Calibration of a chest-mounted wireless sensor device for posture and activity detection

摘要

A method and system for calibrating a wireless sensor device are disclosed. In a first aspect, the method comprises determining a vertical calibration vector and determining a rotation matrix using the vertical calibration vector to line up native axes of the wireless sensor device with body axes. 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 determine a vertical calibration vector and to determine a rotation matrix using the vertical calibration vector to line up native axes of the wireless sensor device with body axes.

主权项

1. A method for calibrating a wireless sensor device, the method comprising:
detecting accelerometer data in 3 axes within a predetermined time period by the wireless sensor device; determining an acceleration vector corresponding to a footstep number; determining a vertical calibration vector using the acceleration vector and a walking detection algorithm, wherein the walking detection algorithm:
calculates a signal magnitude area (SMA) for the predetermined time period using the accelerometer data,calculates a magnitude of acceleration in a horizontal plane and an overall magnitude of acceleration, andcompares the SMA to a first threshold and the overall magnitude of acceleration to both a second threshold and a third threshold for a result of the walking detection algorithm; and determining a rotation matrix using the determined vertical calibration vector to line up native axes of the wireless sensor device with body axes.