Iris Authentication Image Synthesis Using Polarized Light
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Solution Overview
Problem
Current iris authentication techniques face challenges in achieving high accuracy, particularly when external light reflection and birefringence patterns from the cornea interfere with the iris image, leading to incorrect recognition and reduced authentication reliability, especially in casual authentication scenarios where cooperation from the individual is not possible.
Innovation Solution
An image synthesizing apparatus that uses an illuminating device to output linearly polarized light in different polarization directions and a camera to capture images in corresponding polarization directions, synthesizing these images on a pixel-by-pixel basis to reduce specular reflection and birefringence patterns, thereby enhancing iris authentication accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional iris authentication techniques are used, then authentication process is simple, but authentication accuracy deteriorates due to external light reflection and birefringence patterns
Solution Approach 1:
The patent divides the authentication process into multiple stages: capturing images with different polarization directions, synthesizing these images to remove artifacts, and then performing authentication. This segmentation allows each stage to be optimized independently, improving overall accuracy without overwhelming complexity
Solution Approach 2:
The patent introduces polarized light as an intermediary element between the light source and the iris. By using light with specific polarization directions and synthesizing images from multiple polarization angles, the system mediates the interaction between external light and the iris, eliminating harmful reflections and birefringence patterns while maintaining system feasibility
2Measurement precision
If multiple polarization directions are used to reduce reflection, then authentication accuracy improves, but illumination system complexity increases
Solution Approach 1:
The patent employs periodic action by sequentially illuminating the iris with light at different polarization directions (e.g., 0°, 45°, 90°, 135°) and capturing images at each stage. This periodic illumination approach systematically eliminates specular reflection and birefringence artifacts through synthesis, improving image quality without requiring all polarization components to operate simultaneously, thus managing device complexity
3Object-affected harmful factors
If polarized light illumination is applied, then specular reflection is reduced, but device complexity increases due to additional optical components
Solution Approach 1:
The patent introduces polarized light as an intermediary to mediate the interaction between illumination and the iris surface. By controlling the polarization direction of incident light and synthesizing images from multiple angles, the system effectively reduces specular reflection and birefringence artifacts. This intermediary approach addresses the harmful factors while managing device complexity through systematic image processing
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 solution effectively removes specular reflection and birefringence artifacts, resulting in improved iris authentication accuracy and reliability, even in casual authentication scenarios where the individual is unaware of the imaging process.
Implementation Method 1
an illuminating device that outputs linearly polarized light having a first polarization direction and linearly polarized light having a second polarization direction
Implementation Method 2
a camera that captures an image in a third polarization direction including a plurality of pixels and an image in a fourth polarization direction including a plurality of pixels
Implementation Method 3
the first polarization direction, the second polarization direction, the third polarization direction, and the fourth polarization direction are different from one another
Implementation Method 4
an image synthesizing apparatus that uses an illuminating device to output linearly polarized light in different polarization directions and a camera to capture images in corresponding polarization directions, synthesizing these images on a pixel-by-pixel basis to reduce specular reflection and birefringence patterns
Data Source
AI summary
An image synthesizing apparatus includes an illuminating device that outputs linearly polarized light having a first polarization direction and linearly polarized light having a second polarization direction, a camera that captures an image in a third polarization direction including a plurality of pixels and an image in a fourth polarization direction including a plurality of pixels, and a control circuit that synthesizes, on a pixel-by-pixel basis, the image in the third polarization direction and the image in the fourth polarization direction into an authentication image for iris authentication. The first, the second, the third and the fourth polarization directions are different from one another. The camera acquires the image in the third polarization direction using the linearly polarized light in the first polarization direction and acquires the image in the fourth polarization direction using the linearly polarized light in the second polarization direction.