Biometric Authentication Apparatus Reducing Registration Data via Bit Reliability

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Solution Overview

Problem

Biometric authentication systems face challenges in reducing the amount of registration data while maintaining authentication accuracy, as large feature vectors often exceed storage capacity, leading to potential instability in authentication results due to varying bit string generation.

Innovation Solution

A biometric authentication apparatus that extracts feature points from images, calculates feature vectors, binarizes values, and assesses bit string reliability to select and combine only the most stable bit strings within a predetermined size limit, thereby reducing data storage requirements without compromising accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a large number of feature points are extracted and all bit strings are combined for registration, then authentication accuracy is improved, but the storage capacity is exceeded

Engineering Contradiction:
Improveauthentication accuracyVSAvoidregistration data size
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the necessary subset of bit strings from the total feature points, selecting those that contribute most to authentication accuracy while discarding redundant ones. This is achieved by evaluating the contribution of each bit string and selecting only those that meet a predetermined threshold, thereby reducing registration data size while maintaining authentication performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of processing all extracted feature points, the patent applies partial action by selecting only a predetermined number of bit strings for registration. This partial selection approach prevents storage capacity overflow while ensuring that the most significant features are retained for accurate authentication.

Inventive Principle:
Principle #16Partial or excessive action

2Quantity of substance

If bit strings are randomly deleted to reduce data size, then storage capacity is reduced, but authentication accuracy deteriorates

Engineering Contradiction:
Improveregistration data sizeVSAvoidauthentication accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent changes the selection criterion from random deletion to reliability-based selection. By evaluating the reliability of each bit string (how stably it can be converted to a bit string), the system selects bit strings with high reliability for registration, ensuring that authentication accuracy is maintained even when the total number of bit strings is reduced to fit storage capacity.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If bit strings with unstable binarization values are used, then data volume is reduced, but authentication results become unstable

Engineering Contradiction:
Improveregistration data sizeVSAvoidauthentication stability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a reliability evaluation parameter that assesses the stability of binarization for each bit string. Bit strings with low reliability (unstable binarization values) are identified and excluded from registration. This parameter-based filtering ensures that only stable, reliable bit strings are used, preventing authentication instability even when reducing the overall data volume.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3594896B1Biometric authentication device, biometric authentication method, and biometric authentication program
Publication Date: 2023.04.05 FUJITSU LTD
  • EP3594896B1 patent drawingFigure 1
  • EP3594896B1 patent drawingFigure 2
  • EP3594896B1 patent drawingFigure 3

AI summary

Provided is a biometric authentication apparatus capable of reducing an amount of registration data while suppressing deterioration in authentication accuracy. The biometric authentication apparatus includes: a feature point extraction unit configured to extract a plurality of feature points from a biometric image; a feature vector calculation unit configured to calculate feature vectors from the biometric image including each of the feature points, each of the feature vectors corresponding to one of the plurality of the feature points; a bit string calculation unit configured to calculate bit strings by binarizing values of dimensions for each of the calculated feature vectors; a bit reliability calculation unit configured to attach bit reliability to each of the calculated bit strings based on stability of the binarizing of the corresponding feature vector; and a selection unit configured to select the bit strings from the calculated bit strings in accordance with values of the bit reliability, and by selecting the bit strings for authentication in accordance with the values of the bit string reliability, an amount of registration data can be reduced while suppressing deterioration in authentication accuracy.