Method and system for physiological signal processing

• US 20060056641A1
• Filed: 07/01/2005
• Published: 03/16/2006
• Est. Priority Date: 09/15/2004
• Status: Active Grant

• Current Assignee: K/S HIMPP
• Original Assignee: ON Semiconductor Trading, Ltd (ON Semiconductor Corporation)
• Inventors: Johnson, Julie, Nadjar, Hamid Sheikhzadeh, Brennan, Robert L., Cornu, Etienne
• Granted Patent: US 7,953,230 B2
• Time in Patent Office: Days
• US Class Current: 381/67
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: G10L 25/00 Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 muting semiconductor-based amplifiers when some special characteristics of a signal are sensed by a speech detector, e.g. sensing when no signal is present, H03G3/34
• CPC Class Codes: H03H 2021/0041 Subband decomposition
• CPC Class Codes: H03H 21/0012 Digital adaptive filters

Abstract

A method and system for processing of physiological signals is provided. The system processes information signals in subband-domain associated with the physiological signals in time-domain. The information signals are obtained by one or more over-sampled filterbanks. The method and system possibly synthesizes the subband signals obtained by subband processing. The method and system may implement the analysis, subband processing, and synthesis algorithms on over-sampled filterbanks, which are implemented on ultra low-power, small size, and low-cost platform in real-time. The method and system may use over-sampled, Weighted-Overlap Add (WOLA) filterbanks.

Claims

1. A method of processing one or more input signals including one or more physiological signals, comprising the steps of:

providing one or more information signals in a frequency-domain, the information signals being obtained by converting one or more input signals in a time-domain through one or more over-sampled analysis filterbanks;

implementing subband signal processing on the information signals in accordance with an application associated with the physiological signal; and

combining the results of the subband signal processing to provide one or more output signals.

2. A method as claimed in claim 1, wherein the subband signal processing step extracts features from the information signal, and the combining step combines the features.

3. A method as claimed in claim 1, further comprises:

synthesizing one or more subband signals output from the subband signal processing using one or more over-sampled synthesis filterbanks to provide one or more time-domain output signals.

4. A method as claimed in claim 3, wherein the subband signal processing step extracts features from the information signal, and the combining step combines the features, the time-domain signals, or combinations thereof.

5. A method as claimed in claim 1, further comprising the step of:

implementing time-domain signal processing on the input signals.

6. A method as claimed in claim 5, wherein the subband signal processing and the time-domain signal processing are interacted.

7. A method as claimed in claim 5, wherein the subband signal processing step extracts features from the information signal, and the combining step combines the features, the output from the time-domain processing, or combinations thereof.

8. A method as claimed in claim 1, further comprising the step of:

obtaining one or more feedback signals through the combining step; and

providing the feedback signal to the over-sampled analysis filterbank, the subband signal processing, the time-domain processing, or a combination thereof.

9. A method as claimed in claim 1, wherein:

the information signals are obtained by converting one or more input signals in the time-domain through one or more over-sampled, Weighted-Overlap-Add (WOLA) analysis filterbanks and converting the (possibly processed) subband signals back to the time-domain using one or more over-sampled, WOLA synthesis filterbanks.

10. A method as claimed in claim 1, further comprising at least one of the following steps:

storing the subband signal,

transmitting the subband signal, and

receiving the subband signal.

11. A method as claimed in claim 10, wherein the subband processing step obtains, as its input, the stored signal or the received signal.

12. A method as claimed in claim 11, wherein the combining step obtains, as its input, the stored signal or the received signal.

13. A method as claimed in claim 1, further comprising as least one of the following steps:

storing the output of the time-domain processing step,

transmitting the output of the time-domain processing step, and

receiving the output of the time-domain processing step.

14. A method as claimed in claim 13, wherein the time-domain processing step obtains, as its input, the stored signal or the received signal.

15. A method as claimed in claim 13, wherein the combining step obtains, as its input, the stored signal or the received signal.

16. A method as claimed in claim 1, wherein the subband signal processing includes the step of:

implementing beamforming algorithm.

17. A method as claimed in claim 1, wherein the subband signal processing includes the step of:

implementing subband adaptive filtering on the information signals.

18. A method as claimed in claim 1, wherein the subband signal processing includes the step of:

implementing active noise cancellation.

19. A method as claimed in claim 1, wherein the subband signal processing includes the step of:

implementing autocorrelation estimation using one or more complex subband signals by IIR or FIR methods, for the purpose of heartbeat detection or other applications.

40. A stethoscope as claimed in claim 39, wherein the programmable digital signal processor implements the method of claim 1.

20. A system for processing an input signal, comprising:

module for providing one or more information signals in a frequency-domain, the information signals being obtained by converting one or more input signals in a time-domain through an over-sampled filterbank;

module for implementing subband signal processing on the information signals in accordance with an application associated with the input signal; and

a combiner for combining the results of the subband signal processing to provide one or more output signals in the time-domain.

21. A system as claimed in claim 20, wherein the subband signal processing module extracts features from the information signal, and the combiner combines the features.

22. A system as claimed in claim 20, further comprising:

an over-sampled synthesis filterbank for synthesizing one or more subband signals output from the subband signal processing module to provide one or more time-domain signals.

23. A system as claimed in claim 22, wherein the subband signal processing module extracts features from the information signal, and the combiner combines the features, the time-domain signals, or combinations thereof.

24. A system as claimed in claim 20, further comprising:

module for implementing time-domain signal processing on the physiological signal.

25. A system as claimed in claim 24, wherein the subband signal processing module and the time-domain signal processing module interact.

26. A system as claimed in claim 24, wherein the subband signal processing module extracts features from the information signal, and the combiner combines the features, the output from the time-domain processing module, or combinations thereof.

27. A system as claimed in claim 20, further comprising:

a switch for selectively providing a feedback signal output from the combiner or the physiological signal to the over-sampled analysis filterbank.

28. A system as claimed in claim 20, wherein the combiner provides a feedback signal to the subband signal processing module.

29. A system as claimed in claim 20, wherein:

the over-sampled analysis filterbank includes an over-sampled, WOLA analysis filterbank.

30. A system as claimed in claim 20, further comprising module adapted for at least one of the following steps;

storing the subband signal,

transmitting the subband signal, and

receiving the subband signal.

31. A system as claimed in claim 30, wherein the subband processing module obtains, as its input, the stored signal or the received signal.

32. A system as claimed in claim 30, wherein the combiner obtains, as its input, the stored signal or the received signal.

33. A system as claimed in claim 20, further comprising modules adapted for at least one of the following steps;

storing the output of the time-domain processing module,

transmitting the output of the time-domain processing module, and

receiving the output of the time-domain processing module.

34. A system as claimed in claim 33, wherein the time-domain processing module obtains, as its input, the stored signal or the received signal.

35. A system as claimed in claim 34, wherein the combiner obtains, as its input, the stored signal or the received signal.

36. A system as claimed in claim 20, wherein the subband signal processing module implements beamforming algorithm.

37. A system as claimed in claim 20, wherein the subband signal processing module implements subband adaptive filtering on the information signals.

38. A system as claimed in claim 20, wherein the subband signal processing module implements active noise cancellation.

39. A stethoscope for processing a physiological sound signal, comprises:

a diaphragm for amplifying the physiological sound signal;

a microphone for transforming the physiological sound signal to an electrical signal;

one or more programmable digital signal processors for processing one or more electrical signals, implementing one or more over-sampled, WOLA filterbanks;

a resonation chamber enclosing the microphone; and

a receiver for making the output of the programmable digital signal processor audible.