Pose calibrations for inertial sensors in rehabilitation applications

Inertial motion capture systems are now used across a broad range of applications where optical motion capture systems would traditionally be used. The decreasing cost of building inertial sensors has prompted many researchers to build inertial motion capture systems for use in rehabilitation applications where they are used to track body movement. Pose calibrations are the standard method used to estimate and correct for body-sensor alignment when using inertial sensors but they have the potential to introduce a systematic error that is carried through the whole usage session. Pose calibrations are the only suitable method for inexpert users and interactive applications. Validation of the pose calibration methods is carried out using an optical motion capture system. The accuracy of the pose calibration is tested under several practical variations of the technique, we quantify the approximate errors that can be introduced by variations of the implementation and on the choice of pose used. Finally we make recommendations on how an improved pose calibration scheme should be implemented.