Abstract: A system including: a sensor module having an inertial measurement unit and attached to the head of a user. The sensor module is initially calibrated to measure its orientation relative a reference pose. To recalibrate the sensor module according to a calibration pose, a camera of the sensor module is used to capture an image of at least one optical mark (e.g., configured on devices held in hands in the calibration pose in front of the user). A direction identified from the image is rotated according to the rotational transformation between the reference pose and the calibration pose measured by the sensor module and then projected on to a horizontal plane relative to the reference pose. The angle in the horizontal plane between the projected direction and the front facing direction is used for the calibration of the subsequent orientation measurements of the sensor module.

Abstract: Disclosed herein is a data input device and method of operating the same. In one embodiment, a data input device comprises a plurality of inertial sensor units, one or more touch input devices, a microcontroller configured to collect sensor data from the inertial sensors and the one or more touch input devices and process the sensor data to generate processed sensor data, and a wireless transceiver configured to transmit the processed sensor data to a host computer.

Abstract: A system including a plurality sensor modules, each having an inertial measurement unit and attached to a portion of a user (e.g., upper arm, hand, and/or head) to measure the current orientation of the corresponding portion of the user. A computing device coupled to the sensor modules is configured to identify a type of the current pose of the user, compute a front facing direction of the torso of the user from the sensor measurements, select a torso leaning model based on the pose type, project onto a vertical plane the lengthwise directions of the arms of the user as tracked by the sensor modules attached to the upper arms of the user, and calculate a torso leaning angle from the projected lengthwise directions of the arms.

Abstract: A system having sensor modules and a computing device. Each sensor module has an inertial measurement unit attached to a portion of a user to generate motion data identifying a sequence of orientations of the portion. The sensor modules include a first subset and a second subset that share a common sensor module. The computing device provides orientation measurements generated by the first subset as input to a first artificial neural network to obtain at least one first orientation measurement of the common module, provides orientation measurements generated by the second subset as input to a second artificial neural network to obtain at least one second orientation measurement of the common module, and generates, a predicted orientation measurement of the common module by combining the at least one first orientation measurement of the common module and the at least one second orientation measurement of the common module.

Abstract: A system having sensor modules and a computing device. Each sensor module has an inertial measurement unit attached to a portion of a user to generate motion data identifying a sequence of orientations of the portion. The computing device provides the sequences of orientations measured by the sensor modules as input to an artificial neural network, obtains as output from the artificial neural network a predicted orientation measurement of a part of the user, and controls an application by setting an orientation of a rigid part of a skeleton model of the user according to the predicted orientation measurement. The artificial neural network can be trained to predict orientations measured using an optical tracking system based on orientations measured using inertial measurement units and/or to prediction orientation measurements of some rigid parts in a kinematic chain based on orientation measurements of other rigid parts in the kinematic chain.

Abstract: A system including: a first sensor module having an inertial measurement unit and attached to an upper arm of a user, the first sensor module generating first motion data identifying an orientation of the upper arm; a second sensor module having an inertial measurement unit and attached to a hand of the user, the second sensor module generating second motion data identifying an orientation of the hand; and a computing device coupled to the first sensor module and the second sensor module through communication links, the computing device calculating, based on the orientation of the upper arm and the orientation of the hand, an orientation of a forearm connected to the hand by a wrist of the user and connected to the upper arm by an elbow joint of the user.

Abstract: A system having sensor modules and a computing device. Each sensor module has an inertial measurement unit attached to a portion of a user to generate motion data identifying a sequence of orientations of the portion. The sensor modules include a first subset and a second subset that share a common sensor module. The computing device provides orientation measurements generated by the first subset as input to a first artificial neural network to obtain at least one first orientation measurement of the common module, provides orientation measurements generated by the second subset as input to a second artificial neural network to obtain at least one second orientation measurement of the common module, and generates, a predicted orientation measurement of the common module by combining the at least one first orientation measurement of the common module and the at least one second orientation measurement of the common module.

Abstract: A system including: a first sensor module having an inertial measurement unit and attached to an upper arm of a user, the first sensor module generating first motion data identifying an orientation of the upper arm; a second sensor module having an inertial measurement unit and attached to a hand of the user, the second sensor module generating second motion data identifying an orientation of the hand; and a computing device coupled to the first sensor module and the second sensor module through communication links, the computing device calculating, based on the orientation of the upper arm and the orientation of the hand, an orientation of a forearm connected to the hand by a wrist of the user and connected to the upper arm by an elbow joint of the user.

Abstract: A system including: a plurality of sensor modules having inertial measurement units and attached to different parts of a user (e.g., head, hands, arms) to measure their orientations; a plurality of optical marks attached to the user; a camera attached to the user; and a computing device configured to correct an accumulated error by detecting the optical marks in an image generated by the camera and identifying mismatches in directions of the optical marks (or the sensors, or parts of the users) as measured and/or calculated based on the image and the corresponding directions of the optical marks (or the sensors, or parts of the users) as measured and/or calculated from the orientation measurements generated by the sensor modules.

Abstract: A system including a plurality sensor modules, each having an inertial measurement unit and attached to a portion of a user (e.g., upper arm, hand, and/or head) to measure the current orientation of the corresponding portion of the user. A computing device coupled to the sensor modules is configured to identify a type of the current pose of the user, compute a front facing direction of the torso of the user from the sensor measurements, select a torso leaning model based on the pose type, project onto a vertical plane the lengthwise directions of the arms of the user as tracked by the sensor modules attached to the upper arms of the user, and calculate a torso leaning angle from the projected lengthwise directions of the arms.

Abstract: A system including: a sensor module having an inertial measurement unit and attached to the head of a user. The sensor module is initially calibrated to measure its orientation relative a reference pose. To recalibrate the sensor module according to a calibration pose, a camera of the sensor module is used to capture an image of at least one optical mark (e.g., configured on devices held in hands in the calibration pose in front of the user). A direction identified from the image is rotated according to the rotational transformation between the reference pose and the calibration pose measured by the sensor module and then projected on to a horizontal plane relative to the reference pose. The angle in the horizontal plane between the projected direction and the front facing direction is used for the calibration of the subsequent orientation measurements of the sensor module.

Abstract: A system including: a first sensor module having an inertial measurement unit and attached to an upper arm of a user, the first sensor module generating first motion data identifying an orientation of the upper arm; a second sensor module having an inertial measurement unit and attached to a hand of the user, the second sensor module generating second motion data identifying an orientation of the hand; and a computing device coupled to the first sensor module and the second sensor module through communication links, the computing device calculating, based on the orientation of the upper arm and the orientation of the hand, an orientation of a forearm connected to the hand by a wrist of the user and connected to the upper arm by an elbow joint of the user.

Abstract: A system including: a first sensor module having an inertial measurement unit and attached to a palm of a hand of a user; a second sensor module having an inertial measurement unit and attached to a first bone of a finger (e.g., a middle or proximal phalange bone) on the palm; and a computing device coupled to the first sensor module and the second sensor module to calculate, based on the orientation of the palm and the orientation of the first bone, orientations of the second bones of the finger (e.g., a distal or proximal phalange bone, a metacarpal bone of the thumb) that have no separately attached inertial measurement unit, according to a predetermined ratio of rotation from a reference orientation along a same axis of rotation.

Abstract: A system including: two arm modules each having an inertial measurement unit and attached to an upper arm of a user to measure the current orientations of the upper arms of the user; a head module having an inertial measurement unit and attached to the head of the user to measure the current orientation of the head; and a computing device coupled to the arm modules and the head module to calculate, based on the current orientations of the upper arms and the current orientation of the head, the current orientation of the torso of the user.

Abstract: A system including: a sensor module having an inertial measurement unit and attached to an arm of a user. The sensor module is initially calibrated to measure its orientation relative an initial reference pose. To recalibrate the sensor module, the arm of the user is moved to obtain a measurement of an orientation of the arm at a calibration pose relative to the reference pose. The arm is in a horizontal plan in both the calibration pose and the reference pose. Preferably, both arms are straight in the horizontal plane; and the hands meet each other at the calibration pose. The arm module may have twisted around the arm of the user from the time of the initial calibration and the time of recalibration. A twist of the arm module around the arm of the user is computed from the orientation measurement at the reference pose for recalibration.