System and method for acquisition of biopotential signals with motion artifact reduction

• US 9,375,182 B2
• Filed: 12/17/2014
• Issued: 06/28/2016
• Est. Priority Date: 12/23/2013
• Status: Active Grant

• Current Assignee: IMEC International
• Original Assignee: IMEC International
• Inventors: Kim, Hyejung, Helleputte, Nick Van, Yazicioglu, Refet Firat
• Primary Examiner(s): Gedeon, Brian T
• Assistant Examiner(s): Tejani, Ankit D
• Application Number:
  US14/573,714
• Publication Number:
  US 20150173683A1
• Time in Patent Office: 559 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• 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 5/7246 using correlation, e.g. template matching or determination of similarity

Abstract

A biopotential signal acquisition system including an analog readout unit configured to receive an analog biopotential signal, which may be acquired from at least one electrode attached to a body; and to extract an analog measured biopotential signal and an analog reference signal. The system also includes an ADC unit configured to provide a digital version of the analog measured biopotential signal and the analog reference signal, a digital filter unit configured to calculate a digital motion artifact estimate based on the digital version of the measured biopotential signal and the reference signal. The system further comprises a reference signal processing unit configured to convert the reference signal into a new reference signal being provided to the digital filter unit based on the correlation between the measured biopotential signal and the reference signal.

Claims

1. A biopotential signal acquisition system comprising:

a readout unit configured to receive an analogue biopotential signal and to extract, from that received analogue biopotential signal, a measured biopotential signal and a first reference signal;

a reference signal processing unit configured to convert the first reference signal into a second reference signal based on a correlation between the measured biopotential signal and the first reference signal; and

a digital filter unit configured to calculate a digital motion artifact estimate based on a digital version of the measured biopotential signal and the second reference signal,

wherein the correlation between the measured biopotential signal and the first reference signal is estimated by calculating a correlation between the digital motion artifact estimate and the first reference signal.

2. The biopotential signal acquisition system according to claim 1, wherein the correlation between the measured biopotential signal and the first reference signal is estimated by calculating the correlation between the digital motion artifact estimate and a digital version of the first reference signal.

3. The biopotential signal acquisition system according to claim 1, wherein a polarity of the second reference signal is calculated based on the correlation between the measured biopotential signal and the first reference signal.

4. The biopotential signal acquisition system according to claim 3, wherein the polarity of the second reference signal is the same or opposite to a polarity of the first reference signal depending on the correlation between the measured biopotential signal and the first reference signal.

5. The biopotential signal acquisition system according to claim 1, wherein the reference signal processing unit is implemented in an analogue domain part of the system.

6. The biopotential signal acquisition system according to claim 1, wherein the reference signal processing unit is implemented in a digital domain part of the system.

7. The biopotential signal acquisition system according to claim 1, wherein the digital filter unit implements or runs a digital adaptive filter.

8. The biopotential signal acquisition system according to claim 7, wherein the digital adaptive filter is a Least Mean Square (LMS) filter.

9. The biopotential signal acquisition system according to claim 1, wherein the first reference signal is an electrode-tissue impedance signal.

10. The biopotential signal acquisition system according to claim 1, wherein the analogue biopotential signal is an ECG signal.

11. An electronic device comprising a biopotential signal acquisition system according to claim 1.

12. A method for acquisition of biopotential signals, comprising:

extracting, from an analogue biopotential signal, a measured biopotential signal and a first reference signal;

converting the first reference signal into a second reference signal based on a correlation between the measured biopotential signal and the first reference signal;

calculating a polarity of the second reference signal based on the correlation between the measured biopotential signal and the first reference signal; and

calculating a digital motion artifact estimate based on a digital version of the measured biopotential signal and the second reference signal.

13. The method for acquisition of biopotential signals of claim 12, herein the first reference signal is an electrode-tissue impedance signal and the analogue biopotential signal is an ECG signal.

14. The method for acquisition of biopotential signals of claim 12, wherein the polarity of the second reference signal is the same or opposite to a polarity of the first reference signal depending on the correlation between the measured biopotential signal and the first reference signal.

15. The method for acquisition of biopotential signals of claim 12, further comprising:

calculating a correlation between the digital motion artifact estimate and the first reference signal; and

estimating the correlation between the measured biopotential signal and the first reference signal based on the calculated correlation between the digital motion artifact estimate and the first reference signal.

16. A biopotential signal acquisition system comprising:

a readout unit configured to receive an analogue biopotential signal and to extract, from the received analogue biopotential signal, a measured biopotential signal and a first reference signal;

a reference signal processing unit configured to convert the first reference signal into a second reference signal based on a correlation between the measured biopotential signal and the first reference signal, and to calculate a polarity of the second reference signal based on the correlation between the measured biopotential signal and the first reference signal; and

a digital filter unit configured to calculate a digital motion artifact estimate based on the measured biopotential signal and the second reference signal.

17. The biopotential signal acquisition system according to claim 16, wherein the polarity of the second reference signal is the same or opposite to a polarity of the first reference signal depending on the correlation between the measured biopotential signal and the first reference signal.

18. The biopotential signal acquisition system according to claim 16, wherein the reference signal processing unit is implemented in a digital domain part of the system.

19. The biopotential signal acquisition system according to claim 16, wherein the digital filter unit implements or runs a digital adaptive filter.

20. The biopotential signal acquisition system according to claim 16, wherein the first reference signal is an electrode-tissue impedance signal, and the analogue biopotential signal is an ECG signal.