Noise estimation for dynamic sound adjustment

Patent metadata

Field	Value
Publication number	US-10542346-B2
Application number	US-201816215755-A
Country	US
Kind code	B2
Filing date	Dec 11, 2018
Priority date	Sep 30, 2016
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

A system that performs noise estimation for an audio adjustment application comprises a coherence calculator that determines at least one coherence value between microphone signals generated by at least two microphones that each independently senses acoustic energy in a listening space. A first microphone of the at least two microphones generates a first microphone signal from the acoustic energy and a second microphone of the at least two microphones generates a second microphone signal from the acoustic energy. The acoustic energy comprises a combination of an audio signal transduced by one or more speakers and environmental noise of the acoustic energy that is local to the listening space. A noise estimate computation processor determines an estimate of a level of the environmental noise based on the at least one coherence value.

First claim

What is claimed is:

1. A dynamic audio adjustment system, comprising:
one or more signal outputs configured to provide an audio signal to a transducer, the transducer configured to transduce the audio signal into an acoustic signal in a listening space;
a first signal input configured to receive a first signal representative of acoustic energy at a first location in the listening space;
a second signal input configured to receive a second signal representative of acoustic energy at a second location in the listening space;
a coherence calculator configured to determine a coherence value between at least a portion of the first signal and the second signal;
a noise estimate computation processor that derives an estimate of a level of noise in the acoustic energies at the first and second locations in the listening space based on an approximation according to the coherence value and generates an adjustment value from the estimate of the level of noise in the acoustic energies at the first and second locations, respectively; and
a signal adjustment processor configured to apply the adjustment value to the audio signal based on the noise level estimate.

2. The dynamic audio adjustment system of claim 1 , further comprising:
a filter between the first and second signal inputs and the coherence calculator that filters a range of frequencies of the first and second signals; and
a frequency analyzer that arranges the range of frequencies into a plurality of frequency bands, wherein the coherence calculator determines the coherence value from the arrangement of frequency bands.

3. The dynamic audio adjustment system of claim 1 , further comprising:
a first filter that filters a range of frequencies of the first signal received from the first signal input;
a second filter that filters a range of frequencies of the second signal received from the second signal input;
a first frequency analyzer that arranges the filtered range of frequencies from the first filter into a first plurality of frequency bands; and
a second frequency analyzer that arranges the filtered range of frequencies from the second filter into a second plurality of frequency bands, wherein:
the coherence calculator generates a coherence value for each frequency band of the first and second plurality of frequency bands.

4. The dynamic audio adjustment system of claim 3 , wherein the noise estimate computation processor computes a factor from an aggregate of the coherence values for the frequency bands of the first and second plurality of frequency bands to determine the estimate of the level of noise in the listening space.

5. The dynamic audio adjustment system of claim 4 , wherein the noise estimate computation processor applies the factor to an output of the first and second filters to generate the adjustment.

6. The dynamic audio adjustment system of claim 3 , wherein the coherence calculator comprises a plurality of coherence calculators, wherein each of the plurality of coherence calculators includes two inputs for communicating with the first and second frequency analyzers, respectively, wherein the two inputs of each coherence calculator of the plurality of coherence calculators receives a frequency band of the first and second plurality of frequency bands, and each coherence calculator generates a coherence value of the coherence values in response to a comparison of the frequency band received at each of the two inputs.

7. The dynamic audio adjustment system of claim 1 , further comprising a first microphone in communication with the first signal input and a second microphone in communication with the second signal input.

8. A method for audio adjustment, comprising:
providing, by one or more signal outputs, an audio signal to a transducer;
transducing, by the transducer, the audio signal into an acoustic signal in a listening space;
receiving, by a first signal input, a first signal representative of acoustic energy at a first location in the listening space;
receiving, by a second signal input, a second signal representative of acoustic energy at a second location in the listening space;
determining, by a coherence calculator, a coherence value between at least a portion of the first signal and the second signal;
deriving, by a noise estimate computation processor, an estimate of a level of noise in the acoustic energies at the first and second locations in the listening space based on an approximation according to the coherence value and generates an adjustment value from the estimate of the level of noise in the acoustic energies at the first and second locations, respectively; and
applying, by a signal adjustment processor, the adjustment value to the audio signal based on the noise level estimate.

9. The method of claim 8 , further comprising:
filtering, by a filter, a range of frequencies of the first and second signals;
arranging, by a frequency analyzer, the range of frequencies into a plurality of frequency bands; and
determining, by the coherence calculator, the coherence value from the arrangement of frequency bands.

10. The method of claim 8 , further comprising:
filtering, by a first filter, a range of frequencies of the first signal from the first signal input;
filtering, by a second filter, a range of frequencies of the second signal from the second signal input;
arranging, by a first frequency analyzer, the filtered range of frequencies from the first filter into a first plurality of frequency bands;
arranging, by a second frequency analyzer, the filtered range of frequencies from the second filter into a second plurality of frequency bands; and
generating, by the coherence calculator, a coherence value for each frequency band of the first and second plurality of frequency bands.

11. The method of claim 10 , further comprising:
computing, by the noise estimate computation processor, a factor from an aggregate of the coherence values for the frequency bands of the first and second plurality of frequency bands to determine the estimate of the level of noise in the listening space.

12. The method of claim 11 , further comprising:
applying, by the noise estimate computation processor, the factor to an output of the first and second filters to generate the adjustment.

13. The method of claim 10 , wherein the coherence calculator comprises a plurality of coherence calculators, wherein each of the plurality of coherence calculators includes two inputs for communicating with the first and second frequency analyzers, respectively, and wherein the method further comprises:
receiving, by the two inputs of each coherence calculator of the plurality of coherence calculators, a frequency band of the first and second plurality of frequency bands; and
generating, by each coherence calculator, a coherence value of the coherence values in response to a comparison of the frequency band received at each of the two inputs.

14. The method of claim 8 , further comprising a first microphone in communication with the first signal input and a second microphone in communication with the second signal input.

15. A computer program product for audio adjustment, the computer program product comprising:
a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising;
computer readable program code configured to receive a first signal representative of acoustic energy at a first location in a listening space;
computer readable program code configured to receive a second signal representative of acoustic energy at a second location in

Assignees

• Bose Corp

Inventors

• Song Zukui
• Cheung Shiufun

Classifications

• H04R3/005

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

• H04R3/04 Primary

  for correcting frequency response · CPC title

• H04R2499/13

  Acoustic transducers and sound field adaptation in vehicles · CPC title

• H04R2430/03

  Synergistic effects of band splitting and sub-band processing · CPC title

• H04R3/00 Primary

  Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) · CPC title