Millimeter Wave Hand Tracking via Unique Transponder Signals
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Solution Overview
Problem
Current hand-tracking systems for virtual and augmented reality, relying on inertial motion tracking or optical motion capture, face challenges such as drift over time, interference from environmental materials, and inaccurate tracking due to marker visibility issues.
Innovation Solution
A system utilizing a locatable glove equipped with millimeter-wave transponders that re-radiate unique signals, allowing a pose determination device to triangulate the position and orientation of the glove, enabling accurate hand tracking even when markers are not in the direct line of sight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical motion capture with markers is used to track hand position, then the position can be determined visually, but the markers must be in the line of sight of the camera and visually distinct from each other, otherwise tracking accuracy deteriorates
Solution Approach 1:
The patent replaces optical motion capture with millimeter-wave radar-based tracking. The radar system uses electromagnetic waves to detect transponders on the hand, eliminating the need for visual line of sight. The radar waves can penetrate through obstacles and work in various lighting conditions, resolving the contradiction between tracking accuracy and line of sight requirements.
Solution Approach 2:
The patent changes the detection parameter from optical (visible light) to electromagnetic (millimeter-wave). This parameter change allows the system to detect transponders without requiring visual line of sight, as millimeter waves can pass through many materials that block visible light, thereby maintaining tracking accuracy while removing the line of sight constraint.
2Measurement precision
If inertial sensors are placed on a glove to track hand movement, then rotations and hand pose can be determined, but the position in space cannot be captured and the tracking drifts over time
Solution Approach 1:
The patent combines inertial sensors on the glove with external millimeter-wave radar transponders. The inertial sensors provide continuous local orientation data while the radar transponders provide absolute position references. This merging of systems allows the determination of hand pose with accurate spatial positioning that does not drift over time, as the radar periodically corrects the inertial navigation accumulation errors.
3Measurement precision
If multiple positioning transponders are used on the glove, then the position can be triangulated accurately, but each transponder requires unique signal characteristics to be distinguished
Solution Approach 1:
The patent implements periodic transmission of unique signal characteristics from multiple transponders. Each transponder transmits its identification signal at different time intervals or with different periodic patterns, allowing the radar system to distinguish between multiple transponders through time-based or pattern-based differentiation. This enables accurate triangulation of multiple points while managing signal complexity through structured periodic transmission.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides precise and reliable hand tracking by distinguishing individual transponders based on unique signal characteristics, improving accuracy and robustness compared to existing methods.
Implementation Method 1
Each positioning transponder is configured to re-radiate a received signal, the re-radiated signal being unique to the positioning transponder
Data Source
AI summary
A system includes a locatable glove and a pose determination device. The locatable glove includes a glove body worn over a hand of a user, and a plurality of positioning transponders. The positioning transponders are coupled to the glove body at various positions on the glove body, and each re-radiates a received signal, the re-radiated signal unique to the positioning transponder. The pose determination device includes a plurality of antennas and a controller. The antennas are each configured to receive the unique signals re-radiated by the positioning transponders. The antennas are physically separated from each other. The controller is communicatively coupled to the plurality of antennas, and is configured to determine, for each of the received unique signals, a location of the position on the locatable glove of the positioning transponder corresponding to the unique signal.