Line-of-Sight Measurement Using Corneal Reflection Separation
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Solution Overview
Problem
Conventional line-of-sight detection devices struggle to accurately determine the line-of-sight direction when users wear glasses, as reflected light from the glasses is often mistaken for light from the cornea, leading to inaccurate calculations.
Innovation Solution
A measuring apparatus and method that utilizes an illumination unit emitting light of a specific wavelength, a photodetector with two-dimensionally arranged photoelectric converters, and processors to calculate the line-of-sight direction based on light amount distribution information, including optical path length and curvature radius, effectively distinguishing reflected light from the cornea from other surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional line-of-sight detection methods are used, then the detection process is simple, but measurement precision deteriorates when glasses are worn due to inability to distinguish corneal reflection from glass reflection
Solution Approach 1:
The system performs preliminary classification of reflected light by analyzing optical path length and curvature radius before line-of-sight calculation. By pre-identifying whether reflected light originates from the cornea or glasses using these geometric parameters, the system avoids incorrect line-of-sight calculations and maintains high precision even when glasses are worn.
Solution Approach 2:
The system utilizes changes in geometric parameters (optical path length and curvature radius) to differentiate between corneal reflection and glass reflection. By measuring these parameters and comparing them against expected ranges for corneal surfaces, the system can selectively process valid corneal reflection data while filtering out spurious reflections from glasses.
2Loss of information
If multiple reflection sources are present, then light amount distribution information becomes complex, but this enables differentiation between corneal and non-corneal reflections
Solution Approach 1:
The system segments the reflected light information into distinct categories based on optical path length and curvature radius characteristics. By dividing the light amount distribution data into corneal reflection components and non-corneal reflection components, the system can process each segment separately, maintaining information completeness while managing complexity through structured organization.
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
Enables accurate line-of-sight detection by differentiating between corneal and non-corneal reflections, thereby improving the precision of line-of-sight calculations even when glasses are worn.
Implementation Method 1
a photodetector (21) having a plurality of two-dimensionally arranged photoelectric converters
Data Source
AI summary
A measuring apparatus for measuring a user's line-of-sight direction includes an illumination unit configured to emit light of a specific wavelength, a photodetector having a plurality of two-dimensionally arranged photoelectric converters, and configured to acquire light amount distribution information on reflected light of the light emitted by the illumination unit, one or more memories storing instructions, and one or more processors that, upon execution of the instructions, operate to calculate the line-of-sight direction based on the light amount distribution information. The light amount distribution information includes information on a time taken from when the illumination unit emits the light to when the photodetector detects the reflected light or a distance corresponding to the time, and information on an intensity of the reflected light.