Fingerprint Image Standardization for Database Interoperability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fingerprint image processing methods either suffer from reduced information capture due to deformation during contact-based capture or are not interoperable with existing databases when using contactless capture.
Innovation Solution
A method that combines contactless and contact-based image capture, followed by standardization to match the proportions of contact images, using geometric transformations and ridge frequency comparison to ensure compatibility with existing databases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If contact-based capture is used, then interoperability with existing databases is improved, but information loss occurs due to deformation and squashing of the imprint
Solution Approach 1:
The system performs contactless capture before the finger makes contact with the exposure window, preserving the undeformed fingerprint image. This preliminary action allows the system to obtain high-quality, undeformed imprint data without the distortion that occurs during contact-based capture, thereby maintaining information integrity while ensuring database interoperability through subsequent standardization.
Solution Approach 2:
The contactless capture creates a copy of the fingerprint image without physical contact. This optical copy preserves the original undeformed characteristics of the imprint, avoiding the deformation and information loss associated with contact-based methods. The copied image can then be standardized to match database requirements while retaining the quality benefits of contactless acquisition.
2Loss of information
If contactless capture is used, then information quality is improved by capturing undeformed imprints, but interoperability with existing databases deteriorates
Solution Approach 1:
The system changes the parameter of image proportions through standardization processing. By adjusting the dimensions and aspect ratio of the contactless captured image to match the standard proportions required by existing databases, the system maintains the high information quality of undeformed imprints while achieving interoperability. This parameter transformation allows the system to bridge the gap between contactless capture advantages and database compatibility requirements.
Solution Approach 2:
The standardization process acts as an intermediary between the contactless capture output and the existing database requirements. This intermediate processing step transforms the high-quality contactless images into a format compatible with legacy databases, allowing the system to leverage the advantages of contactless capture without sacrificing interoperability. The standardization serves as a mediator that reconciles the conflicting requirements of information quality and database compatibility.
3Illumination intensity
If optical coupling is used for contact capture, then contrast is improved through total reflection, but reliability deteriorates due to environmental dependence and fragile coatings
Solution Approach 1:
The system extracts the fingerprint image acquisition from the contact interface, performing capture in the space upstream before the finger contacts the exposure window. This extraction eliminates the need for optical coupling through contact, removing the source of reliability problems associated with environmental dependence and fragile coatings. The contrast enhancement is achieved through alternative illumination methods that do not rely on total reflection at the contact interface.
Solution Approach 2:
The system replaces the mechanical contact-based optical coupling system with a contactless optical field-based capture system. By substituting the mechanical contact interface with non-contact optical fields, the system eliminates the fragility and environmental sensitivity of optical coupling while maintaining or improving image quality. This substitution removes the reliable but fragile coating requirement and environmental dependencies associated with contact-based optical coupling.
Data Source
AI summary
A method for processing at least an imprint image of an individual using a processing device that comprises an exhibition glass sheet having a surface for receiving said imprint. The method includes acquiring without contact at least one image of the imprint present in the space upstream from the said surface and which has not yet been in contact with it and detecting the contact between the imprint and the exhibition glass sheet; acquiring by contact at least one image of the imprint after contact with the exhibition glass sheet; and standardizing at least one of the contact-less images in proportions that are identical to those of one of the contact images by analysing at least one of the contact-less images and at least one of the contact images.