Fingerprint Sensor Area Coverage Verification

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Solution Overview

Problem

Fingerprint sensors often activate prematurely or unintentionally due to incomplete finger coverage, leading to unnecessary power consumption and resource usage, as existing methods may not accurately determine whether the entire sensor area is covered by a finger.

Innovation Solution

A method that involves acquiring an image of the fingerprint and dividing the image area into overlapping regions to ensure comprehensive coverage analysis, using image analysis to determine if the finger covers the entire sensor area before activating the sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the sensor activates without verifying complete finger coverage, then the system responds quickly and processes are initiated promptly, but the sensor activates prematurely or unintentionally leading to unnecessary power consumption and resource usage

Engineering Contradiction:
Improveresponse speedVSAvoidpower consumption
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by performing coverage verification before activating the fingerprint sensor. The system divides the sensor area into multiple sub-areas and checks whether each sub-area is covered by the finger in advance. Only after confirming complete coverage does the system activate the sensor and initiate processing, thereby preventing premature activation and unnecessary power consumption while maintaining quick response when proper coverage is achieved

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the sensor checks only certain points or partial areas of the fingerprint, then the detection process is simpler and faster, but non-covered sensor areas may be missed leading to incomplete or inaccurate detection

Engineering Contradiction:
Improvedetection complexityVSAvoidcoverage detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies segmentation by dividing the sensor area into multiple sub-areas and independently checking coverage for each sub-area. This ensures that every portion of the sensor is verified for finger coverage, preventing missed detections while maintaining manageable complexity through systematic division of the detection task

Inventive Principle:
Principle #1Segmentation

3Productivity

If the sensor uses non-overlapping regions to divide the sensor area, then the analysis is computationally simpler and faster, but gaps between regions may cause non-covered areas to be missed

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidcoverage detection reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies dynamics by using overlapping regions instead of static non-overlapping divisions. The overlapping design creates dynamic redundancy where each boundary area is covered by multiple regions, ensuring that no non-covered gaps can be missed. This approach maintains processing efficiency while significantly improving detection reliability through the overlapping verification mechanism

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3679518B1Method and fingerprint sensing system for determining that a finger covers a sensor area of a fingerprint sensor
Publication Date: 2024.07.24 FINGERPRINT CARDS ANACATUM IP AB
  • EP3679518B1 patent drawingFigure 1~2
  • EP3679518B1 patent drawingFigure 3~4
  • EP3679518B1 patent drawingFigure 5a~5b

AI summary

The present disclosure relates to a method of determining that a finger covers a sensor area of a fingerprint sensor. The method comprises, on a surface of the fingerprint sensor, receiving a finger having a fingerprint topography. The method also comprises, by means of the fingerprint sensor, acquiring an image of the fingerprint of the received finger. The method also comprises dividing an image area (41)of the acquired image, corresponding to the sensor area of the fingerprint sensor, into a plurality of image regions (r), said regions partly overlapping each other and covering the whole image area. The method also comprises, based on image analysis of each of the plurality of image regions, determining that the finger covers the whole sensor area.