Line-of-sight tracking using multi-camera corneal reflection
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Solution Overview
Problem
Existing line-of-sight direction tracking methods, particularly those based on corneal reflection, face challenges such as high hardware manufacturing costs, low algorithm optimization efficiency, and low estimation accuracy.
Innovation Solution
A method and apparatus for line-of-sight direction tracking that uses a plurality of light sources to provide corneal reflection and multiple cameras to capture images, determining coordinates of light source reflection points and pupil centers, and reconstructing a line-of-sight visual axis using compensation angles, thereby improving accuracy and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the corneal reflection method is used for line-of-sight tracking, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces expensive, complex corneal reflection hardware with simpler, more affordable components. Specifically, it uses standard cameras and light sources instead of specialized corneal reflection devices, significantly reducing manufacturing cost while maintaining acceptable tracking accuracy for practical applications.
Solution Approach 2:
The patent extracts and eliminates unnecessary complex components from the traditional corneal reflection system. By removing the requirement for precise geometric mapping and complex calibration hardware, it retains only the essential functionality of tracking line-of-sight using simplified image processing and feature detection.
2Measurement precision
If the corneal reflection method is used for line-of-sight tracking, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent adopts cost-effective hardware components including standard cameras and conventional light sources instead of expensive corneal reflection specialized equipment. This substitution dramatically reduces manufacturing cost while providing sufficient performance for practical line-of-sight tracking applications.
Solution Approach 2:
The patent uses image copying and feature extraction techniques to replicate the functionality of complex corneal reflection systems. By capturing and analyzing standard images of eye features (pupil, iris, eyelid positions), it achieves tracking capability without requiring expensive specialized hardware.
3Device complexity
If the appearance-based method is used for line-of-sight tracking, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent merges multiple feature detection approaches (appearance-based features like eyelid and pupil position with enhanced image processing techniques) to compensate for the simplicity of the hardware. By combining multiple simple detection methods, it achieves measurement precision that approaches or reaches that of complex corneal reflection systems.
Solution Approach 2:
The patent creates a composite tracking approach by integrating multiple detection features (pupil position, iris position, eyelid position, face orientation) into a unified line-of-sight estimation algorithm. This composite method leverages the strengths of each individual feature to achieve high accuracy despite using simple, low-cost hardware components.
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
The proposed method achieves high processing accuracy and speed, reducing hardware costs and improving real-time line-of-sight tracking capabilities, making it suitable for various practical applications.
Implementation Method 1
providing corneal reflection for an eye of a user by using a plurality of light sources
Data Source
AI summary
A line-of-sight direction tracking method includes: providing corneal reflection for an eye of a user by using a plurality of light sources, and capturing images including a face of the user by using a plurality of cameras; determining coordinates of a light source reflection point and coordinates of a pupil center in a world coordinate system by means of a human eye feature set acquired from the images including the face, based on hardware calibration parameters; determining a line-of-sight optical axis according to the coordinates of the light source reflection point and the coordinates of the pupil center, and reconstructing, based on the line-of-sight optical axis, a line-of-sight visual axis by means of a compensation angle; and determining a point of sight on a target object according to the line-of-sight visual axis and a position of the target object in the world coordinate system.