Green-Light PPG Filtering for Real-Time Motion Artifact Removal
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Solution Overview
Problem
Existing methods for filtering pulse signal motion interference in photoplethysmography (PPG) signals require large amounts of data, complex calculations, multiple PPG sensors, are limited to static measurements, and lack real-time processing capabilities, particularly in the presence of motion artifacts and ambient light interference.
Innovation Solution
A method involving real-time irradiation of a moving human body with a green light source, preprocessing using infinite impulse response filters, and adaptive filtering based on acceleration data to remove motion artifacts, without requiring multiple sensors or extensive data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods for filtering pulse signal motion interference are used, then motion artifact can be reduced, but large amounts of data are required and calculation process becomes complicated
Solution Approach 1:
The patent changes the parameter of light wavelength from conventional red/infrared to green light (500-560nm), which fundamentally alters the interaction with blood and tissue. This parameter change enables effective pulse signal detection with simpler processing requirements, as green light provides superior contrast for blood volume changes during motion, thereby reducing the computational complexity needed for motion artifact filtering while maintaining reliability
2Measurement precision
If existing filtering methods are applied, then pulse signal quality can be improved, but multiple PPG sensors are required
Solution Approach 1:
The patent segments the signal processing into distinct stages: green light illumination for signal acquisition, preprocessing stage for baseline and high-frequency noise removal, and adaptive filtering stage for motion artifact reduction. This segmentation allows a single PPG sensor to achieve the same signal quality that would otherwise require multiple sensors, as each processing stage targets specific interference components independently
3Productivity
If conventional pulse signal processing is used, then heart rate monitoring can be performed, but real-time processing during motion is not achieved
Solution Approach 1:
The patent implements continuous real-time processing through adaptive filtering that operates continuously during motion activities. The green light PPG signal is processed in real-time with continuous adaptive filtering that adjusts to changing motion conditions, ensuring both real-time productivity and maintained reliability of heart rate monitoring during exercise and daily activities
4Measurement precision
If motion artifact filtering is performed, then signal-to-noise ratio can be improved, but ambient light interference remains a problem
Solution Approach 1:
The patent utilizes color changes by selecting green light (500-560nm) as the illumination wavelength, which exploits the differential absorption characteristics of blood and tissue at this wavelength. Green light is strongly absorbed by oxygenated and deoxygenated blood while providing good tissue penetration, thereby improving signal-to-noise ratio for pulse detection. Additionally, green light sensors can selectively filter ambient light through wavelength-specific detection, reducing the impact of non-green ambient light sources
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
Enhances the accuracy and reliability of heart rate measurement by effectively filtering motion interference in real-time, using a simple calculation process and a single PPG sensor, improving signal-to-noise ratio and reducing motion artifacts.
Implementation Method 1
irradiating a skin of a target human body in motion with a green light source in real time, so as to acquire a corresponding pulse signal
Implementation Method 2
a photodiode is used to measure the change in the intensity of reflected light caused by a blood flow
Data Source
AI summary
The present disclosure provides a method, an apparatus and a system for filtering pulse signal motion interference. The method comprises: irradiating a skin of a target human body in motion with a green light source in real time, so as to acquire a corresponding pulse signal from the target human body in real time; preprocessing the acquired pulse signal; and adaptively filtering the preprocessed pulse signal based on acceleration data of the target human body acquired in real time, so as to filter out a motion artifact interference of the pulse signal. The present disclosure can effectively improve the accuracy and effectiveness of filtering the pulse signal motion interference of a person in motion without a large amount of data, with a simple calculation process and without a plurality of PPG sensors, and can effectively improve the real-time performance for filtering the pulse signal motion interference.