Visual Axis Estimation for Objective Gaze Verification
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Solution Overview
Problem
Existing visual function test and training devices rely on subjective responses, making it difficult for examiners to ensure that test subjects or trainees are gazing at the correct positions, particularly in cases involving infants or young children, which compromises the reliability of the tests and training.
Innovation Solution
A visual function test and training device that includes a test subject display and operator display, using a visual axis estimation method to objectively determine the gaze position of the test subject or trainee, with infrared lighting and cameras to calculate the visual axis and display the corresponding position on the operator's screen, allowing for accurate alignment and confirmation of gaze.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If subjective response methods are used for visual function testing, then the testing process is simple, but the reliability of the test results deteriorates because the examiner cannot objectively verify the test subject's gaze position
Solution Approach 1:
The patent introduces an intermediary system consisting of cameras, lighting devices, and a control unit that objectively captures and analyzes the test subject's eye position. This intermediary mechanism bridges the gap between the simple subjective response method and reliable objective verification, allowing the examiner to confirm gaze position without directly observing the subject's eyes.
Solution Approach 2:
The patent replaces the mechanical/subjective verification method (examiner directly observing the subject's eyes) with an optical-electronic system (cameras and image processing). This substitution eliminates the limitations of human observation and provides reliable, objective gaze position detection.
2Measurement precision
If direct observation of the test subject's eyes is performed, then gaze position can be verified, but the testing process becomes complex and time-consuming
Solution Approach 1:
The system enables self-service measurement by having the test subject simply respond to test stimuli while the camera system automatically captures and analyzes their gaze position. The control unit processes the image data and provides feedback without requiring the examiner to manually observe or adjust the subject's eye position, thus saving time while maintaining precision.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit provides real-time or near-real-time information about the test subject's gaze position. This feedback loop allows the system to automatically verify whether the subject is looking at the intended target, enabling rapid confirmation of gaze accuracy without manual intervention.
3Reliability
If complex eye tracking equipment is used to verify gaze position, then objective verification is achieved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent extracts only the essential components needed for gaze position verification - a camera to capture eye images and a control unit to process them - rather than implementing a complete, complex eye tracking system. This extraction approach achieves reliable objective verification while keeping the device complexity manageable.
Solution Approach 2:
The system uses a standard camera to capture an optical copy (image) of the test subject's eye, which is then processed to determine gaze position. This copying approach avoids the need for specialized, complex eye tracking hardware while achieving the same verification reliability.
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
Enhances the reliability of visual function tests by objectively confirming the gaze position, ensuring that the test subject or trainee is correctly aligned, even with subjects who cannot provide reliable subjective feedback, such as infants.
Implementation Method 1
a lighting device that illuminates an eye of the test subject with light; preferably, the lighting device is an infrared lighting device
Implementation Method 2
an eyeball camera that images mainly an eyeball of the test subject; a visual axis estimation portion that estimates a visual axis of the test subject
Data Source
AI summary
The visual function test device of an embodiment comprises a test subject display device and an operator display device. A target display portion displays a target image to be viewed by the test subject onto the test subject display device. A visual axis estimation portion estimates a visual axis of the test subject when the target image is viewed. A position display portion displays a display position of the test target image and a viewpoint position that corresponds to the estimated visual axis, onto the operator display device, and thus a tester can objectively recognize a gazing state of the test subject and surely perform the test, which enhances the reliability of the test.