Iris Capture Camera Positioning via Specularity Feedback
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Solution Overview
Problem
Existing iris code-based identification systems face challenges in ensuring consistent camera positioning during image capture, which affects the reliability of iris codes and is particularly problematic for species like horses where the iris-sclera boundary is obscured, making it difficult to determine the absolute size of the iris boundary.
Innovation Solution
The method calculates the camera's position relative to the eye using the specularity pattern created by light sources, allowing for real-time verification of optimal camera positioning, ensuring consistent image capture conditions and improving identification system reliability by analyzing the positional relationship between light sources, the object lens, and the cornea's curvature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the camera position is not strictly controlled during image capture, then the operation flexibility is improved, but the reliability of iris code identification deteriorates due to varying camera positions affecting image consistency
Solution Approach 1:
The patent uses the specularity pattern (reflected light positions) as feedback to determine camera position relative to the eye. By analyzing the positions of specular highlights from multiple light sources, the system calculates camera-to-eye distance and angular orientation, then uses this feedback to normalize iris images and compensate for position variations, maintaining identification reliability without strict physical constraints on camera placement
Solution Approach 2:
The patent changes the parameter of camera position from a fixed constraint to a variable that is measured via specularity pattern analysis and compensated through image normalization. By transforming the camera position parameters (distance, angle) derived from specularity into normalization factors, the system adapts the iris capture process to varying camera positions rather than requiring fixed positioning
2Ease of operation
If the camera-to-eye distance varies during image capture, then the ease of operation is improved, but the manufacturing precision of iris code quality deteriorates due to inconsistent image scale and perspective
Solution Approach 1:
The specularity pattern provides feedback on camera-to-eye distance by measuring the separation between reflected light spots from multiple light sources. This distance information is fed back to calculate a normalization scale factor, ensuring that iris images captured at different distances are rescaled to a consistent reference size, thereby maintaining iris code quality consistency regardless of varying camera distances
Solution Approach 2:
The patent transforms the camera-to-eye distance parameter from a source of quality variation into a useful measurement for normalization. By deriving distance from specularity pattern geometry and using it to adjust image scale, the system converts a problematic variable parameter into a corrective factor that ensures consistent iris code quality
3Ease of operation
If the camera is not aligned with the line of sight of the eye, then the ease of operation is improved, but the measurement precision of iris pattern detection deteriorates due to oblique viewing angles
Solution Approach 1:
The specularity pattern provides feedback on camera angular orientation relative to the eye's line of sight by analyzing the asymmetric positions of reflected light spots. This angular information is fed back to calculate rotation correction factors, enabling the system to geometrically transform oblique iris images into frontally-aligned representations, thereby maintaining iris pattern detection precision even when the camera is not perfectly aligned with the line of sight
4Reliability
If additional light sources and specularity analysis are added to determine camera position, then the reliability of image capture conditions is improved, but the device complexity increases
Solution Approach 1:
The patent makes the existing light sources in the camera system serve multiple functions: they provide illumination for capturing the iris image and simultaneously create the specularity pattern that encodes camera position information. By extracting positional data from the same light sources already present in the system, the patent avoids adding separate positioning hardware, thereby improving reliability without proportionally increasing device 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 enhances the reproducibility of image capture conditions, reduces the impact of camera position on iris codes, and improves the reliability of the identification system, especially for species like horses where the iris-sclera boundary is obscured, by providing additional information for normalizing the iris image.
Implementation Method 1
detecting a specularity pattern that is created by reflection of light from said at least two light sources at a cornea of the eye
Data Source
AI summary
A method of capturing image data for iris code based identification of vertebrates, including humans, comprises the steps of:recording a digital image of an eye with a camera equipped with at least two light sources that have a fixed spatial relationship to an object lens of the camera;locating the eye in the digital image by detecting a specularity pattern that is created by reflection of light from said at least two light sources at a cornea of the eye; andcalculating information on the position of the camera relative to the eye on the basis of said fixed spatial relationship between the light sources and the object lens and on the basis of said specularity pattern.