Robust voice activity detector system for use with an earphone
View Patent ↗An electronic device or method for adjusting a gain on a voice operated control system can include one or more processors and a memory having computer instructions. The instructions, when executed by the one or more processors causes the one or more processors to perform the operations of receiving a first microphone signal, receiving a second microphone signal, updating a slow time weighted ratio of the filtered first and second signals, and updating a fast time weighted ratio of the filtered first and second signals. The one or more processors can further perform the operations of calculating an absolute difference between the fast time weighted ratio and the slow time weighted ratio, comparing the absolute difference with a threshold, and increasing the gain when the absolute difference is greater than the threshold. Other embodiments are disclosed.
1. A method of adjusting a gain on a voice operated control system, comprising:
receiving a first microphone signal;
receiving a second microphone signal;
filtering the first microphone signal to provide a filtered first microphone signal;
filtering the second microphone signal to provide a filtered second microphone signal;
updating a slow time weighted ratio of the filtered first and second microphone signals;
updating a fast time weighted ratio of the filtered first and second microphone signals, wherein the fast time weighted ratio is calculated, based on a fast time weighted average of the filtered first microphone signal that is calculated based on a fast time weighting coefficient that is greater than a slow time weighting coefficient utilized in a slow time weighted average of the filtered first microphone signal utilized in calculating the slow time weighted ratio;
calculating an absolute difference between the fast time weighted ratio and the slow time weighted ratio;
comparing the absolute difference with a threshold; and
increasing the gain on the voice operated control system when the absolute difference is greater than the threshold, wherein a voice activity status is utilized to control the gain on the voice operated control system and to adjust a level of a signal directed to a voice receiving system in communication with the voice operated control system.
2. The method of claim 1 , wherein the threshold is fixed.
3. The method of claim 1 , further comprising:
band limiting or band pass filtering the first microphone signal to provide the filtered first microphone signal;
band limiting or band pass filtering the second microphone signal to provide filtered second microphone signal;
calculating a power estimate of the filtered first microphone signal including the fast time weighted average and the slow time weighted average of the filtered first microphone signal; and
calculating a power estimate of the filtered second microphone signal including a fast time weighted average and a slow time weighed average of the filtered second microphone signal.
4. The method of claim 3 , wherein the threshold is dependent on the slow time weighted average.
5. The method of claim 3 , wherein band limiting or band pass filtering comprises using a weighted fast Fourier transform operation.
6. The method of claim 1 , wherein the threshold value is set to a time averaged value of the absolute difference.
7. The method of claim 6 , wherein the threshold value is set to the time averaged value of the absolute difference using a leaky integrator used for time smoothing.
8. The method of claim 1 , further comprising determining the current voice activity status based on the comparison step.
9. The method of claim 1 , further comprising determining the current voice activity status using Singular Value Decomposition, a neural net system, or a bounded probability value.
10. An electronic device for adjusting a gain on a voice operated control system, comprising:
a processor; and
a memory having computer instructions, wherein the instructions, when executed by the processor, cause the processor to perform operations comprising:
receiving a first microphone signal;
receiving a second microphone signal;
filtering the first microphone signal to provide a filtered first microphone signal;
filtering the second microphone signal to provide a filtered second microphone signal;
updating a slow time weighted ratio of the filtered first and second microphone signals;
updating a fast time weighted ratio of the filtered first and second microphone signals, wherein the fast time weighted ratio is calculated, based on a fast time weighted average of the filtered first microphone signal that is calculated based on a fast time weighting coefficient that is greater than a slow time weighting coefficient utilized in a slow time weighted average of the filtered first microphone signal utilized in calculating the slow time weighted ratio;
calculating an absolute difference between the fast time weighted ratio and the slow time weighted ratio;
comparing the absolute difference with a threshold; and
increasing the gain on the voice operated control system when the absolute difference is greater than the threshold, wherein a voice activity status is utilized to control the gain on the voice operated control system and to adjust a power utilized in a wireless voice communication system in communication with the voice operated control system.
11. The electronic device of claim 10 , wherein the operations further comprise:
band limiting or band pass filtering the first microphone signal to provide the filtered first microphone signal;
band limiting or band pass filtering the second microphone signal to provide the filtered second microphone signal;
calculating a power estimate of the filtered first microphone signal including the fast time weighted average and the slow time weighted average of the filtered first microphone signal; and
calculating a power estimate of the filtered second microphone signal including a fast time weighted average and a slow time weighed average of the filtered second microphone signal.
12. The electronic device of claim 11 , wherein the threshold is fixed or the threshold is dependent on the slow time weighted average.
13. The electronic device of claim 10 , wherein the first microphone signal is received by an ambient signal microphone and the second microphone signal is received by an ear canal microphone.
14. The electronic device of claim 13 , wherein the ambient signal microphone and the ear canal microphone are part of an earphone device having a sound isolating barrier or a partially sound isolating barrier to isolate the ear canal microphone from an ambient environment.
15. The electronic device of claim 10 , wherein the electronic device is one of a headphone, a headset, an earpiece, or an ear bud.
16. The electronic device of claim 10 , wherein the operations further comprise determining the current voice activity status based on comparing the absolute difference with the threshold.
17. The electronic device of claim 10 , wherein the operations further comprise determining the current voice activity status using Singular Value Decomposition, to neural net systems, or a bounded probability value.
18. The electronic device of claim 10 , wherein the first microphone signal, the second microphone signal, or both are processed using an analog or a digital band-pass filter.
19. The electronic device of claim 10 , wherein increasing the gain comprises increasing the gain of first microphone signal, the second microphone signal, an output of a voice activity detector, an output of the voice operated control system, an output of the electronic device, or any combination hereof.
20. The electronic device of claim 10 , wherein at least one characteristic of the first and second microphone signals comprises a short-term power estimate.