Wavelet-based analysis of pulse oximetry signals
First Claim
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1. A method of measuring physiological parameters, comprising the steps of:
- using a pulse oximeter to obtain a pulse oximetry signal;
decomposing the pulse oximetry signal by wavelet transform analysis;
deriving a continuous wavelet transform surface;
plotting the surface against a location parameter and a scale parameter; and
following a feature on the plotted surface to derive one or more physiological parameters.
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Abstract
A pulse oximetry signal, suitably a photoplethysmogram (PPG), is decomposed by wavelet transform techniques, and the decomposed signal analysed to provide selected physiological data. The signal may be processed to remove noise, artefacts, or transient features. Information on respiration may also be recovered.
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Citations
35 Claims
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1. A method of measuring physiological parameters, comprising the steps of:
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using a pulse oximeter to obtain a pulse oximetry signal; decomposing the pulse oximetry signal by wavelet transform analysis; deriving a continuous wavelet transform surface; plotting the surface against a location parameter and a scale parameter; and following a feature on the plotted surface to derive one or more physiological parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A physiological measurement system comprising:
- a pulse oximeter which includes an optical probe and circuit means connected to the probe to derive a pulse oximetry signal from a subject when the probe is applied to the subject, and signal processing means arranged to;
receive the pulse oximetry signal; decompose the pulse oximetry signal by wavelet transform analysis, said wavelet transform analysis employing a continuous wavelet function; derive a wavelet time-scale energy surface; plot the surface against a location parameter and a scale parameter; and follow a feature on the plotted surface to derive one or more physiological parameters. - View Dependent Claims (31)
- a pulse oximeter which includes an optical probe and circuit means connected to the probe to derive a pulse oximetry signal from a subject when the probe is applied to the subject, and signal processing means arranged to;
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32. A method of measuring physiological parameters, comprising the steps of:
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using a pulse oximeter to obtain a pulse oximetry signal; decomposing the pulse oximetry signal by wavelet transform analysis; deriving a continuous wavelet transform surface; plotting the surface against a location parameter and a scale parameter; identifying one or more ridges caused by respiration, then; (a) identifying and following high amplitude ridges; (b) extracting phase information from along the ridge; (c) analyzing amplitude modulation; (d) analyzing frequency modulation; and (e) deriving information relating to respiration by polling between the results of methods (a) to(d). - View Dependent Claims (33, 34, 35)
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Specification