APPARATUS AND METHOD FOR ECG MOTION ARTIFACT REMOVAL

• US 20160058386A1
• Filed: 03/17/2014
• Published: 03/03/2016
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: WANG, JIN, ZHAO, DAN, SHI, CHENG, LI, WEI
• Granted Patent: US 9,931,081 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence

Abstract

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.

Claims

1. An apparatus for reducing motion artifact in an ECG signal of a patient, the apparatus comprising:

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.

2. The apparatus of claim 1, wherein the one or more cut off frequencies of the filtering comprise a signal frequency of the acceleration signal.

3. The apparatus of claim 2, wherein the signal frequency of the acceleration signal is determined according to the time interval between two successive peak values of the acceleration signal.

4. The apparatus of claim 1, wherein the one or more cut off frequencies of the filtering comprise N frequencies corresponding to top N power energy of the power spectrum of the acceleration signal.

5. The apparatus of claim 4, wherein N is in range of [1, 10].

6. The apparatus of claim 5, wherein N is 3.

7. The apparatus of claim 1, wherein the apparatus further comprises:

an adaptive filter configured to perform an adaptive filtering of the ECG signal with the acceleration signal; and

the calculating unit is configured to calculate the mean value beat from the adaptive filtered ECG signal;

the first obtaining unit is configured to obtain the residual signal based on the adaptive filtered ECG signal and the mean value beat calculated from the adaptive filtered ECG signal.

8. The apparatus of claim 1, wherein the first obtaining unit comprises:

a subtracting unit configured to subtract the mean value beat from the ECG signal to obtain the residual signal.

9. The apparatus of claim 1, wherein the second obtaining unit comprises:

an adding unit configured to add the filtered residual signal back to the mean value beat to obtain the modified ECG signal.

10. (canceled)

11. A method of reducing motion artifact in an ECG signal of a patient, the method comprising the steps of:

calculating a mean value beat from the ECG signal;

obtaining a residual signal based on the ECG signal and the mean value beat calculated from the ECG signal;

performing filtering of the residual signal with one or more cut off frequencies; and

obtaining a modified ECG signal based on the filtered residual signal and the mean value beat;

wherein the method further comprises;

determining the one or more cut off frequencies of the filtering based on an acceleration signal representative of motion status of the patient.

12. The method of claim 11, wherein the step of determining comprises:

determining a signal frequency of the acceleration signal as the cut off frequency of the filtering.

13. The method of claim 12, wherein the step of determining comprises:

determining the signal frequency of the acceleration signal according to the time interval between two successive peak values of the acceleration signal.

14. The method of claim 11, wherein the step of determining comprises:

determining N frequencies corresponding to top N power energy of the power spectrum of the acceleration signal as the cut off frequencies of the filtering.

15. The method of claim 11, wherein, prior to the step of calculating, the method further comprises:

performing an adaptive filtering of the ECG signal with the acceleration signal; and

in the step of calculating, the mean value beat is calculated from the adaptive filtered ECG signal;

in the step of obtaining the residual signal, the residual signal is obtained based on the adaptive filtered ECG signal and the mean value beat calculated from the adaptive filtered ECG signal.