Line-of-Sight Detection With Corneal Reflex Light Switching
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Solution Overview
Problem
Existing line-of-sight detection devices face reduced accuracy due to the reflected image of detection light being present at the boundary between the cornea and sclera, where the cornea and sclera have different curvature radii.
Innovation Solution
A line-of-sight detection device with multiple light sources that adjust emission based on the target distance between the pupil center and corneal reflex center to optimize the formation of the reflected image within the cornea, using a display unit, imaging unit, position detection unit, and light source control unit to calculate the gaze point accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single light source is used to emit detection light to the eyeball, then the device structure is simple, but the reflected image may be present at the boundary between cornea and sclera reducing detection accuracy
Solution Approach 1:
The single light source is divided into multiple light sources (first light source and second light source) positioned at different locations. Each light source emits detection light from a different angle, allowing the reflected images to be formed at different positions on the eyeball surface. This segmentation enables the system to avoid the boundary region between cornea and sclera by selecting appropriate light sources based on eyeball position, thereby maintaining high detection accuracy.
Solution Approach 2:
The system dynamically selects which light source to use based on the detected position of the eyeball. The light source selection is not fixed but changes according to real-time eyeball position feedback. This dynamic adaptation ensures that the reflected image is always formed on the cornea rather than at the cornea-sclera boundary, maintaining detection accuracy across different eyeball positions.
2Measurement precision
If the reflected image is formed at the boundary between cornea and sclera, then the detection system can operate with fixed light source position, but the different curvature radii of cornea and sclera reduce detection accuracy
Solution Approach 1:
The system employs dynamic light source selection based on real-time detection of eyeball position. When the eyeball moves to different positions, the control unit determines which light source will produce a reflected image on the cornea rather than at the cornea-sclera boundary. This dynamic adaptation ensures consistent high precision in gaze point calculation regardless of eyeball position.
Solution Approach 2:
The system changes the operational parameters by switching between different light sources based on eyeball position. Each light source has different characteristics in terms of the position where it forms reflected images. By selecting the appropriate light source parameter set based on current eyeball position, the system maintains optimal detection conditions and avoids regions with different curvature radii that would reduce accuracy.
3Measurement precision
If multiple light sources are used to ensure reflected image remains within cornea, then detection accuracy is improved, but the device complexity and control requirements increase
Solution Approach 1:
The control system is segmented into simple decision logic that determines which light source to activate based on detected eyeball position. Rather than complex continuous control, the system uses discrete selection between predefined light source options. This segmented control approach manages complexity while achieving the goal of keeping the reflected image within the cornea for accurate detection.
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
Enhances detection accuracy by ensuring the reflected image remains within the cornea, thereby improving the precision of gaze point calculation.
Implementation Method 1
a light source configured to emit detection light to apply the detection light to at least one of eyeballs of a subject... capturing an image of the eyeball to which the detection light is applied... a position of a corneal reflex center that indicates a center of a corneal reflex
Data Source
AI summary
A line-of-sight detection device includes a display unit configured to display an image, light sources configured to emit detection light to apply the detection light to an eyeball of a subject, an imaging unit configured to capture an image of the eyeball to which the detection light is applied, a position detection unit configured to detect, from the captured image, a position of a pupil center of the eyeball to which the detection light is applied and a position of a corneal reflex center, a gaze point detection unit configured to calculate a position of a gaze point of the subject based on the positions of the pupil center and corneal reflex center, and a light source control unit configured to change the light source for emitting the detection light among the light sources based on a target distance between the pupil center and the corneal reflex center.