Light Field Eye Tracking via Intensity Sensors
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Solution Overview
Problem
Existing eye-tracking systems face limitations such as high costs, computational intensity, inaccurate tracking due to unwanted reflections, and poor suitability for different users with varying eye configurations, leading to unreliable gaze direction determination.
Innovation Solution
An eye-tracking system comprising multiple light-sensing units with at least three light sensors and a converging lens, which collect and process light intensity data to determine the direction and orientation of the user's eye, allowing for precise gaze direction calculation without cameras, suitable for various users and adaptable to movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera-based eye-tracking systems are used, then gaze direction can be tracked, but manufacturing cost and computational processing requirements increase significantly
Solution Approach 1:
The patent replaces camera-based image processing with a light sensor array that directly measures light intensity variations. Instead of using complex computational algorithms to analyze camera images, the system uses simple photodetectors to capture reflected light patterns, significantly reducing computational requirements while maintaining tracking accuracy.
Solution Approach 2:
The patent extracts only the essential light intensity information from the eye reflection, discarding unnecessary visual data. By using light sensors instead of cameras, the system captures only the critical intensity variations needed for gaze determination, eliminating the need for complex image processing pipelines.
2Device complexity
If light sensors are used to track eye reflections, then computational processing is reduced, but signal-to-noise ratio decreases due to unwanted reflections
Solution Approach 1:
The patent employs multiple light sensors positioned at specific locations to detect light reflections from different parts of the eye. By strategically placing sensors to capture reflections from the cornea and iris, the system enhances the signal-to-noise ratio while maintaining low computational requirements. The local positioning of sensors allows selective detection of relevant reflection patterns.
Solution Approach 2:
The patent divides the light detection function into multiple independent light sensors, each capturing specific reflection patterns from different eye regions. This segmentation allows the system to process individual sensor signals separately, filtering out unwanted reflections more effectively while keeping computational complexity low.
3Ease of manufacture
If light sensor-based eye tracking is used, then manufacturing cost is reduced, but accuracy for different users with varying eye configurations deteriorates
Solution Approach 1:
The patent implements a dynamic calibration process that adapts the light sensor readings to each user's specific eye configuration. The system performs initial calibration to determine individual characteristics such as vertex distance and interpupillary distance, then uses these parameters to adjust subsequent tracking measurements, ensuring high accuracy across different users while maintaining low manufacturing cost.
Solution Approach 2:
The patent changes the measurement parameters based on user-specific characteristics. By adjusting detection parameters according to individual eye configurations captured during calibration, the system maintains high accuracy across diverse users. The light sensor array dynamically modifies its measurement approach based on calibrated user parameters.
4Measurement precision
If camera-based eye tracking is used, then gaze direction can be determined, but system reliability decreases due to movement during use
Solution Approach 1:
The patent replaces camera-based tracking with light sensor-based detection that is less sensitive to relative movement between the device and the eye. The light sensors detect reflection patterns that remain stable even when the device moves, as the optical path changes are minimal compared to camera-based image distortion. This substitution significantly improves tracking reliability during device movement.
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 a simple, accurate, and reliable method for real-time gaze direction tracking, reducing computational load and improving accuracy across different users and configurations.
Implementation Method 1
a converging lens employed to converge light signals incident thereupon towards one or more of the at least three light sensors
Implementation Method 2
collect sensor data from individual light sensors of a given light-sensing unit at a given instant of time, the sensor data being indicative of respective light intensities of the light signals sensed by the individual light sensors
Data Source
AI summary
An eye-tracking system includes light-sensing units, each light-sensing unit including at least three light sensors and converging lens to converge light signals towards one or more of at least three light sensors; and processor(s) configured to: collect sensor data from individual light sensors, sensor data being indicative of respective light intensities of light signals sensed by individual light sensors; determine direction from which light signals are incident upon light-sensing unit, based on differences in light intensities of light signals; determine orientation of user's eye relative to given light-sensing unit, based on direction from which light signals are incident upon light-sensing unit and light intensities of light signals; and determine gaze direction of user's eye, based on orientation of user's eye and position of light-sensing unit relative to user's eye.