Method and system for physiological signal processing

• US 7,953,230 B2
• Filed: 07/01/2005
• Issued: 05/31/2011
• 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, Cornu, Etienne, Brennan, Robert L.
• Primary Examiner(s): Chin; Vivian
• Assistant Examiner(s): KURR, JASON RICHARD
• Application Number:
  US11/174,366
• Publication Number:
  US 20060056641A1
• Time in Patent Office: 2,160 Days
• Field of Search: 381/67, 381/98, 381/56, 381/122, 381/102, 600/481, 600/483, 600/508, 600/528, 600/586
• 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:

converting one or more input signals in a time-domain into one or more information signals in a frequency domain through an over-sampled analysis filterbank, the one or more input signals including one or more physiological signals;

implementing subband signal processing on the information signals in accordance with an application associated with the physiological signal, the subband signal processing step including extracting one or more features from the information signal;

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

combining the one or more features with the one or more time domain output signals, in the time-domain.

2. A method as claimed in claim 1, wherein the combining step combines the features, time-domain signals associating with the physiological signals, or combinations thereof.

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

implementing time-domain signal processing on the physiological signal that is provided to the over-sampled analysis filterbank as the input signal.

4. A method as claimed in claim 3, wherein the subband signal processing and the time-domain signal processing are interacted.

5. A method as claimed in claim 3, wherein the combining step combines the one or more features, the output from the time-domain processing, or combinations thereof.

6. A method as claimed in claim 1, 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 as the input signal.

7. A method as claimed in claim 1, wherein the step of converting comprises:

converting the one or more input signals in the time-domain through one or more over-sampled, Weighted-Overlap-Add (WOLA) analysis filterbanks, and

the method comprising;

converting the (possibly processed) subband signals back to the time-domain using one or more over-sampled, WOLA synthesis filterbanks.

8. 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.

9. A method as claimed in claim 8, wherein the subband processing step obtains, as its input, the stored signal or the received signal.

10. A method as claimed in claim 9, wherein the combining step obtains, as its input, the stored signal or the received signal.

11. 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.

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

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

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

implementing beamforming algorithm.

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

implementing subband adaptive filtering on the information signals.

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

implementing active noise cancellation.

17. 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.

18. A method according to claim 1, comprising:

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

37. A stethoscope as claimed in claim 36, wherein the programmable digital signal processor implements the method of claim 1.

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

module for converting one or more input signals in a time-domain into one or more information signals in a frequency domain, the one or more input signals including one or more physiological signals;

module for implementing subband signal processing on the information signals in accordance with an application associated with the input signal, the subband signal processing module including a module for extracting one or more features from the information signal;

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;

a combiner for combining the one or more features with the one or more time domain output signals, in the time-domain.

20. A system as claimed in claim 19, wherein the combiner combines the features, time-domain signals associating with the physiological signals, or combinations thereof.

21. A system as claimed in claim 19, further comprising:

module for implementing time-domain signal processing on the physiological signal that is provided to the over-sampled analysis filterbank as the input signal.

22. A system as claimed in claim 21, wherein the subband signal processing module and the time-domain signal processing module interact.

23. A system as claimed in claim 21, wherein the combiner combines the one or more features, the output from the time-domain processing module, or combinations thereof.

24. A system as claimed in claim 19, comprising:

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

25. A system as claimed in claim 19, wherein the combiner provides a feedback signal to the subband signal processing module.

26. A system as claimed in claim 19, wherein:

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

27. A system as claimed in claim 19, 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.

28. A system as claimed in claim 27, wherein the subband processing module obtains, as its input, the stored signal or the received signal.

29. A system as claimed in claim 27, wherein the combiner obtains, as its input, the stored signal or the received signal.

30. A system as claimed in claim 19, 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.

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

32. A system as claimed in claim 31, wherein the combiner obtains, as its input, the stored signal or the received signal.

33. A system as claimed in claim 19, wherein the subband signal processing module implements beamforming algorithm.

34. A system as claimed in claim 19, wherein the subband signal processing module implements subband adaptive filtering on the information signals.

35. A system as claimed in claim 19, wherein the subband signal processing module implements active noise cancellation.

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

an over-sampled filterbank for transforming an electrical signal associating with a physiological sound signal into a plurality of subband signals;

an adjustor for implementing subband gain adjustment to the subband signals from the over-sampled analysis filterbank;

a first processing module for decimating and encoding the subband signals output from the over-sampled analysis filterbank, during a record operation;

a second processing module for decoding and interpolating the decimated, encoded subband signals output from the first processing module, during a playback operation;

an over-sampled synthesis filterbank coupling to a main audio output channel and an auxiliary channel, for synthesizing an output from the adjustor in the main channel and synthesizing the output from the second processing module in the auxiliary channel; and

a feedback path for feed-backing an output of the auxiliary channel to the over-sampled analysis filterbank in the playback operation.