System and method for removing artifacts from waveforms

• US 20070073124A1
• Filed: 09/29/2005
• Published: 03/29/2007
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Mannheimer, Paul, Li, Li
• Granted Patent: US 7,725,147 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4875 Hydration status, fluid retention of the body
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06F 2218/06 by applying a scale-space analysis, e.g. using wavelet analysis

Abstract

A technique is provided for processing a physiological signal to compensate for artifacts. The technique includes identifying artifacts within the physiological signal. The technique also includes performing one or more multi-resolution decompositions, such as wavelet transformations, on the physiological signal and compensating for the identified artifacts in some or all of the respective decomposition components. The modified decomposition components may be reconstructed to generate an artifact-compensated signal which may be provided to a monitor or other device which is otherwise not configured to compensate for signal artifacts.

Claims

1. A method for processing a physiological signal, the method comprising the acts of:

identifying one or more artifacts in a physiological signal;

performing one or more multi-resolution decompositions on the physiological signal to generate two or more decomposition products; and

compensating for the one or more artifacts in the two or more decomposition products to generate modified decomposition products.

2. The method of claim 1, wherein the two or more decomposition components comprise high-passed and low-passed signal components.

3. The method of claim 1, wherein the two or more decomposition products comprise wavelet coefficients.

4. The method of claim 1, comprising reconstructing the modified decomposition products to generate an artifact-compensated signal.

5. The method of claim 4, comprising processing the artifact-compensated signal at a downstream device to derive one or more physiological characteristics of interest.

6. The method of claim 5, wherein the downstream device is not configured to perform artifact compensation.

7. The method of claim 1, wherein the physiological signal is a waveform.

8. The method of claim 1, wherein the one or more multi-resolution decompositions comprise one or more wavelet decompositions.

9. The method of claim 1, wherein the physiological signal comprises a pulse oximetry signal.

10. The method of claim 1, wherein the one or more multi-resolution decompositions are implemented as a filter bank.

11. One or more machine-readable media, comprising:

a routine configured to identify one or more artifacts in a physiological signal;

a routine configured to perform one or more multi-resolution decompositions on the physiological signal to generate two or more decomposition products; and

a routine configured to compensate for the one or more artifacts in the two or more decomposition products to generate modified decomposition products.

12. The one or more machine-readable media of claim 11, wherein the two or more decomposition components comprise high-passed and low-passed signal components.

13. The one or more machine-readable media of claim 11, wherein the two or more decomposition products comprise wavelet coefficients.

14. The one or more machine-readable media of claim 11, comprising a routine configured to reconstruct the modified decomposition products to generate an artifact-compensated signal.

15. The one or more machine-readable media of claim 14, wherein the routine configured to reconstruct the modified decomposition products performs an inverse wavelet transform of one or more modified wavelet coefficients.

16. The one or more machine-readable media of claim 11, wherein the one or more multi-resolution decompositions are implemented as a filter bank.

17. A physiological monitoring system, comprising:

a sensor configured to generate a physiological signal; and

a monitor configured to receive an artifact-compensated signal derived from the physiological signal, wherein the artifact-compensated signal is generated by identifying one or more artifacts in the physiological signal, by performing one or more multi-resolution decompositions on the physiological signal to generate two or more decomposition products;

by compensating for the one or more artifacts in the two or more decomposition products to generate modified decomposition products, and by reconstructing the modified decomposition products to generate the artifact-compensated signal.

18. The physiological monitoring system of claim 17, wherein the artifact-compensated signal is generated by at least one the sensor, one or more cables connecting the sensor and the monitor, an intermediate monitor disposed between the sensor and the monitor, or a conversion device disposed between the sensor and the monitor.

19. The physiological monitoring system of claim 17, wherein the artifact-compensated signal is generated by one or more processing components disposed within the sensor or between the sensor and the monitor.

20. The physiological monitoring system of claim 17, wherein the monitor is further configured to process the artifact-compensated signal to derive one or more physiological characteristics of interest.

21. The physiological monitoring system of claim 17, wherein the two or more decomposition components comprise high-passed and low-passed signal components.

22. The physiological monitoring system of claim 17, wherein the two or more decomposition components comprise wavelet coefficients.

23. The physiological monitoring system of claim 17, wherein the monitor is not configured to perform artifact compensation.

24. The physiological monitoring system of claim 17, wherein the sensor comprises a pulse oximetry sensor.

25. The physiological monitoring system of claim 17, wherein the monitor comprises a pulse oximetry monitor or a multi-parameter monitor.

26. The physiological monitoring system of claim 17, wherein the one or more multi-resolution decompositions comprise one or more wavelet decompositions.

27. A physiological sensor, comprising:

an emitter configured to emit light;

a detector configured to generate a signal in response to the emitted light; and

one or more processing components configured to process the signal to generate an artifact-compensated signal.

28. The physiological sensor of claim 27, wherein the emitter comprises one or more light emitting diodes.

29. The physiological sensor of claim 27, wherein the detector comprises one or more photodetectors.

30. The physiological sensor of claim 27, wherein the one or more processing components are configured to identify one or more artifacts in the signal, to perform one or more multi-resolution decompositions on the signal to generate two or more decomposition products, to compensate for the one or more artifacts in the two or more decomposition products to generate modified decomposition products, and to reconstruct the modified decomposition products to generate the artifact-compensated signal.

31. The physiological sensor of claim 30, wherein the two or more decomposition components comprise high-passed and low-passed signal components.

32. The physiological sensor of claim 30, wherein the two or more decomposition components comprise wavelet coefficients.

33. The physiological sensor of claim 30, wherein the one or more multi-resolution decompositions comprise one or more wavelet decompositions.

34. The physiological sensor of claim 27, wherein the sensor comprises a pulse oximetry sensor.

35. A cable, comprising:

one or more processing components configured to process an initial signal to generate an artifact-compensated signal.

36. The cable of claim 35, wherein the cable connects a physiological sensor to a physiological monitor.

37. The cable of claim 36, wherein the physiological sensor comprises a pulse oximetry sensor.

38. The cable of claim 37, wherein the physiological monitor comprises one of a pulse oximetry monitor or a multi-parameter monitor.

39. The cable of claim 35, wherein the cable connects a first monitor to a second monitor.

40. The cable of claim 39, wherein the first monitor comprises a pulse oximetry monitor and the second monitor comprises a multi-parameter monitor.

41. The cable of claim 35, wherein the one or more processing components are configured to identify one or more artifacts in the initial signal, to perform one or more multi-resolution decompositions on the initial signal to generate two or more decomposition products, to compensate for the one or more artifacts in the two or more decomposition products to generate modified decomposition products, and to reconstruct the modified decomposition products to generate the artifact-compensated signal.

42. The cable of claim 41, wherein the two or more decomposition components comprise high-passed and low-passed signal components.

43. The cable of claim 41, wherein the two or more decomposition components comprise wavelet coefficients.

44. The cable of claim 41, wherein the one or more multi-resolution decompositions comprise one or more wavelet decompositions.

45. An electronic device, comprising:

one or more processing components configured to receive a signal generated by a physiological sensor, to process the signal to generate an artifact-compensated signal, and to transmit the artifact-compensated signal to a monitor which is not configured to perform artifact compensation.

46. The electronic device of claim 45, wherein the electronic device comprises a physiological monitor.

47. The electronic device of claim 46, wherein the physiological monitor comprises one of a pulse oximetry monitor or a multi-parameter monitor.

48. The electronic device of claim 45, wherein the physiological sensor comprises a pulse oximetry sensor.

49. The electronic device of claim 45, wherein the monitor comprises one of a pulse oximetry monitor or a multi-parameter monitor.

50. The electronic device of claim 45, wherein the one or more processing components are configured to identify one or more artifacts in the signal, to perform one or more multi-resolution decompositions on the signal to generate two or more decomposition products, to compensate for the one or more artifacts in the two or more decomposition products to generate modified decomposition products, and to reconstruct the modified decomposition products to generate the artifact-compensated signal.

51. The electronic device of claim 50, wherein the two or more decomposition components comprise high-passed and low-passed signal components.

52. The electronic device of claim 50, wherein the two or more decomposition components comprise wavelet coefficients.

53. The electronic device of claim 50, wherein the one or more multi-resolution decompositions comprise one or more wavelet decompositions.