Wearable monitoring devices with passive and active filtering
A wearable device includes a housing with a window and an electronic module supported by the housing. The electronic module includes a photoplethysmography sensor, a motion sensor, and a signal processor that processes signals from the motion sensor and signals from the photoplethysmography sensor. The signal processor is configured to remove frequency bands from the photoplethysmography sensor signals that are outside of a range of interest using a band-pass filter to produce pre-conditioned signals, and to further process the pre-conditioned signals using the motion sensor signals to reduce motion artifacts from footsteps during subject running. The device includes non-air light transmissive material in optical communication with the photoplethysmography sensor and the window that serves as a light guide for the photoplethysmography sensor. The window optically exposes the photoplethysmography sensor to a body of a subject wearing the device via the non-air light transmissive material.
1. A limb-worn or digit-worn device, comprising:
a housing comprising at least one window;
an electronic module supported by the housing, the electronic module comprising at least one photoplethysmography (PPG) sensor comprising a plurality of optical emitters for generating visible light and infrared light, and at least one optical detector, at least one motion sensor configured to measure footstep information from the limb of the subject, and at least one signal processor configured to process signals from the at least one motion sensor and signals from the at least one PPG sensor, wherein the at least one signal processor is configured to remove frequency bands from the signals from the at least one PPG sensor that are outside of a range of interest using at least one band-pass filter to produce pre-conditioned signals, and to further process the pre-conditioned signals using the signals from the at least one motion sensor to reduce motion artifacts from footsteps during subject running; and
non-air light transmissive material in optical communication with the at least one PPG sensor and the window, wherein the at least one window optically exposes the at least one PPG sensor to a body of a subject wearing the device, wherein the non-air light transmissive material comprises inner and outer surfaces, and wherein the outer surface of the non-air light transmissive material comprises cladding material that defines a light guiding region that serves as a light guide for the at least one PPG sensor.
2. The device of claim 1 , wherein the at least one motion sensor comprises an optical motion noise sensor.
3. The device of claim 1 , wherein the at least one motion sensor comprises an inertial sensor.
4. The device of claim 1 , wherein the at least one signal processor is further configured to filter the pre-conditioned signals via at least one of the following: adaptive filtering, phase filtering, and frequency filtering.
5. The device of claim 1 , wherein the non-air light transmissive material comprises at least one optical lens in optical communication with the at least one PPG sensor.
6. The device of claim 1 , wherein the at least one signal processor is further configured to process the pre-conditioned signals to determine a real-time heart rate and a real-time respiration rate for the subject.
7. The device of claim 1 , wherein the at least one signal processor is further configured to process the pre-conditioned signals to determine a real-time heart rate and real-time heart rate variability (HRV) for the subject.
8. The device of claim 1 , wherein the at least one signal processor is further configured to process the pre-conditioned signals to determine a real-time heart rate for the subject and to generate data integrity information about the real-time heart rate.
9. The device of claim 1 , wherein the at least one signal processor is further configured to process the pre-conditioned signals to determine a real-time heart rate and real-time blood oxygenation for the subject.
10. The device of claim 1 , wherein the at least one signal processor is further configured to process the pre-conditioned signals to determine a real-time heart rate and real-time blood pulse volume for the subject.
11. The device of claim 10 , wherein the at least one signal processor is further configured to process the pre-conditioned signals using an integration circuit to estimate blood volume over each blood pulse.
12. The device of claim 1 , wherein the at least one signal processor is further configured to process the pre-conditioned signals, after motion artifacts have been reduced from the pre-conditioned signals, to determine a real-time heart rate for the subject.
13. The device of claim 1 , wherein the at least one signal processor is further configured to process the pre-conditioned signals and the signals from the at least one motion sensor to determine a real-time heart rate for the subject.
14. The device of claim 1 , wherein the at least one signal processor is further configured to process the pre-conditioned signals to determine a real-time blood pressure for the subject.