Time of Flight Eye Tracker for Direct Lens Accommodation
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Solution Overview
Problem
Current eye tracking systems for augmented, mixed, and virtual reality are computationally intensive and require complex optical sensors to detect corneal reflections and image features, failing to provide direct information on eye accommodation, which is indirectly inferred from vergence.
Innovation Solution
A Time of Flight (ToF) eye tracker that emits pulses of light towards the pupil, retroreflected by the retina, detected by a camera assembly, and processed using a virtual eye model to determine eye tracking information and lens accommodation, reducing the need for complex image processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex optical sensors and image processing methods are used to detect corneal reflections, then eye tracking information can be obtained, but computational complexity increases and the system becomes more complex
Solution Approach 1:
The patent replaces complex optical sensing systems with a time-of-flight measurement system. Instead of using sophisticated optical sensors to detect corneal reflections and perform complex image processing, the system uses a light source and sensor to measure the time it takes for light to travel to and from the eye, thereby determining eye tracking information with reduced computational requirements.
2Loss of information
If complex image processing is used to analyze corneal reflections, then eye tracking data can be extracted, but processing time and computational resources increase
Solution Approach 1:
The patent substitutes complex image processing algorithms with direct time-of-flight measurements. By measuring the time it takes for light to travel to the eye and reflect back, the system obtains eye tracking information without requiring sophisticated image analysis, thereby reducing processing time while maintaining data completeness.
3Loss of information
If indirect methods are used to infer eye accommodation from vergence, then accommodation information can be obtained, but measurement precision decreases
Solution Approach 1:
The patent replaces indirect inference methods with direct time-of-flight measurement for determining eye accommodation. By measuring the time it takes for light to travel through the eye's optical path, the system directly obtains accommodation information without relying on vergence calculations, thereby improving measurement precision.
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 solution enables efficient and direct determination of eye tracking information and lens accommodation, reducing computational complexity and providing accurate gaze direction and focus adjustment in AR/VR systems.
Implementation Method 1
an illumination source configured to emit pulses of light toward a pupil of an eye, wherein the pulses of light are retroreflected by a retina of the eye
Implementation Method 2
a camera assembly configured to detect the retroreflected pulses of light. The ToF eye tracker also includes a controller configured to determine ToF information for one or more of the retroreflected pulses of light
Data Source
AI summary
A time of flight (ToF) eye tracker includes an illumination source configured to emit pulses of light toward a pupil of an eye, wherein the pulses of light are retroreflected by a retina of the eye. The ToF eye tracker also includes a camera assembly configured to detect the retroreflected pulses of light. The ToF eye tracker also includes a controller configured to determine ToF information for one or more of the retroreflected pulses of light, and determine eye tracking information for the user's eye using the determined ToF information and a virtual eye model.