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: An apparatus having a ring-shaped housing configured to be wrapped round a finger of a user, the ring-shaped housing having an opening or a joint at a first point round the finger and a first contiguous section that is at a location opposite to the first point across a central axis of the ring-shaped housing; an antenna configured in the ring-shaped housing in the contiguous section; an inertial measurement unit configured to measure motions of the finger; a light-emitting diode (LED) indicator configured on an outer portion of the ring-shaped housing; a charging pad configured to charge a battery configured in the ring-shaped housing; and/or a touch pad configured to receive touch input from a finger of the user.

Abstract: A system to track orientations of parts of a user based on both images and inertial measurement units (IMUs). For example, the system receives images showing a portion of the user wearing sensor modules. The system receives a first set of orientation measurements generated by the sensor modules attached to some parts of the user. The system determines the second set of orientation measurements of one or more features of the portion of the user from the images. The system provides the first set of orientation measurements and the second set of orientation measurements as input to an artificial neural network that is configured to predict orientation measurements of the one or more other parts of the user that would be measured by additional sensor modules if the additional sensor modules were to be attached to the other parts of the user.

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 configured to track its orientation. In a kinematic chain, multiple rigid parts of a user are connected via joints. At least one rigid part is not independently tracked using sensor modules. The computing device computes the estimates of the orientation of the rigid part, separately using an artificial neural network model or using assumed orientation relations. During a sequence of actions performed by the user, orientation estimates produced by one technique can be more accurate than another technique at some time instances, but less accurate at other time instances. An artificial neural network is trained to classify the accuracy the estimates and/or to combine the estimates to provide improved orientation estimates for the duration of the sequence of actions.

Abstract: Automatically switching between different modes of using user motions to control applications running in a computing device. For example, the computing device communicates with devices attached to portions of a user (e.g., arm, hand) respectively to receive motion-based measurement data. One of the devices is attached to a portion of the user (e.g., hand) and capable of tracking six independent motions of the portion of the user. The computing device can generate input controls for one or more applications running therein using measurements based on the six independent motions in a first mode, and using measurements based on three of the six independent motions in a second mode. Based on an indication derived from inputs, or the lack of inputs, from some of the devices attached to the portions of the user, the computing device can automatically switch between the first and second modes.

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 having a plurality of sensor modules and a stereo camera and a computing device. Each sensor module has an inertial measurement unit (IMU) measuring its orientation relative to a reference orientation. Different IMUs may have different reference orientations. To calibrate the IMUs with respect to a common reference (e.g., defined based on a standardized pose of a user), the stereo camera captures a stereo image of a respective sensor module attached to a respective portion of the user; the inertial measurement unit of the respective sensor module generates an orientation measurement at a time of capturing the stereo image; and the computing device calculates, based on the stereo image, at least one orientation and uses the orientation and the orientation measurement in determining a rotation that calibrates measurements of the inertial measurement unit relative to the common reference.

Abstract: A system including a plurality of sensor modules, each module having an inertial measurement unit (IMU) and being attached to a respective body 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 that a user is at a predefined pose, which the predefined pose of the user is representative of the forearms and the upper arms of the user lying in a horizontal plane. A head mount display (HMD) attached to a head of the user using a camera to generate camera data, the HMD calculating the first length using the camera data, and the first length is calculated as corresponds to a distance between hands of the user and shoulders of the user; the computing device determining one or more lengths of one or more bones of the user based on the first length and the plurality of orientations of arm bones of the user at the predefined pose.

Abstract: A method to calibrate orientation measurements of an inertial measurement unit of a sensor device based on an image of a portion of a user to which the sensor device is attached. For example, the sensor device can be configured to be attached to the middle phalange of the index finger and configured with a touch pad. In response to the determination that the thumb of the user is placed on the touch pad of the sensor device, the camera of the system can capture the image showing that the hand of the user. A convolutional neural network is configured to determine, from the image, orientations of predefined features of the hand of the user. A further artificial neural network is configured to determine the orientation of the sensor device based on the orientations of the predefined features to calibrate the orientation measurements of the inertial measurement unit.

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 data input device having 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. A method can include: receiving sensor data from a handheld device; calculating hand movement characteristics in three dimensional space based on the sensor data; calculating the position and orientation of the components of the handheld device; identifying positions and movements of one or more fingers of a user manipulating the handheld device; identifying a gesture from the positions and movements of one or more fingers of a user manipulating the handheld device; identifying a recognized gesture corresponding to the identified gesture; and dispatching an event notifying the gesture to an application.

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.

Abstract: A handheld controller having at least one input device, a left capacitive sensor electrode mounted in a left portion of the handheld device; a right capacitive sensor electrode mounted in a right portion of the handheld device; and a microcontroller. The input device is configured to receive user inputs provided via a finger of the hand holding the handheld controller. The handheld controller is symmetric from left to right. The microcontroller is configured to determine whether the hand is a left hand or a right hand based on measurements made via the left capacitive sensor electrode and the right capacitive sensor electrode and dynamically configures the handheld controller has left-handed or right-handed based on the measurements.

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.

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: 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 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: 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 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.