Controller Tracking via Light Focus Analysis
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Solution Overview
Problem
Existing controller-tracking systems in immersive XR environments are inefficient and unreliable, especially at longer ranges and with multiple controllers, due to limitations in light-based tracking methods.
Innovation Solution
A controller-tracking system using a camera on a head-mounted display that detects light sources on controllers, determining their focus level and distance to accurately calculate the controller's pose in a global coordinate space, enabling reliable tracking of one or more controllers over a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light-emitting elements are arranged on controllers for tracking, then controller visibility and tracking capability are improved, but tracking range is limited to considerably shorter distances and becomes error-prone at longer ranges
Solution Approach 1:
The patent changes the optical parameters of the light sources by using multiple wavelengths (colors) of light instead of a single wavelength. This allows the camera to determine distance through focus analysis, extending the reliable tracking range from short distances to distances up to 1.5 meters or more while maintaining tracking reliability.
Solution Approach 2:
The patent introduces focus information as an intermediary measurement between the light source and the camera. By analyzing the focus level of light sources at different wavelengths, the system can determine distance information, which then enables accurate pose calculation at extended ranges beyond what direct light detection could achieve.
2Measurement precision
If multiple light sources are used on controllers, then tracking accuracy over distance is improved, but the system becomes more complex
Solution Approach 1:
The patent uses multiple wavelengths of light from the same or different light sources, leveraging the optical property that different wavelengths focus at different distances. This approach achieves precise distance measurement without requiring complex additional hardware, as the focus difference itself becomes the measurement parameter.
Solution Approach 2:
The existing camera hardware is made multi-functional by using it not only for detecting the presence and position of light sources but also for determining distance through focus analysis. This eliminates the need for separate distance measurement devices, reducing overall system complexity while improving measurement precision.
3Measurement precision
If focus level analysis is performed on light sources, then distance determination accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent transforms the camera's focus state into a measurable parameter for distance determination. By analyzing the focus level of light sources at different wavelengths in captured images, the system can accurately determine distance without requiring complex additional processing hardware, as the focus information is inherently captured by the camera sensor.
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
The system provides simple, reliable, and accurate real-time tracking of controllers, suitable for ranges from 20 cm to 1.5 meters, and supports multiple controllers simultaneously, enhancing user interaction in XR environments.
Implementation Method 1
determine a level of focussing of the at least one light source in the at least one image, based on characteristics associated with pixels of the at least one image segment; determine a distance between the at least one camera and the at least one light source, based on the level of focussing of the at least one light source
Data Source
AI summary
A controller-tracking system includes: camera(s) arranged on head-mounted display (HMD); one or more light sources arranged on controller(s) to be tracked, and controller(s) being associated with the HMD. The light sources provide light having wavelength(s). The processor(s) are configured to receive image(s) representing controller(s); identify image segment(s) in image(s) that represents light source(s); determine level of focussing of light source(s) in image(s), based on characteristics associated with pixels of image segment(s); determine distance between camera(s) and light source(s), based on level of focussing, intrinsic parameters of camera(s), and reference focussing distance corresponding to wavelength of light provided by light source(s); and determine pose of controller(s) in global coordinate space of real-world environment, using distance between camera(s) and light source(s).