System and method for processing low signal-to-noise ratio signals

• US 20050027519A1
• Filed: 07/06/2004
• Published: 02/03/2005
• Est. Priority Date: 11/09/1998
• Status: Active Grant

• Current Assignee: Vivosonic, Inc.
• Original Assignee: Vivosonic, Inc.
• Inventors: Li, Xinde, Kunov, Hans, Sokolov, Yuri
• Granted Patent: US 7,286,983 B2
• Time in Patent Office: Days
• US Class Current: 704/226
• CPC Class Codes: A61B 5/121 evaluating hearing capacity
• CPC Class Codes: G10L 21/02 Speech enhancement, e.g. noise reduction or echo cancellation reducing echo effects in line transmission systems H04B3/20; echo suppression in hands-free telephones H04M9/08
• CPC Class Codes: G10L 21/0232 Processing in the frequency domain
• CPC Class Codes: G10L 21/06 Transformation of speech into a non-audible representation, e.g. speech visualisation or speech processing for tactile aids G10L15/26 takes precedence

Abstract

A system and method for use in a real time system and for processing a signal with a low signal-to-noise ratio (SNR). The system comprises a model for modeling an expected signal and a filter that uses the model for filtering the signal. The filter is used for generating a prediction of the signal and an error variance matrix. The system further comprises an adaptive element for modifying the error variance matrix such that the bandwidth of the filter is widened, wherein the filter behaves like an adaptive filter.

Claims

1. A signal processor for use in a real time system and for processing a signal with a low signal-to-noise ratio (SNR) comprising:

a model for modeling an expected signal;

a filter using said model for filtering said signal for generating a prediction of said signal and an error variance matrix; and

an adaptive element for modifying said error variance matrix such that the bandwidth of said filter is widened;

wherein said filter behaves like an adaptive filter.

2. A signal processor as defined in claim 1, wherein said filter is a Kalman filter

3. A signal processor as defined in claim 2, wherein said Kalman filter is digital.

4. A system for processing a signal with a low signal-to-noise ratio (SNR) for providing output to an operator comprising:

a model for modeling an expected signal;

a filter using said model for filtering said signal for generating a prediction of said signal and an error variance matrix; and

an adaptive element for modifying said error variance matrix such that the bandwidth of said filter is widened;

a processor for processing said filtered signal for determining signal characteristics of said signal;

an output for providing said signal characteristics to said operator;

wherein said system provides said output to said operator in real-time.

5. A system as defined in claim 4, wherein said filter is a Kalman filter.

6. A system as defined in claim 5, wherein said Kalman filter is digital.

7. A system as defined in claim 6, wherein said output is visually presented to said operator.

8. A system as defined in claim 7, wherein said visual output is displayed to said operator on monitor.

9. A system as defined in claim 6, further comprising a digital to analog converter for providing said an analog signal to said operator, said analog signal dependant on said signal characteristics.

10. A system as defined in claim 9, wherein said analog output is an audio output.

11. A system as defined in claim 10, wherein said analog output is a direct representation of said input signal.

12. A system as defined in claim 11, wherein the frequency of said audio output is adjusted such that it lies within the range of human hearing.

13. A system as defined in claim 11, wherein the amplitude of said audio output is increased.

14. A system as defined in claim 10, wherein said audio output is used for alerting said operator that said input signal has passed a predetermined threshold.

15. A system as defined in claim 5, wherein said input signal is a physiological signal.

16. A system as defined in claim 15, wherein said physiological signal is a distinguishing ear-originated distortion product (DPOAE).

17. A system as defined in claim 15, wherein said physiological signal is a auditory steady state response (ASSR).

18. A method for processing a signal with a low signal-to-noise ratio (SNR) for providing output to an operator comprising:

modeling an expected signal;

filtering said signal for generating a prediction of said signal and an error variance matrix;

modifying said error variance matrix such that the bandwidth of said filter is widened;

processing said filtered signal for determining signal characteristics;

providing said signal characteristics to said operator;

wherein said method provides said output to said operator in real-time.

19. A method as defined in claim 18 wherein said filtering is performed by a Kalman filter.

20. A method as defined in claim 19, wherein said Kalman filter is a digital filter.

21. A method as defined in claim 19, further comprising the steps of:

converting said processed digital response signal to an analog format;

providing said analog processed response signal to an operator.

22. A method as defined in claim 21, wherein said analog output is an audio output.

23. A method as defined in claim 22, wherein said analog output is a direct representation of said input signal.

24. A method as defined in claim 23, wherein the frequency of said audio output is adjusted such that it lies within the range of human hearing.

25. A method as defined in claim 24, wherein the amplitude of said audio output is increased.

26. A method as defined in claim 22, wherein said audio output is used for alerting said operator that said input signal has passed a predetermined threshold.

27. A method as defined in claim 19, wherein said physiological signal is a distinguishing ear-originated distortion product (DPOAE).

28. A method as defined in claim 19, wherein said physiological signal is a auditory steady state response (ASSR).