ECG Motion Artifact Removal via Acceleration-Adaptive Filtering
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Solution Overview
Problem
ECG signals are distorted by motion artifacts due to patient movement, leading to unacceptable signal degradation and potential diagnostic errors, which existing technologies have not adequately addressed.
Innovation Solution
An apparatus and method that utilize a calculating unit to determine the mean value beat from the ECG signal, obtain a residual signal, and perform filtering with cut-off frequencies based on an acceleration signal representing the patient's motion status, specifically blocking frequency components that introduce interference, thereby reducing motion artifacts and improving signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive filtering with triaxial accelerometer is used to remove motion artifacts, then motion artifact reduction is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the necessary acceleration signal component (along the direction of electrode movement) from the triaxial accelerometer, rather than using all three axes. This reduces the amount of reference signal data needed for adaptive filtering, thereby simplifying the device while maintaining motion artifact reduction effectiveness.
Solution Approach 2:
The patent makes the filter coefficients and cut-off frequencies adaptive by using acceleration signal characteristics. The same filtering framework can handle different motion intensities and frequencies by dynamically adjusting parameters, making the system universally applicable to various motion scenarios without requiring multiple fixed-filter configurations.
2Measurement precision
If filtering with multiple cut off frequencies is applied to residual signal, then signal quality is improved, but computational cost increases
Solution Approach 1:
The patent applies filtering selectively - first applying a coarse filter with fewer cut-off frequencies to the residual signal, then optionally applying additional filtering only to specific frequency bands where motion artifacts are most prominent. This partial action approach maintains signal quality in critical bands while reducing overall computational burden compared to uniform multi-frequency filtering across the entire spectrum.
Solution Approach 2:
The patent applies different filtering strengths and cut-off frequencies to different frequency bands of the ECG signal based on where motion artifacts are most likely to occur. Rather than applying uniform filtering across all frequencies, the system concentrates computational resources on the frequency bands most affected by motion, achieving good signal quality with reduced overall computation.
Data Source
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AI summary
The invention proposes an apparatus for reducing motion artifact in an ECG signal of a patient. The apparatus comprises a calculating unit configured to calculate a mean value beat from the ECG signal; a first obtaining unit configured to obtain a residual signal based on the ECG signal and the mean value beat calculated from the ECG signal; a filtering unit configured to perform filtering of the residual signal with one or more cut off frequencies; a second obtaining unit configured to obtain a modified ECG signal based on the filtered residual signal and the mean value beat; and a determining unit configured to determine the one or more cut off frequencies of the filtering based on an acceleration signal representative of motion status of the patient. By using the proposed apparatus, motion artifacts can be greatly removed from the ECG signal and the quality of the ECG signal can be therefore improved.