Posture calibration for activity monitoring
A method and system for activity monitoring of a user are disclosed. In a first aspect, the method comprises calibrating posture by the user to determine a calibration vector. The method includes validating the calibration vector by comparing an anteroposterior axis to a threshold, wherein activity of the user is monitored using the validated calibration vector. In a second aspect, a wireless sensor device comprises a processor and a memory device coupled to the processor, wherein the memory device includes an application that, when executed by the processor, causes the processor to receive a posture calibration request from the user and to determine a calibration vector based on the received request. The application, when executed by the processor, further causes the processor to validate the calibration vector by comparing an anteroposterior axis to a threshold, wherein activity of the user is monitored using the validated calibration vector.
1. A method for activity monitoring of a user, the method comprising:
calibrating posture by the user to determine a calibration vector; and
validating the calibration vector by comparing an anteroposterior axis to a threshold, wherein activity of the user is monitored by any of:
pedometer activity using a vertical component of an acceleration vector of the user;
fall detection using p-norm of an acceleration vector of the user to detect an impact and an angle of the acceleration vector with respect to the validated calibration vector thereby determining a horizontal position of the user after impact; and
posture detection using both an acceleration vector of the user and the validated calibration vector.
2. The method of claim 1 , further comprising:
in response to a validation failure, monitoring the activity of the user independent of the calibration vector and reporting an unknown posture for the user; and
calibrating the posture implicitly when the user is walking.
3. The method of claim 2 , further comprising:
in response to the validation failure, determining whether to recalibrate the posture explicitly.
4. The method of claim 1 , wherein the validating further comprises:
ensuring a magnitude of acceleration along the anteroposterior axis is less than the threshold.
5. The method of claim 2 , wherein the validation failure occurs when a magnitude of acceleration along the anteroposterior axis is greater than or equal to the threshold.
6. The method of claim 1 , wherein calibrating the posture further comprises any of the user notifying a wireless sensor device when the user is in a vertical position and the user placing the wireless sensor device on the user's chest when the user is in a vertical position.
7. The method of claim 6 , wherein the notifying further comprises any of tapping of the wireless sensor device, selecting a button of the wireless sensor device, and interacting with a mobile application interface of the wireless sensor device.
8. The method of claim 6 , further comprising:
in response to the placing, recognizing contact impedance to show attachment by the wireless sensor device.
9. The method of claim 2 , wherein calibrating the posture implicitly further comprises deriving a vertical position by a wireless sensor device based on an acceleration vector corresponding to footsteps when the user is walking.
10. The method of claim 2 , wherein the monitoring the activity of the user independent of the calibration vector further comprises any of:
monitoring pedometer activity using 2-norm of an acceleration vector of the user; and
monitoring fall detection using p-norm of the acceleration vector to detect an impact.
11. The method of claim 1 , further comprising:
attaching a wireless sensor device to the user in any orientation and on any location.
12. The method of claim 1 , further comprising:
relaying notification information of the activity monitoring of the user to another user or device.
13. A wireless sensor device for activity monitoring of a user, the wireless sensor device comprising:
a processor; and
a memory device coupled to the processor, wherein the memory device includes an application that, when executed by the processor, causes the processor to:
receive a posture calibration request from the user;
determine a calibration vector based on the received request; and
validate the calibration vector by comparing an anteroposterior axis to a threshold, wherein activity of the user is monitored by any of:
pedometer activity using a vertical component of an acceleration vector of the user;
fall detection using p-norm of an acceleration vector of the user to detect an impact and an angle of the acceleration vector with respect to the validated calibration vector thereby determining a horizontal position of the user after impact; and
posture detection using both an acceleration vector of the user and the validated calibration vector.
14. The wireless sensor device of claim 13 , wherein the application, when executed by the processor, further causes the processor to:
in response to a validation failure, monitor the activity of the user independent of the calibration vector and report an unknown posture for the user; and
calibrate the posture implicitly when the user is walking.
15. The wireless sensor device of claim 13 , wherein to validate further comprises to ensure a magnitude of acceleration along the anteroposterior axis is less than the threshold.
16. The wireless sensor device of claim 14 , wherein the validation failure occurs when a magnitude of acceleration along the anteroposterior axis is greater than or equal to the threshold.
17. The wireless sensor device of claim 14 , wherein to monitor the activity of the user independent of the calibration vector further comprises causing the processor to perform any of:
monitoring pedometer activity using 2-norm of an acceleration vector of the user; and
monitoring fall detection using p-norm of the acceleration vector to detect an impact.
18. The wireless sensor device of claim 13 , wherein the application, when executed by the processor, further causes the processor to:
relay notification information of the activity monitoring of the user to another user or device.