Head-Mounted Display Hinge Calibration for Accurate 6DoF Pose Tracking
Solution Overview
Problem
Existing XR HMDs face challenges in consistently determining accurate six degrees of freedom (6DoF) poses due to suboptimal calibration, particularly with limitations in known parameters and feature availability, leading to inefficient virtual content rendering and user interaction.
Innovation Solution
Utilize HMD hinge motion to calibrate the device by detecting movement of the display hinge through sensors like IMUs, optical encoders, or strain gauges, leveraging known start and stop points to determine calibration parameters and pose constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods are used for HMD, then the calibration process can be completed with existing parameters, but the accuracy of 6DoF pose determination is suboptimal
Solution Approach 1:
The patent performs preliminary actions by utilizing the known hinge motion range and start/stop points before conducting the actual calibration. The system pre-establishes the relationship between hinge position and display orientation, which serves as a foundation for more accurate 6DoF pose determination without requiring complex real-time calculations
Solution Approach 2:
The patent introduces hinge motion as an intermediary element to bridge the calibration process. By using the mechanical hinge's known motion characteristics as a mediator, the system can determine display orientation and calculate 6DoF poses more accurately without directly relying on complex sensor fusion alone
2Measurement precision
If more calibration parameters are used to improve accuracy, then the 6DoF pose determination becomes more accurate, but the calibration process becomes more complex and time-consuming
Solution Approach 1:
The patent utilizes preliminary information about the hinge's range of motion and endpoint positions to streamline the calibration process. By pre-knowing the hinge motion characteristics, the system reduces the time required for calibration while maintaining high accuracy in 6DoF pose determination
Solution Approach 2:
The patent changes the approach by incorporating hinge position parameters into the calibration process. Instead of relying solely on traditional sensor calibration parameters, the system integrates hinge motion parameters to achieve accurate pose determination more efficiently
3Measurement precision
If hinge motion is utilized for calibration, then the accuracy of pose determination is enhanced, but the device requires additional sensors and measurement capabilities
Solution Approach 1:
The patent applies universality by making existing sensors serve multiple functions. The same sensors used for tracking head motion are also utilized to detect hinge position and orientation, eliminating the need for dedicated hinge sensors while maintaining calibration accuracy
Solution Approach 2:
The system performs self-service calibration by using its own existing sensor suite to detect hinge motion and determine display orientation. The HMD uses its inherent sensing capabilities to calibrate itself without requiring external calibration equipment or additional specialized sensors
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
Enhances the accuracy and efficiency of 6DoF pose determination, improving the seamless integration of virtual content with the real world and enhancing user interaction in XR environments.
Implementation Method 1
obtaining, by one or more sensors of the HMD, sensor measurements during rotation of a display of the HMD between a first end of a range of motion of a hinge of the display about an axis and a second end of the range of motion of the hinge about the axis
Data Source
AI summary
Systems and techniques are described herein for using head mounted display (HMD) hinge motion to calibrate the head mounted device. For example, an device (or component of the device) can obtain, via one or more sensors, sensor measurements during rotation of a display of the HMD between a first end of a range of motion of a hinge of the display about an axis and a second end of the range of motion of the hinge about the axis; determine parameters of the HMD based on the sensor measurements and the rotation of the display between the first end of the range of motion of the hinge and the second end of the range of motion of the hinge about the axis; and determine pose information for the HMD based on the determined parameters.