Eye Tracking Illumination Brightness Correction
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Solution Overview
Problem
Existing methods for detecting a user's line-of-sight on an observation surface, such as those using corneal reflex images, suffer from notable brightness unevenness in eye images, especially when the distance between light sources and the eyeball is short.
Innovation Solution
An electronic apparatus and method that includes acquiring an image of an eyeball illuminated by multiple light sources, determining the distance from the eyeball to the image sensor, and correcting brightness unevenness using a correction amount based on the distance information, or adjusting the light-emitting amounts of the light sources based on their positional relationship with the image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple light sources are positioned close to the eyeball for effective illumination, then the illumination intensity is improved, but brightness unevenness in the captured image worsens
Solution Approach 1:
The patent applies local quality by assigning different light-emitting amounts to different light sources based on their individual positions relative to the eyeball and image sensor. Each light source's emission is locally adjusted rather than using uniform illumination, thereby achieving uniform brightness distribution across the captured eye image while maintaining effective illumination intensity.
Solution Approach 2:
The patent changes the parameter of light-emitting amount for each light source based on calculated correction amounts that consider positional relationships. By dynamically adjusting emission parameters of individual light sources rather than using fixed uniform illumination, the system resolves the contradiction between sufficient illumination and uniform brightness distribution.
2Device complexity
If the distance from light sources to eyeball is shortened for compact device design, then device complexity is reduced, but brightness unevenness increases
Solution Approach 1:
The patent compensates for the brightness unevenness caused by short light source-eyeball distance by dynamically changing the light-emitting parameters. The control unit calculates correction amounts based on positional relationships and adjusts each light source's emission accordingly, enabling compact device design without sacrificing image quality.
3Ease of manufacture
If light sources are positioned outside the eyepiece for easier manufacturing, then ease of manufacture is improved, but brightness unevenness in captured images worsens
Solution Approach 1:
The patent applies local quality by individually adjusting the light-emitting amount of each light source based on its specific position outside the eyepiece. The control unit calculates position-dependent correction amounts and applies local compensation to each light source, enabling easy manufacturing configuration while maintaining uniform brightness distribution in captured images.
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 solution effectively suppresses brightness unevenness in captured eye images, improving the accuracy of line-of-sight detection and reducing errors associated with focus adjustment and image processing.
Implementation Method 1
a plurality of light sources configured to illuminate an eyeball; an image sensor configured to capture the eyeball illuminated by the plurality of light sources
Implementation Method 2
the line-of-sight is detected using the positional relationship between a corneal reflex image formed by the reflected light from the corner and the center of a pupil
Data Source
AI summary
An electronic apparatus according to the present invention includes at least one memory and at least one processor which function as: a first acquisition unit configured to acquire an image of an eyeball illuminated by a plurality of light sources and captured by an image sensor; a second acquisition unit configured to acquire distance information that indicates a distance from the eyeball to the image sensor; and a correction unit configured to correct brightness unevenness of the image with a correction amount in accordance with the distance information.