Contactless Mobile Fingerprint Recognition Through Protective Films

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Solution Overview

Problem

Existing fingerprint recognition methods on mobile devices face challenges in performance due to the use of contact-type sensors, which are affected by protective films, and the need for specific installation locations, limiting user convenience.

Innovation Solution

A contactless fingerprint recognition method using an optical sensor and machine learning models to acquire and process hand images, segment fingertips, and extract fingerprint information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a contact-type fingerprint sensor is used in a mobile device, then the device can be made portable and accessible, but the fingerprint recognition performance is lowered when a protective film is attached to the display panel

Engineering Contradiction:
Improveportability and accessibilityVSAvoidfingerprint recognition performance
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces an optical sensor as an intermediary component that captures images of the fingerprint through the display panel and protective film. This intermediary approach allows the system to obtain fingerprint data without direct contact, thereby maintaining recognition performance even when a protective film is present on the display panel.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical contact-type sensor system with an optical imaging system. Instead of using physical contact between the sensor and fingerprint, the system uses optical fields to capture fingerprint images through the display panel, eliminating the degradation caused by protective films.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a separate fingerprint recognition device is used, then accurate fingerprint recognition can be achieved, but the user cannot carry the device and is limited to specific installation locations

Engineering Contradiction:
Improvefingerprint recognition accuracyVSAvoidlocation flexibility and user convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent merges the fingerprint recognition functionality with the mobile device itself by integrating an optical sensor into the device structure. This combination allows the mobile device to perform both its primary functions and fingerprint recognition, eliminating the need for separate dedicated devices and enabling portability while maintaining recognition capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent makes the mobile device universal by enabling it to perform multiple functions including fingerprint recognition. The optical sensor integration allows the device to serve as both a general-purpose mobile device and a fingerprint recognition device, providing location flexibility and user convenience without sacrificing recognition accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If image processing steps are added to extract hand image, fingertip image, and fingerprint information, then fingerprint recognition performance is improved, but device complexity increases

Engineering Contradiction:
Improvefingerprint recognition performanceVSAvoidimage processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the image processing into distinct sequential steps: first extracting the hand image from the original image, then extracting the fingertip image from the hand image, and finally extracting fingerprint information from the fingertip image. This segmentation approach organizes the complex processing into manageable stages, improving recognition performance while structuring the complexity in a systematic manner.

Inventive Principle:
Principle #1Segmentation

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

Improves fingerprint recognition performance by enabling user convenience and maintaining accuracy regardless of location, leveraging optical sensors and machine learning for enhanced image processing.

Implementation Method 1

acquiring an original image including a user's hand using an optical sensor included in a terminal

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4654159A1Fingerprint recognition method using mobile device and apparatus employing same
Publication Date: 2025.11.26 XPERIX INC
  • EP4654159A1 patent drawingFigure 1~2
  • EP4654159A1 patent drawingFigure 3~4
  • EP4654159A1 patent drawingFigure 5(a)~5(b)

AI summary

A method for fingerprint recognition using a mobile device and an apparatus using the same are disclosed. A method for recognizing a fingerprint in a contactless manner according to an embodiment may comprising: acquiring an original image including a user's hand using an optical sensor included in a terminal, acquiring a hand image from the original image using a neural network model based on the original image, acquiring at least one fingertip image based on the hand image, and acquiring at least one fingerprint information from the at least one fingertip image.