claim 1 further comprising applying the adjusted forward path frequency-dependent gains independently to each signal received from the plurality of microphones at a matrix mixer prior to combining each of the received signals.

7. The method of claim 1 where each of the adjustment of the forward path frequency-dependent gains is a constant adjustment applied across all frequencies.

8. The method of claim 1 where the act of generating transfer function estimates from each of a plurality of loudspeakers to each of the plurality of microphones in the vehicle occurs through a calibration process.

9. The method of claim 1 where the act of adjusting forward path frequency-dependent gains comprises attenuating a subset of aural frequency bands and reducing gain across all frequencies of the aural signals that comprise the microphone signals.

10. A non-transitory machine-readable medium encoded with machine-executable instructions, where execution of the machine-executable instructions is for:
generating maximum forward path frequency-dependent gains for each of the plurality of loudspeakers to each of the plurality of microphones;
generating forward path frequency-dependent gains independently that are applied to a plurality of loudspeaker signals, each of the loud speaker signals drive one of the plurality of loudspeakers, respectively; and
adjusting forward path frequency-dependent gains based on the maximum forward path frequency-dependent gains to prevent the actual forward path frequency-dependent gains from exceeding the maximum forward path frequency-dependent gains;
wherein the maximum forward path frequency-dependent gains are inversely related to an estimated or a measured noise within the vehicle cabin, equalization conditions that modify speech within the vehicle cabin, and an echo reduction within the vehicle cabin.

11. The non-transitory machine-readable medium of claim 10 further comprising non-transitory machine-readable medium encoded with machine-executable instructions for generating transfer function estimates from each of a plurality of loudspeakers to each of a plurality of microphones in the vehicle, and a frequency-dependent tuning factor.

12. The non-transitory machine-readable medium of claim 10 where the maximum forward path frequency-dependent gains are inversely proportional to a transfer function estimate.

13. The non-transitory machine-readable medium of claim 10 further comprising non-transitory machine-readable medium encoded with machine-executable instructions for applying the adjusted forward path frequency-dependent gains to the voice signals that are converted into electrical signals by the plurality of microphones.

14. The non-transitory machine-readable medium of claim 10 further comprising non-transitory machine-readable medium encoded with machine-executable instructions for applying the adjusted forward path frequency-dependent gains independently to each signal received from the plurality of microphones prior to combining each of the received signals.

15. The non-transitory machine-readable medium of claim 14 where each signal received from the plurality of microphones comprises a voice signal.

16. The non-transitory machine-readable medium of claim 10 further comprising non-transitory machine-readable medium encoded with machine-executable instructions for applying the adjusted forward path frequency-dependent gains independently to each signal received from the plurality of microphones at a matrix mixer prior to combining each of the received signals.

17. The non-transitory machine-readable medium of claim 10 where each of the adjustment of the forward path frequency-dependent gains comprises a constant adjustment applied across all frequencies.

18. The non-transitory machine-readable medium of claim 10 where the generating transfer function estimates from each of a plurality of loudspeakers to each of the plurality of microphones in the vehicle occurs through a calibration process.

19. The non-transitory machine-readable medium of claim 10 where the adjusting forward path frequency-dependent gains comprises attenuating a subset of aural frequency bands and reducing gain across all frequencies of the aural signals that comprise the microphone signals.

20. A system that mitigates feedback in an audio system that adjust voice signals in a vehicle cabin comprising:
feedback control means for generating maximum forward path frequency-dependent gains based on transfer function estimates and a frequency-dependent tuning factor for each of the plurality of loudspeakers to each of the plurality of microphones; and
adaptive gain equalization means for calculating forward path frequency-dependent gains independently that are applied to a plurality of loudspeaker signals, each of the loud speaker signals drive one of the plurality of loudspeaker signals, respectively;
where the feedback control means adjusts the forward path frequency-dependent gains based on the maximum forward path frequency-dependent gains to prevent the actual forward path frequency-dependent gains from exceeding the maximum forward path frequency-dependent gains
wherein the maximum forward path frequency-dependent gains are inversely related to an estimated or a measured noise within the vehicle cabin, equalization conditions that modify speech within the vehicle cabin, and an echo reduction within the vehicle cabin.

21. The system of claim 20 further comprising calibration means for generating the transfer function estimates from each of a plurality of loudspeakers to each of a plurality of microphones in the vehicle.

22. The system of claim 20 further comprising a mixer means that combines each signal received f

Assignees

• Ontario Inc 2236008
• Ontario Inc 2236008

Inventors

• Every Mark Robert

Classifications

• H04R3/04

  for correcting frequency response · CPC title

• H04R3/02 Primary

  for preventing acoustic reaction {, i.e. acoustic oscillatory feedback (specially adapted for hearing aids H04R25/453)} · CPC title

• H04R3/005

  for combining the signals of two or more microphones (specially adapted for hearing aids H04R25/407) · CPC title

• H04R2499/13

  Acoustic transducers and sound field adaptation in vehicles · CPC title

• H04R2430/01

  Aspects of volume control, not necessarily automatic, in sound systems · CPC title