3D Face Authentication Using Multi-Distance Image Sizing

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Solution Overview

Problem

Conventional face ID systems are vulnerable to spoofing techniques, such as using 2D images or 3D models, due to their reliance on limited large-scale facial structures, which compromises security while trying to minimize resource usage and avoid false negatives.

Innovation Solution

A passive 3D object authentication method that captures images of a user's face at multiple distances to extract deterministic structural dimensions, computing normalization factors to differentiate between authentic and spoofed faces, enhancing security without excessive resource consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional face ID systems use limited large-scale facial structures for rapid recognition, then processing speed and battery efficiency are improved, but security vulnerability to spoofing increases

Engineering Contradiction:
Improvebattery usageVSAvoidsecurity against spoofing
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent transitions from 2D facial structure recognition to 3D depth-aware recognition by capturing images at multiple distances and computing depth values based on dimensional relationships between facial features. This dimensional enhancement allows the system to verify genuine 3D facial geometry while maintaining efficient processing through normalized dimensional comparisons rather than exhaustive analysis.

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

2Productivity

If conventional face ID systems use simple facial structure comparison, then processing speed is improved, but measurement precision for spoof detection deteriorates

Engineering Contradiction:
Improveprocessing speedVSAvoiddimensional measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary capture of multiple images at different distances during a registration phase, establishing baseline dimensional relationships and depth values for genuine facial structures. During authentication, these pre-established references enable rapid verification through comparison of dimensional ratios and depth relationships, achieving both speed and precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs dynamic image capture at multiple distances rather than static single-distance imaging. By capturing images at varying distances and computing dimensional relationships that remain consistent across distance changes, the system achieves robust depth-aware verification. The normalization process dynamically adjusts for imaging distance variations, maintaining measurement precision across different capture conditions.

Inventive Principle:
Principle #15Dynamics

3Reliability

If face ID systems implement advanced spoof detection, then security is improved, but device complexity and resource consumption increase

Engineering Contradiction:
Improvesecurity levelVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or hardware-based 3D sensing systems with a computational approach using standard imaging sensors. By capturing multiple 2D images at different distances and deriving 3D dimensional relationships through image processing and mathematical computations, the system achieves sophisticated spoof detection without requiring specialized hardware, thereby maintaining device simplicity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system introduces computational algorithms as intermediaries between the imaging sensor and authentication decision. These algorithms process captured images to extract dimensional relationships, compute depth values, and compare facial geometries, serving as a software layer that enables advanced security verification using conventional imaging hardware.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS11830284B2Passive three-dimensional object authentication based on image sizing
Publication Date: 2023.11.28 SHENZHEN GOODIX TECH CO LTD
  • US11830284B2 patent drawing
  • US11830284B2 patent drawing
  • US11830284B2 patent drawing

AI summary

Techniques are described for passive three-dimensional (3D) object authentication based on image sizing, such as for biometric facial recognition. For example, during a registration routine, an imaging system captures images of a registering user's face at multiple distances. The images can be processed to extract registration dimensions, including individual deterministic structural dimensions, dimensional relationships that are static over changes in imaging distance, and dimensional relationships that changes predictably over changes in imaging distance. During an authentication routine, the imaging system again captures authentication images of an authenticating user's face (purportedly the previously registered user) at some authentication imaging distance and processes the images to extract authentication dimensions. Expected and actual dimensional quantities are computed from the authentication and registration dimensions and are compared to determine whether the authenticating user's face appears to be authorized as previously registered and/or is a spoof.