Iris Authentication Color Contact Lens Detection

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Solution Overview

Problem

Existing iris authentication systems struggle to determine whether a color contact lens is worn, as the lens changes the entire iris color and not just a specific region, making it difficult to differentiate from the original iris image, especially under varying illumination conditions.

Innovation Solution

An image processing device that calculates feature amounts in both visible and near-infrared wavelength bands to determine the presence of a color contact lens by analyzing the reflectance differences in these bands, using a ratio of pixel values to differentiate between iris images with and without the lens.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If color contact lens is used to change iris color, then the iris color can be changed to match fashion or clothing, but the captured iris image becomes a combination image that is not suitable for authentication

Engineering Contradiction:

Improveiris color customizationVSAvoidauthentication accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the visible spectrum into multiple wavelength bands (e.g., blue, green, red, infrared) and analyzes the reflectance characteristics of the iris at each band. By segmenting the spectral analysis, the system can identify the specific wavelength patterns that indicate color contact lens usage versus natural iris reflectance, thereby detecting the presence of the lens while maintaining authentication capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of analysis from single-wavelength color detection to multi-wavelength spectral reflectance measurement. By measuring reflectance across different wavelength bands and comparing the patterns, the system can distinguish between the spectral signature of a natural iris and one altered by a color contact lens, resolving the contradiction between color customization and authentication reliability.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If simple color determination is used to detect color contact lens, then the detection method is simple, but it is difficult to determine the presence or absence of wearing a color contact lens because the lens changes the entire iris color

Engineering Contradiction:

Improvedetection method complexityVSAvoidcolor contact lens detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from two-dimensional color analysis (hue saturation value) to a multi-dimensional spectral analysis across multiple wavelength bands. This dimensional expansion allows the system to capture the spectral fingerprint of the iris, which provides sufficient discrimination to detect color contact lenses with high accuracy while maintaining relatively simple processing through pattern recognition in the spectral domain.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If density of specific region is used to determine prosthetic eye, then the method can identify prosthetic eyes, but it cannot determine whether color contact lens is worn on the iris

Engineering Contradiction:

Improveprosthetic eye detectionVSAvoiddetection scope

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal detection framework based on multi-wavelength spectral reflectance analysis that can handle multiple detection scenarios: natural iris authentication, prosthetic eye detection, and color contact lens detection. By using the same spectral measurement approach and comparing reflectance patterns across different wavelength bands, the system can adapt to detect different types of iris alterations without requiring separate specialized methods for each case.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Effectively determines the presence or absence of a color contact lens on the iris, enhancing the accuracy of iris authentication by accounting for reflectance changes across multiple wavelength bands.

Implementation Method 1

calculates a first feature amount in a first wavelength band using an image in the first wavelength band in an iris used for authentication of a person; calculates a second feature amount in a second wavelength band using an image in the second wavelength band in the iris

Methodology Applied

Scientific EffectReflectance: Reflection

Data Source

PatentUS12014573B2Image processing device, authentication system, image processing method, authentication method, and recording medium

Publication Date: 2024.06.18 NEC CORP

AI summary

In order to determine whether a color contact lens is being worn on an iris, this image processing device includes: a first feature amount calculation means for using an image of the iris in a first wavelength band to calculate a first feature amount in the first wavelength band, said iris being used in authentication of a person; a second feature amount calculation means for using an image of the iris in a second wavelength band to calculate a second feature amount in the second wavelength band; and a covering determination means for determining, on the basis of the first feature amount and the second feature amount, whether a color contact lens is present on the iris.