Hand Biometric Imaging With Multi-Exposure Illumination Control
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Solution Overview
Problem
Biometric authentication systems face challenges in capturing images under optimal illumination conditions due to variations in user hand positioning, leading to inconsistent image quality and reduced authentication accuracy.
Innovation Solution
A biometric authentication device that controls illumination and imaging units based on multiple exposure parameters to capture images suitable for biometric authentication, using a control unit to adjust exposure settings in a time division manner to maintain consistent biometric luminance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If image sets are captured at adjusted time intervals under multiple different irradiation conditions, then biometric authentication can be performed, but it becomes difficult to acquire image sets captured under all irradiation conditions depending on the adjusted time intervals and user hand movement speed
Solution Approach 1:
The patent applies dynamics by making the time interval between image captures variable rather than fixed. The control unit dynamically adjusts the time interval based on detected hand movement speed - using shorter intervals when hands move quickly and longer intervals when hands are stationary. This dynamic adaptation ensures complete capture of all illumination conditions while matching the actual pace of user actions, resolving the contradiction between authentication reliability and capture completeness.
2Speed
If high-speed imaging is performed, then image capture speed increases, but it becomes difficult to control the ON and OFF of illumination in accordance with imaging timing of the camera
Solution Approach 1:
The patent applies preliminary action by pre-establishing a fixed temporal relationship between illumination cycles and camera shutter operations. The control unit configures the illumination unit to complete multiple ON-OFF cycles within a predetermined total time period, and the camera is set to capture images at predetermined intervals within this framework. This preliminary configuration ensures reliable synchronization even during high-speed imaging, as the timing relationship is established in advance rather than requiring real-time adjustment.
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 device ensures consistent image quality for biometric information extraction by adjusting exposure parameters, enhancing authentication accuracy and efficiency.
Implementation Method 1
an illumination unit configured to illuminate the hand of the person to be authenticated
Implementation Method 2
an imaging unit configured to capture an image of at least a part of a hand of a person to be authenticated
Data Source
AI summary
A biometric authentication device includes: an imaging unit configured to capture an image of a hand of a person to be authenticated; an illumination unit configured to illuminate the hand of the person to be authenticated; a control unit configured to control at least one of the imaging unit or the illumination unit based on a plurality of different exposure parameters; and an authentication unit configured to extract biometric information of the person to be authenticated from each of a plurality of captured images, and authenticate the person to be authenticated based on the biometric information of the person to be authenticated and previously registered biometric information of each of a plurality of persons to be authenticated. The plurality of captured images are captured by the imaging unit according to each of the exposure parameters.