View-through Sensor Eye Tracking via Ambient Light Reflection
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Solution Overview
Problem
Current wearable eye trackers fail to achieve high tracking rates with sub-millimeter accuracy while consuming low power, leading to high costs and cumbersome designs, particularly in virtual reality applications where gaze tracking is essential for user interaction and energy efficiency.
Innovation Solution
A view-through eye-tracking system using a support structure with a view-through sensor and peripheral light-sensing regions to track eye movement by sensing light intensity reflected from the eye, employing a gaze-inference algorithm and predictive inferencing to determine and predict pupil location, without the need for active emitters, thus reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera-based eye tracking with intensive image processing is used, then tracking accuracy is improved, but power consumption increases
Solution Approach 1:
The patent extracts only the essential light-sensing function from complex camera-based systems, using simple photodiodes to detect light intensity changes caused by pupil movement. This eliminates the need for intensive image processing while maintaining tracking capability, thereby reducing power consumption significantly.
Solution Approach 2:
The patent replaces expensive, power-hungry camera modules with inexpensive photodiodes that consume minimal power. Although photodiodes provide simpler measurement capability, their low cost and ultra-low power consumption make them suitable for wearable applications where battery life is critical.
2Measurement precision
If high tracking rates with sub-millimeter accuracy are achieved, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical and computational systems (cameras, image processing algorithms) with a simpler optical detection approach using photodiodes. The system relies on direct light intensity measurement rather than complex image analysis, thereby reducing device complexity while achieving high tracking accuracy.
Solution Approach 2:
The patent changes the measurement parameter from full image data to simple light intensity values. By monitoring intensity changes at multiple photodiode positions, the system can infer pupil location with high precision without requiring complex processing, thus simplifying the overall system.
3Reliability
If cameras and active infrared emitters are used for gaze tracking, then tracking functionality is achieved, but form factor and power consumption worsen
Solution Approach 1:
The patent removes the active infrared emitter component from the system, relying instead on ambient light reflected from the eye. This extraction of the emitter simplifies the form factor and reduces power consumption while maintaining gaze tracking functionality through intelligent light sensing.
Solution Approach 2:
The photodiodes serve multiple functions: they detect both the position of the pupil and the intensity of reflected light. By using the same sensing elements for both position and intensity measurement, the system reduces component count and simplifies the overall form factor.
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 enables accurate and efficient eye movement tracking at high rates with low power consumption, suitable for virtual reality applications, allowing for cost-effective and portable gaze tracking without the need for external battery packs.
Implementation Method 1
tracking eye movement via light reflected from the exterior of the eye
Implementation Method 2
sense intensity of light reflecting off of the exterior of the subject eye
Data Source
AI summary
View-through sensors each locatable proximate to an eye of a user and for use while the user is engaged in viewing activity. Each view-through sensor has a view-through region that allows the user to view through the sensor. An active peripheral region at least partially surrounds the view-through region and includes multiple light-sensing regions for sensing light reflected from an eye. In some embodiments, the view-through sensor is configured to use environmental light for eye tracking. When the view-through sensor uses environmental light, spatial and temporal information about the intensity of the environmental light can be used to enhance eye-tracking performance. This information can be obtained, for example, from light-sensing regions on the reverse side of the view-through sensor, from an electronic display, or from a forward-facing camera. In some embodiments, the view-through sensor includes light-emitting regions that emit the light that the sensor uses to track eye movement.