Gaze Tracking Using Eyeball Center as Fixed Parameter
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Solution Overview
Problem
Existing gaze-tracking technologies require complex configurations with multiple cameras and light sources, and often necessitate calibration, limiting their accuracy and user convenience.
Innovation Solution
A gaze-tracking device utilizing a single camera and single light source, which calculates the gaze vector by combining corneal reflection and eyeball center techniques, eliminating the need for calibration by using the eyeball center as a fixed parameter in a facial-model coordinate system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two cameras and two light sources are used for gaze tracking, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple cameras and light sources into a single integrated camera system. The single camera captures both the face image and corneal reflection information simultaneously, eliminating the need for multiple separate components while maintaining gaze tracking accuracy through combined image processing algorithms.
Solution Approach 2:
The single camera is designed to perform multiple functions: capturing face geometry, detecting pupil position, and analyzing corneal reflections. This multi-functional approach replaces the need for dedicated separate cameras and light sources, reducing device complexity while preserving measurement precision through sophisticated image analysis.
2Measurement precision
If calibration is performed for accurate gaze tracking, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The system performs automatic calibration using the user's own facial features and corneal reflection patterns. The algorithm automatically identifies anatomical landmarks and computes individual eye geometry parameters without requiring the user to manually adjust settings or follow complex calibration procedures, making the system both accurate and easy to use.
Solution Approach 2:
The system performs preliminary calibration during the initial setup by capturing a brief facial image and automatically computing all necessary geometric parameters. This preliminary action stores the individualized eye model for future use, eliminating the need for repeated calibration sessions and improving both accuracy and user convenience.
3Measurement precision
If multiple cameras and light sources are used, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent combines multiple optical components into a single camera module, significantly reducing the number of parts that need to be manufactured and assembled. This integration simplifies the manufacturing process, reduces assembly complexity, and lowers production costs while maintaining the precision previously achieved only with multiple 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
This configuration enables accurate gaze tracking without calibration, improving accuracy and user convenience by simplifying the setup and eliminating the need for multiple cameras and light sources.
Implementation Method 1
acquires an eyeball-image, this being an image of a subject looking at a predetermined screen imaging eyeballs while light from a predetermined light source is reflected by the eyeballs
Data Source
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AI summary
A corneal-reflection-based gaze detection section (28) calculates a time series of a three-dimensional gaze vector in a camera coordinate system from a time series of facial images. A face position-and-orientation estimation section (24) estimates a time series of a three-dimensional position and orientation of a face. An eyeball-center-coordinates transformation section (32) calculates a time series of a three-dimensional position of the eyeball center in a coordinate system of a three-dimensional facial model. A fixed parameter calculation section (33) calculates for use as a fixed parameter a three-dimensional position of the eyeball center in the three-dimensional facial-model coordinate system. An eyeball-center-based gaze detection section (36) uses the three-dimensional position of the eyeball center calculated by the fixed parameter calculation section (33) to calculate a three-dimensional gaze vector from a three-dimensional position of the eyeball center to a three-dimensional position of a pupil center in the camera coordinate system. This enables accurate gaze tracking to be performed using a simple configuration and without performing calibration.