Skin Reflectance Test Chart for Wavelength-Specific Capture
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Solution Overview
Problem
Existing image analysis techniques struggle to acquire appropriate skin images when using light of a specific wavelength, leading to issues like overexposure and black crushing, which affect the quality of images used in face authentication and similar applications.
Innovation Solution
A test chart with a sheet member featuring multiple skin reflection regions, each indicating a specific reflectance to a first wavelength light, is used in conjunction with an image analysis apparatus that acquires and analyzes chart images to determine the suitability of the light environment for photographing, allowing for adjustments to ensure appropriate image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If light of a specific wavelength is used for photographing skin images, then the image capture speed is improved, but the image quality deteriorates due to overexposure and black crushing
Solution Approach 1:
The patent applies preliminary action by measuring the reflectance characteristics of skin at specific wavelengths before actual photographing. The reflectance measurement is performed in advance to determine appropriate illumination intensity and exposure parameters, preventing overexposure and black crushing during the actual image capture process.
2Measurement precision
If illuminance correction is performed using RGB values and correction factors, then the color accuracy is improved, but the processing complexity increases
Solution Approach 1:
The patent replaces the complex mechanical/image processing system with a simpler optical measurement approach. Instead of using RGB values and computational correction factors, the system directly measures reflectance characteristics at specific wavelengths using optical sensors, eliminating the need for complex color space conversions and illuminance correction calculations.
3Manufacturing precision
If multiple correction factors are used to achieve preferable brightness, then the image quality is improved, but the measurement and adjustment time increases
Solution Approach 1:
The patent extracts only the essential reflectance measurement at specific wavelengths, removing unnecessary correction steps. By directly measuring skin reflectance characteristics at the wavelengths used for photographing, the system determines optimal exposure parameters without needing multiple correction factors, significantly reducing measurement and adjustment time.
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
Enables the acquisition of appropriate skin images by checking and adjusting the light environment, thereby improving the quality of images for biometric authentication.
Implementation Method 1
a plurality of first skin reflection regions formed on the sheet member, each of the plurality of first skin reflection regions indicating a reflectance of a skin with respect to first wavelength light
Data Source
AI summary
A test chart TC1 includes a sheet member ST, and a plurality of first skin reflection regions SA1 to SA4 formed on the sheet member ST. Each of the plurality of first skin reflection regions SA1 to SA4 indicates a reflectance of a skin with respect to first wavelength light.