Sensor system for heart rate measurement per axis of shared orientation
First Claim
1. A wearable sensor system for providing heart rate measurement per shared axis of orientation, wherein the wearable sensor system is susceptible to motion artifacts that can adversely affect heart rate determinations, the system comprising:
- an accelerometer configured to provide accelerometer measurements for at least first and second accelerometer axes of orientation that are orthogonal to one another;
a photoplethysmography (PPG) optical sensor having at least first and second linear configurations of light processing elements that are orthogonal to one another; and
a housing configured to support and position the accelerometer and the first and second linear configurations of light processing elements of the PPG optical sensor so that the first linear configuration of light processing elements and the first accelerometer axis of orientation have a first shared axis of orientation, and the second linear configuration of light processing elements and the second accelerometer axis of orientation have a second shared axis of orientation;
the housing having a surface with one or more light pass-through sections forming at least first and second linear configurations matching the at least first and second linear configurations of the light processing elements, and the housing aligning the first and second linear configurations of light processing elements with the first and second linear configurations formed by the one or more light pass-through sections;
wherein the surface of the housing with the one or more light pass-through sections is configured to be in contact with skin of a user when the wearable sensor system is worn;
wherein data captured for the first and second shared axes of orientation between the accelerometer and the PPG optical sensor are time synchronized to provide co-sampled measurements from the accelerometer and the PPG optical sensor; and
at least one processor configured totransform the co-sampled accelerometer measurements for each of the first and second shared axes of orientation into respective motion data;
transform the co-sampled PPG measurements for each of the first and second shared axes of orientation into respective heart rate data;
for each shared axis of orientation, of the first and second shared axes of orientation, compare the respective motion data to the respective heart rate data to identify, based on the comparison therebetween, any data point of the respective motion data and any data point of the respective heart rate data for the shared axis of orientation that satisfy matching criteria;
for each shared axis of orientation, of the first and second shared axes of orientation, create respective motion artifact compensated heart rate data by discarding any data point of the respective heart rate data identified as satisfying the matching criteria; and
determine a heart rate value based on the respective motion artifact compensated heart rate data for at least one of the first and second shared axes of orientation.
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Accused Products
Abstract
Technology is described for a wearable sensor system including an accelerometer and a PPG optical sensor having light processing elements including at least one photodetector in at least one linear configuration sharing an axis of orientation with the accelerometer. Heart rate measurements determined from reflected light detected by a photodetector of the light processing elements in a linear configuration are co-sampled with accelerometer measurements for one of its axes sharing its orientation with the linear configuration, thus providing per axis measurements which provide more precise data points for more easily compensating for motion artifacts in heart rate data. A wrist wearable biometric monitoring device is also described which embodies the wearable sensor system and performs active motion artifact compensation.
42 Citations
13 Claims
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1. A wearable sensor system for providing heart rate measurement per shared axis of orientation, wherein the wearable sensor system is susceptible to motion artifacts that can adversely affect heart rate determinations, the system comprising:
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an accelerometer configured to provide accelerometer measurements for at least first and second accelerometer axes of orientation that are orthogonal to one another; a photoplethysmography (PPG) optical sensor having at least first and second linear configurations of light processing elements that are orthogonal to one another; and a housing configured to support and position the accelerometer and the first and second linear configurations of light processing elements of the PPG optical sensor so that the first linear configuration of light processing elements and the first accelerometer axis of orientation have a first shared axis of orientation, and the second linear configuration of light processing elements and the second accelerometer axis of orientation have a second shared axis of orientation; the housing having a surface with one or more light pass-through sections forming at least first and second linear configurations matching the at least first and second linear configurations of the light processing elements, and the housing aligning the first and second linear configurations of light processing elements with the first and second linear configurations formed by the one or more light pass-through sections; wherein the surface of the housing with the one or more light pass-through sections is configured to be in contact with skin of a user when the wearable sensor system is worn; wherein data captured for the first and second shared axes of orientation between the accelerometer and the PPG optical sensor are time synchronized to provide co-sampled measurements from the accelerometer and the PPG optical sensor; and at least one processor configured to transform the co-sampled accelerometer measurements for each of the first and second shared axes of orientation into respective motion data; transform the co-sampled PPG measurements for each of the first and second shared axes of orientation into respective heart rate data; for each shared axis of orientation, of the first and second shared axes of orientation, compare the respective motion data to the respective heart rate data to identify, based on the comparison therebetween, any data point of the respective motion data and any data point of the respective heart rate data for the shared axis of orientation that satisfy matching criteria; for each shared axis of orientation, of the first and second shared axes of orientation, create respective motion artifact compensated heart rate data by discarding any data point of the respective heart rate data identified as satisfying the matching criteria; and determine a heart rate value based on the respective motion artifact compensated heart rate data for at least one of the first and second shared axes of orientation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for use with a wearable sensor system that includes an accelerometer, a photoplethysmography (PPG) optical sensor, and a housing,
the accelerometer configured to provide accelerometer measurements for at least first and second accelerometer axes of orientation that are orthogonal to one another, the PPG optical sensor having at least first and second linear configurations of light processing elements that are orthogonal to one another, and the housing configured to support and position the accelerometer and the first and second linear configurations of light processing elements of the PPG optical sensor so that the first linear configuration of light processing elements and the first accelerometer axis of orientation have a first shared axis of orientation, and the second linear configuration of light processing elements and the second accelerometer axis of orientation have a second shared axis of orientation, the housing having a surface with one or more light pass-through sections forming at least first and second linear configurations matching the at least first and second linear configurations of the light processing elements, and the housing aligning the first and second linear configurations of light processing elements with the first and second linear configurations formed by the one or more light pass-through sections, wherein the surface of the housing with the one or more light pass-through sections is configured to be in contact with skin of a user when the wearable sensor system is worn, the method for active motion artifact compensation of heart rate data based on measurements taken for at least the first and second axes of orientation shared by the light processing elements of the PPG optical sensor and the accelerometer, the method comprising: -
obtaining co-sampled accelerometer measurement data and PPG measurement data for at least the first and second axes of orientation shared by the accelerometer and the light processing elements of the PPG optical sensor; transforming the co-sampled accelerometer measurement data for each of the at least first and second shared axes of orientation into respective motion data defined in terms of one or more reference parameters; transforming the co-sampled PPG measurement data for each of the at least first and second shared axes of orientation into respective heart rate data defined in terms of the same one or more reference parameters; for each shared axis of orientation, of the first and second shared axes of orientation, identifying any data point of the respective motion data and any data point of the respective heart rate data that satisfy matching criteria; and for each shared axis of orientation, of the first and second shared axes of orientation, creating respective motion artifact compensated heart rate data by discarding any data point of the respective heart rate data identified as satisfying the matching criteria. - View Dependent Claims (10, 11, 12, 13)
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Specification