Fingerprint Verification Using Reflected and Transmitted Light

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Solution Overview

Problem

Existing fingerprint verification technologies lack accuracy in detecting forgery due to reliance on comparison of reflected and transmitted light images from the same finger, failing to distinguish between genuine and forged fingerprints effectively.

Innovation Solution

A determination device and method that utilizes both reflected and transmitted light images of a fingerprint, comparing these images to determine authenticity by analyzing characteristic differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reflected light image and transmitted light image comparison is used for forgery detection, then the device can identify genuine fingers, but it cannot detect forged fingers with high accuracy

Engineering Contradiction:

Improveforgery detection accuracyVSAvoidreal-forgery determination precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the verification process into two independent stages: first verifying fingerprint pattern matching using reflected light images, then verifying blood vessel pattern matching using transmitted light images. This segmentation allows each verification stage to focus on specific characteristics, with the blood vessel verification specifically targeting forged fingers that may pass fingerprint pattern matching. The segmented approach resolves the contradiction by enabling high reliability in forgery detection through multi-stage verification while maintaining measurement precision through specialized pattern recognition at each stage.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If only fingerprint pattern matching is performed, then verification is simple, but forged fingerprints cannot be detected

Engineering Contradiction:

Improveverification process complexityVSAvoidforgery detection capability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The verification process is segmented into distinct fingerprint pattern verification and blood vessel pattern verification stages. This segmentation adds reliability by introducing blood vessel verification to detect forged fingers, while managing complexity through modular design where each verification stage operates independently with dedicated processing paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces blood vessel images as an intermediary verification layer between fingerprint pattern matching and final authentication. This intermediary verification mechanism detects forged fingers that may have authentic fingerprint patterns, thereby improving reliability without requiring complete redesign of the verification system. The blood vessel verification acts as a mediator that bridges fingerprint verification and security requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If multiple verification stages are added to detect forgeries, then detection accuracy improves, but processing time increases

Engineering Contradiction:

Improveforgery detection precisionVSAvoidverification processing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary fingerprint pattern verification using reflected light images before proceeding to blood vessel verification using transmitted light images. This preliminary action allows the system to quickly eliminate genuine fingers that match fingerprint patterns, reserving the more time-consuming transmitted light imaging and blood vessel analysis for cases where fingerprint verification is inconclusive or indicates potential forgery. This preliminary filtering approach maintains high detection precision while minimizing overall processing time.

Inventive Principle:

Principle #10Preliminary action

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

Accurately distinguishes between genuine and forged fingerprints with high precision, preventing unauthorized access by detecting counterfeit methods such as transparent films or resin duplicates.

Implementation Method 1

a reflected light image obtained by photographing a fingerprint of a finger by light reflected by a surface of the finger

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

a transmitted light image obtained by photographing the fingerprint of the finger by light transmitted through the finger

Methodology Applied

Scientific EffectLight transmission: Absorption (EM radiation)

Data Source

PatentUS20250356688A1Device, fingerprint input device and machine-readable medium

Publication Date: 2025.11.20 NEC CORP

AI summary

A device is not able to detect the forgery of a finger with high accuracy by the comparison of a reflected light image and a transmitted light image that are obtained from the same finger. A determination device is provided with an input means for receiving the reflected light image obtained by photographing a fingerprint of a finger with light reflected from the surface of the finger and the transmitted light image obtained by photographing the fingerprint of the finger with light transmitted through the finger, and a determination means for comparing the reflected light image and the transmitted light image, and outputting a real-forgery determination result of the fingerprint of the finger.