Abstract: A system to combine inertial-based measurements and optical-based measurements via a Kalman-type filter. For example, a sensor module uses an inertial measurement unit to generate first positions and first orientations of the sensor module at a first time interval during a first period of time containing multiple of the first time interval. At least one camera is used to capture images of the sensor module at a second time interval, larger than the first time interval, during the first period of time containing multiple of the second interval. Second positions and second orientations of the sensor module during the first period of time are computed from the images. The filter receives the first positions, the first orientations, the second positions, and the second orientations to generate estimates of position and orientation of the sensor module at a time interval no smaller than the first time interval.

Abstract: A system, having: a first sensor module having an inertial measurement unit and configured to be attached to a forearm of a user and to generate first motion data identifying an orientation of the forearm connected between a hand of the user and an upper arm of the user; a second sensor module having an inertial measurement unit and configured to be attached to the hand of the user and to generate second motion data identifying an orientation of the hand; and a computing device communicatively coupled to the first sensor module and the second sensor module through communication links, the computing device configured to calculate, based on the orientation of the forearm, a position of the forearm, and the orientation of the hand, an orientation of the upper arm.

Abstract: A method including receiving, in a computing device, periodic measurements of accelerations from a plurality of sensor modules. The computing device determines whether each respective sensor module of the sensor modules is attached to a respective part of a user from the periodic measurements of accelerations from the plurality of sensor modules as received. In response to the determination that each respective sensor module of the sensor modules is attached to the respective part of the user, the method includes initiating, by the computing device, a calibration operation to calibrate orientation measurements of the sensor modules relative to a common reference system defined based on an orientation of the user.

Abstract: A system, having: a first sensor module having an inertial measurement unit and configured to be attached to a forearm of a user and to generate first motion data identifying an orientation of the forearm connected between a hand of the user and an upper arm of the user; a second sensor module having an inertial measurement unit and configured to be attached to the hand of the user and to generate second motion data identifying an orientation of the hand; and a computing device communicatively coupled to the first sensor module and the second sensor module through communication links, the computing device configured to calculate, based on the orientation of the forearm, a position of the forearm, and the orientation of the hand, an orientation of the upper arm.

Abstract: A method including receiving, in a computing device, periodic measurements of accelerations from a plurality of sensor modules. The computing device determines whether each respective sensor module of the sensor modules is attached to a respective part of a user from the periodic measurements of accelerations from the plurality of sensor modules as received. In response to the determination that each respective sensor module of the sensor modules is attached to the respective part of the user, the method includes initiating, by the computing device, a calibration operation to calibrate orientation measurements of the sensor modules relative to a common reference system defined based on an orientation of the user.

Abstract: A system including a computing device receiving a first indication, the first indication indicating that a plurality of sensor modules are positioned in placeholders in a container device, wherein the placeholders are configured to hold the plurality of sensor modules at pre-determined positions and orientations in the container device. In response to the first indication, the computing device calibrates orientation measurements of the plurality or sensor modules relative to a first common reference system based on the pre-determined positions and orientations in the container device.