Motion Artifact Removal in Physiological Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for removing motion artifacts from physiological measurements, such as PPG signals, are ineffective when accelerometer signals are not correlated with PPG distortion, leading to deteriorated signal quality.
Innovation Solution
A method and device that detect two or more motion cycles using a tri-axial accelerometer, construct a noise reference based on phase-locked artifact components of the PPG signal, and apply adaptive filtering to remove artifacts, enhancing the correlation between motion and physiological signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If adaptive filtering with accelerometer signals is applied to remove motion artifacts from PPG signals, then motion artifacts are removed, but signal quality deteriorates when accelerometer signals are not correlated with PPG distortion
Solution Approach 1:
The patent changes the reference signal from raw accelerometer data to a processed reference signal that is specifically correlated with the PPG distortion. By transforming the reference signal parameters through segmentation and artifact extraction, the system ensures optimal correlation between the reference signal and the actual PPG distortion, resolving the mismatch issue that causes signal quality deterioration
Solution Approach 2:
The patent introduces an intermediary processing step where a reference signal is constructed from segments of the PPG signal itself during motion cycles. This intermediary reference signal acts as a mediator that is guaranteed to be correlated with the PPG distortion, unlike direct accelerometer signals, thus preventing signal quality deterioration while still enabling effective artifact removal
2Measurement precision
If motion cycles are detected and noise reference is constructed from PPG signal segments, then signal quality is optimized, but computational complexity increases
Solution Approach 1:
The patent segments the PPG signal into motion-related segments based on detected motion cycles. This segmentation allows the system to extract only the artifact components during motion periods, reducing the amount of data that needs to be processed and stored, thereby optimizing signal quality without excessive computational burden
Solution Approach 2:
The patent applies partial action by focusing computational resources only on segments of the PPG signal that contain motion artifacts. By detecting motion cycles and processing only those segments, the system avoids unnecessary computation on clean signal portions, achieving optimal signal quality with reduced computational complexity
Data Source
AI summary
A method and device for removal of artifacts in physiological measurements. The method comprising the steps of obtaining a physiological signal of a user; obtaining corresponding motion data representative of motion of the user; detecting two or more motion cycles in the motion data; constructing a noise reference based on segments of the physiological signal corresponding to the two or more motion cycles respectively, and filtering the physiological signal with the noise reference.