ELECTROCARDIOGRAM BASELINE REMOVAL

• US 20140222350A1
• Filed: 06/07/2012
• Published: 08/07/2014
• Est. Priority Date: 09/08/2011
• Status: Active Grant

• Current Assignee: Dragerwerk AG & Company KGaA (FPS Vermögensverwaltung GmbH)
• Original Assignee: Draeger Medical Systems Incorporated (Dragerwerk AG)
• Inventors: Chen, Yu, Zheng, Ling
• Granted Patent: US 9,480,411 B2
• Time in Patent Office: Days
• US Class Current: 702/19
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: G06F 2218/02 Preprocessing

Abstract

A system includes a low pass-filter and a Savitzky-Golay filter. The low-pass filter receives and processes a first electrocardiogram signal. The filter removes at least the high frequency components of the first electrocardiogram signal. The Savitzky-Golay filter estimates a baseline variation of the first electrocardiogram signal from the filtered first electrocardiogram signal. Related apparatus, systems, techniques and articles are also described.

Claims

1. A system comprising:

a low-pass filter to receive and process a first electrocardiogram signal, the filter removing at least high frequency components of the first electrocardiogram signal; and

a Savitzky-Golay filter to estimate a baseline variation of the first electrocardiogram signal from the filtered first electrocardiogram signal.

2. The system of claim 1, further comprising:

a delay module to time shift the first electrocardiogram signal; and

a combination module configured to combine the time shifted first electrocardiogram signal and the baseline variation estimate thereby producing a second electrocardiogram signal with the baseline variation removed.

3. The system of claim 2, further comprising:

a down-sampler configured to reduce the sampling rate of the filtered first electrocardiogram signal; and

an up-sampler configured to increase the sampling rate of the baseline variation estimate.

4. The system of claim 1, wherein the low-pass filter has a cutoff frequency of about 0.8 hertz.

5. The system of claim 1, wherein the first electrocardiogram signal is sampled at a rate of about 500 hertz.

6. The system of claim 1, wherein the polynomial degree of the Savitzky-Golay filter is between about 2 and about 10.

7. The system of claim 1, wherein the window size of the Savitzky-Golay filter is less than about 750.

8. The system of claim 3, wherein the down-sampler reduces the sample rate of the filtered first electrocardiogram signal by a factor of about 40 and the up-sampler increases the sample rate of the baseline variation estimate by a factor of about 40.

9. The system of claim 3, wherein the up-sampler performs linear interpolation.

10. A method comprising:

receiving a first electrocardiogram signal;

processing the first electrocardiogram signal in a filter thereby removing at least high frequency components of the first electrocardiogram signal;

processing the filtered first electrocardiogram signal in a Savitzky-Golay filter to estimate a baseline variation of the first electrocardiogram signal; and

providing the estimate of the baseline variation.

11. The method of claim 10, further comprising:

delaying the first electrocardiogram signal; and

combining the delayed first electrocardiogram signal and the baseline variation estimate thereby producing a second electrocardiogram signal with the baseline variation removed.

12. The method of claim 11, further comprising:

down-sampling the filtered first electrocardiogram signal; and

up-sampling the baseline variation estimate.

13. The method of claim 10, wherein at least the frequencies above about 0.8 hertz are removed from the received first electrocardiogram signal.

14. The method of claim 10, wherein the received first electrocardiogram signal has been sampled at a rate of about 500 hertz.

15. The method of claim 10, wherein the polynomial degree of the Savitzky-Golay filter is between about 2 and about 10.

16. The method of claim 10, wherein the window size of the Savitzky-Golay filter is less than about 750.

17. A system comprising:

at least one data processor;

memory storing instructions which, when executed by the at least one data processor, causes the at least one data processor to perform operations comprising;

receiving a first electrocardiogram signal;

processing the first electrocardiogram signal in a filter thereby removing at least high frequency components of the first electrocardiogram signal;

processing the filtered first electrocardiogram signal in a Savitzky-Golay filter to estimate a baseline variation of the first electrocardiogram signal;

providing the estimate of the baseline variation.

18. The system of claim 17, the operations further comprising:

delaying the first electrocardiogram signal; and

combining the delayed first electrocardiogram signal and the baseline variation estimate thereby producing a second electrocardiogram signal with the baseline variation removed.

19. The system of claim 18, the operations further comprising:

down-sampling the filtered first electrocardiogram signal; and

up-sampling the baseline variation estimate.

20. The system of claim 17, wherein providing the estimate of the baseline variation includes providing for further processing, storage, transmission, or display.