Biometric Face Capture Device With Diffuse Illumination Housing
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Solution Overview
Problem
Existing biometric face detection systems require trained personnel and specific lighting conditions to capture high-quality frontal images, which are often not available in ID card issuance settings, leading to unreliable data acquisition.
Innovation Solution
A device with a diffusely illuminated housing and a deflection mirror that allows untrained personnel to capture biometric features, featuring a semi-transparent mirror and projection-based user guidance for ensuring suitable illumination and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a semi-transparent mirror and deflecting mirror system is used to enable self-capture, then ease of operation is improved, but device complexity increases
Solution Approach 1:
A semi-transparent mirror is introduced as an intermediary element between the user and the camera. This mirror allows the user to see themselves while being captured, enabling self-positioning without requiring trained personnel. The semi-transparent mirror acts as a mediator that simultaneously permits optical passage for capture and visual feedback for user guidance.
Solution Approach 2:
The system enables users to perform their own face capture without assistance from trained personnel. Through the combination of the semi-transparent mirror for self-visualization and projection-based guidance instructions, users can independently position themselves correctly and complete the biometric enrollment process autonomously.
2Illumination intensity
If diffuse illumination is implemented through housing design, then illumination quality is improved, but manufacturing precision requirements increase
Solution Approach 1:
The housing is designed with a curved, hemispherical inner surface instead of flat surfaces. This spherical geometry naturally diffuses light uniformly across the capture area, creating optimal illumination conditions for biometric capture. The curved surface scatters light in multiple directions, eliminating harsh shadows and hot spots that would occur with flat surfaces.
Solution Approach 2:
The illumination quality is improved by changing the geometric parameters of the housing from conventional flat-walled designs to a curved hemispherical configuration. This parameter change in the housing geometry fundamentally alters the light distribution pattern, transforming direct lighting into diffuse illumination without requiring additional lighting components.
3Ease of operation
If a projection device is added for user guidance, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The deflecting mirror serves multiple functions: it directs light from the face to the camera for capture, and simultaneously acts as a projection surface for displaying guidance instructions to users. By making the mirror semi-transparent, the system enables the projection device to communicate with users without adding separate display hardware, achieving multi-functionality with existing components.
4Volume of moving object
If the receiving opening is positioned close to the camera for compact design, then device compactness is improved, but measurement precision may deteriorate
Solution Approach 1:
The deflecting mirror folds the optical path by changing the dimensionality of light propagation. Instead of requiring a straight-line path from face to camera, the mirror redirects light at an angle, effectively extending the optical path length within a compact physical footprint. This allows the maintaining of adequate face-camera distance while keeping the device compact.
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
Enables reliable biometric data capture by untrained users in variable lighting conditions, meeting ISO specifications and ensuring high-quality facial images for biometric comparison algorithms.
Implementation Method 1
a semi-transparent mirror is arranged between the person and the camera and is oriented such that, on the side of the semi-transparent mirror facing the person, the path of light incident on the semi-transparent mirror is parallel to the path of the portion of this light reflected back from the semi-transparent mirror
Implementation Method 2
the housing may contain light sources to create diffuse illumination and/or have a diffusely reflective inner surface
Data Source
Figure 1
AI summary
Device (10) for capturing biometric features of a person's face (12), comprising a housing (14), a receiving aperture (16) designed for placement at a short distance in front of a face (12) to be captured, a camera (18) designed for capturing the biometric features, and a deflecting mirror (20) arranged in the housing (14) to direct light reflected from the face (12) to be captured, placed in front of the receiving aperture (16), into the camera (18), wherein the housing (14) is designed to provide diffuse illumination of the face (12) to be captured, placed in front of the receiving aperture (16).