Visual Line Detection Using Dual Light Sources and Corneal Curvature
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Solution Overview
Problem
Accurate detection of the pupil center is crucial for precise viewpoint detection, but existing methods face challenges in distinguishing the pupil from the iris, especially when using a single light source, leading to difficulties in calculating the visual line direction.
Innovation Solution
A visual line detection apparatus employing two light sources positioned outside cameras, which are turned on at different times, allowing for precise detection of pupil and corneal reflection centers, and calculating corneal curvature radii to determine the viewpoint, using a virtual light source to convert coordinate values into world coordinates for accurate visual line detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light source is used for detecting the eyeball, then the device complexity is reduced, but the measurement precision of pupil center and visual line direction deteriorates
Solution Approach 1:
The invention divides the detection task into two separate light source functions: one light source illuminates the eyeball for pupil center detection, while another light source creates corneal reflection for curvature center detection. This segmentation allows each light source to be optimized for its specific detection purpose, thereby improving overall measurement precision without requiring a single complex multi-functional light source system.
Solution Approach 2:
The invention introduces corneal reflection as an intermediary element to detect the corneal curvature center. By using the reflection of light from the corneal surface, the system can indirectly determine the curvature center position, which serves as a key reference point for calculating visual line direction. This intermediary approach enables accurate pupil center detection by providing a stable reference frame.
2Device complexity
If the pupil center is not accurately calculated, then the device simplicity is maintained, but the measurement precision of viewpoint detection deteriorates
Solution Approach 1:
The invention implements a feedback mechanism where the detected corneal curvature center position is used to correct and refine the pupil center detection. The corneal curvature information serves as feedback that helps adjust and improve the accuracy of pupil center calculation, creating a self-correcting detection system that enhances viewpoint detection precision without significantly increasing device complexity.
Solution Approach 2:
The invention transitions from two-dimensional image plane coordinates to three-dimensional world coordinates by incorporating corneal curvature information. This dimensional transformation allows the system to calculate the actual spatial position of the pupil center and viewpoint in 3D space, significantly improving measurement precision while maintaining a relatively simple detection apparatus structure.
3Measurement precision
If corneal curvature radius calculation is added to the detection system, then the measurement precision of visual line direction is improved, but the device complexity increases
Solution Approach 1:
The invention makes the existing position detection unit multi-functional by enabling it to detect both pupil center position and corneal reflection position. This single unit performs multiple detection functions, allowing the system to calculate corneal curvature radius using the same hardware infrastructure, thereby improving visual line direction accuracy without proportionally increasing device complexity.
Solution Approach 2:
The invention performs preliminary detection of corneal reflection position and curvature radius calculation before final viewpoint detection. By pre-calculating the corneal curvature radius and storing it as reference data, the system prepares essential parameters in advance, which streamlines the subsequent visual line direction calculation process and reduces real-time computational 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 enables high-precision detection of the visual line direction by distinguishing the pupil from the iris effectively and calculating the corneal curvature center, thereby improving the accuracy of viewpoint detection.
Implementation Method 1
a light source (103a, 103b) configured to irradiate an eyeball of a subject with detection light
Data Source
AI summary
A visual line detection apparatus includes a light source, a position detection unit configured to detect positions of pupil centers and positions of corneal reflection centers, a curvature radius calculation unit configured to calculate corneal curvature radii from a position of the light source and the positions of the corneal reflection centers, a viewpoint detection unit configured to detect viewpoints from the positions of the pupil centers and the corneal curvature radii, an extraction unit configured to extract pupil parameters indicating sizes of the pupils of the right and left respective eyeballs from the image of the eyeballs, and a correction unit configured to correct the viewpoint of the left eyeball and the viewpoint of the right eyeball on the basis of the pupil parameters and calculate a synthesized viewpoint.