System and method for implementing real-time adaptive threshold triggering in acoustic detection systems
First Claim
1. A device, comprising;
- a noise state estimator to monitor an audio signal, estimate a level of background noise in the audio signal, and output the estimate of the level of background noise;
a static offset generator coupled to said noise state estimator to receive the estimate of the level of background noise, apply an offset from the estimate of the level of background noise to form a static threshold, and output the static threshold;
a dynamic offset generator to generate a dynamic offset from a post-trigger level of background noise and output the dynamic offset from the post-trigger level of background noise;
circuitry coupled to said static offset generator and said dynamic offset generator to receive the static threshold and the dynamic offset from the post-trigger level of background noise, apply the dynamic offset from the post-trigger level of background noise to the static threshold to form an adaptive threshold, and output the adaptive threshold; and
an audio signal/adaptive threshold (AS/AT) comparator to compare the audio signal to the adaptive threshold and generate a trigger signal if a magnitude of the audio signal is greater than a magnitude of the adaptive threshold.
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Abstract
A system and method to generate a trigger signal based on a real-time adaptive threshold. The system may include a microphone to receive an audio signal, a device to generate a trigger signal based on a real-time adaptive threshold coupled to the microphone to form an adaptive threshold and generate a trigger signal if a magnitude of the audio signal is greater than a magnitude of the adaptive threshold. The system may also include a waveform capture module coupled to the microphone to receive the audio signal and convert the audio signal into a series of waveform packets and a waveform analysis processor to extract characteristics from the waveform packets.
44 Citations
37 Claims
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1. A device, comprising;
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a noise state estimator to monitor an audio signal, estimate a level of background noise in the audio signal, and output the estimate of the level of background noise;
a static offset generator coupled to said noise state estimator to receive the estimate of the level of background noise, apply an offset from the estimate of the level of background noise to form a static threshold, and output the static threshold;
a dynamic offset generator to generate a dynamic offset from a post-trigger level of background noise and output the dynamic offset from the post-trigger level of background noise;
circuitry coupled to said static offset generator and said dynamic offset generator to receive the static threshold and the dynamic offset from the post-trigger level of background noise, apply the dynamic offset from the post-trigger level of background noise to the static threshold to form an adaptive threshold, and output the adaptive threshold; and
an audio signal/adaptive threshold (AS/AT) comparator to compare the audio signal to the adaptive threshold and generate a trigger signal if a magnitude of the audio signal is greater than a magnitude of the adaptive threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 34, 35, 36, 37)
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18. A method, comprising:
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monitoring an audio signal;
estimating a level of background noise in the audio signal;
generating a static threshold by applying an offset from the estimate of the level of background noise;
generating a dynamic offset from a post-trigger level of background noise;
generating an adaptive threshold by applying the dynamic offset to the static threshold;
comparing a magnitude of the adaptive threshold to a magnitude of the audio signal; and
generating a trigger signal if the magnitude of the audio signal is greater than the magnitude of the adaptive threshold. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 33)
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30. The method according to claim 30, said generating a dynamic offset further comprising:
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storing a value representing a peak amplitude of the audio signal in a second peak register when a second trigger is generated;
storing one of the values representing an instance of an exponentially decaying sinusoidal waveform in a static register;
multiplying the value representing a peak amplitude of the audio signal when a second trigger is generated by the value stored in the static register to produce an updated dynamic offset;
comparing the dynamic offset to the updated dynamic offset; and
generating a re-trigger signal if the updated dynamic offset is greater than the dynamic offset. - View Dependent Claims (31, 32)
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Specification