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 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 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 sensor manager for virtual reality, augmented reality, mixed reality, or extended reality, configured to: communicate with at least one input module attached to a user, the at least one input module having at least one inertial measurement unit and at least one sensor separate from the inertial measurement unit; receive, from the at least one sensor, at least one indicator of time instance; identify, based on the at least one indicator, a segment of motion inputs generated by the at least one inertial measurement unit; and determine a gesture classification from the segment of motion inputs.

Abstract: A sensor manager for virtual reality, augmented reality, mixed reality, or extended reality, configured to: communicate with a plurality of input modules attached to different parts of a user; communicate, with an application that generates a virtual reality content presented to the user; determine a context of the application, including geometry data of objects in the virtual reality content with which the user is allowed to interact with, commands to operate the objects, and gestures usable to invoke the respective commands; process input data received from the input modules to recognize gestures performed by the user; and communicate with the application to invoke commands identified based on the context of the application and the gestures recognized from the input data.

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: 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 device having a ring-shaped housing configured to be wrapped around a finger of a user, the ring-shaped housing having a base portion and a clip portion, the clip portion connected to the base portion via a hinge, wherein the clip portion is configured to attach to a phalange of a user's hand; and a sensor physically attached to the base portion, the sensor including at least one electrical component.

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: An apparatus having a touch pad configured to receive touch input from a finger of the user, wherein a surface of the touch pad has a curved portion for sensing touch; 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: 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 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: 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: 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, 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 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 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 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: 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.