Iris Recognition with Colored Contact Lens Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Colored contact lenses can reduce the matching accuracy of iris recognition systems by altering the appearance of the iris.

Innovation Solution

An iris recognition system that includes a determination unit to identify whether a colored contact lens is worn, and a matching unit that uses a feature amount extracted from a region excluding a predetermined range near the outer circumference of the iris for matching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the entire iris region is used for matching, then the matching accuracy is improved, but the matching accuracy deteriorates when colored contact lenses are worn

Engineering Contradiction:

Improvematching accuracyVSAvoidmatching accuracy under colored contact lens condition

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The iris region is divided into multiple segments: the entire iris region is initially used for matching to maximize accuracy, but when colored contact lenses are detected, the system segments out the outer circumference region (where the colored lens affects the iris) and excludes it from the matching process. This segmentation allows the system to maintain high matching accuracy using the unaffected inner iris regions while avoiding the harmful effects of colored contact lenses.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the iris are treated differently based on their susceptibility to colored contact lens effects. The outer circumference region is identified as having degraded quality when colored lenses are worn, while the inner iris regions maintain their quality. The system applies local quality assessment by selectively excluding only the affected outer region while preserving the use of the unaffected inner regions for matching.

Inventive Principle:

Principle #3Local quality

2Reliability

If the outer circumference region of the iris is excluded from matching, then the influence of colored contact lenses is reduced, but the amount of usable iris information decreases

Engineering Contradiction:

Improvematching accuracy under colored contact lens conditionVSAvoidusable iris information

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The system extracts and removes only the specific problematic portion (the outer circumference region of the iris) that is affected by colored contact lenses, while retaining and utilizing the remaining inner iris regions for matching. This selective extraction minimizes the loss of usable iris information by excluding only what is necessary to eliminate the colored lens interference.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of excluding the entire iris region or using a fixed threshold, the system dynamically determines the extent of exclusion based on detection results. The outer circumference exclusion radius is set to be sufficient to remove colored lens effects but not excessively large to avoid unnecessary loss of valid iris information. This partial action approach balances reliability improvement with information preservation.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20250029352A1Iris recognition system, iris recognition method, and storage medium

Publication Date: 2025.01.23 NEC CORP

AI summary

An example embodiment includes: a determination unit that, based on an image including an eye of a recognition subject, determines whether or not a colored contact lens is worn; and a matching unit that, when it is determined by the determination unit that the colored contact lens is worn, performs matching of the iris by using a feature amount extracted from a region excluding a predetermined range including an outer circumference of the iris out of a region of the iris included in the image.