Contactless Fingerprint Acquisition Using Stereo Imaging
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Solution Overview
Problem
Conventional contact-based fingerprint scanners face challenges in acquiring high-quality, large-area fingerprints due to physical contact requirements, which can cause distortions and blurriness, and contactless scanners often have limited image quality and reliability.
Innovation Solution
A contactless fingerprint acquisition device with multiple image capturing devices arranged at a predetermined baseline distance and angle, along with a lighting unit, captures partial fingerprint images, generating disparity maps and depth information to reconstruct a 3D fingerprint model and stitch images for improved quality and area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If contact-based fingerprint scanning is used to acquire large area fingerprints, then the fingerprint area coverage is improved, but the image quality deteriorates due to distortions and blurriness caused by physical contact
Solution Approach 1:
The patent replaces the mechanical contact-based scanning system with a contactless optical scanning system using multiple cameras and lighting units. This substitution eliminates physical contact between the scanner and finger, thereby avoiding distortions and blurriness while maintaining large area coverage through multi-view imaging and 3D reconstruction
Solution Approach 2:
The patent transitions from 2D contact-based imaging to 3D contactless imaging by using multiple cameras positioned at different angles and heights. The 3D fingerprint model reconstruction enables comprehensive coverage of large area fingerprints while maintaining image quality through spatial diversity of capture perspectives
2Ease of operation
If contactless fingerprint scanning is used to avoid physical contact, then the hygiene and authentication speed are improved, but the image quality and reliability deteriorate
Solution Approach 1:
The patent combines multiple image capturing devices and lighting units into an integrated contactless scanning system. By merging multiple partial fingerprint images from different perspectives and stitching them together, the system achieves both contactless operation for hygiene and speed, and high image quality through composite imaging
Solution Approach 2:
The patent creates multiple optical copies of the fingerprint from different angles and perspectives using multiple cameras. These copies are then processed and stitched to form a complete high-quality fingerprint image, maintaining contactless operation while improving image quality through redundant capture
3Area of stationary object
If multiple image capturing devices are used to improve fingerprint area coverage, then the image quality is improved, but the device complexity increases
Solution Approach 1:
The patent segments the fingerprint acquisition task across multiple image capturing devices positioned at different locations. Each device captures a specific portion or perspective of the fingerprint, and the segmented images are later stitched together. This segmentation enables large area coverage while managing device complexity through distributed functionality
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
The solution enables the acquisition of high-quality, large-area fingerprint images without physical contact, enhancing image quality and reliability while reducing distortion and blurriness, and supporting various user interaction methods.
Implementation Method 1
at least two image capturing devices located in the housing and arranged in a predetermined baseline distance, each image capturing device having an optical axis in a predetermined angle with the vertical direction
Implementation Method 2
a lighting unit in the housing for illuminating the at least one finger
Implementation Method 3
generating disparity maps and depth information to reconstruct a 3D fingerprint model
Data Source
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AI summary
A device and a method for contactless fingerprint acquisition is provided. The contactless fingerprint acquisition device can comprise: a housing including a finger scanning area for at least one finger; at least two image capturing devices located in the housing and arranged in a predetermined baseline distance, each image capturing device having an optical axis in a predetermined angle with the vertical direction; and, a lighting unit in the housing for illuminating the at least one finger. The at least two image capturing devices are operable to acquire a plurality of partial fingerprint images of the at least one finger, and the plurality of partial fingerprint images correspond to different portions of the at least one finger.