Laser Interferometry Eye Position Tracking
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Solution Overview
Problem
Current eye position determination methods are limited in precision and flexibility, particularly in space-constrained devices like smartglasses, where accurate eye tracking is needed for effective information display.
Innovation Solution
The method employs laser feedback interferometry measurements, integrating rotational velocity over a time segment using a geometric eye model to determine eye position with high accuracy, and incorporates triangulation calculations and signal-to-noise ratio analysis to identify eye components and transitions, enabling precise eye position determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If camera-based systems or electrical property measurement systems are used to determine eye position, then eye tracking functionality is achieved, but device size and complexity increase, making them unsuitable for space-constrained devices like smartglasses
Solution Approach 1:
The patent replaces mechanical/camera-based eye tracking systems with a laser-based interferometry system. The laser feedback interferometry unit uses optical interference patterns to measure eye component position and velocity, eliminating the need for bulky camera systems while achieving high measurement precision suitable for smartglasses.
Solution Approach 2:
The patent extracts and measures only the essential parameters (position and velocity of eye components) using laser interferometry, rather than capturing full image data. This extraction approach reduces data processing requirements and enables compact device design while maintaining accurate eye position determination.
2Measurement precision
If laser feedback interferometry is used to determine eye position, then measurement precision and flexibility are improved, but the complexity of processing measurement values and determining rotational velocity increases
Solution Approach 1:
The patent applies a geometric eye model that pre-establishes the functional relationship between linear velocity components and rotational velocity. This preliminary modeling allows the system to directly calculate rotational velocity from measured linear velocity without complex real-time processing, reducing computational complexity while maintaining precision.
Solution Approach 2:
The patent introduces a geometric eye model as an intermediary between the raw laser interferometry measurements and the final eye position determination. This model serves as a mathematical bridge that simplifies the transformation from linear velocity measurements to rotational velocity and position calculations.
3Measurement precision
If integration of rotational velocity is performed to determine eye position, then precision is improved, but the time required for calculation increases
Solution Approach 1:
The patent performs continuous integration of rotational velocity over time segments to determine eye position. This continuous integration approach maintains high precision by constantly updating position based on velocity measurements, while the use of predetermined time segments optimizes calculation efficiency for real-time tracking applications.
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 provides precise eye position determination with up to 1° degree accuracy, suitable for smartglasses and other space-constrained devices, ensuring information is displayed in the correct viewing direction, and allows for both current and future eye positions to be determined.
Implementation Method 1
receiving laser feedback interferometry measurement values of a laser feedback interferometry measurement of an eye by means of at least one laser interferometry unit, wherein the measurement values are based on at least one laser signal reflected on a component of the eye
Data Source
AI summary
A method for determining an eye position. The method includes: receiving laser feedback interferometry measurement values of a laser feedback interferometry measurement of an eye by means of at least one laser interferometry unit; determining a velocity component of the component of the eye relative to the laser feedback interferometry unit based on the laser feedback interferometry measurement values; determining a rotational velocity of the eye about an axis of rotation based on the rotational velocity about the axis of rotation by integrating the rotational velocity over a predetermined time segment; and providing the eye position.