Iris Image ROI Control for Eye Position Fluctuation
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Solution Overview
Problem
Existing image processing systems struggle to capture iris patterns with sufficient quality for authentication and verification under conditions of large subject-to-image pick-up distance, wide field of view, and subject movement, as they lack the necessary resolution and frame rate.
Innovation Solution
A system comprising multiple iris image pick-up devices stacked vertically, with region-of-interest mode and synchronized illumination, controlled by a controller to achieve high resolution and frame rate, allowing for precise iris image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the distance between the subject and the image pick-up means is increased, then the field of view is widened, but the resolution of the iris pattern deteriorates
Solution Approach 1:
The patent divides the image capture process into two stages: first capturing a wide-field overview image to locate the eye position, then capturing a high-resolution iris pattern image by moving the image pick-up means closer to the subject's eye. This segmentation allows the system to achieve both wide field of view for subject acquisition and high resolution for iris authentication.
2Productivity
If the frame rate is increased to capture moving subjects, then the ability to photograph moving irises is improved, but the image quality or resolution may deteriorate
Solution Approach 1:
The system first captures a low-resolution overview image at high frame rate to detect eye position and determine when the subject is in the appropriate position. Only after this preliminary detection does it trigger the high-resolution iris capture. This preliminary action allows the system to maintain high frame rate capability while ensuring high image quality for authentication.
3Measurement precision
If the granularity is decreased to 50 μm for high resolution, then the iris pattern detail is improved, but the difficulty of photographing under distance conditions increases
Solution Approach 1:
The patent employs dynamic adjustment of the image pick-up means, moving it from a distant position (for wide field of view) to a close position (for high-resolution capture). This dynamic positioning resolves the contradiction by allowing the system to achieve 50 μm granularity only when the subject is in the optimal capture position, making high-resolution photographing feasible despite the initial distance.
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
Enables high-quality iris pattern capture suitable for authentication and verification even with long distances and subject movement, reducing retry rates due to eye position fluctuations.
Implementation Method 1
in the photographing of an iris, near-infrared light is applied to eyes of a subject
Data Source
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AI summary
According to the present disclosure, the reacquisition of an image caused by fluctuations in the eye position is reduced. A controller (500) controls the readout of an image from iris image pick-up devices (401 to 404) for performing image pick-up of an iris of a subject. In the control of the readout of an image from the iris image pick-up devices, the controller (500) sets a region of interest to be treated as a target of the image readout. The controller (500) stores past information, and in the case of performing image processing on the same subject, the controller (500) determines whether or not an eye region of the subject was successfully covered by the region of interest used in the past. In the case of determining that the eye region of the subject was not successfully covered, the controller (500) corrects the readout of an image from the iris image pick-up devices.