Pupil Detection Light Source Device Glasses Reflection Cancellation
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Solution Overview
Problem
Existing pupil detection devices face challenges in accurately detecting pupils when the subject wears glasses, as the shape and position of the reflection image from the glasses can interfere with the detection process, leading to erroneous identification of glasses-reflected images as pupils. Additionally, previous technologies struggle with maintaining sufficient brightness differences between light and dark pupil images, which affects detection accuracy.
Innovation Solution
A pupil detection light source device that emits illumination light for light and dark pupil images from different positions, using three light sources: one inside or near the aperture for the light pupil image, another inside or near the aperture for the dark pupil image, and a third source positioned apart from the aperture to enhance brightness differences and cancel glasses-reflected images by generating a suitable image difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If illumination light sources are arranged at different positions to expand brightness difference between light and dark pupil images, then detection accuracy is improved, but glasses-reflected images cause erroneous detection
Solution Approach 1:
The illumination system is segmented into multiple light sources positioned at different locations (inside aperture and outside aperture). Each light source group illuminates from a different angle, creating distinct reflection patterns. The pupil detection process segments the images by calculating differences between images illuminated by different light source groups, thereby separating the pupil signal from glasses reflection noise.
Solution Approach 2:
Light sources are asymmetrically positioned both inside and outside the aperture, creating illumination paths with different geometric relationships to the glasses and pupil. This asymmetric arrangement ensures that glasses reflections from different light sources appear at different positions in the captured images, allowing the differential processing to effectively cancel out the asymmetric reflection patterns while preserving the symmetric pupil features.
2Measurement precision
If multiple light sources are used to cancel glasses-reflected images, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
Multiple light sources serve dual functions: (1) They collectively provide sufficient illumination to expand the brightness difference between light and dark pupil images, and (2) their different positions create different glasses reflection patterns that enable cancellation through differential processing. This multi-functionality allows the same light source arrangement to simultaneously address both illumination requirements and reflection cancellation requirements.
Solution Approach 2:
The solution adds a spatial dimension to the illumination arrangement by positioning light sources both inside and outside the aperture in different directions. This dimensional expansion creates multiple illumination paths that approach the subject from different angles, enabling the system to generate multiple images with different reflection characteristics that can be differentially processed to eliminate glasses interference.
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 allows for improved detection of the pupil by expanding the brightness difference between light and dark pupil images, effectively removing glasses-reflected images and enhancing the accuracy of pupil detection.
Implementation Method 1
a first illumination light source, having a first wavelength component that makes a bright pupil by reflection in a subject's pupil
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
A pupil detection light source device includes an aperture (8) disposed to face a subject to allow light from a pupil of the subject to pass therethrough, a light-emitting element (3A) configured to emit illumination light for obtaining a light pupil image toward the subject from the inside or the vicinity of the aperture when seen from the subject, a light-emitting element (3B) configured to emit illumination light for forming a glasses-reflected image obtained by canceling a glasses-reflected image of the light pupil image using an image difference toward the subject from the inside or the vicinity of the aperture when seen from the subject, and a light-emitting element (3C) configured to emit illumination light for obtaining a dark pupil image toward the subject from a position spaced apart from the aperture when seen from the subject, wherein the glasses-reflected image in which a difference between the light pupil image and the dark pupil image is taken is canceled by the light-emitting elements (3A and 3B), and at the same time, a difference in brightness of the pupil of the subject is expanded by the light-emitting elements (3A and 3C).