Optomechanical PPG Sensing for Motion Artifact Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wearable devices struggle with motion-related noise in biometric signals, particularly in photoplethysmography (PPG) sensors, as existing methods to use accelerometer- or gyroscopic-based signals for noise reference have limited success in accurately representing motion noise characteristics.
Innovation Solution
A biometric sensor module with optically isolated pathways for physiological and motion information, using optical emitters and detectors to generate separate signals for physiological and motion data, which are then processed to remove motion artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometer- or gyroscopic-based signals are used as motion noise references for cleaning up PPG signals, then motion-related noise can be reduced, but the motion noise characteristics are not accurately represented leading to limited success
Solution Approach 1:
The patent introduces an optomechanical sensing pathway as an intermediary element that directly captures motion artifacts affecting the PPG signal. Instead of using accelerometer or gyroscope signals as indirect references, the optomechanical pathway serves as a direct mediator that measures the same motion-induced optical scattering changes that contaminate the PPG signal, enabling accurate motion artifact removal through signal processing.
2Measurement precision
If complex signal processing is applied to extract pure biometric information from motion-related noise, then biometric information accuracy improves, but processing complexity increases
Solution Approach 1:
The patent segments the optical sensing into two distinct pathways: one for capturing PPG signals containing both biometric information and motion artifacts, and another optomechanical pathway dedicated solely to capturing motion artifact characteristics. This segmentation allows the system to separately process and subtract motion artifacts from the PPG signal, simplifying the overall processing approach compared to trying to extract pure biometric information directly from a single contaminated signal.
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 effectively isolates and removes motion artifacts from biometric signals, enhancing the clarity and accuracy of physiological data obtained from wearable devices.
Implementation Method 1
sensing light from the at least one emitter scattered from the body by blood flow
Implementation Method 2
sensing light from the at least one emitter scattered by body motion
Data Source
Figure 1~4
Figure 5
Figure 6
AI summary
Methods and apparatus are described for facilitating the extraction of cleaner biometric signals from biometric monitors. A motion reference signal is generated independently from a biometric signal and then the motion reference signal is used to remove motion artifacts from the biometric signal.