Fingerprint Sensor CAC Parameter Selection for Unlocking Speed
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Solution Overview
Problem
Current fingerprint recognition technologies face challenges in reducing the unlocking time of terminal devices, which is a key competitive factor for manufacturers, and also struggle with false rejection rates, especially when dealing with wet fingers or unstable hand conditions.
Innovation Solution
A method that involves detecting a touch operation and receiving a first fingerprint image based on default CAC parameters, while simultaneously receiving multiple second fingerprint images using different CAC parameters to determine a target fingerprint image with the best quality, thereby improving image clarity and reducing false rejection rates by ensuring the finger is in a steady state before image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sequential fingerprint image acquisition method is used, then the system ensures image quality through careful processing, but the unlocking time becomes too long
Solution Approach 1:
The system performs preliminary actions by acquiring multiple fingerprint images with different CAC parameters before final matching. The processor acquires first fingerprint images using default CAC parameters and second fingerprint images using multiple different CAC parameters in advance, then selects the best quality image for matching, thereby reducing overall unlocking time while ensuring image quality
Solution Approach 2:
The system dynamically adjusts CAC parameters to optimize fingerprint image acquisition. By using multiple different CAC parameters for acquiring second fingerprint images and selecting the best quality image dynamically, the system adapts to varying finger conditions (such as wet fingers) and reduces false rejection rates while maintaining efficient unlocking
2Reliability
If multiple fingerprint images are acquired with different CAC parameters, then the false rejection rate decreases, but the processing complexity increases
Solution Approach 1:
The system applies partial action by acquiring a specific number of second fingerprint images with different CAC parameters rather than exhaustive acquisition. The processor selects at least one second fingerprint image with the best quality from multiple acquisitions, balancing the need for reduced false rejection with acceptable processing complexity
Solution Approach 2:
The system changes CAC parameters to improve fingerprint image quality and reduce false rejection rates. By acquiring images with multiple different CAC parameters and selecting the best quality image, the system handles varying finger conditions (such as wet fingers) without significantly increasing processing complexity
3Stability of the object's composition
If the system waits for steady state before image capture, then image stability improves, but the response time increases
Solution Approach 1:
The system performs preliminary image acquisition actions without waiting for complete steady state. The processor acquires multiple fingerprint images in quick succession using different CAC parameters, then selects the best quality image from these preliminary acquisitions, thereby reducing response time while maintaining image stability through multi-image selection
Data Source
AI summary
A method for controlling unlocking is provided. The method includes the following operations. A touch operation of a finger of user on a fingerprint recognition sensor of a terminal is detected. A first fingerprint image is received according to a preset capacity auto control (CAC) parameter corresponding to a default finger, the finger of the user is in the steady state. N second fingerprint images are received according to N sets of CAC parameters; N is an integer greater than 1. A target fingerprint image is determined and matched. The terminal is unlocked when the target fingerprint image is matched.