Systems And Methods For Adaptively Filtering Signals

• US 20100016676A1
• Filed: 09/30/2008
• Published: 01/21/2010
• Est. Priority Date: 07/15/2008
• Status: Abandoned Application

• Current Assignee: Nellcor Puritan Bennett Ireland
• Original Assignee: Nellcor Puritan Bennett Ireland
• Inventors: Addison, Paul Stanley, Watson, James Nicholas
• Application Number:
  US12/242,871
• Publication Number:
  US 20100016676A1
• Time in Patent Office: Days
• US Class Current: 600/300
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/726 using Wavelet transforms

Abstract

According to embodiments, systems and method are provided for adaptively filtering signals. A combination of filtering techniques is described in which non-wavelet based filtering techniques are used with wavelet-based filtering techniques to filter an input signal. One or more physiological parameters may then be determined from the filtered output signal.

Claims

1. A method for filtering a signal, the method comprising:

receiving an input signal;

filtering the received input signal using a first adaptive filtering technique to produce a first filtered signal; and

filtering the first filtered signal using a wavelet filtering technique to produce an output filtered signal.

2. The method of claim 1, wherein receiving an input signal comprises receiving at least one photoplethysmograph (PPG) signal.

3. The method of claim 1, wherein filtering the received input signal using a first adaptive filtering technique comprises generating a reference signal from the received input signal.

4. The method of claim 3, wherein filtering the received input signal using a first adaptive filtering technique additionally comprises filtering the received input signal using an adaptive correlation canceller and the generated reference signal.

5. The method of claim 1, wherein filtering the first filtered signal using a wavelet filtering technique comprises transforming the first filtered signal using a continuous wavelet transform.

6. The method of claim 5, wherein filtering the first filtered signal using a wavelet filtering technique comprises generating a scalogram of the continuous wavelet transform of the first filtered signal.

7. The method of claim 6 further comprising identifying at least one artifact in the scalogram.

8. The method of claim 1, wherein filtering the first filtered signal using a wavelet filtering technique comprises generating at least two scalograms from the first filtered signal, wherein at least one of the at least two scalograms is a residual scalogram.

9. The method of claim 1 further comprising determining at least one physiological parameter from the output filtered signal.

10. A method for filtering a signal, the method comprising:

receiving an input signal;

filtering the received input signal using a wavelet filtering technique to produce a first filtered signal; and

filtering the first filtered signal using an adaptive filtering technique to produce an output filtered signal.

11. A system for filtering a signal, the system comprising:

a sensor capable of generating an input signal; and

a processor capable of;

filtering the input signal using a first adaptive filtering technique to produce a first filtered signal; and

filtering the first filtered signal using a wavelet filtering technique to produce an output filtered signal.

12. The system of claim 11, wherein the sensor is capable of generating at least one photoplethysmograph (PPG) signal.

13. The system of claim 11, wherein the processor is capable of generating a reference signal from the input signal.

14. The system of claim 13, wherein the processor is capable of filtering the input signal using an adaptive correlation canceller and the generated reference signal.

15. The system of claim 11, wherein the processor is capable of transforming the first filtered signal using a continuous wavelet transform.

16. The system of claim 15, wherein the processor is capable of generating a scalogram of the continuous wavelet transform of the first filtered signal.

17. The system of claim 16 wherein the processor is capable of identifying at least one artifact in the scalogram.

18. The system of claim 11, wherein the processor is capable of generating at least two scalograms from the first filtered signal, wherein at least one of the at least two scalograms is a residual scalogram.

19. The system of claim 11 wherein the processor is capable of determining at least one physiological parameter from the output filtered signal.

20. A computer-readable medium for use in detecting an artifact in a signal, the computer-readable medium having computer program instructions recorded thereon for:

receiving an input signal;

filtering the received input signal using a first adaptive filtering technique to produce a first filtered signal; and

filtering the first filtered signal using a wavelet filtering technique to produce an output filtered signal.