Fingerprint Sensor Gain Sequencing for Unlock Speed

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Solution Overview

Problem

Fingerprint unlocking devices face inefficiencies as they require different gain settings for fingers with varying dryness levels, leading to prolonged unlocking times and poor user experience.

Innovation Solution

A control method and device that sequences gain usage based on past success rates, using machine learning to determine the optimal gain for fingerprint image acquisition and sequential adjustment when initial attempts fail, thereby reducing the number of images needed for successful unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If different gain settings are used for fingers with varying dryness levels, then fingerprint image quality (S/N ratio) is improved, but unlocking time increases

Engineering Contradiction:

Improvefingerprint image qualityVSAvoidunlocking time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-acquiring fingerprint images at multiple gain settings and pre-processing them into templates during enrollment. This preparation work is done in advance so that during actual unlocking, the system only needs to compare the newly captured image against pre-processed templates, significantly reducing the time required while maintaining the ability to handle different finger conditions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically selects the appropriate gain setting based on real-time detection of finger conditions (dryness level). Instead of using a fixed gain or sequentially trying multiple gains, the system adapts the gain selection to match the current finger state, optimizing both image quality and unlocking speed for each specific situation

Inventive Principle:

Principle #15Dynamics

2Reliability

If multiple fingerprint images are acquired with different gains, then successful unlocking rate is improved, but device complexity increases

Engineering Contradiction:

Improvesuccessful unlocking rateVSAvoidcontrol logic complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system implements feedback mechanisms where the outcome of each unlocking attempt (success/failure) and the detected finger conditions are fed back into the system. This feedback is used to update the selection criteria for gain settings and to refine the matching algorithms, improving the successful unlocking rate while keeping the control logic adaptive rather than overly complex

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes parameters (gain settings) based on detected conditions rather than implementing complex control logic. By adjusting the gain parameter according to finger dryness level and using pre-processed templates, the system achieves high reliability with simpler operational complexity during the actual unlocking process

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10452886B2Control method, control device, and electronic device

Publication Date: 2019.10.22 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

A control method for controlling an electronic device is provided. The control method includes sequencing the number of usage times of each of gains used by a fingerprint sensor of the electronic device when fingerprint unlocking of the electronic device is successful, and controlling the fingerprint sensor to directly use a gain with the maximum number of usage times to obtain a fingerprint image to conduct fingerprint unlocking.