Eye Gaze Detection Using Asymmetric Illumination and Sequential Lighting
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Solution Overview
Problem
Conventional eye gaze detection apparatuses are complex and large due to the need for two light sources with a minimum distance between them, which complicates accurate detection and separation of corneal reflection points.
Innovation Solution
An eye gaze detection apparatus using two light sources disposed at outer positions relative to cameras, with one light source lit at a time to capture images, allowing for improved pupil differentiation and gaze detection accuracy without the need for a large distance between light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two light sources are used to detect corneal reflection points, then eye gaze detection accuracy is improved, but the apparatus becomes complicated and large in size
Solution Approach 1:
The patent segments the illumination function by using two separate light sources positioned at different locations (first light source at first position, second light source at second position). Each light source independently illuminates the eyeball from its specific position, allowing the imaging unit to capture distinct corneal reflection points that can be separately detected and processed to calculate the corneal curvature center with high accuracy.
Solution Approach 2:
The patent introduces an intermediary computational approach where the corneal curvature center is calculated based on the positional relationship between the first and second corneal reflection points detected from separate illuminations. This intermediary calculation method enables accurate eye gaze detection without requiring direct physical measurement of the corneal curvature, thereby simplifying the overall system architecture.
2Area of stationary object
If two light sources are placed close together, then the apparatus size is reduced, but the reflection points overlap making detection difficult
Solution Approach 1:
The patent employs asymmetric positioning of the two light sources relative to the eyeball. The first light source is positioned at a first position and the second light source at a second position, creating non-symmetric illumination angles. This asymmetric arrangement ensures that the corneal reflection points generated by each light source are spatially separated in the captured image, preventing overlap and enabling accurate detection even when the light sources are positioned relatively close together.
3Measurement precision
If two light sources are placed far apart, then reflection points are easily separated, but the apparatus becomes large
Solution Approach 1:
The patent resolves the spatial constraint by utilizing angular/positional dimension rather than solely linear distance. Instead of placing light sources far apart in linear space, the system positions them at different angular positions relative to the eyeball (first position and second position). This dimensional approach allows the corneal reflection points to be separated in the image plane through angular differentiation, achieving accurate separation without requiring large physical distances between light sources.
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 configuration enables accurate detection of the pupil and corneal reflection centers, improving eye gaze detection accuracy and allowing for a more compact apparatus design.
Implementation Method 1
an on-eyeball reflection of light emitted from a light source is detected
Data Source
AI summary
An eye gaze detection apparatus includes a plurality of illuminators each including a light source for emitting light and disposed symmetrically with respect to a predetermined position, a plurality of imaging units each disposed at an inner or outer position with respect to the plurality of illuminators, a position detector configured to detect a first position indicating a pupil center and a second position indicating a corneal reflection center based on an image of an eyeball of a subject, the image being captured by the imaging unit with the light emitted by the illuminator, and a calculator configured to calculate a fourth position indicating a corneal curvature center, based on the predetermined position, a third position on a display, the first position, and the second position.