Biometric Face Detection Device with Folded Optical Path

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Solution Overview

Problem

Existing devices for detecting biometric features of a person's face often produce images with aberrations, leading to false rejections in automated border control systems, which are time-consuming, costly, and pose a security risk, especially when using automatic passport photo machines with suboptimal image quality and user guidance.

Innovation Solution

A device with a camera and a mirror arrangement that folds the beam path, combined with an inclined operating unit for optimal optical path length, an overview camera for depth information, and adjustable illumination, including near-infrared capabilities and glasses detection, to ensure high-quality image capture and presentation attack detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a camera is arranged directly facing the person to capture biometric features, then the device structure is simplified, but optical aberrations occur and image quality deteriorates

Engineering Contradiction:
Improvedevice structureVSAvoidimage quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The optical path is segmented into multiple components: a first mirror arrangement to fold the beam path, and a second mirror arrangement with a semi-transparent mirror to separate transmission and reflection paths. This segmentation allows the camera to be positioned optimally while avoiding direct optical aberrations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Mirror arrangements serve as intermediary elements between the camera and the person's face. The semi-transparent mirror acts as a mediator that transmits light for capturing the face while reflecting light for mirroring the person's face, enabling high-quality image capture without direct camera-face alignment issues.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the camera is positioned close to the person to reduce beam path length, then the device becomes more compact, but optical aberrations increase and image quality decreases

Engineering Contradiction:
Improvedevice compactnessVSAvoidimage quality
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The beam path is folded in three-dimensional space using mirror arrangements, transforming a linear optical path into a multi-dimensional path. This allows the camera to be positioned at an optimal distance while maintaining a compact device footprint through spatial folding rather than linear extension.

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

3Manufacturing precision

If professional photography equipment is used to ensure high image quality, then image quality improves, but the device becomes more complex and costly

Engineering Contradiction:
Improveimage qualityVSAvoiddevice structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mirror arrangements serve multiple functions simultaneously: they fold the beam path, separate transmission and reflection paths, enable optimal camera positioning, and maintain compact device structure. This multi-functionality achieves high image quality without requiring complex professional photography equipment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If manual verification is performed to ensure accurate biometric identification, then identification accuracy improves, but processing time increases and productivity decreases

Engineering Contradiction:
Improveidentification accuracyVSAvoidprocessing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system captures high-quality biometric images automatically through optimized optical paths and mirror arrangements, enabling self-service operation. The device produces sufficient quality images for automated recognition without requiring manual verification, thus maintaining high productivity while ensuring identification accuracy.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution generates high-quality biometric data images that meet ISO standards, reducing false rejections and ensuring that only real persons are identified, while maintaining a compact and cost-effective device structure.

Implementation Method 1

a mirror arrangement which folds a beam path running between the person's face to be captured and the camera

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The second mirror arrangement comprises a semi-transparent mirror that transmits light for capturing the face by means of the camera and reflects light for mirroring the person's face

Methodology Applied
Scientific EffectLight transmission and reflection: Reflection

Implementation Method 3

a camera directed at a first mirror arrangement to capture a beam path striking a second mirror arrangement

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3425560B1Device and method for detecting biometric features of a person's face
Publication Date: 2021.11.17 BUNDESDRUCKEREI GMBH
  • EP3425560B1 patent drawingFigure 1
  • EP3425560B1 patent drawingFigure 2
  • EP3425560B1 patent drawingFigure 3

AI summary

The invention relates to a device (100) for capturing biometric features of a person's face (110), comprising a housing (101) having a housing front (102) facing the person and in which a camera (103) having a first focal length for capturing the biometric features and a mirror (104) for folding a beam path (105) running between the person's face (110) and the camera (103) are arranged, as well as an operating unit (107) that is in wireless or wired communication connection (111) with an evaluation and/or control unit (109) and is arranged between the housing front (102) and the person. To generate a predetermined length of the beam path (105), the operating unit (107) is arranged at an angle (α) to the housing front (102). The invention further relates to a corresponding method.