System and method for detecting transitions between sitting and standing states

Abstract

A system and method are described herein for detecting a user's transition between sitting and standing postures. Transitions between sitting and standing states are reliably detected using an accelerometer attached to the user. By modeling error introduced by the accelerometer, and correcting for this error, transitions between sitting and standing states are reliably detected. A microprocessor coupled to the accelerometer converts the captured accelerometer data to approximate vertical acceleration. Vertical velocity, which includes accelerometer error, is determined from the approximate vertical acceleration. The vertical velocity is corrected, and the corrected vertical velocity used to determine vertical displacement. Transitions between sitting and standing states are determined from the vertical displacement.

What is claimed is: 
     
         1 . A method of detecting a user transition between sitting and standing states comprising:
 capturing, by a tri-axial accelerometer attached to a user, a plurality of points of accelerometer data over a period of time,   determining, by a microprocessor, a plurality of points of approximate vertical acceleration due to user motion from the plurality of points of accelerometer data,   determining, by the microprocessor, a plurality of points of vertical velocity from the plurality of points of approximate vertical acceleration due to user motion,   segmenting, by the microprocessor, the plurality of points of vertical velocity,   correcting, by the microprocessor, each of the segments of points of vertical velocity,   determining, by the microprocessor, a segment of points of vertical displacement for each corrected segment of points of vertical velocity, and   detecting, by the microprocessor, a user transition between sitting and standing states from the segments of points of vertical displacement.