Selection Of Signal Regions For Parameter Extraction
First Claim
1. A method of extracting a signal parameter from a generally repetitive signal, comprising:
- obtaining an original photoplethysmograph (PPG) signal from a sensor;
applying a filter transformation to the original PPG signal to substantially remove a pulse component from the original PPG signal and produce a baseline PPG signal;
determining one or more regions of the baseline PPG signal by applying a threshold to the baseline PPG signal, wherein the values of the threshold depend, at least in part, on a set of signal amplitude values of the baseline PPG signal;
selecting a region from the one or more regions, and processing a portion of the original PPG signal corresponding to the selected region; and
extracting the signal parameter from the processed portion of the original PPG signal.
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Abstract
According to embodiments, techniques for extracting a signal parameter from a selected region of a generally repetitive signal are disclosed. A pulse oximetry system including a sensor or probe may be used to obtain an original photoplethysmograph (PPG) signal from a subject. A filter transformation may be applied to the original PPG signal to produce a baseline PPG signal. The baseline PPG signal may contain artifacts and/or noise, and a region of the baseline PPG signal suitable for extracting the signal parameter may be selected. A suitable region of the baseline PPG signal may be selected by applying one or more thresholds to the baseline PPG signal, where the values of the thresholds may be set based on derivative values, amplitude-based percentiles, and/or local minima and maxima of the baseline PPG signal. A portion of the original PPG signal corresponding to the selected region may be processed, and the signal parameter may be extracted from the processed region. In an embodiment, the signal parameter may correspond to the respiration rate of a patient.
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Citations
20 Claims
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1. A method of extracting a signal parameter from a generally repetitive signal, comprising:
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obtaining an original photoplethysmograph (PPG) signal from a sensor; applying a filter transformation to the original PPG signal to substantially remove a pulse component from the original PPG signal and produce a baseline PPG signal; determining one or more regions of the baseline PPG signal by applying a threshold to the baseline PPG signal, wherein the values of the threshold depend, at least in part, on a set of signal amplitude values of the baseline PPG signal; selecting a region from the one or more regions, and processing a portion of the original PPG signal corresponding to the selected region; and extracting the signal parameter from the processed portion of the original PPG signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for extracting a signal parameter from a generally repetitive signal, comprising:
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a sensor for obtaining an original photoplethysmograph (PPG) signal; a processor coupled to the sensor, wherein the processor is configured to; apply a filter transformation to the original PPG signal to substantially remove a pulse component from the original PPG signal to produce a baseline PPG signal; determine one or more regions of the baseline PPG signal by applying a threshold to the baseline PPG signal, wherein the values of the threshold depend, at least in part, on a set of signal amplitude values of the baseline PPG signal; select a region from the determined one or more regions; process a portion of the original PPG signal corresponding to the selected region; and extract the signal parameter from the processed portion of the original PPG signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification