Method and system for extracting cardiac parameters from plethysmographic signals
First Claim
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1. A method for extracting a cardiac component from a plethysmographic signal comprising:
- performing, by a computer, a frequency domain filtering operation on a plethysmographic signal producing a first filtered signal, the plethysmographic signal comprising a cardiac component responsive to cardiac motion and a non-cardiac component;
performing, by a computer, a time domain filtering operation on the first filtered signal to produce a second filtered signal, the second filtered signal comprising the cardiac component and a reduced non-cardiac component;
outputting the second filtered signal.
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Abstract
A method and system for extracting cardiac parameters from a plethysmographic signal is described wherein the plethysmographic signal is passed through a first filter to remove non-cardiac components of the signal. A second filter averages a plurality of cardiac cycles and cardiac parameters are extracted from the averaged cardiac signal.
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Citations
15 Claims
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1. A method for extracting a cardiac component from a plethysmographic signal comprising:
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performing, by a computer, a frequency domain filtering operation on a plethysmographic signal producing a first filtered signal, the plethysmographic signal comprising a cardiac component responsive to cardiac motion and a non-cardiac component; performing, by a computer, a time domain filtering operation on the first filtered signal to produce a second filtered signal, the second filtered signal comprising the cardiac component and a reduced non-cardiac component; outputting the second filtered signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 14)
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10. A system for extracting a cardiac component from a plethysmographic signal comprising a processor coupled to a memory, wherein the memory includes stored instructions for causing the processor to
perform a frequency domain filtering operation on a plethysmographic signal producing a filtered signal , wherein the plethysmographic signal comprises a cardiac component responsive to cardiac motion and a non-cardiac component, and wherein the frequency domain filtering operation comprises applying a band-pass filter having a lower corner frequency that varies in dependence on current heart rate; -
performing a time domain filtering operation on the first filtered signal to produce a second filtered signal, wherein the time domain filtering operation is based on the occurrences of electrocardiographic R waves, and wherein the second filtered signal comprises the cardiac component and a reduced non-cardiac component; and output the second filtered signal. - View Dependent Claims (11, 12, 13, 15)
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Specification