Adaptive equalization system
View Patent ↗An adaptive equalization system that adjusts the spectral shape of a speech signal based on an intelligibility measurement of the speech signal may improve the intelligibility of the output speech signal. Such an adaptive equalization system may include a speech intelligibility measurement module, a spectral shape adjustment module, and an adaptive equalization module. The speech intelligibility measurement module is configured to calculate a speech intelligibility measurement of a speech signal. The spectral shape adjustment module is configured to generate a weighted long-term speech curve based on a first predetermined long-term average speech curve, a second predetermined long-term average speech curve, and the speech intelligibility measurement. The adaptive equalization module is configured to adapt equalization coefficients for the speech signal based on the weighted long-term speech curve.
1. An adaptive equalization method comprising:
generating a speech intelligibility value from a speech signal by a computer processor;
selecting a plurality of predetermined long-term average speech curves;
generating a weighted long-term target spectral shape curve by the computer processor based on the plurality of long-term average speech curves and the speech intelligibility value; and
adapting equalization coefficients for the speech signal by the computer processor based on the weighted long-term target spectral shape curve;
where the plurality of long-term average speech curves change based on speech signal conditions.
2. The method of claim 1 where the plurality of predetermined long-term average speech curves comprise long-term average speech shapes.
3. The method of claim 1 where the plurality of predetermined long-term average speech curves are selected based on a source of the speech signal.
4. The method of claim 1 where the plurality of predetermined long-term average speech curves are selected based on gender.
5. The method of claim 1 where the speech signal conditions reflect quiet conditions or noisy conditions.
6. The method of claim 1 where the plurality of predetermined long-term average speech curves are selected based on a level of vocal effort used to generate the speech signal.
7. The method of claim 6 where the level of vocal effort reflects a normal vocal effort, a raised vocal effort, or a shout vocal effort.
8. The method of claim 1 further comprising adjusting one or more of the plurality of predetermined long-term average speech curves based on a user's environment.
9. The method of claim 1 further comprising adjusting one or more of the plurality of predetermined long-term average speech curves based on an additive noise level.
10. The method of claim 1 further comprising adjusting one or more of the plurality of predetermined long-term average speech curves based on room acoustics.
11. The method of claim 1 further comprising adjusting one or more of the plurality of predetermined long-term average speech curves based on a microphone frequency response.
12. The method of claim 1 where the weighted long-term target spectral shape curve comprises a template.
13. The method of claim 12 where the template comprises an output template.
14. The method of claim 1 further comprising adjusting the equalization coefficients in response to signal conditions.
15. The method of claim 1 , where generating the speech intelligibility value comprises:
obtaining a signal power measurement for a frequency band of the speech signal;
obtaining a background noise level for the frequency band of the speech signal; and
obtaining the speech intelligibility value from the signal power measurement and a background noise level associated with the frequency band of the speech signal.
16. The method of claim 1 , where adapting the equalization coefficients comprises:
applying a prior version of the equalization coefficients to a power spectrum of the speech signal to generate an equalized signal; and
adapting the equalization coefficients to generate an adapted version of the equalization coefficients based on the equalized signal and the weighted long-term target spectral shape curve.
17. An adaptive equalization system, comprising:
a computer processor;
a speech intelligibility measurement module executable by the computer processor to process a speech intelligibility value of a speech signal;
a spectral shape adjustment module executable by the computer processor to process a weighted long-term target spectral shape curve that varies with speech signal conditions and is based on a plurality of predetermined long-term average speech curves and the speech intelligibility value; and
an adaptive equalization module executable by the computer processor to process equalization coefficients for the speech signal based on the weighted long-term target spectral shape curve.
18. The system of claim 17 where the plurality of predetermined long-term average speech curves include a first speech template in quiet conditions and a second speech template in noisy conditions.
19. The system of claim 17 where the plurality of predetermined long-term average speech curves are selected based on gender.
20. The system of claim 17 where the plurality of predetermined long-term average speech curves are selected based on a level of vocal effort that reflects a normal vocal effort, a raised vocal effort, or a shout vocal effort.