Specularity-Free Iris Capture via Dynamic Illumination Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Iris recognition systems face challenges in capturing clear images of spectacle-wearing users due to the formation of optical artifacts like specular reflections, which can lead to false negative verification results and require users to remove their spectacles, making un-manned applications impractical.
Innovation Solution
The method involves illuminating the user's eye from different positions to shift specular images away from the iris region, allowing for clear image capture without requiring users to remove their spectacles, using a system with adjustable illumination sources and image capture devices to vary the optical path and position of the specular image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the user removes their spectacles prior to image capture, then the clarity of the iris image is improved, but the ease of operation deteriorates as users cannot remove spectacles in unmanned applications
Solution Approach 1:
The patent changes the illumination parameters by using multiple illumination positions arranged in different orientations relative to the camera axis. By varying the illumination angle parameter, the system captures images where specular reflections from spectacles are shifted away from the iris region, thereby maintaining image clarity without requiring users to remove their spectacles.
Solution Approach 2:
The patent introduces a spatial dimension by arranging illumination sources at multiple positions (e.g., left and right of the camera axis) rather than using a single illumination direction. This multi-dimensional illumination approach allows the system to capture the iris from angles that minimize specular reflection interference while keeping the camera and user position fixed.
2Measurement precision
If multiple illumination positions are used to shift specular images, then the clarity of the iris image is improved, but the device complexity increases due to additional illumination sources
Solution Approach 1:
The patent designs the illumination system so that multiple illumination sources serve dual purposes: they provide necessary lighting for iris capture and simultaneously enable specular reflection management through angular variation. This multi-functionality reduces the need for separate specular reflection mitigation devices, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The system implements dynamic illumination control by selectively activating different illumination sources based on detected specular reflection patterns. Rather than having all illumination sources continuously active, the system dynamically switches between positions to optimize image quality while minimizing energy consumption and system complexity.
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 approach enables the capture of specularity-free images of the iris, improving the accuracy and usability of iris recognition systems in both manned and unmanned applications by minimizing user involvement and reducing false negative verification results.
Implementation Method 1
A portion of the incident light is reflected by the spectacles, whilst the majority of the incident light is reflected by the eye
Data Source
AI summary
The present invention concerns a method for capturing an image of an iris free of specularities from a spectacle-wearing user for use in an iris recognition identification system, which includes an illumination source and an image capture device. The method comprises illuminating the user's eye from a first illumination position associated with a first optical path, and capturing a first image of the eye; and determining if the first image comprises a specular image in a first region of interest, the specular image being formed by light reflected from the spectacles. If a specular image is present, the method further comprises illuminating the eye from a second illumination position associated with a second optical path different to the first optical path, such that the specular image is shifted to a second region; and capturing a second image of the eye.