Method of processing cardiovascular sound signals
First Claim
1. A method comprising:
- a. receiving a cardiovascular sound signal;
b. generating an autocorrelation signal from an autocorrelation of said cardiovascular sound signal;
c. generating a math model envelope of a single heart cycle extending between primary and secondary peaks of said autocorrelation signal, wherein said math model envelope comprises a first lobe corresponding to an S1 region of said single heart cycle and a second lobe corresponding to an S2 region of said single heart cycle, and said first and second lobes are each of like polarity relative to a common reference;
d. generating a bootstrap filter envelope by averaging data of said cardiovascular sound signal from a plurality of corresponding heart cycles within a corresponding plurality of heart cycle boundaries so as to generate averaged heart cycle data, wherein the operation of averaging of said data is over a period of one heart cycle, and said plurality of heart cycle boundaries are located within said cardiovascular sound signal responsive to a convolution of said math model envelope with said cardiovascular sound signal; and
e. locating a set of start points of each of a plurality of heart cycle signals in said cardiovascular sound signal responsive to a convolution of said bootstrap filter envelope with said cardiovascular sound signal.
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Abstract
A math model envelope of a single heartbeat between primary and secondary peaks of an autocorrelation of a received cardiovascular sound signal comprises an S1 lobe and a like-polarity S2 lobe. A bootstrap filter envelope is generated by averaging data from a plurality of heart cycles within heart cycle boundaries located responsive to a convolution of the envelope with the cardiovascular sound signal. Start points of a plurality of heart cycle signals are located from a convolution of the bootstrap filter envelope with the cardiovascular sound signal. The S1 and S2 regions are located within a cardiovascular sound signal responsive to peak and valley locations thereof and responsive to a phase window signal generated by filtering an average of a plurality of heart cycle signals, wherein the peak and valley locations are located responsive to a second derivative of the phase window signal and responsive to the start points.
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Citations
26 Claims
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1. A method comprising:
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a. receiving a cardiovascular sound signal; b. generating an autocorrelation signal from an autocorrelation of said cardiovascular sound signal; c. generating a math model envelope of a single heart cycle extending between primary and secondary peaks of said autocorrelation signal, wherein said math model envelope comprises a first lobe corresponding to an S1 region of said single heart cycle and a second lobe corresponding to an S2 region of said single heart cycle, and said first and second lobes are each of like polarity relative to a common reference; d. generating a bootstrap filter envelope by averaging data of said cardiovascular sound signal from a plurality of corresponding heart cycles within a corresponding plurality of heart cycle boundaries so as to generate averaged heart cycle data, wherein the operation of averaging of said data is over a period of one heart cycle, and said plurality of heart cycle boundaries are located within said cardiovascular sound signal responsive to a convolution of said math model envelope with said cardiovascular sound signal; and e. locating a set of start points of each of a plurality of heart cycle signals in said cardiovascular sound signal responsive to a convolution of said bootstrap filter envelope with said cardiovascular sound signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method, comprising:
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a. receiving either a cardiovascular sound signal or a corresponding smoothed cardiovascular sound signal; b. if said cardiovascular sound signal is not said smoothed cardiovascular sound signal, then smoothing said cardiovascular sound signal so as to generate said smoothed cardiovascular sound signal; c. if said cardiovascular sound signal is not a narrowband cardiovascular sound signal, then either generating said narrowband cardiovascular sound signal from said cardiovascular sound signal, OR receiving said narrowband cardiovascular sound signal that was previously generated from said cardiovascular sound signal, wherein said narrowband cardiovascular sound signal has a bandwidth greater than 130 Hz and less than 460 Hz; d. locating a set of start points of each of a plurality of heart cycle signals in said smoothed cardiovascular sound signal; e. averaging said plurality of heart cycle signals in said smoothed cardiovascular sound signal so as to generate an average envelope signal; f. filtering said average envelope signal so as to enhance S1 and S2 regions and so as to generate a corresponding phase window signal; g. locating a plurality of peaks and valleys in said average envelope signal responsive to a second derivative of said phase window signal; h. determining peak and valley locations of said S1 and S2 regions in said cardiovascular sound signal responsive to corresponding peaks and valleys of said plurality of peaks and valleys in said average envelope signal and responsive to said set of start points of each of said plurality of heart cycle signals in said smoothed cardiovascular sound signal; and i. determining indices of said S1 and S2 regions within said smoothed cardiovascular sound signal responsive to said peak and valley locations of said S1 and S2 regions in said smoothed cardiovascular sound signal and responsive to said phase window signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification