Non-Contact SpO2 Detection Using Multi-Wavelength Camera Imaging
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Solution Overview
Problem
Current methods for monitoring oxygen saturation (SpO2) in individuals, such as those with respiratory diseases or heart failure, often require contact-based equipment, which can be inconvenient and impractical for continuous monitoring, especially in situations like driving or home care.
Innovation Solution
A non-contact biological information detection system using a camera that captures images with both visible and infrared light, processing these images to calculate the ratio of amplitude fluctuations in red and infrared wavelengths, allowing for the estimation of oxygen saturation concentration without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact type pulse oximeter is used to measure SpO2, then measurement precision is improved, but ease of operation deteriorates due to requiring physical contact and mounting on fingertip
Solution Approach 1:
The patent replaces the mechanical contact-based pulse oximeter system with an optical imaging system using cameras. Instead of physically mounting a sensor on the fingertip, the system uses visible light and infrared light cameras to capture images of the subject's face or body, eliminating the need for physical contact while enabling continuous remote monitoring of SpO2 levels.
Solution Approach 2:
The patent introduces light (visible and infrared) as an intermediary medium to transmit biological information from the subject to the camera sensor. By using light reflection and absorption properties of hemoglobin in blood vessels, the system indirectly measures SpO2 without direct contact, resolving the contradiction between measurement accuracy and operational convenience.
2Ease of operation
If non-contact camera-based pulse detection is used, then ease of operation is improved, but measurement precision deteriorates due to difficulty in detecting pulse signal from distant images
Solution Approach 1:
The patent segments the detection process into multiple wavelength channels (visible light and infrared light). By separately capturing images at different wavelengths and processing the signals independently, the system enhances the ability to detect pulse signals from distant non-contact images, improving measurement precision while maintaining ease of operation.
Solution Approach 2:
The patent changes the detection parameter from single-wavelength intensity measurement to multi-wavelength spectral analysis. By measuring reflectance or absorption at multiple wavelengths and analyzing the spectral characteristics, the system can more accurately extract pulse signals from distant images, overcoming the precision limitation of simple non-contact methods.
3Device complexity
If single wavelength detection is used, then device complexity is reduced, but measurement precision deteriorates due to inability to distinguish hemoglobin oxygenation states
Solution Approach 1:
The patent segments the light detection into multiple wavelength bands (visible and infrared). By using multiple cameras or a multi-spectral camera system, it captures images at different wavelengths simultaneously, enabling differentiation of hemoglobin oxygenation states through spectral analysis while maintaining relatively simple device architecture.
Solution Approach 2:
The patent makes the camera system multi-functional by using it for both visible light imaging and infrared light detection. This allows a single integrated system to perform both structural imaging and physiological parameter measurement (SpO2), reducing overall device complexity while achieving precise hemoglobin oxygenation detection through multi-wavelength analysis.
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 continuous, non-invasive monitoring of SpO2 levels from a distance, facilitating early detection of sudden condition changes related to respiratory diseases or heart failure.
Implementation Method 1
a first wavelength fluctuation detection section that detects a temporal variation of a wavelength of light reflected from a face of the subject with visible light
Implementation Method 2
a pulse oximeter is contact type equipment that is mounted on a fingertip and irradiates infrared light (IR) and red light on a finger from above to measure an absorption amount of hemoglobin
Data Source
AI summary
A biological information detection apparatus for measuring a SpO2 without contact from a distant position includes a camera that acquires an image with visible and infrared light, a first wavelength fluctuation detection section detects a temporal variation of a wavelength of an image with the visible light to generate a first wavelength difference data signal, a first amplitude detection section detects an amplitude of the first wavelength difference data signal, a second wavelength fluctuation detection section detects a temporal variation of a wavelength of an image with the infrared light to generate a second wavelength difference data signal, a second amplitude detection section detects an amplitude of the second wavelength difference data signal, a ratio calculation section calculates a ratio between the amplitudes of the first and second wavelength difference data signals, and an oxygen saturation concentration calculation section calculates an oxygen saturation concentration based on the calculated amplitude ratio.