6-DOF Tracking via Synchronized Camera Exposure and LED Flashing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current head-mounted display devices face challenges in 6-degree-of-freedom tracking due to high cost, power consumption, and tracking stability issues, particularly with multiple cameras and electromagnetic/ultrasonic sensors being prone to interference and errors.
Innovation Solution
A head-mounted display system with two channels of tracking cameras and IMU sensors, where camera exposure durations and LED light synchronization are optimized to ensure accurate 6-degree-of-freedom tracking data for both the head and hand, reducing system load and power consumption by controlling odd and even frames separately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If more than two tracking cameras are provided on the head-mounted display device, then tracking performance is improved, but cost and power consumption increase
Solution Approach 1:
The patent combines visual tracking (two cameras) with inertial tracking (IMU sensors on both head-mounted device and handle controller) into a unified 6-DOF tracking system. The IMU sensors provide continuous motion data that complements the visual tracking, allowing the system to achieve high tracking performance without requiring multiple power-consuming cameras.
Solution Approach 2:
The two tracking cameras serve multiple functions: they track both the head-mounted display device and the handle controller simultaneously, and they work in conjunction with the IMU sensors to provide comprehensive 6-DOF tracking data for both devices, reducing the need for additional dedicated sensors.
2Measurement precision
If more than two tracking cameras are provided on the head-mounted display device, then tracking performance is improved, but device complexity increases
Solution Approach 1:
The patent merges the tracking functions into a unified system using two cameras plus IMU sensors on both devices. This combination provides complete 6-DOF tracking capability without the complexity of multiple separate camera systems, as the IMU sensors handle the heavy lifting for motion detection while the cameras provide visual confirmation and geometric pattern tracking.
Solution Approach 2:
The tracking system is segmented into two independent but coordinated subsystems: one on the head-mounted display device (two cameras + first IMU sensor) and one on the handle controller (geometric pattern + second IMU sensor). This segmentation allows each subsystem to be optimized independently while working together to achieve comprehensive tracking.
3Measurement precision
If electromagnetic or ultrasonic transmitters are provided on the handle controller, then 6-DOF tracking is achieved, but tracking stability deteriorates due to environmental interference
Solution Approach 1:
The patent replaces electromagnetic/ultrasonic tracking systems with an optical-mechanical system using two tracking cameras and geometric patterns. This substitution eliminates susceptibility to electromagnetic and ultrasonic environmental interference, providing more stable and reliable tracking performance in complex environments.
Solution Approach 2:
The geometric pattern on the handle controller serves as an intermediary that the two tracking cameras can reliably detect and track. This visual intermediary is immune to electromagnetic and ultrasonic interference, providing stable tracking data even in environments with complex signal interference.
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 reduces cost and power consumption while maintaining tracking accuracy and stability, alleviating CPU resource conflicts and improving user experience by optimizing camera placement and LED synchronization.
Implementation Method 1
the geometric pattern on the handle controller of the user is tracked in real time
Implementation Method 2
inertial-navigation data of the first IMU sensor
Data Source
AI summary
A head-mounted display system and a 6-degree-of-freedom tracking method and apparatus thereof are disclosed. The method includes: controlling two channels of tracking cameras so that central moments of exposure durations of each frame of the two channels of tracking cameras are same, and controlling so that a lightening moment of the LED lights on the handle controller is synchronized with the middle moment of the exposure duration of an even-number frame of the two channels of tracking cameras; calculating 6-degree-of-freedom tracking data of the head-mounted display device in a three-dimensional space in real time according to acquired image data of an odd-number frame of the two channels of tracking cameras; and calculating 6-degree-of-freedom tracking data of the handle controller in the three-dimensional space in real time according to acquired image data of an even-number frame of the two channels of tracking cameras.