Consolidated voice activity detection and noise estimation
View Patent ↗Methods and apparatus compensating for background noise associated with a transmitted signal. In a first embodiment, an adder combines an echo estimate with the the transmitted signal to form a processed signal, a noise reduction circuit uses a background noise estimate to subtract the background noise from the processed signal, and a non-linear processor uses the background noise estimate to combine a compensating background noise signal with the proccssed signal. In another embodiment, the noise reduction circuit divides the processed signal into sub-bands. With variations of an embodiment, the nonlinear processor is a sub-band non-linear processor, the processed signal is divided into sub-bands, and the background estimate includes sub-band noise estimates.
1. An apparatus that compensates for background noise associated with a transmitted signal, the apparatus comprising:
an adder that combines an echo estimate with the transmitted signal to generate a processed signal;
a noise reduction circuit that uses a background noise estimate to subtract the background noise from the processed signal; and
a non-linear processor that uses the background noise estimate to combine a compensating background noise signal with the processed signal, wherein the noise reduction circuit precedes the non-linear processor in the apparatus, and wherein the background noise estimate approximates acoustically derived background noise.
2. The apparatus of claim 1 , wherein the noise reduction circuit divides the processed signal into a plurality of sub-bands, and wherein the non-linear processor is: sub-band non-linear processor.
3. The apparatus of claim 2 , wherein operation of the non-linear processor is merged into sub-band operation of the noise reduction circuit.
4. The apparatus of claim 1 , wherein the noise reduction circuit divides the processed signal into a plurality of sub-bands, and wherein the non-linear processor operates in a sub-band domain.
5. The apparatus of claim 1 , wherein the noise reduction circuit divides the processed signal into a plurality of sub-bands and wherein the background noise esimate comprises a plurality of sub-band noise estimates.
6. The apparatus of claim 1 , wherein the noise reduction circuit divides the processed signal into a plurality of sub-bands and wherein the background noise estimate comprises a plurality of sub-band noise estimates and a broadband estimate.
7. The apparatus of claim 1 , wherein the noise reduction circuit and the non-linear processor are integrated.
8. A method for compensating for background noise associated with a transmitted signal, the method comprising:
combining an echo estimate with the transmitted signal to generate a processed signal;
generating a background noise estimate;
subtracting the background noise from the processed signal, using the background noise estimate; and
injecting a comfort noise signal into the processed signal, using the background noise estimate, wherein the background noise estimate approximates acoustically derived background noise.
9. The method of claim 8 , wherein generating the background noise estimate comprises dividing the processed signal into a plurality of sub-bands, determining a plurality of sub-band noise estimates, and combining the plurality of sub-band noise estimates.
10. The method of claim 9 , wherein generating the background noise estimate further comprises combining the plurality of sub-band noise estimates with a broadband estimate.
11. A computer-readable medium having computer-executable instructions for performing the method recited in claim 10 .
12. A computer-readable medium having computer-executable instructions for performing the method recited in claim 9 .
13. The method of claim 8 , wherein subtracting the background noise from the processed signal comprises:
combining a compensating background noise signal with the processed signal, wherein the compensating background noise signal is determined from the background noise estimate.
14. A computer-readable medium having computer-executable instructions for performing the method recited in claim 13 .
15. A computer-readable medium having computer-executable instructions for performing the method recited in claim 8 .
16. An apparatus that compensates for background noise associated with a transmitted signal, the apparatus comprising:
an adder that combines an echo estimate with the transmitted signal to generate a processed signal;
a noise reduction circuit that uses a background noise estimate to spectrally subtract the background noise from the processed signal; and
a non-linear processor that uses the background noise estimate to inject a comfort noise signal into the processed signal, wherein the noise reduction circuit precedes the non-linear processor in the apparatus, and wherein the background noise estimate approximates acoustically derived background noise.
17. The apparatus of claim 16 , wherein the noise reduction circuit divides the processed signal into a plurality of sub-bands, and wherein the non-linear processor is sub-band non-linear processor.
18. The apparatus of claim 16 , wherein the noise reduction circuit divides the processed signal into a plurality of sub-bands, and wherein the non-linear processor operates in a sub-band domain.
19. The apparatus of claim 16 , wherein the noise reduction circuit divides the processed signal into a plurality of sub-bands and wherein the background noise estimate comprises a plurality of sub-band noise estimates.
20. The apparatus of claim 16 , wherein operation or the non-linear processor is integrated into sub-band operation of the noise reduction circuit.