System and method for acoustically identifying gunshots fired indoors
AssigneeTyco Fire & Security GmbH
InventorsWesley C. Pirkle, Richard L. Shoaf
Life of this patent
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Abstract
A system and method for acoustically detecting the firing of gunshots indoors employs multiple microphones (15, 20) which are utilized individually and in combination to detect sounds inside a building or other structure and, upon sensing a loud impulsive sound which is indicative of a gunshot, processing signals from both microphones (15, 20) to determine if the sound is that of a gunshot. The system and method relies on the acoustic signature of the noise as collected, with the acoustic signature being analyzed to arrive at values which are then compared to adjustable levels that signify a gunshot.
Claims23
A method of acoustically detecting a gunshot with a sensor that comprises a first microphone having a low sensitivity, a second microphone being more sensitive than the first microphone, a processor and a computer board, the method comprising the steps of:
- a) identifying, with the first microphone, when an incoming acoustic signal has a peak amplitude level greater than a trigger threshold established for a potential gunshot;
- b) if the potential gunshot is identified in step a), analyzing signals sensed by the first microphone in multiple, distinct frequency ranges to avoid false positive identification of gunshot occurrences;
- c) comparing, in response to the potential gunshot being identified, a value calculated based on signals from a second microphone corresponding to the potential gunshot with a threshold value used to determine gunshot occurrences;
- and
- d) determining that an occurrence of a gunshot has been detected based on results from both steps b) and c) to verify the occurrence of the gunshot;
- wherein the first microphone and the second microphone both are electrically connected to the processor and arranged orthogonal to one another on the computer board.
A method of acoustically detecting a gunshot comprising the steps of:
- a) identifying when an incoming acoustic signal sensed with a first microphone, having a low sensitivity, has a peak amplitude level greater than a trigger threshold established for a potential gunshot;
- b) if a potential gunshot is identified in step a), analyzing signals sensed by the first microphone in multiple, distinct frequency ranges;
- c) comparing a value calculated based on signals from a second microphone, which is more sensitive than the first microphone, with a threshold value;
- and
- d) determining that an occurrence of a gunshot has been detected based on results from both steps b) and c), wherein the method is limited to determining the occurrence of a gunshot within a building or other structure and further comprises establishing operational and nominal threshold values for the method, wherein determining that an occurrence of a gunshot has been detected requires, in addition to requirements of steps a) and c), a determination that additional requirements of at least two comparisons between values calculated based on signals from the first microphone and the operational and nominal threshold values have been met.
A system for acoustically detecting a gunshot within a building or other structure comprising:
- a sensor including a first microphone having a low sensitivity and a second microphone which is more sensitive than the first microphone;
- and
- a controller configured to determine an occurrence of a gunshot within the building or other structure based on signals received from each of the first and second microphones, wherein the controller determines the occurrence of the gunshot by performing the steps of:
- a) identifying, with the first microphone, when an incoming acoustic signal has a peak amplitude level greater than a trigger threshold established for a potential gunshot;
- b) if the potential gunshot is identified in step a), analyzing signals sensed by the first microphone in multiple, distinct frequency ranges to avoid false positive identification of gunshot occurrences;
- c) comparing, in response to the potential gunshot being identified, a value calculated based on signals from the second microphone corresponding to the potential gunshot with a threshold value used to determine gunshot occurrences;
- and
- d) determining that an occurrence of a gunshot has been detected based on results from both steps b) and c) to verify the occurrence of the gunshot;
- wherein the first microphone and the second microphone both are electrically connected to a processor and arranged orthogonal to one another on a computer board.
Dependencies are inferred from the claim text.