Active Head-Mounted Display Calibration for Visual Field Testing
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Solution Overview
Problem
The introduction of visual field testing into head-mounted display devices is hindered by the absence of cyclotorsion, which causes misalignment of the visual field when the user tilts their head, and the lack of uniform curvature in display surfaces, leading to inaccurate testing results.
Innovation Solution
Implementing specialized sensors and software in head-mounted displays to detect head tilts and adjust visual field testing patterns, and using calibration mechanisms to align eye tracking data with stimulus locations, ensuring accurate visual field assessments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If visual field testing is adapted to head-mounted display devices, then accessibility and cost-effectiveness are improved, but measurement precision deteriorates due to the absence of cyclotorsion and non-uniform display surfaces
Solution Approach 1:
The patent transforms the fixed, uniform curvature parameters of traditional visual field analyzers into variable parameters that adapt to the head-mounted display's actual geometry and the user's head position. The system dynamically adjusts stimulus presentation locations and visual field mapping parameters based on detected head orientation and display surface characteristics, enabling accurate testing despite the absence of cyclotorsion and non-uniform display surfaces.
Solution Approach 2:
The patent replaces the mechanical chin rest and head positioning mechanisms of traditional visual field analyzers with electronic sensor systems. Inertial measurement units (IMUs) and eye tracking sensors substitute for mechanical constraints, detecting head position and orientation electronically to compensate for the lack of physical head stabilization, thereby maintaining measurement accuracy while improving accessibility.
2Measurement precision
If head tilts are prevented using conventional structures like chin rests, then measurement precision is improved, but device complexity and ease of operation worsen due to specialized structures
Solution Approach 1:
The patent replaces mechanical head-positioning structures with electronic sensing and software-based compensation systems. Inertial measurement units and eye tracking sensors detect head orientation and position, while algorithms dynamically adjust stimulus presentation to account for head tilts, eliminating the need for physical chin rests or specialized mounting structures.
Solution Approach 2:
The system performs self-calibration and self-correction by using its own sensors to detect head position and automatically adjusting visual field presentation parameters. The head-mounted display compensates for its own misalignment through real-time detection and correction algorithms, eliminating the need for external positioning structures.
3Measurement precision
If head tilts are detected and corrected in real-time, then measurement precision is improved, but device complexity increases due to specialized sensors and software
Solution Approach 1:
The patent integrates multiple functions into existing head-mounted display components. The same display screen used for visual stimulation also serves as the reference frame for detecting head orientation. Existing eye tracking sensors and inertial measurement units, originally designed for other purposes, are repurposed for visual field testing calibration, reducing the need for specialized additional components.
Solution Approach 2:
The system uses its own embedded sensors and processing capabilities to perform real-time head tilt detection and correction without requiring external specialized equipment. The head-mounted display self-calibrates during the testing process by comparing expected stimulus locations with actual eye gaze data, automatically compensating for head orientation changes.
Data Source
AI summary
Some systems and methods disclosed herein facilitate calibration of a head-mounted display while a visual test is performed. One mechanism of facilitating calibration involves detecting, as a visual test is being performed, that the user's eyes moved in the direction of a displayed stimulus but have not stopped at the point of where the stimulus is displayed, and instead stopped at a different point (e.g., a threshold distance away from the stimulus). Based on that detection, the system may determine that the user has seen the stimulus and that calibration of the sensors is needed. The system may then record that the user has seen the stimulus and perform sensor calibration before displaying the next stimulus.