Multi-band Infrared Camera Wavelength Selection for Skin Detection
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Solution Overview
Problem
Existing infrared camera systems for skin detection in vehicle occupancy and facial recognition applications are cost-inefficient due to the need for multiple wavelength bands, which increases the system's cost without maximizing skin detection capabilities.
Innovation Solution
A method for selecting an optimal wavelength band combination for multi-band infrared cameras, using a pixel classification algorithm and objective function to determine the most effective filter band combination for skin detection, with specific filters peaked in ranges such as 1000-1150 nm, 1400-1500 nm, and 1550-1650 nm, optimizing the camera for 3 or 4-band configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of wavelength bands is increased to maximize skin reflectance detection, then the detection precision is improved, but the device cost increases
Solution Approach 1:
The patent changes the parameter of wavelength band selection from a comprehensive multi-band approach to a specific 3-band or 4-band combination (1000-1150 nm, 1400-1500 nm, 1550-1650 nm, and optionally 1150-1400 nm). This parameter optimization achieves maximum skin reflectance detection precision while minimizing the number of filters required, thereby reducing system cost.
2Reliability
If more wavelength bands are added to the camera, then the skin detection capability is improved, but the manufacturing cost increases
Solution Approach 1:
The patent extracts only the essential wavelength bands needed for skin detection from the full spectrum. By identifying and selecting specifically the 1000-1150 nm, 1400-1500 nm, and 1550-1650 nm bands (and optionally 1150-1400 nm), the system removes unnecessary filters and components, reducing manufacturing complexity and cost while maintaining reliable skin detection capability.
3Device complexity
If a 3-band or 4-band filter configuration is used, then the system cost is reduced, but the skin detection performance may be compromised
Solution Approach 1:
The patent optimizes the parameter combination of wavelength bands to achieve the best performance-cost balance. By carefully selecting the specific ranges of 1000-1150 nm, 1400-1500 nm, 1550-1650 nm, and optionally 1150-1400 nm, the system achieves maximum skin reflectance detection precision with only 3 or 4 bands, proving that reduced band count does not compromise performance when the right parameters are selected.
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 enables cost-effective skin detection in infrared images by maximizing the detection of skin reflectance, improving the performance of vehicle occupancy detection and facial recognition systems while reducing the number of required wavelength bands.
Implementation Method 1
A first filter has a transmittance peaked in the range of 1000 nm to 1150 nm. A second filter has a transmittance peaked in the range of 1400 nm to 1500 nm. A third filter has a transmittance peaked in the range of 1550 nm to 1650 nm.
Implementation Method 2
The characteristic of human reflectance in the NIR range includes a drop from 1000 nm to 1450 nm, a small rise to 1650 nm, a drop to 1900 nm, and then remains relatively constant for a range of wavelengths.
Data Source
AI summary
What is disclosed is a system and method for selecting the optimal wavelength ban combination for a multi-band infrared camera system which is optimized for skin detection. An objective function is constructed specifically for this application from classified performance and the algorithm generates wavelengths by maximizing the objective function. A specific wavelength band combination is selected which maximizes the objective function. Also disclosed is a 3-band and 4-band camera system with filters each having a transmittance of one of a combination of wavelength bands optimized to detect skin in the infrared band. The camera systems disclosed herein find their intended uses in a wide array of vehicle occupancy detection systems and applications. Various embodiments are disclosed.