Structured Illumination Eye Tracking Spatial Coordinates
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Solution Overview
Problem
Existing eye tracking technologies face challenges in accurately measuring eye movement due to complex biological structures and optical reflections, such as red-eye effects and variations in eyeball surface profiles, which affect signal strength and quality.
Innovation Solution
The use of structured illumination with modulated light patterns, such as grid or coded speckle patterns, to create a spatial coordinate system for imaging the eye, allowing for accurate detection and tracking of unique physical features like the iris or vessel prints, reducing reliance on signal strength and improving immunity to optical distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional eye tracking methods are used to detect eye movement, then the system can operate with simpler components, but measurement precision deteriorates due to complex biological structures and optical reflections affecting signal quality
Solution Approach 1:
The patent uses structured light patterns (grids, coded speckle patterns) projected onto the eye to create spatial coordinate systems. These optical patterns reflect off eye features like the iris and cornea, allowing the imaging system to track eye movement by monitoring changes in the reflected pattern geometry rather than relying on signal strength from simple illumination. This approach improves measurement precision by providing robust spatial reference frames that are immune to variations in eye surface profiles and reflections.
2Measurement precision
If structured illumination with modulated light patterns is used to create spatial coordinate systems, then measurement precision improves by reducing reliance on signal strength, but device complexity increases due to additional optical components and processing requirements
Solution Approach 1:
The system performs preliminary action by projecting structured light patterns onto the eye before capturing images. The modulated light patterns (grids, coded speckle patterns) are pre-configured to create known spatial coordinate systems that will be reflected off the eye features. This preliminary structuring of illumination allows the imaging system to subsequently track eye movement by comparing the deformed reflected patterns against the known original patterns, improving detection accuracy without requiring complex real-time signal processing.
Solution Approach 2:
The structured light patterns serve as an intermediary between the illumination source and the eye features. Instead of directly illuminating the eye and relying on reflected signal strength, the system introduces modulated light patterns that act as a mediator. These patterns reflect off the eye features and carry spatial information back to the imaging system, enabling accurate tracking while simplifying the relationship between illumination and detection components.
3Reliability
If traditional illumination methods are used without structured light patterns, then device complexity is reduced, but reliability deteriorates due to interference from unwanted light reflections and distortions
Solution Approach 1:
The patent converts the harmful effect of optical reflections and distortions into a beneficial feature. Instead of trying to eliminate reflections from the cornea and iris, the structured light patterns are designed to reflect off these features in predictable ways. The corneal reflection and iris reflections become part of the spatial coordinate system, providing additional reference points for tracking. By modulating the light patterns and analyzing their geometric deformation rather than signal strength, the system turns optical interference into reliable tracking information.
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 enables reliable and accurate tracking of eye movement by processing overall spatial patterns, effectively overcoming interference from unwanted light reflections and distortions, allowing for precise monitoring of eye position and motion.
Implementation Method 1
an optical device placed on the support structure to receive the illumination probe light and to direct the illumination probe light to illuminate an eye of the user
Implementation Method 2
an optical detector array placed on the support structure to include optical detectors to capture images of the eye under illumination to produce detector signals from the optical detectors
Data Source
AI summary
Disclosed are techniques and devices for optical eye tracking based on imaging the eye and tracking certain images of eye features in the eye. The disclosed techniques and devices can be implemented to use structured light to illuminate an eye for obtaining images of the eye to generate accurate eye movement information.