US9271064B2ActiveUtilityA1
Method and system for contact sensing using coherence analysis
Est. expiryNov 13, 2033(~7.3 yrs left)· nominal 20-yr term from priority
H04R 2430/01H04R 25/43H04R 2499/11H04R 1/2853H04R 3/005H04R 2430/03H04R 1/1041G06F 3/017H03K 2217/94005G06F 3/02H03K 17/94
46
PatentIndex Score
0
Cited by
15
References
24
Claims
Abstract
Herein provided is a method for acoustical switching suitable for use with a microphone enabled electronic device. The method includes capturing a first microphone signal from a first microphone on a device, analyzing the first microphone signal for a contact event versus a non-contact event, and directing the electronic device to switch a processing state responsive to detection of either the contact event or non-contact event. In another configuration, additional microphone can be added for performing coherence analysis between at least two microphone signals mounted on or in the device. At least one parameter settings of the device can be changed in response to at least one detected physical contact on the device. Other embodiments are disclosed.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A method for acoustical switching suitable for use with a microphone enabled electronic device, the method comprising the steps of:
capturing a first microphone signal from a first microphone on a device;
by way of a processor on, in or operatively coupled to, the device communicatively coupled to the first microphone:
analyzing the first microphone signal for a contact event versus a non-contact event;
directing the electronic device to switch a processing state responsive to a detection of either the contact event or non-contact event,
capturing a second microphone signal from a second microphone on the device;
by way of the processor communicatively coupled to the first microphone and communicatively coupled to the second microphone:
performing a coherence function on the first microphone signal and the second microphone signal;
generating a smoothed coherence function from the coherence function;
resolving a peak in the smoothed coherence function;
comparing the peak in the smoothed coherence function to a threshold; and
deciding the physical contact has occurred if the peak is greater than the threshold.
2. The method of claim 1 , wherein the processing state responsive to detecting the contact event comprises at least one of performing a user interface action, a command response, an automatic interaction or a recording.
3. The method of claim 1 , wherein the processing state responsive to detecting the non-contact event comprises at least one of performing a voice communication, a data communication, an event detection, a speech recognition, a key word detection, or an SPL measurement.
4. The method of claim 1 configured for contact sensing suitable for use with the microphone enabled electronic device, further comprising the steps of:
analyzing the coherence function to determine if a physical contact due to touch occurred on the device.
5. The method of claim 4 , further comprising discriminating between the physical contact with a high inter-microphone coherence and an airborne event with a low inter-microphone coherence.
6. The method of claim 4 , further comprising
providing a change to at least one parameter setting on the electronic device responsive to determining the physical contact occurred,
wherein the first microphone and the second microphone are acoustical-mechanically coupled together on the electronic device.
7. The method of claim 6 , further comprising
resolving one or more peaks in the coherence function;
evaluating a time window between the one or more peaks;
setting a contact detection status to a negative value for de-bouncing if the time window is less than a previous time window, otherwise setting the contact detection status to a positive value.
8. The method of claim 7 , further comprising
counting a number of the contact detection status events for positive values; and
differentiating between a single tap and a double tap from analysis of the contact detection status if the number is within a time period.
9. The method of claim 4 , wherein the coherence function is a function of the power spectral densities, Pxx(f) and Pyy(f), of x and y, and the cross power spectral density, Pxy(f), of x and y, as:
C
x
y
(
f
)
=
P
x
y
(
f
)
2
P
x
x
(
f
)
P
y
y
(
f
)
.
10. The method of claim 4 , wherein a length of power spectral densities and a cross power spectral density of the coherence function are within 2 to 5 milliseconds.
11. The method of claim 4 , wherein a time-smoothing parameter for updating power spectral densities and a cross power spectral density is within 0.2 to 0.5 seconds.
12. The method of claim 4 , further comprising:
tuning a cavitational acoustic resonance by way of resonant air channels; and
reducing sensitivity of the coherence function to an airborne event from the tuned cavitational acoustic resonance of the first and second microphone signals.
13. The method of claim 12 , further comprising
producing a spectral notch specific to the airborne sound event by shaping the resonant air channel to decrease the coherence function for the airborne sound in a frequency band of interest.
14. A system for acoustical switching suitable for use with a microphone enabled electronic device, the system comprising:
a first microphone on or in the device for capturing a first microphone signal; an acoustic switch communicatively coupled to the first microphone;
a second microphone for capturing a second microphone signal, and the processor communicatively coupled to the first microphone and the second microphone, the processor configured for:
analyzing the first microphone signal for a contact event versus a non-contact event;
directing the electronic device to switch a processing state responsive to a detection of either the contact event or non-contact event;
performing a coherence function on the first microphone signal and the second microphone signal;
generating a smoothed coherence function from the coherence function;
resolving a peak in the smoothed coherence function;
comparing the peak in the smoothed coherence function to a threshold; and
deciding the physical contact has occurred if the peak is greater than the threshold.
15. The system of claim 14 , wherein the processing state, by way of a processor on, or operatively coupled to the device, responsive to detecting the contact event comprises at least one of performing a user interface action, a command response, an automatic interaction or a recording.
16. The system of claim 14 , wherein the processing state, by way of a processor on, or operatively coupled to the device, responsive to detecting the non-contact event comprises at least one of a voice communication, a data communication, an event detection, a speech recognition or a key word detection.
17. The system of claim 14 configured for contact sensing on a device, the processor further configured for:
analyzing the coherence function to determine if a physical contact due to touch occurred on the device.
18. The system of claim 17 , wherein the processor discriminates between the physical contact with a high inter-microphone coherence and an airborne event with a low inter-microphone coherence.
19. The system of claim 17 , wherein the processor performs the steps of:
providing a user interface command to the device responsive to determining the physical contact occurred,
wherein the first microphone and the second microphone are acoustical-mechanically coupled together on the device.
20. The system of claim 17 , wherein the processor performs the steps of:
resolving one or more peaks in the coherence function;
evaluating a time window between the one or more peaks;
setting a contact detection status to a negative value for de-bouncing if the time window is less than a previous time window, otherwise setting the contact detection status to a positive value.
21. The system of claim 19 , wherein the processor performs the steps of:
counting a number of the contact detection status events for positive values; and
differentiating between a single tap and a double tap from analysis of the contact detection status if the number is within a time period.
22. The system of claim 19 , wherein the processor generates a coherence as a function of the power spectral densities, Pxx(f) and Pyy(f), of x and y, and the cross power spectral density, Pxy(f), of x and y, as:
C
x
y
(
f
)
=
P
x
y
(
f
)
2
P
x
x
(
f
)
P
y
y
(
f
)
.
23. The system of claim 19 , further comprising:
a first acoustic cavity above the first microphone to create a first resonant air channel;
a second acoustic cavity above the second microphone to create a second resonant air channel;
wherein the processor performs the steps of tunes an acoustic resonance of the first and second microphone signals by way of the first and second resonant air channels; and
reduces a sensitivity of the coherence function to an airborne sound event from the tuned cavitational acoustic resonance of the first and second microphone signals.
24. The system of claim 22 , wherein the shaping of the first and second resonant air channels decreases the coherence function in a frequency band of interest and produces a spectral notch specific to the airborne event to reduce false positives.Cited by (0)
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