Self-Supervised Face Quality Recognition via Live-Image Similarity

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Solution Overview

Problem

Conventional methods for face image quality recognition in eKYC processes are inefficient due to extensive manual labeling required for binary classification, which is time-consuming and not effective in assessing the quality of ID images accurately.

Innovation Solution

A self-supervised face quality recognition method that pairs ID face images with live face images to generate similarity scores, allowing for the training of a multiclass classification or regression model without manual labeling, enabling accurate quality ranking and classification of ID face images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If binary classification model is used for face image quality recognition, then the model can output two classes (acceptable/unacceptable quality), but extensive manual labeling is required which is time-consuming

Engineering Contradiction:
Improvemodel training efficiencyVSAvoidmanual labeling time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The system uses live face images as self-generated training labels by comparing them with ID face images through similarity scoring. This self-service mechanism eliminates the need for external manual labeling, allowing the model to train automatically using the eKYC system's own operational data.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary similarity scoring between live and ID face images before model training. By pre-processing and ranking images based on similarity scores, the system prepares labeled training data in advance, reducing the time required during actual model training and deployment.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If binary classification is used, then the process is simpler, but the quality assessment accuracy is reduced compared to multiclass classification

Engineering Contradiction:
Improvequality assessment accuracyVSAvoidmodel complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the quality assessment into multiple discrete quality levels (e.g., top 10%, middle 10%, bottom 10% percentiles) rather than a single binary classification. This segmentation allows for more precise quality measurement while maintaining manageable model complexity through hierarchical or staged processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a one-dimensional binary classification to a multi-dimensional quality spectrum by introducing similarity scores as an additional dimension. This allows the model to assess quality along multiple axes (similarity score, ranking percentile, quality level) simultaneously, improving measurement precision without proportionally increasing complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If manual labeling is performed extensively to achieve high accuracy, then model accuracy improves, but productivity decreases

Engineering Contradiction:
Improvemodel accuracyVSAvoidmodel training productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system generates its own training labels automatically by computing similarity scores between live and ID face images. This self-service approach eliminates the need for human annotators, maintaining high model accuracy through consistent automated labeling while dramatically improving training productivity and throughput.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements feedback loops where similarity scoring results from actual eKYC operations are fed back into the training process. This continuous feedback mechanism allows the model to learn from real-world data patterns, improving accuracy over time while maintaining high productivity through automated iterative training.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11393235B2Face image quality recognition methods and apparatuses
Publication Date: 2022.07.19 ZOLOZ PTE LTD
  • US11393235B2 patent drawing
  • US11393235B2 patent drawing
  • US11393235B2 patent drawing

AI summary

Disclosed are computer-implemented methods, non-transitory computer-readable media, and systems for identity document face image quality recognition. One computer-implemented method includes pairing, for each user of a plurality of users and to form a pair of face images, an identity document (ID) face image and a live face image. For each pair of face images and based on a face similarity between the ID face image and the live face image, a similarity score for the ID face image is generated. Based on ID face images and similarity scores corresponding to the ID face images, a model for ID face image quality recognition is trained.