Biometric Sensor Signal Processing for Dry Finger Recognition
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Solution Overview
Problem
Biometric information detection devices, such as fingerprint sensors, often inaccurately recognize biometric data due to external environment conditions, particularly in cases of abnormal contact states like dry fingers, where the difference in light reflection between ridges and valleys is not clearly distinguished.
Innovation Solution
A biometric information detecting device that uses multiple reference conditions to process electrical signals from a measurer, converting them into digital signals using analog-to-digital converters with different reference ranges and gains, allowing for improved recognition by synthesizing the results to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single reference condition is used for processing biometric signals, then the device complexity is low, but the measurement precision deteriorates under abnormal contact conditions
Solution Approach 1:
The patent segments the signal processing function by dividing it into multiple processing paths, each handling different reference conditions (normal and abnormal contact states). The determiner unit processes signals under multiple reference conditions separately, allowing accurate recognition under various contact states without requiring a single complex adaptive system.
Solution Approach 2:
The patent implements dynamic reference condition selection by enabling the system to adaptively switch between different reference conditions based on the actual contact state. The controller determines whether to apply normal or abnormal contact reference conditions dynamically, optimizing measurement precision for the current situation without increasing structural complexity.
2Measurement precision
If multiple reference conditions are used to process electrical signals, then the biometric information recognition accuracy is improved, but the processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing multiple reference conditions (normal and abnormal contact state references) before actual biometric measurement. When a signal is received, the system quickly determines which reference condition applies and processes the signal against the appropriate pre-prepared reference, avoiding time-consuming real-time adaptation while maintaining high accuracy.
3Adaptability or versatility
If the reference range is widened to accommodate abnormal contact states, then the adaptability is improved, but the measurement precision for normal states deteriorates
Solution Approach 1:
The patent applies local quality by providing different optimized reference conditions for different contact states rather than using a single generalized reference. The normal contact reference condition is optimized for standard fingerprint placement, while the abnormal contact reference condition is specifically optimized for dry finger or reduced contact area scenarios, allowing each reference to maintain high precision for its intended purpose.
Data Source
AI summary
A biometric information detecting device includes a measurer, a determiner, a controller, and a processor. The measurer measures biometric information of a user as an electrical signal. The determiner is connected to the measurer to receive the electrical signal, processes the electrical signal according to a first reference condition to output a first result signal, and processes the electrical signal according to a second reference condition to output a second result signal. The controller controls the determiner such that the determiner is operated in the first reference condition or the second reference condition, and the processor processes the first and second result signals to obtain the biometric information of the user.