Adaptive PPG Monitoring for Motion Artifact and Power Control
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Solution Overview
Problem
Conventional photoplethysmography (PPG) devices face challenges in maintaining consistent skin contact during physical activity, leading to reduced signal quality due to motion artifacts, and high power consumption, especially during exercise, which affects the accuracy of heart rate and breathing rate measurements.
Innovation Solution
A monitoring device with a processor that adjusts signal analysis frequency and sensor interrogation power based on detected changes in activity, using optical sensors with adjustable algorithms and power management to optimize data collection during varying activity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor interrogation power is increased to maintain signal quality during physical activity, then the measurement precision is improved, but the use of energy increases
Solution Approach 1:
The patent implements dynamic adjustment of sensor interrogation power based on detected activity levels. The processor monitors motion sensors to determine when the subject is engaged in physical activity and automatically increases sensor interrogation power during these periods to maintain signal quality, then reduces power during rest periods to conserve battery life.
Solution Approach 2:
The system changes the interrogation power parameter in response to detected activity states. When motion sensors detect physical activity, the system increases the power level for optical sensor interrogation to overcome motion artifacts and maintain measurement precision. When activity decreases, the power parameter is reduced to conserve energy.
2Measurement precision
If the signal analysis frequency is increased to capture physiological data during physical activity, then the measurement precision is improved, but the use of energy increases
Solution Approach 1:
The processor dynamically adjusts the signal analysis frequency based on detected activity levels. During physical activity, the system increases the sampling rate and analysis frequency to capture rapid physiological changes and maintain data accuracy. During rest periods, the analysis frequency is reduced to minimize processing power consumption.
Solution Approach 2:
The system modifies the signal analysis frequency parameter in response to activity detection. When motion sensors indicate physical activity, the processor increases the frequency at which physiological signals are sampled and analyzed to ensure accurate capture of heart rate and breathing rate variations. When activity decreases, this parameter is lowered to conserve energy.
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
The solution enhances the accuracy of physiological data collection during physical activity while conserving power, allowing for more precise monitoring without compromising battery life.
Implementation Method 1
Photoplethysmography (PPG) is based upon shining light into the human body and measuring how the scattered light intensity changes with each pulse of blood flow
Implementation Method 2
measuring how the scattered light intensity changes with each pulse of blood flow
Data Source
Figure 1A~1B
Figure 1C
Figure 2A~2B
AI summary
A monitoring device configured to be attached to a body of a subject includes a sensor configured to detect and/or measure physiological information from the subject, and a processor coupled to the sensor that is configured to receive and analyze signals produced by the sensor. The processor is configured to change signal analysis frequency and/or sensor interrogation power in response to detecting a change in subject activity, a change in subject stress level, a change in environmental conditions, a change in time, and/or a change in location of the subject.