Optical Fingerprint Verification Ambient Light Adaptation

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Solution Overview

Problem

Optical fingerprint identification in mobile terminals is affected by external ambient light, leading to deviations in fingerprint data and matching results, which existing technologies have not adequately addressed.

Innovation Solution

The method involves controlling an optical sensor to detect ambient light intensity and using an application processor to determine whether fingerprint data matches a set of target fingerprint template data pre-stored in the mobile terminal, with the option to collect multiple sets of fingerprint template data based on different ambient light intensities to select the set with minimum noise, and adjusting fingerprint collection based on time and motion detection to improve matching accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If optical fingerprint identification component uses reflected light to form fingerprint image, then fingerprint identification can be implemented, but ambient light interference causes deviation in fingerprint data and affects matching accuracy

Engineering Contradiction:
Improvefingerprint matching accuracyVSAvoidambient light interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the 'Blessing in disguise' principle by converting the harmful ambient light interference into a useful parameter for identification. Instead of simply blocking or filtering ambient light, the system captures the ambient light characteristics along with the fingerprint reflection and uses this combined information to enhance matching accuracy. The ambient light that was previously considered noise is now transformed into additional biometric information that can distinguish between different fingers more reliably.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If multiple sets of fingerprint template data are collected based on different ambient light intensities, then matching accuracy under various lighting conditions is improved, but device complexity and processing time increase

Engineering Contradiction:
Improvefingerprint matching reliability under different lighting conditionsVSAvoidsystem complexity for collecting and managing multiple template sets
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements the 'Dynamics' principle by making the fingerprint template selection adaptive and dynamic rather than static. The system automatically selects which fingerprint template set to use based on the current ambient light conditions detected during authentication. This dynamic adaptation allows the system to maintain high matching accuracy across varying lighting environments without requiring complex manual configuration or user intervention to choose between different template sets.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If fingerprint template data is pre-stored for different ambient light intensities, then matching accuracy is improved, but memory requirements and data storage complexity increase

Engineering Contradiction:
Improvefingerprint data accuracy under different light intensitiesVSAvoidamount of stored fingerprint template data
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies the 'Preliminary action' principle by pre-collecting and storing multiple sets of fingerprint template data under different ambient light intensities during device setup or initial registration. This preliminary preparation ensures that when authentication is needed, the system already has pre-processed template data ready for various lighting conditions, eliminating the need for real-time processing and conversion during actual fingerprint verification.

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

This approach enhances the accuracy and reliability of fingerprint verification by reducing the impact of ambient light on fingerprint matching and preventing spurious triggering, thereby improving the success rate of optical fingerprint matching.

Implementation Method 1

The optical sensor is configured to detect a current external ambient light intensity

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

the light passes through a displaying screen surface pressed with a fingerprint and then may be reflected to the optical fingerprint identification component, the optical fingerprint identification component receives the reflected light and converts the light into fingerprint data

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3399461B1Optical fingerprint verification method and mobile terminal
Publication Date: 2019.12.11 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP3399461B1 patent drawingFigure 1a~1b
  • EP3399461B1 patent drawingFigure 1c~1d
  • EP3399461B1 patent drawingFigure 1e

AI summary

Embodiments of the present disclosure provide an optical fingerprint verification method and a mobile terminal (500). The method may include: controlling (201, 303, 403) the optical sensor to detect an external ambient light intensity when the mobile terminal acquires a fingerprint collecting instruction; controlling (202, 305, 409) the optical fingerprint identification component to collect fingerprint data; and determining (203, 306, 410) whether the fingerprint data matches to a set of target fingerprint template data corresponding to the external ambient light intensity via the AP, and when the fingerprint data matches to the set of target fingerprint template data, determining (204, 307, 411) that a fingerprint verification is passed.