Touchless Palmprint Acquisition Using Display Screen Illumination
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Solution Overview
Problem
Current palmprint recognition technologies rely on contact-based scanners, which raise hygiene concerns and limit the application of palmprint recognition due to environmental and equipment cost constraints, and touchless methods face challenges with natural light affecting image contrast.
Innovation Solution
A touchless palmprint acquisition method using a terminal device with a screen and front-facing camera, where the screen emits light to improve palmprint recognizability by adjusting brightness and displaying high-brightness or blue/purple backgrounds, and providing real-time feedback to guide user positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact-based scanners are used to acquire palmprint images, then the recognizability and accuracy of palmprint features are improved, but hygiene concerns arise and the requirements on working environment and equipment cost increase
Solution Approach 1:
The patent replaces the mechanical contact-based scanning system with an optical imaging system using a camera and display screen. The display screen emits light to illuminate the palm without physical contact, and the camera captures the reflected light to form an image, thereby eliminating hygiene concerns while maintaining palmprint acquisition capability
Solution Approach 2:
The patent introduces light as an intermediary between the user and the sensing system. The display screen emits light that reflects off the palm to the camera, creating an optical path that enables touchless imaging. This intermediary approach allows accurate palmprint capture without direct contact between the sensor and the palm
2Ease of manufacture
If natural light or yellowish/reddish light is used for touchless palmprint acquisition, then the equipment cost is reduced, but the contrast of the palmprint image deteriorates
Solution Approach 1:
The patent changes the parameter of light wavelength by emitting blue light (shorter wavelength) from the display screen. This parameter change improves the contrast between the palmprint features and the background, as blue light enhances the visibility of skin texture and creases compared to yellowish or reddish light
Solution Approach 2:
The patent changes the color of the illumination light from natural or warm white light to blue light. This color change optimizes the contrast of palmprint images by exploiting the optical properties of skin tissue, which reflects blue light in a way that enhances the visibility of ridges, valleys, and creases
3Measurement precision
If the display screen emits blue light to improve image contrast, then the palmprint recognizability is enhanced, but the energy consumption of the display increases
Solution Approach 1:
The patent employs periodic or intermittent illumination rather than continuous blue light emission. The display screen emits blue light only when needed for image capture, synchronized with the camera's operation, thereby reducing overall energy consumption while maintaining sufficient contrast for accurate palmprint recognition
Solution Approach 2:
The patent uses blue light emission selectively and partially - only in the specific wavelength range that provides optimal contrast, and only for the duration necessary to capture the image. This partial action approach achieves the necessary contrast enhancement without the excessive energy consumption of continuous full-spectrum 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 method enhances palmprint recognizability without additional hardware, reduces environmental requirements, and facilitates efficient, hygienic, and user-friendly palmprint recognition, applicable to personal mobile devices and public terminals.
Implementation Method 1
the screen emits light and serves as a supplementary light source
Data Source
AI summary
The present invention describes a device and method for touchless palmprint acquisition. The method can be applied to a terminal device (including but not limited to mobile phones, tablet computers and other portable devices) with a display screen and a front-facing camera. The camera is used to capture images of palms. The screen is used as a supplementary light source. When lighting condition in the palm area is undesirable, the screen changes its display to improve the lighting condition inside the palm, which increases the recognizability of the palmprint. The palmprint acquisition device and method described in the present invention can be directly applied to existing terminal devices without requiring any additional hardware. By adopting a variety of ways to change the display of the built-in screen of the terminal device, the lighting condition of the palm area will be improved and the recognizability of the palmprint will be increased.