Fingerprint Sensor Noise Mitigation via Sampling Matrix and Linear Filter
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Solution Overview
Problem
Fingerprint sensors face challenges in noise reduction, particularly due to time-variant or random noise introduced during sequential acquisition of fingerprint images, which affects the accuracy of fingerprint pattern determination.
Innovation Solution
A method involving a sampling matrix that represents the sampling pattern for acquiring fingerprint images, followed by the application of a linear filter tailored to the sampling strategy for noise reduction, allowing for post-processing of the images to enhance noise mitigation without requiring hardware adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hardware configuration is used for noise compensation, then noise reduction effectiveness is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces hardware-based noise compensation with a software/firmware processing method. The sampling matrix and linear filter are implemented through computational algorithms rather than physical hardware modifications, thereby reducing device complexity while maintaining noise reduction effectiveness. The processing unit applies the sampling matrix to acquired fingerprint images and uses linear filters to mitigate noise, achieving the same goal without additional hardware components.
2Measurement precision
If redundant sensing elements are introduced for noise reduction, then measurement precision is improved, but device complexity and silicon area increase
Solution Approach 1:
The patent changes the processing parameters through software rather than modifying the physical sensor structure. The sampling matrix and linear filter parameters are adjusted computationally to achieve noise reduction and improve measurement precision without adding redundant sensing elements. This allows flexible control of compensation levels without increasing silicon area or device complexity.
3Productivity
If block based sequential sampling is used, then productivity is improved, but measurement precision deteriorates due to time-variant noise
Solution Approach 1:
The patent applies preliminary noise mitigation processing by introducing a sampling matrix before final image processing. The sampling matrix is designed to account for the sequential block sampling pattern and potential time-variant noise, preparing the data in advance to reduce measurement errors while maintaining the efficient sequential acquisition method.
Solution Approach 2:
The patent employs feedback through iterative optimization of the sampling matrix and linear filter parameters. The system processes acquired fingerprint images through the sampling matrix and linear filter, then uses the results to refine the processing parameters, continuously improving measurement precision while maintaining productivity through the efficient sequential sampling approach.
Data Source
AI summary
The present invention generally relates to a method for removing disturbances in an image captured by a fingerprint sensor, and specifically to reduction of noise in an acquired fingerprint image by incorporating the sensing principle into the applied method for noise reduction, wherein the noise reduced image is used for determining a representation of a fingerprint pattern. Advantages with the invention include enhanced determination of fingerprint patterns from fingerprint images captured using a fingerprint sensor. The invention also relates to a corresponding electronic device and to a computer program product.