Contactless Fingertip Imaging With Enlarged Fingerprint Focus Feedback
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Solution Overview
Problem
Existing biometric systems face challenges in capturing focused fingerprint images due to varying finger sizes among users, leading to difficulties in fingerprint authentication, especially when using wide-angle cameras on devices like smartphones or tablets.
Innovation Solution
A biometric information acquisition assistance device and method that captures fingertip images in a contactless state, generates a first fingertip image by cutting out a region including the detected fingertip, and displays a second enlarged image outside the fingertip region on a monitor, providing an evaluation of focus suitability for fingerprint authentication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide-angle camera is used to capture fingertip images, then the field of view is increased and more of the finger can be seen, but the focus on the fingerprint becomes insufficient and image quality deteriorates
Solution Approach 1:
The patent transitions from a single 2D captured image to a multi-dimensional display solution by showing both the original captured image and an enlarged fingertip image simultaneously on the display unit. This dimensional expansion allows users to view the overall finger position while also seeing the detailed fingerprint focus quality, resolving the contradiction between wide field of view and sharp focus.
Solution Approach 2:
The patent segments the display into multiple regions: the captured image region showing the overall fingertip position and the enlarged fingertip image region showing the detailed fingerprint. This segmentation allows each region to serve its specific purpose - the captured image provides context and positioning, while the enlarged image provides focus assessment, thereby resolving the focus quality issue.
2Measurement precision
If the fingertip is positioned closer to the camera to improve focus, then the fingerprint becomes sharper, but the fingertip region becomes too small in the captured image for accurate positioning
Solution Approach 1:
By displaying the enlarged fingertip image in addition to the captured image, the system creates a new visual dimension that shows detailed fingerprint focus without requiring the fingertip to occupy a large area in the original captured image. Users can assess focus quality in the enlarged view while maintaining proper positioning guidance from the captured image.
Solution Approach 2:
The patent creates an enlarged copy of the fingertip region from the captured image and displays it separately. This copy allows users to evaluate fingerprint focus quality in detail without altering the original captured image or requiring the fingertip to be larger in the main view, thus resolving the contradiction between focus sharpness and region size.
3Ease of operation
If guidance markings are displayed on the screen to instruct finger placement, then positioning is improved, but the images captured still may not be in focus due to varying finger sizes
Solution Approach 1:
The patent implements a feedback mechanism by displaying the captured image and enlarged fingertip image on the screen, allowing users to see whether their finger placement results in proper focus. This visual feedback complements the guidance markings, enabling users to adjust their positioning based on real-time image quality assessment, thereby resolving the focus quality issue despite varying finger sizes.
Solution Approach 2:
The system performs preliminary capture and display of the fingertip image before final authentication, allowing users to assess focus quality and reposition if necessary. This preliminary action with visual feedback ensures that only properly focused images proceed to authentication, resolving the issue of varying finger sizes affecting focus quality.
Data Source
AI summary
A biometric information acquisition assistance device includes an acquisition unit configured to acquire a captured image of at least one fingertip captured in a contactless state, a detection unit configured to detect the at least one fingertip shown in the captured image, a generation unit configured to generate a first fingertip image obtained by cutting out a fingertip region including the detected fingertip, and a control unit configured to generate a biometric information acquisition screen including the captured image and a second fingertip image disposed outside a first region including the fingertip region of the fingertip and obtained by enlarging the first fingertip image, and output the biometric information acquisition screen to a monitor.