3D Eye Tracking via Optical Triangulation
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Solution Overview
Problem
Existing eye-tracking systems that rely on imaging are slow, expensive, bulky, and require significant processing power, making them unsuitable for many applications, and there is a need for systems that can create three-dimensional maps of eyes without image processing.
Innovation Solution
A system that steers a scan beam in a two-dimensional pattern over an eye using a source module and an angle-sensitive detector to triangulate the three-dimensional location of reflection points, allowing for the construction of a three-dimensional map of the eye and determination of the gaze vector without image processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If imaging systems (cameras, FPA) are used for eye tracking, then three-dimensional eye mapping can be achieved, but the system becomes slow, expensive, bulky and requires considerable processing power
Solution Approach 1:
The patent replaces complex imaging systems with a light source and photodetector arrangement that uses optical triangulation. Instead of capturing images and processing them computationally, the system directly measures eye position through geometric relationships between light emission, reflection off the eye, and detection at known angles, eliminating the need for complex image processing hardware and software
Solution Approach 2:
The patent introduces light as an intermediary medium to transfer information about eye position. By emitting light at known angles and detecting reflected light at measured angles, the system uses light propagation and reflection as a mediator to encode spatial information that can be decoded through geometric calculation rather than image processing
2Loss of information
If imaging systems are used for eye tracking, then comprehensive eye information can be obtained, but the system latency increases and speed decreases
Solution Approach 1:
The patent substitutes computational image processing with direct optical measurement and geometric calculation. By using the known geometry of light source positions, detection angles, and the law of triangulation, the system obtains eye position information through immediate mathematical computation rather than time-consuming image analysis algorithms
Solution Approach 2:
The patent changes the measurement parameters from two-dimensional image coordinates requiring complex reconstruction to direct three-dimensional angular measurements. By measuring light reflection angles at multiple known source positions, the system directly obtains spatial parameters through trigonometric relationships, reducing computational latency while maintaining information completeness
3Measurement precision
If imaging systems are used for eye tracking, then detailed eye feature detection is possible, but the system cost and bulk increase
Solution Approach 1:
The patent replaces bulky imaging systems with a compact light source and photodetector arrangement. The system uses the human eye itself as part of the optical path, eliminating the need for large lenses, sensors, and processing hardware required by traditional imaging systems, thereby reducing weight and bulk while maintaining measurement precision
Solution Approach 2:
The patent makes the user's eye serve multiple functions: as the target object, as part of the optical path (reflecting surface), and as the measurement medium. This eliminates the need for separate imaging components, reducing system bulk while maintaining the ability to detect detailed eye features through angular measurements
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 efficient and accurate three-dimensional eye tracking, suitable for applications like eye imaging and gaze direction determination, with improved speed, cost-effectiveness, and reduced processing requirements compared to traditional imaging-based systems.
Implementation Method 1
detect reflections from one or more reflection points in the scan region at an angle-sensitive detector
Implementation Method 2
its three-dimensional location is determined by triangulation based on the geometry of the system and the angles at which light is incident on, and reflected from, that reflection point
Data Source
AI summary
Aspects of the present disclosure describe systems and methods for eye-tracking by steering a scan beam in a two-dimensional pattern over a scan region on the eye and detecting light reflected from a plurality of reflection points in the scan region at an angle-sensitive detector. The three-dimensional location of each reflection point is determined by triangulating the instantaneous propagation directions of the scan beam and the reflected signal from that reflection point. Gaze direction for the eye is determined from the locations of the reflection points in three-dimensional space.