Signal processing apparatus and method
First Claim
1. A pulse oximetry system for the determination of a physiological parameter wherein said pulse oximetry system is configured to remove motion artifacts from physiological signals, comprising:
- an optical sensor for providing said pulse oximetry system with photo-plethysmographic data, wherein said sensor comprises a light emitting diode for emitting light and a photo-detector for detecting said light, wherein said detected light contains information on the photo-plethysmographic data; and
a processor for processing the photo-plethysmographic data, wherein said processor is configured to;
(a) acquire said photo-plethysmographic data;
(b) transform the photo-plethysmographic data into frequency domain data;
(c) analyze the frequency domain data to determine a result;
(d) determine a time domain data photo-plethysmographic signal using said result of said analysis of said frequency domain data;
(e) analyze a mathematical transformation of the time domain photo-plethysmographic signal to identify parameters;
(f) use said parameters to determine whether an artifact is present and to identify a physiological signal; and
(g) determine a physiological parameter from said physiological signal.
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Accused Products
Abstract
A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, a transformation is used to evaluate a ratio of the two measured signals in order to find appropriate coefficients. The measured signals are then fed into a signal scrubber which uses the coefficients to remove the unwanted portions. The signal scrubbing is performed in either the time domain or in the frequency domain. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. In another embodiment, an estimate of the pulserate is obtained by applying a set of rules to a spectral transform of the scrubbed signal. In another embodiment, an estimate of the pulserate is obtained by transforming the scrubbed signal from a first spectral domain into a second spectral domain. The pulserate is found by identifying the largest spectral peak in the second spectral domain.
925 Citations
26 Claims
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1. A pulse oximetry system for the determination of a physiological parameter wherein said pulse oximetry system is configured to remove motion artifacts from physiological signals, comprising:
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an optical sensor for providing said pulse oximetry system with photo-plethysmographic data, wherein said sensor comprises a light emitting diode for emitting light and a photo-detector for detecting said light, wherein said detected light contains information on the photo-plethysmographic data; and a processor for processing the photo-plethysmographic data, wherein said processor is configured to; (a) acquire said photo-plethysmographic data; (b) transform the photo-plethysmographic data into frequency domain data; (c) analyze the frequency domain data to determine a result; (d) determine a time domain data photo-plethysmographic signal using said result of said analysis of said frequency domain data; (e) analyze a mathematical transformation of the time domain photo-plethysmographic signal to identify parameters; (f) use said parameters to determine whether an artifact is present and to identify a physiological signal; and (g) determine a physiological parameter from said physiological signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 17)
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11. A pulse oximetry system for the determination of a physiological parameter wherein said pulse oximetry system is configured to remove motion artifacts from physiological signals, comprising:
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an optical sensor for providing said pulse oximetry system with photo-plethysmographic data, wherein said sensor comprises a light emitting diode for emitting light and a photo-detector for detecting said light, wherein said detected light contains information on the photo-plethysmographic data; and a processor for processing the photo-plethysmographic data, wherein said processor is configured to; (a) analyze frequency domain data derived from said photo-plethysmographic data to determine a result, (b) determine a time domain photo-plethysmographic signal using said result of said analysis of said frequency domain data; (c) analyze a mathematical transformation of the time domain photo-plethysmographic signal to identify parameters; and (d) use the identified parameters to determine whether an artifact is present and to identify a physiological signal.
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12. A pulse oximetry system for the determination of a physiological parameter wherein said pulse oximetry system is configured to remove motion artifacts from physiological signals, comprising:
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a sensor for providing said pulse oximetry system with plethysmographic data, wherein said sensor comprises a light emitter for emitting light and a photo-detector for detecting said light, wherein said detected light contains information on the plethysmographic data; and a processor for processing the plethysmographic data, wherein said processor is configured to; (a) acquire said plethysmographic data; (b) transform the plethysmographic data into frequency domain data; (c) analyze the frequency domain data to determine a result; (d) determine a time domain data plethysmographic signal using said result of said analysis of said frequency domain data; (e) analyze the time domain plethysmographic signal to identify parameters; (f) use said parameters to discriminate a physiological signal from a distortion; and (g) determine a physiological parameter from said physiological signal. - View Dependent Claims (13, 14, 15, 16, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A pulse oximetry system for the determination of a physiological parameter wherein said pulse oximetry system is configured to remove motion artifacts from physiological signals, comprising:
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a sensor for providing said pulse oximetry system with plethysmographic data, wherein said sensor comprises a light emitter for emitting light and a photo-detector for detecting said light, wherein said detected light contains information on the plethysmographic data; and a processor for processing the plethysmographic data, wherein said processor is configured to; (a) analyze frequency domain data derived from said plethysmographic data to determine a result, (b) determine a time domain plethysmographic signal using said result of said analysis of the frequency domain data; (c) analyze the time domain plethysmographic signal to identify parameters; and (d) use the identified parameters to discriminate a physiological signal from a distortion.
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Specification