Method, apparatus and system for removing motion artifacts from measurements of bodily parameters
First Claim
1. A method of removing motion artifacts from electrical signals representative of attenuated light signals, comprising:
- transforming the electrical signals into frequency domain data;
identifying a plurality of candidate peaks from said frequency domain data;
narrow band pass filtering at each of said plurality of candidate peaks;
developing parameters associated with each of said plurality of identified candidate peaks;
analyzing each of said plurality of candidate peaks with respect to at least some of said developed parameters; and
arbitrating between at least some of said plurality of candidate peaks employing at least some of said developed parameters to select a best frequency.
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Accused Products
Abstract
A method for removing motion artifacts from devices for sensing bodily parameters and apparatus and system for effecting same. The method includes analyzing segments of measured data representing bodily parameters and possibly noise from motion artifacts. Each segment of measured data may correspond to a single light signal transmitted and detected after transmission or reflection through bodily tissue. Each data segment is frequency analyzed to determine up to three candidate peaks for further analysis. Each of the up to three candidate frequencies may be filtered and various parameters associated with each of the up to three candidate frequencies are calculated. The best frequency, if one exists, is determined by arbitrating the candidate frequencies using the calculated parameters according to predefined criteria. If a best frequency is found, a pulse rate and SpO2 may be output. If a best frequency is not found, other, conventional techniques for calculating pulse rate and SpO2 may be used. The above method may be applied to red and infrared pulse oximetry signals prior to calculating pulse rate and/or pulsatile blood oxygen concentration. Apparatus and systems disclosed are configured to perform methods disclosed according to the invention.
34 Citations
48 Claims
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1. A method of removing motion artifacts from electrical signals representative of attenuated light signals, comprising:
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transforming the electrical signals into frequency domain data;
identifying a plurality of candidate peaks from said frequency domain data;
narrow band pass filtering at each of said plurality of candidate peaks;
developing parameters associated with each of said plurality of identified candidate peaks;
analyzing each of said plurality of candidate peaks with respect to at least some of said developed parameters; and
arbitrating between at least some of said plurality of candidate peaks employing at least some of said developed parameters to select a best frequency. - 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 method of determining pulse rate and blood oxygen saturation from electrical signals representative of attenuated light signals and motion artifacts, comprising:
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acquiring a segment of red data and a segment of IR data from each of the electrical signals representative of attenuated light signals;
transforming both said segment of red data and said segment of IR data into red and IR frequency domain data, respectively;
identifying a plurality of candidate peaks from said red and IR frequency domain data;
narrow band pass filtering at each of said plurality of candidate peaks;
developing parameters associated with each of said plurality of identified candidate peaks;
analyzing each of said plurality of candidate peaks with respect to at least some of said developed parameters;
arbitrating between at least some of said plurality of candidate peaks employing at least some of said selected parameters to select a best frequency;
outputting pulse rate and saturation relating to said best frequency; and
repeating the above steps for new segments of data. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A circuit card for use in a pulse oximetry system to remove motion-induced noise artifacts from attenuated light signals, said circuit card comprising:
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a circuit board for mounting electronic circuitry and interfacing with the pulse oximetry system;
a processor mounted on said circuit board for processing input signals according to instructions; and
a memory for storing a computer program, wherein said memory is operably coupled to said processor, and wherein said computer program includes instructions for implementing a method of removing motion artifacts from said attenuated light signals, said method comprising;
acquiring a segment of red data and a segment of IR data from said attenuated light signals to obtain said electrical signals representative of said attenuated light signals;
conditioning said electrical signals to reduce spectral leakage;
transforming said electrical signals into frequency domain data;
identifying a plurality of candidate peaks from said frequency domain data;
narrow band pass filtering at each of said plurality of candidate peaks;
developing parameters associated with each of said plurality of identified candidate peaks;
analyzing each of said plurality of candidate peaks with respect to at least some of said developed parameters;
arbitrating between at least some of said plurality of candidate peaks employing at least some of said developed parameters to select a best frequency; and
repeating the above steps with a new segment of data. - View Dependent Claims (43, 44, 45, 47)
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46. A pulse oximeter for removing motion-induced noise artifacts from electrical signals representative of attenuated light signals comprising an input device, an output device, and a motion artifact circuit card, wherein said motion artifact circuit card comprises:
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a circuit board for mounting electronic circuitry and interfacing with the pulse oximeter;
a processor mounted on said circuit board for processing at least one input signal according to instructions; and
a memory for storing a computer program, wherein said memory is operably coupled to said processor, and wherein said computer program includes instructions for implementing a method of removing motion artifacts from said attenuated light signals, said method comprising;
acquiring a segment of red data and a segment of IR data from said attenuated light signals to obtain said electrical signals representative of said attenuated light signals;
conditioning said electrical signals to reduce spectral leakage;
transforming said electrical signals into frequency domain data;
identifying a plurality of candidate peaks from said frequency domain data;
narrow band pass filtering at each of said plurality of candidate peaks;
developing parameters associated with each of said plurality of identified candidate peaks;
analyzing each of said plurality of candidate peaks with respect to at least some of said developed parameters;
arbitrating between at least some of said plurality of candidate peaks employing at least some of said developed parameters to select a best frequency; and
repeating the above steps with a new segment of data.
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48. A pulse oximetry system for removing motion-induced noise artifacts from electrical signals representative of attenuated light signals comprising an input device, an output device, and a motion artifact circuitry, wherein said motion artifact circuitry includes:
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a processor for processing at least one input signal according to instructions; and
a memory operably coupled to said processor for storing a computer program, wherein said computer program includes instructions for implementing a method of removing motion artifacts from said measured pulse oximetry signal, wherein said method comprises;
acquiring a segment of red data and a segment of IR data from said attenuated light signals to obtain said electrical signals representative of said attenuated light signals;
conditioning said electrical signals to reduce spectral leakage;
transforming said electrical signals into frequency domain data;
identifying a plurality of candidate peaks from said frequency domain data;
narrow band pass filtering at each of said plurality of candidate peaks;
developing parameters associated with each of said plurality of identified candidate peaks;
analyzing each of said plurality of candidate peaks with respect to at least some of said developed parameters;
arbitrating between at least some of said plurality of candidate peaks using at least some of said developed parameters to select a best frequency;
outputting pulse rate and saturation relating to said best frequency; and
repeating the above steps for new segments of data.
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Specification