Fingerprint Recognition Device Dynamic Exposure Control
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Solution Overview
Problem
Optical fingerprint recognition devices face significant variability in recognition rates due to differences in fingerprint status and environmental conditions, leading to inconsistent performance.
Innovation Solution
A fingerprint recognition system that includes a display panel, a light source device to irradiate light onto a transparent substrate on the screen, an image sensor to capture the fingerprint image, and an image sensor controller to adjust exposure time based on the contrast ratio of the fingerprint image, optimizing the recognition process by selecting the best exposure time for clear fingerprint imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed exposure time is used for fingerprint imaging, then the device structure is simple, but the fingerprint recognition rate varies significantly with fingerprint status and environment
Solution Approach 1:
The patent applies dynamics by making the exposure time adjustable rather than fixed. The image sensor controller dynamically changes the exposure time based on the contrast ratio of captured fingerprint images, allowing the system to adapt to different fingerprint statuses (dry, wet, oily) and environmental conditions, thereby resolving the contradiction between reliability and fixed structure
Solution Approach 2:
The patent implements feedback control where the contrast ratio of the fingerprint image is measured and used to adjust the exposure time for subsequent imaging. This closed-loop feedback mechanism enables the system to automatically optimize recognition accuracy based on real-time image quality assessment, improving reliability without requiring complex manual intervention
2Measurement precision
If multiple exposure times are used to capture fingerprints, then image quality improves, but the sensing time increases
Solution Approach 1:
The patent changes the exposure time parameter based on fingerprint image contrast ratio. Instead of using multiple fixed exposure times, the system adjusts the exposure time parameter dynamically according to the measured contrast, achieving high image quality while minimizing sensing time by using only the necessary exposure duration for each specific fingerprint condition
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
This approach enhances the fingerprint recognition rate by improving image sharpness and contrast, thereby improving the reliability of fingerprint authentication regardless of the fingerprint status or environment.
Implementation Method 1
an image sensor configured to obtain a fingerprint image with light reflected from a fingerprint contacting the transparent substrate on the screen
Data Source
AI summary
A fingerprint recognition system may comprise: a display panel configured to display an image on a screen; a light source device configured to irradiate light onto a transparent substrate disposed on the screen of the display panel; an image sensor configured to obtain a fingerprint image with light reflected from a fingerprint contacting the transparent substrate on the screen; and an image sensor controller configured to control an exposure time of the image sensor to obtain the fingerprint image based on a contrast ratio of the fingerprint image.