Fingerprint Registration via Enlarged Image Preview
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Solution Overview
Problem
Existing fingerprint registration methods face challenges due to varying finger sizes, leading to potential misalignment and focus issues when imaging, which can result in inadequate biometric data extraction for authentication.
Innovation Solution
A fingerprint registration method and user terminal device that image a fingertip, generate an enlarged image, and allow user confirmation before transmitting suitable fingertip images for authentication, ensuring proper focus and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a guide image indicating outer shape is displayed for imaging positioning, then imaging position alignment is improved, but imaging focus accuracy deteriorates due to varying finger sizes
Solution Approach 1:
The patent divides the imaging process into two distinct stages: first capturing a wide-angle overview image to identify finger position and shape, then capturing a focused fingertip image based on the identified position. This segmentation allows the guide image to serve positioning purposes while the subsequent focused capture ensures authentication-quality imaging regardless of finger size variations
Solution Approach 2:
The patent performs preliminary imaging to acquire overview information about the finger's position, shape, and size before performing the actual authentication imaging. This preliminary action enables the system to pre-determine the appropriate focus distance and imaging parameters based on the detected finger characteristics, ensuring both alignment and focus accuracy
2Area of stationary object
If wide-angle camera is used for fingertip imaging, then imaging area coverage is improved, but image quality for authentication deteriorates
Solution Approach 1:
The patent segments the imaging function into two distinct phases: a wide-angle overview capture phase that covers the entire finger to determine positioning, followed by a focused fingertip capture phase that achieves authentication-quality image resolution. This segmentation allows each phase to optimize for its specific purpose without compromise
Solution Approach 2:
The patent introduces an intermediary processing step that analyzes the wide-angle overview image to determine the optimal focus distance and imaging parameters for the subsequent authentication capture. This intermediary analysis acts as a bridge between the wide-angle positioning and the high-quality authentication imaging
3Device complexity
If fixed imaging distance is used, then device simplicity is improved, but adaptability to different finger sizes deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of imaging parameters based on real-time detection of finger characteristics from the overview image. The focus distance, magnification, and capture timing are dynamically determined according to the detected finger size and position, allowing the system to adapt to various finger dimensions while maintaining a relatively simple device structure
Solution Approach 2:
The patent changes imaging parameters such as focus distance and magnification based on the detected finger characteristics from the overview image. By adjusting these parameters dynamically according to finger size variations, the system achieves adaptability across different users without requiring complex mechanical adjustment mechanisms
Data Source
AI summary
This fingerprint registration method by a user terminal device includes: capturing an image of a fingertip by a camera provided to the user terminal device; generating and displaying an enlarged image obtained by enlarging a fingertip image that includes the captured fingertip; receiving a user operation whether or not the fingertip image is to be registered for fingerprint authentication on the basis of the enlarged image; and transmitting, to an external server as fingerprint data, the fingertip image on which registration operation has been performed through the user operation.