FREQUENCY DOMAIN PROJECTION ALGORITHM
First Claim
1. A device for predicting heart rate (HR), comprising:
- a first sensor configured to generate raw HR signals;
a second sensor configured to generate acceleration signals along at least a first direction; and
processing circuitry capable of;
generating a frequency domain (FD) representation of the raw HR signals to provide a FD raw HR signal waveform;
generating a FD representation of the acceleration signals to provide a FD acceleration signal waveform along the first direction;
scaling a peak in the FD acceleration signal waveform at a first frequency to represent a peak at the same first frequency in the FD raw HR signal waveform;
subtracting the scaled peak of the FD acceleration signal waveform from the FD raw HR signal waveform to obtain a FD projected HR signal waveform;
selecting the frequency corresponding to the maximum peak of the FD projected HR signal waveform; and
predicting a HR based on the selected frequency.
1 Assignment
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Accused Products
Abstract
An algorithm for determining heart rate by removing motion artifacts from a PPG signal in the frequency domain utilizes a principal component analysis. Some examples of the present disclosure process PPG signals in combination with accelerometer signals to remove unwanted artifacts in the frequency domain. For example, principal components of the accelerometer signal can be generated and combined with the PPG signal to filter out acceleration contributions represented in the PPG signal to reveal heart rate peaks. Additionally, in some examples, templates may be stored for correlation with candidate heart rate peaks to select those peaks with the highest correlations with the stored templates.
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Citations
26 Claims
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1. A device for predicting heart rate (HR), comprising:
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a first sensor configured to generate raw HR signals; a second sensor configured to generate acceleration signals along at least a first direction; and processing circuitry capable of; generating a frequency domain (FD) representation of the raw HR signals to provide a FD raw HR signal waveform; generating a FD representation of the acceleration signals to provide a FD acceleration signal waveform along the first direction; scaling a peak in the FD acceleration signal waveform at a first frequency to represent a peak at the same first frequency in the FD raw HR signal waveform; subtracting the scaled peak of the FD acceleration signal waveform from the FD raw HR signal waveform to obtain a FD projected HR signal waveform; selecting the frequency corresponding to the maximum peak of the FD projected HR signal waveform; and predicting a HR based on the selected frequency. - View Dependent Claims (2, 3)
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4. A device for predicting heart rate (HR), comprising:
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a first sensor configured to generate time domain raw HR signals; a second sensor configured to generate time domain acceleration signals along first, second and third directions; and processing circuitry capable of; performing a principal component analysis of the time domain acceleration signals along the first, second and third directions to provide time domain principal components acceleration waveforms of the time domain acceleration signals having scores along the principal component axes PC1 and PC2; generating a frequency domain (FD) representation of the time domain raw HR signals to provide a FD raw HR signal waveform; generating a FD representation of the time domain principal components acceleration waveforms to provide FD acceleration signal waveforms corresponding to the principal component axes PC1 and PC2 and designating the corresponding waveforms as FD PC1 acceleration signal waveforms and FD PC2 acceleration signal waveforms respectively; and utilizing the FD PC1 acceleration signal waveforms, the FD PC2 acceleration signal waveforms and the FD raw HR signal waveform to predict the HR. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A device for predicting heart rate (HR), comprising:
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a first sensor configured to generate time domain raw HR signals; a second sensor configured to generate time domain acceleration signals along first, second and third directions; and processing circuitry capable of; performing a principal component analysis of the time domain acceleration signals along the first, second and third directions to provide time domain principal components acceleration waveforms of the time domain acceleration signals having scores along the principal component axes PC1 and PC2; generating a frequency domain (FD) representation of the time domain raw HR signals to provide a FD raw HR signal waveform; generating a FD representation of the time domain principal components acceleration waveforms to provide FD acceleration signal waveforms corresponding to the principal component axes PC1 and PC2 and designating the corresponding waveforms as FD PC1 acceleration signal waveforms and FD PC2 acceleration signal waveforms respectively; and utilizing the FD PC1 acceleration signal waveforms, the FD PC2 acceleration signal waveforms, the FD raw HR signal waveform and a plurality of spectral heart rate templates to generate a plurality of correlation values to predict the HR. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A device for adjusting a data sampling window size for processing data comprising:
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a first sensor for accumulating the data during the sampling window; processing circuitry capable of ; determining a current value associated with the accumulated data; comparing the determined current value with a previously determined value of the data; adjusting the data sampling window size depending on the results of the comparison. - View Dependent Claims (18)
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19. A method for predicting heart rate (HR), comprising:
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generating time domain raw HR signals; generating time domain acceleration signals along first, second and third directions; performing a principal component analysis of the time domain acceleration signals along the first, second and third directions to provide time domain principal components acceleration waveforms of the time domain acceleration signals having scores along the principal component axes PC1 and PC2; generating a frequency domain (FD) representation of the time domain raw HR signals to provide a FD raw HR signal waveform; generating a FD representation of the time domain principal components acceleration waveforms to provide FD acceleration signal waveforms corresponding to the principal component axes PC1 and PC2 and designating the corresponding waveforms as FD PC1 acceleration signal waveforms and FD PC2 acceleration signal waveforms respectively; and utilizing the FD PC1 acceleration signal waveforms, the FD PC2 acceleration signal waveforms and the FD raw HR signal waveform to predict the HR. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A method for predicting heart rate (HR), comprising:
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generating time domain raw HR signals; generating time domain acceleration signals along first, second and third directions; performing a principal component analysis of the time domain acceleration signals along the first, second and third directions to provide time domain principal components acceleration waveforms of the time domain acceleration signals having scores along the principal component axes PC1 and PC2; generating a frequency domain (FD) representation of the time domain raw HR signals to provide a FD raw HR signal waveform; generating a FD representation of the time domain principal components acceleration waveforms to provide FD acceleration signal waveforms corresponding to the principal component axes PC1 and PC2 and designating the corresponding waveforms as FD PC1 acceleration signal waveforms and FD PC2 acceleration signal waveforms respectively; and utilizing the FD PC1 acceleration signal waveforms, the FD PC2 acceleration signal waveforms, the FD raw HR signal waveform and a plurality of spectral heart rate templates to generate a plurality of correlation values to predict the HR. - View Dependent Claims (26)
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Specification