Headgear Tracking Using IR Reflective Points and Optical Filtering
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Solution Overview
Problem
Existing headgear tracking systems face challenges in accurately determining angular orientation, particularly in cluttered environments, due to the need for active or passive fiducials that increase complexity, size, weight, and cost, and require precise mounting and unique identification.
Innovation Solution
A method and device using infra-red (IR) reflective points on headgear, filtered to allow only IR light to pass, allowing for accurate determination of angular orientation by imaging and processing the filtered light to identify and position these points, eliminating the need for active or passive fiducials and simplifying the tracking system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active or passive fiducials are used for tracking, then tracking accuracy is improved, but device complexity, size, weight, and cost increase
Solution Approach 1:
The patent extracts and eliminates the fiducial markers from the tracking system, replacing them with natural anatomical landmarks (eyes, nose, mouth) as tracking points. This removes the need for additional fiducial components while maintaining tracking functionality through image processing and feature detection algorithms.
Solution Approach 2:
The camera system serves multiple functions: it captures video for display, performs facial feature detection for tracking, and enables head orientation calculation. This multi-functionality eliminates the need for separate fiducial markers and dedicated tracking hardware, reducing overall system complexity.
2Measurement precision
If active or passive fiducials are used for tracking, then tracking accuracy is improved, but size and weight increase
Solution Approach 1:
The patent removes fiducial markers from the headgear assembly, eliminating their weight contribution. The tracking system now relies solely on the camera and processing unit, reducing the overall weight of the wearable device.
Solution Approach 2:
The system uses software-based feature detection instead of physical fiducial markers, replacing tangible components with computational methods. This digital approach eliminates the weight of physical tracking markers while maintaining tracking precision.
3Measurement precision
If fiducials are used for tracking, then unique identification is achieved, but mounting precision requirements increase
Solution Approach 1:
The patent eliminates fiducial markers that require precise mounting, replacing them with naturally occurring facial features. This removes the manufacturing and mounting precision requirements associated with fiducial placement while maintaining unique identification capability through facial geometry.
Solution Approach 2:
The system uses the user's own facial features as tracking points, which are inherently unique and require no external mounting or calibration. The facial landmarks serve themselves as identification markers, eliminating the need for precise fiducial mounting procedures.
4Reliability
If fiducials are used in cluttered environments, then tracking is possible, but system complexity increases
Solution Approach 1:
The camera system performs both video capture and facial feature detection simultaneously. The same imaging device used for display purposes also enables tracking in cluttered environments through algorithmic identification of facial landmarks, avoiding the need for specialized fiducial-based tracking hardware.
Solution Approach 2:
The patent replaces the mechanical/optical fiducial marker system with a computational image processing approach. Software algorithms detect and track facial features directly from video frames, eliminating the need for physical fiducial markers and reducing system complexity while maintaining reliability in cluttered environments.
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 clutter, simplifies the system, reduces size and weight, and allows for adaptable tracking across various headgear forms, achieving accurate three or six degrees of freedom in real-time angular orientation determination with reduced complexity and cost.
Implementation Method 1
filtering light reflected from at least some of the tracking points of the headgear to allow only light in an IR wavelength band to pass
Implementation Method 2
each of the tracking points comprising an infra-red (IR) reflective point
Data Source
AI summary
A method of determining the angular orientation of headgear is described. The headgear has tracking points being at least four tracking points, the relative position of the tracking points is calibrated and stored as relative position information, each of the tracking points comprises an infra-red (IR) reflective point. Light reflected from at least some of the tracking points of the headgear is filtered to allow only light in an IR wavelength band to pass. The filtered IR light is imaged to provide a detected image including at least some of the tracking points. At least some of the tracking points in the detected image are identified, and the position of the identified tracking points in the detected image is determined. The angular orientation of the headgear is determined in multiple different angular directions based on the stored relative position information and the position of the identified tracking points.