Breathing Apparatus Speech Enhancement
First Claim
1. A breathing apparatus speech enhancement system comprising:
- a breathing mask;
a primary sensor on the breathing mask and configured to produce a primary signal;
at least one reference sensor on the breathing mask and configured to produce a reference signal; and
,a processor which combines at least the primary signal and the reference signal to produce an output signal with an enhanced speech component.
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Accused Products
Abstract
Speech enhancement in a breathing apparatus is provided using a primary sensor mounted near a breathing mask user'"'"'s mouth, at least one reference sensor mounted near a noise source, and a processor that combines the signals from these sensors to produce an output signal with an enhanced speech component. The reference sensor signal may be filtered and the result may be subtracted from the primary sensor signal to produce the output signal with an enhanced speech component. A method for detecting the exclusive presence of a low air alarm noise may be used to determine when to update the filter. A triple filter adaptive noise cancellation method may provide improved performance through reduction of filter maladaptation. The speech enhancement techniques may be employed as part of a communication system or a speech recognition system.
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Citations
24 Claims
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1. A breathing apparatus speech enhancement system comprising:
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a breathing mask; a primary sensor on the breathing mask and configured to produce a primary signal; at least one reference sensor on the breathing mask and configured to produce a reference signal; and
,a processor which combines at least the primary signal and the reference signal to produce an output signal with an enhanced speech component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of analyzing a digitized audio signal to detect the exclusive presence of an alarm signal, the method comprising:
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receiving a digitized audio signal; determining the energy of the digitized audio signal; determining a peak count of the number of consecutive energy samples below a first threshold; determining a valley count of the number of consecutive energy samples above a second threshold; determining an alarm count of the number of consecutive samples for which the peak count and valley count are below a third threshold; and declaring the exclusive presence of the alarm signal when the alarm count exceeds a fourth threshold.
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21. A system for analyzing a digitized audio signal to detect the exclusive presence of an alarm signal, the system comprising a processor configured to:
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receive a digitized audio signal; determine the energy of the digitized audio signal; determine a peak count of the number of consecutive energy samples below a first threshold; determine a valley count of the number of consecutive energy samples above a second threshold; determine an alarm count of the number of consecutive samples for which the peak count and valley count are below a third threshold; and declare the exclusive presence of the alarm signal when the alarm count exceeds a fourth threshold.
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22. A method of processing a digitized primary audio signal to reduce a noise component of the primary audio signal, the method comprising:
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receiving a digitized primary audio signal; receiving at least one digitized reference audio signal; filtering the at least one reference signal with an output filter to produce an output filtered reference signal; subtracting the output filtered reference signal from the primary signal to produce an output signal; filtering the at least one reference signal with an evaluation filter to produce an evaluation filtered reference signal; subtracting the evaluation filtered reference signal from the primary signal to produce an evaluation signal; filtering the at least one reference signal with an update filter to produce an update filtered reference signal; subtracting the update filtered reference signal from the primary signal to produce an update signal; modifying the update filter based on the reference signal and the update signal; modifying the evaluation filter based on the update filter; and modifying the output filter based on the output signal and the evaluation signal. - View Dependent Claims (23, 24)
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Specification