Matrix Optical Sensor Eyeball Tracking via Reflected Light Energy
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Solution Overview
Problem
Conventional eyeball tracking systems face limitations in accuracy and convenience due to low contrast ratios between the pupil and eye white, especially under conditions like glasses obstruction or pathological changes, leading to reduced resolution and usability, particularly for disabled individuals attempting to control computers.
Innovation Solution
An eyeball locating method and system utilizing a matrix optical sensor to detect the energy of reflected light, calculating characteristic values such as contrast ratio, width, and displacement of the pupil, and comparing these to determine pupil changes, with an application program controlling the sensor to enhance accuracy and convenience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical detection is used to capture pupil image, then the system can track eyeball movement, but the contrast ratio between pupil and eye white is too low to measure accurately
Solution Approach 1:
The patent applies color/reflectivity changes by illuminating the eyeball with light that reflects differently from the pupil and eye white. The pupil reflects less light (darker) while the eye white reflects more light (brighter), creating sufficient contrast for accurate measurement. This is achieved by detecting the reflected light energy distribution across multiple pixels to determine pupil position.
2Reliability
If frame-mounted CCD detector is used, then eyeball tracking can be achieved, but the system requires the user to wear the frame which reduces convenience
Solution Approach 1:
The patent merges the light source and detector into a single integrated module that can be embedded in display devices or other equipment. This eliminates the need for separate frame-mounted detectors, allowing non-contact eyeball tracking without requiring users to wear additional devices, thereby improving convenience while maintaining tracking reliability.
Solution Approach 2:
The integrated light source and detector module can be incorporated into various display devices and equipment, making the eyeball tracking function universal and applicable across different scenarios without requiring specialized wearable frames.
3Measurement precision
If piezoelectric sensor is used to detect eye pressure change, then eyeball movement can be detected, but the electrical signal measurement is easily influenced by sweat
Solution Approach 1:
The patent replaces the piezoelectric mechanical/electrical sensing system with an optical detection system. Instead of measuring electrical signals from eye pressure changes (which are susceptible to sweat interference), the system uses light reflection detection to determine pupil position, eliminating the harmful effect of sweat on measurement accuracy.
4Reliability
If magnetic field is formed around eyeball to measure movement, then eyeball tracking can be achieved, but the device complexity increases
Solution Approach 1:
The patent replaces the complex magnetic field-based detection system with a simpler optical detection system using light sources and photodetectors. This substitution reduces device complexity while maintaining eyeball tracking capability, as the optical system requires fewer components and simpler signal processing compared to magnetic field generation and measurement.
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 system improves the accuracy of eyeball tracking by effectively determining pupil changes and movement, enabling more reliable and convenient control of computer cursors and other interfaces, even in challenging conditions, thus enhancing usability for disabled users.
Implementation Method 1
shining light on the eye white and the pupil wherein at least a part of the light is reflected by the eye white and the pupil, so as to form a reflecting light; detecting the energy of the reflecting light
Data Source
AI summary
An eyeball locating system includes a display panel, an application program and a matrix optical sensor. The matrix optical sensor is disposed in the display panel. The application program controls the matrix optical sensor, executing an eyeball locating method to measure the movement of an eyeball including an eye white and a pupil. The method includes: providing a default graph showing the change of light energy; defining a default characteristic value of the pupil according to the default graph; shining light on the eye white and the pupil, a part of the light reflected by the eye white and the pupil to form a reflecting light; detecting the reflecting light energy to form a measured graph showing the change of reflected light energy; calculating a measured characteristic value according to the measured graph; and comparing the default with the measured characteristic values to determine the change of the pupil.