Optical Fingerprint Sensor Scattered Light Authentication
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Solution Overview
Problem
Conventional optical fingerprint sensors are vulnerable to unauthorized access due to limitations in analyzing reflected light, making them susceptible to counterfeit fingerprints.
Innovation Solution
The use of scattered light image detection and processing techniques to determine unique light scattering characteristics of a fingerprint, which are compared to reference characteristics for authentication, enhancing the robustness against false fingerprints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical fingerprint sensors analyze reflected light, then the device structure remains simple, but the sensor becomes vulnerable to counterfeit fingerprints
Solution Approach 1:
The optical detection system is segmented into multiple independent detection channels: reflected light detection for fingerprint pattern recognition and transmitted light detection for blood vessel verification. This segmentation allows each channel to perform specialized functions, improving security while maintaining manageable system complexity through modular architecture
Solution Approach 2:
A light source acts as an intermediary that emits light through the fingerprint sensor area, enabling transmitted light detection. This intermediary component facilitates the detection of light scattering characteristics and blood vessel patterns without requiring complex direct contact mechanisms, thereby enhancing security while controlling device complexity
2Measurement precision
If the sensor uses transmitted light detection, then authentication accuracy improves, but the device complexity increases
Solution Approach 1:
The optical detection system performs multiple functions using a unified approach: it detects reflected light for fingerprint ridge-valley pattern recognition and transmitted light for blood vessel and light scattering characteristic analysis. This multi-functionality improves authentication accuracy while avoiding the need for entirely separate detection systems, thus controlling device complexity
Solution Approach 2:
The system changes detection parameters by measuring light scattering characteristics at multiple wavelengths and analyzing both reflected and transmitted light intensities. These parameter changes enable the sensor to distinguish between genuine fingerprints and counterfeits through complex authentication algorithms, improving accuracy while managing complexity through software-based analysis
3Reliability
If the sensor analyzes light scattering characteristics, then protection against false fingerprints improves, but the detection process becomes more complex
Solution Approach 1:
The optical detection system continuously captures light scattering characteristics during the fingerprint placement and authentication process. By maintaining continuous detection and analysis of light transmission and scattering patterns, the system builds comprehensive authentication data without requiring complex sequential measurement steps, thereby improving reliability while simplifying the detection process
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 effectively differentiates genuine fingerprints from counterfeit ones by leveraging the unique scattering properties of human skin, thereby improving the security of fingerprint-based access control systems.
Implementation Method 1
The optical sensor is configured to detect scattered light associated with fingerprints within a sensing region
Data Source
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AI summary
A method and apparatus for authenticating a fingerprint image captured through an optical sensor. For at least some embodiments, light scattering characteristics associated with a fingerprint are determined and compared to a reference light scattering characteristic. The fingerprint is authenticated when the light scattering characteristics are within a threshold difference of the reference light scattering characteristic. For some embodiments, the light scattering characteristics associated with the fingerprint are compared to light scattering characteristics associated with one or more reference (enrollment) images. For at least some embodiments, the light scattering characteristics may be based on a correlation value based on identified pixels and one or more pixels neighboring the identified pixel.