Iris Authentication Correction for Colored Contact Lens Interference

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Solution Overview

Problem

Colored contact lenses affect iris authentication precision by altering the iris image, leading to reduced authentication accuracy.

Innovation Solution

An authentication device and method that identifies the colored contact lens pattern, extracts a corrected iris region by removing the colored region, and calculates a feature value for authentication, using reference images and product catalogs to match with pre-registered iris features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If colored contact lenses are worn to achieve decorative effects, then the iris appearance is altered, but authentication precision is reduced

Engineering Contradiction:
Improveiris appearance variationVSAvoidauthentication precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent extracts and removes the colored contact lens region from the iris image through shadow region detection and image correction techniques, isolating the authentic iris pattern from the decorative overlay to enable accurate authentication

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent detects and analyzes color variations in the iris image to identify regions affected by colored contact lenses, using color difference calculations to distinguish between natural iris pigmentation and artificial coloring

Inventive Principle:
Principle #32Color changes

2Reliability

If shadow region removal is performed to correct iris images, then the influence of contact lenses is reduced, but a method for colored contact lens correction is not available

Engineering Contradiction:
Improveauthentication reliabilityVSAvoidapplicability to colored contact lenses
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the approach from simple shadow removal to comprehensive color parameter analysis, using multiple color space transformations and threshold adjustments to effectively handle the specific challenges of colored contact lens detection and removal

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3859664B1Authentication device, authentication method, and recording medium
Publication Date: 2026.02.18 NEC CORP
  • EP3859664B1 patent drawingFigure 1
  • EP3859664B1 patent drawingFigure 2
  • EP3859664B1 patent drawingFigure 3

AI summary

A reduction in the authentication precision of iris authentication can be prevented even when a colored contact lens is worn. An authentication device 11 includes an image acquisition unit 111, an identification unit 121, and an authentication unit 151. The image acquisition unit 111 acquires an image of an eye of a subject. The identification unit 121 identifies the colored pattern of a colored contact lens worn by the subject by comparing a reference image with the image of the eye. The authentication unit 151 identifies the subject, using a feature in a region other than a colored region of the colored pattern in the iris region of the eye.