Camera Biometrical Signal Extraction Using Selective Optical Filtering
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Solution Overview
Problem
Conventional camera-based SpO2 monitoring is impractical due to complexity, cost, and alignment requirements, limiting its application in sports, home-use, and smart devices.
Innovation Solution
A camera with a filter blocking visible light up to 550 nm, using a color sensor to generate combined color signals, which are processed to extract biometrical signals like SpO2, heart rate, and respiratory rate, leveraging standard RGB sensors and minimizing the need for custom optical filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional camera-based SpO2 monitoring uses two monochrome cameras with optical band-pass filters, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent combines multiple functions (color filtering, infrared blocking, and SpO2 measurement) into a single color camera system. Instead of using two separate monochrome cameras with different band-pass filters, the invention uses one color camera with a selectively transmissive filter that blocks visible light up to 550nm and infrared light above 700nm, allowing simultaneous capture of relevant wavelengths through the camera's RGB sensors.
Solution Approach 2:
The color camera system performs multiple functions: it captures visible light in the 500-700nm range for color information, blocks unwanted visible light below 550nm, blocks infrared light above 700nm, and enables SpO2 monitoring through the combined RGB channels. This multi-functional approach replaces the need for specialized monochrome cameras with different filters.
2Measurement precision
If conventional camera-based SpO2 monitoring uses two monochrome cameras with optical band-pass filters, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs a standard color camera with a relatively simple selectively transmissive filter instead of expensive specialized monochrome cameras with complex optical band-pass filters. The filter blocks visible light up to 550nm and infrared light above 700nm, providing adequate SpO2 monitoring capability at a lower manufacturing cost.
Solution Approach 2:
The invention changes the spectral transmission parameters of the filter to block visible light in the 400-550nm range and infrared light above 700nm, while allowing transmission in the 550-700nm range. This parameter optimization enables effective SpO2 monitoring using a color camera with modified filter characteristics rather than expensive specialized sensors.
3Measurement precision
If conventional camera-based SpO2 monitoring uses two monochrome cameras with optical band-pass filters, then measurement precision is improved, but alignment complexity increases
Solution Approach 1:
The patent merges the functionality of two separate monochrome cameras into a single color camera system. By using one camera with RGB sensors and a selectively transmissive filter, the invention eliminates the need for precise spatial alignment between multiple cameras, simplifying the system while maintaining SpO2 monitoring capability.
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 results in a simpler, cost-effective camera system capable of robust biometrical signal detection, including SpO2 monitoring, under various lighting conditions, and can extract multiple vital signs like heart rate and respiratory rate.
Implementation Method 1
a filter for blocking incident visible light in a wavelength range up to at least 550 nm, in particular up to at least 600 nm
Implementation Method 2
a color sensor for receiving said filtered incident light and generating three different color signals
Implementation Method 3
The changing absorbance of each of the two wavelengths is measured, allowing determination of the absorbances due to the pulsing arterial blood alone
Data Source
AI summary
The present invention relates to a camera (1, 1′) for generating a biometrical signal of a living being comprising: a filter (11) for blocking incident visible light in a wavelength range up to at least 550 nm, a color sensor (12, 12′) for receiving said filtered incident light and generating at least two different color signals (5, 6, 9), a combination unit (15) for generating at least one combined color signal (7a, 7b) by combining said at least two color signals, and a processing unit (16) for processing said at least one combined color signal and extracting at least one biometrical signal (8) of said living being (3).