Polarizing Filter for Vein Authentication Image Clarity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image capture devices for vein authentication face challenges in capturing clear images due to light leakage, reflection, and contrast issues, particularly when trying to capture vein patterns across the entire finger, leading to reduced image accuracy and suitability for biometric authentication.
Innovation Solution
An image capture device that uses a light source emitting polarized infrared light, combined with a polarizing filter to block non-transmitted light and transmit diffused transmitted light, improving image clarity and accuracy by reducing halation and brightness unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple light sources are arranged in a longitudinal direction of the finger to capture vein patterns, then the coverage area is improved, but the device complexity increases and manufacturing precision requirements increase
Solution Approach 1:
The patent divides the light source into multiple segments arranged in the longitudinal direction of the finger. Each light source illuminates a specific region, and together they cover the entire finger area. This segmentation allows comprehensive coverage while maintaining a relatively simple overall structure compared to using a single large complex light source system.
2Ease of manufacture
If the hole size for light source arrangement is increased, then the ease of manufacture is improved, but light leakage occurs causing saturation and reduced image contrast
Solution Approach 1:
The patent introduces a light-shielding plate as an intermediary component between the light sources and the imaging area. This plate with a precisely positioned hole serves as a mediator that allows controlled light passage while preventing unwanted light leakage. The light-shielding plate enables larger hole sizes for ease of manufacture while maintaining image contrast by blocking stray light paths.
3Illumination intensity
If light amount is increased to improve transmitted light at the pad part, then the illumination intensity is improved, but halation occurs at the knuckle part reducing image capturing accuracy
Solution Approach 1:
The patent applies local quality by using multiple light sources positioned at different locations along the finger's longitudinal axis. Each light source provides localized illumination optimized for its specific region - the pad area receives sufficient light intensity while the knuckle area is illuminated in a way that prevents overexposure and halation. This localized approach allows different illumination characteristics for different finger regions.
4Device complexity
If a simple optical system is used, then the device complexity is reduced, but image capturing accuracy deteriorates due to light leakage and reflection
Solution Approach 1:
The patent introduces a polarizing filter as an intermediary optical component that selectively transmits polarized light while blocking non-polarized reflected light and light leakage. This simple addition to the optical system significantly improves image capturing accuracy by eliminating unwanted light paths without requiring a complex optical design. The polarizing filter acts as a mediator that maintains system simplicity while enhancing image quality.
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 enhances image capturing accuracy and clarity, allowing for effective biometric authentication without the need for complex optical systems or precise light source arrangement, while ensuring safety and cost-effectiveness.
Implementation Method 1
a light source that radiates polarized light of an infrared ray
Implementation Method 2
polarized light of an infrared ray
Implementation Method 3
a polarizing filter that blocks non-transmitted light that has been in the polarized light radiated from the light source and has not been transmitted through the image capturing target and transmitted light that has been in the polarized light and has been transmitted through the image capturing target without diffusion inside the image capturing target, and transmits transmitted light that has been in the polarized light and has been diffused inside the image capturing target and transmitted therethrough
Data Source
AI summary
Image capturing accuracy is improved while a simple optical system is used. An image capture device includes: a polarizing filter that blocks non-transmitted light that has been in polarized light of an infrared ray radiated from a light source and has not been transmitted through an image capturing target and transmitted light that has been in the polarized light and has been transmitted through the image capturing target without diffusion inside the image capturing target, and transmits transmitted light that has been in the polarized light and has been diffused inside the image capturing target and transmitted therethrough; and an image sensor that receives the light that has been transmitted through the polarizing filter and captures an image of the image capturing target.