Retinal Reflection Gaze Tracking Using Lenslet Arrays
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Solution Overview
Problem
Current gaze tracking systems are often inaccurate, especially those that do not require users to wear devices, and there is a need for a more precise method to determine gaze direction without the need for any wearable equipment.
Innovation Solution
A method involving illuminating an eye with light to form an image on the retina, capturing the reflected light with a sensor, and analyzing the signal to determine the gaze direction, which may include identifying lines of symmetry or elliptical properties of the reflected image, potentially using multiple light sources and lenslets to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gaze tracking system does not require the user to wear any device, then the ease of operation is improved, but the measurement precision deteriorates
Solution Approach 1:
The patent introduces an intermediary optical element (lenslet array or gradient index lens) positioned between the eye and the sensor. This intermediary manipulates the returning light to create multiple virtual images of the pupil, enabling accurate gaze tracking without wearable devices on the user. The intermediary transforms the optical path to extract gaze information from the pattern of light returning from the retina.
Solution Approach 2:
The patent segments the returning light into multiple distinct images using a lenslet array or gradient index lens. Each lenslet creates a separate virtual image of the pupil, and the relative positions of these segmented images encode the gaze direction. This segmentation allows the system to extract precise gaze information from the distributed light patterns without requiring wearable sensors.
2Device complexity
If traditional optical methods track reflections from the cornea or lens surfaces, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
Instead of tracking reflections from external surfaces (cornea or lens) as in traditional methods, this patent inverts the approach by tracking light that has traveled through the entire optical path to the retina and returned. The system analyzes the pattern of returning light to determine gaze direction, effectively measuring from the deepest reflecting surface (retina) rather than from external surfaces, thereby improving precision while maintaining relatively simple device complexity.
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 a more accurate and device-free method for tracking gaze direction by analyzing the reflected light patterns, improving the precision of gaze determination without the need for wearable equipment.
Implementation Method 1
illuminating an eye with light from a light source so as to cause a first image of the light source to be formed on a retina of the eye
Implementation Method 2
capturing the light returning from the retina with a sensor so as to receive at least a portion of a second image of the first image on the sensor
Data Source
AI summary
A method, including illuminating an eye with light from a light source (62) so as to cause a first image (80) of the light source to be formed on a retina (78) of the eye. The method also includes capturing the light returning from the retina with a sensor (148) so as to receive at least a portion of a second image (130) of the first image on the sensor, and analyzing a signal from the sensor in order to determine a gaze direction of the eye.