Fingerprint Recognition Interference Fringe Imaging
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Solution Overview
Problem
Conventional fingerprint recognition apparatuses face manufacturing complexity due to the need for custom projections on the platen to match individual ridge distances, leading to high costs and complexity in producing disposable platen surfaces.
Innovation Solution
The apparatus projects interference fringes onto a fingerprint using a monochromatic light source, optical component, and transparent member, creating a contour image based on height differences between ridges and valleys, which enhances image resolution and simplifies the apparatus design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If custom projections are added to the platen to match individual ridge distances, then image resolution is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces an optical component as an intermediary element that projects interference fringes onto the fingerprint. This optical component acts as a mediator between the light source and the fingerprint, creating the necessary measurement pattern without requiring modifications to the platen structure itself. The interference fringes serve as the measurement pattern that interacts with the fingerprint ridges and valleys, enabling high-resolution imaging through optical interference rather than physical projections.
Solution Approach 2:
The patent replaces the mechanical approach of creating physical projections on the platen with an optical approach using interference fringes. Instead of mechanically manufacturing custom projection structures on the platen surface, the system uses optical interference phenomena to create the necessary measurement pattern. This substitution of mechanical structures with optical fields simplifies the platen design while maintaining or improving measurement precision.
2Measurement precision
If custom projections are added to the platen to match individual ridge distances, then image resolution is improved, but manufacturing cost increases
Solution Approach 1:
The optical component serving as an intermediary eliminates the need for expensive custom platen manufacturing. By placing the interference pattern projection function in the optical component rather than the platen, the system allows for the use of standard, off-the-shelf platen materials while achieving high-resolution imaging through the optical interference fringes projected by the specialized optical component.
Solution Approach 2:
The patent replaces expensive mechanical projection structures with an optical interference system. Instead of manufacturing complex three-dimensional projection features on the platen, the system uses two-dimensional optical interference patterns that can be generated by standard optical components. This substitution dramatically reduces manufacturing costs while maintaining measurement precision.
3Ease of manufacture
If the apparatus uses a simple transparent platen without projections, then manufacturing complexity is reduced, but image resolution decreases
Solution Approach 1:
The optical component acts as an intermediary that compensates for the simplicity of the transparent platen. By introducing the interference fringe projection function through the optical component, the system maintains the manufacturing simplicity of a basic transparent platen while achieving high measurement precision through the optical interference pattern that interacts with the fingerprint features.
Solution Approach 2:
The patent replaces the need for complex mechanical platen structures with an optical interference system. The simple transparent platen is sufficient when combined with the optical component that projects interference fringes, thereby achieving high-resolution fingerprint imaging without requiring expensive or complex platen manufacturing.
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 approach improves fingerprint image quality, reduces the size of the recognition apparatus, and increases counterfeiting difficulty by creating a unique contour image that is hard to replicate, thereby enhancing data security.
Implementation Method 1
projects interference fringes on a fingerprint using a monochromatic light source, optical component, and transparent member
Implementation Method 2
utilizes the optical path difference caused by the height differences between ridges and valleys of the fingerprint to create a contour image
Data Source
AI summary
An apparatus and method for fingerprint recognition comprises a light source, an optical component, an imaging device and a processor. The light source directs a monochromatic light through the optical component and then forms a plurality of interference fringes on a fingerprint desired to be recognized; the imaging device receives an optical image signal of the interference fringes reflected from the fingerprint and transfers it to an electrical image signal; the processor creates a contour image of the fingerprint according to the electrical image signal for post-recognition.