Wind noise detection and suppression
View Patent ↗Wind noise is detected in and removed from an acoustic signal. Features may be extracted from the acoustic signal. The extracted features may be processed to classify the signal as including wind noise or not. The wind noise may be removed before or during processing of the acoustic signal. The wind noise may be suppressed by estimating a wind noise model, deriving a modification, and applying the modification to the acoustic signal. In audio devices with multiple microphones, the channel exhibiting wind noise (i.e., acoustic signal frame associated with the wind noise) may be discarded for the frame in which wind noise is detected.
1. A method for performing noise reduction, comprising:
transforming an acoustic signal from time domain to frequency domain sub-band signals;
extracting a feature from a sub-band of the acoustic signal;
detecting the presence of wind noise based on the feature;
generating a modification to suppress the wind noise based on the feature; and
applying the modification to suppress the wind noise before reducing environmental noise within the acoustic signal.
2. The method of claim 1 , wherein the feature includes a ratio between an energy level in a low frequency sub-band and a total signal energy.
3. The method of claim 1 , wherein the feature includes a variance of a ratio between an energy in a low frequency sub-band and a total signal energy.
4. The method of claim 1 , further comprising characterizing a sub-band signal as having wind noise.
5. The method of claim 4 , wherein the characterizing is based on a characterization engine trained with wind noise data.
6. The method of claim 5 , wherein an output of the characterization engine includes a binary classification.
7. The method of claim 4 , further comprising smoothing the characterization of wind noise over frames of the acoustic signal.
8. The method of claim 1 , wherein the modification includes deriving a wind noise model by fitting a function to a signal spectrum for the acoustic signal.
9. The method of claim 1 , further comprising:
extracting another feature from the sub-band of the acoustic signal; and
detecting the presence of wind noise further based on the other feature.
10. The method of claim 9 , wherein the feature and the other feature include two of an energy ratio of low frequency energy to a total energy, and a mean of the energy ratio.
11. The method of claim 1 , wherein the acoustic signal is received from one microphone.
12. A system for reducing noise in an acoustic signal, the system comprising:
a first microphone configured to receive a first acoustic signal;
a memory;
a wind noise characterization engine stored in the memory and executable to provide a wind noise characterization of the first acoustic signal;
a mask generator stored in the memory and executable to generate a modification to suppress the wind noise; and
a modifier module configured to apply the modification to suppress the wind noise based on the wind noise characterization, before environmental noise is reduced within the acoustic signal.
13. The system of claim 12 , further comprising a feature extraction module stored in memory and executable to extract features from the acoustic signal, the wind noise characterization based on the features.
14. The system of claim 12 , further comprising a transform module stored in memory and executable to transform the acoustic signal from a time domain to a frequency domain.
15. The system of claim 12 , further comprising a second microphone, the wind noise characterization engine configured to characterize the acoustic signals from the first microphone and the second microphone independently.
16. The system of claim 15 , further comprising determining a coherence function between the first and second microphone acoustic signals.
17. The system of claim 15 , further comprising ignoring the acoustic signal from the microphone in which the wind noise is detected.
18. A non-transitory computer readable storage medium having embodied thereon a program, the program being executable by a processor to perform a method for reducing noise in an audio signal, the method comprising:
transforming an acoustic signal from time domain to frequency domain sub-band signals;
extracting a feature from a sub-band of the acoustic signal;
detecting the presence of wind noise based on the feature;
generating a modification to suppress the wind noise based on the feature; and
applying the modification to suppress the wind noise before reducing environmental noise within the acoustic signal.
19. The non-transitory computer readable storage medium of claim 18 , wherein the feature is associated with a low frequency sub-band.
20. The non-transitory computer readable storage medium of claim 18 , the method further comprising characterizing a sub-band signal as having wind noise.
21. The non-transitory computer readable storage medium of claim 18 , the method further comprising generating the modification to suppress the wind noise based on the feature.
22. A method for performing noise reduction, comprising:
transforming an acoustic signal from time domain to frequency domain sub-band signals;
extracting two or more different features from a sub-band of the acoustic signal, the two or more different features each comprising one of a ratio between energy levels in low frequency bands and a total signal energy, a mean of the ratio, a variance of the ratio, and a coherence between microphone signals;
detecting the presence of wind noise based on the two or more features;
generating a modification to suppress the wind noise based on the two or more features; and
applying the modification to suppress the wind noise before reducing environmental noise within the acoustic signal.