Under-Screen Optical Fingerprint Sensor Anti-Spoofing via Color Analysis
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Solution Overview
Problem
Fingerprint recognition technologies face challenges in providing high-performance anti-spoofing capabilities without increasing production costs, particularly in under-screen optical fingerprint recognition systems, where methods involving additional light sources or optical film layers raise production costs.
Innovation Solution
The method involves dividing the image sensor and display device into sensing and display blocks, respectively, to emit specific wavelengths of light and compare the reflected light intensity and color coordinates of a test object with pre-registered reference information, determining authenticity based on consistency within a defined color interval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional infrared light sources or optical film layers are added to improve anti-spoofing capability, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The image sensor is divided into multiple sensing blocks, and the display device is divided into corresponding display blocks. Each sensing block senses light reflected from specific display blocks, enabling spatially-resolved color analysis for anti-spoofing without adding complex hardware layers.
Solution Approach 2:
The existing display panel serves dual purposes: displaying images and providing light sources for fingerprint sensing. The display blocks emit different colored lights (red, green, blue) that are used to illuminate the finger, eliminating the need for separate infrared light sources or additional optical layers.
2Measurement precision
If multiple light-emitting blocks with different luminous colors are used to improve skin color analysis accuracy, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The display blocks emit different colored lights in sequential periods rather than simultaneously. The sensing blocks sequentially capture reflected light from red, green, and blue display blocks, enabling multi-wavelength color analysis while reducing total energy consumption compared to simultaneous multi-color illumination.
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 enables high-efficiency anti-spoofing recognition without increasing the production cost of the recognition module by effectively distinguishing between real and fake fingerprints through skin color analysis, enhancing security without additional cost.
Implementation Method 1
each sensing block respectively senses the image light intensity of the image reflected to the sensing block generated by a different display block irradiates light onto a reference object and a test object
Implementation Method 2
confirms whether the fingerprint comes from a real finger of a holder of the registered fingerprint through the specific skin color expressed by the absorption and reflection of specific wavelengths of light by the skin
Data Source
AI summary
An image sensing method, applicable to the anti-spoofing recognition of under screen optical fingerprint sensing, is provided, including: dividing the image sensor into sensing blocks, dividing the display area of the display device correspondingly according to the sensing area, and the display area including the light-emitting area; defining the luminous color of each display area and the color coordinate value of each luminous color; each sensing block sensing the light intensity of the image reflected to the sensing block from the display block emitting the light onto the reference object and the test object to be measured; calculating the anti-spoofing reference color information of the reference object and registering in the system; when sensing the fingerprint image, first obtaining the light intensity of each block, then calculating the color information of the test object; and finally, comparing the color information with the registered anti-spoofing reference color information.