System for suppressing rain noise

• US 20050114128A1
• Filed: 12/08/2004
• Published: 05/26/2005
• Est. Priority Date: 02/21/2003
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Harman Becker Automotive Systems GmbH (Samsung Electronics Co. Ltd.)
• Inventors: Hetherington, Phillip A., Groves, Adrian R.
• Granted Patent: US 7,949,522 B2
• Time in Patent Office: Days
• US Class Current: 704/233
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: G10L 21/0232 Processing in the frequency domain

Abstract

A voice enhancement logic improves the perceptual quality of a processed signal. The voice enhancement system includes a noise detector and a noise attenuator. The noise detector detects and models the noise associated with rain. The noise attenuator dampens or reduces the rain noise from a signal to improve the intelligibility of an unvoiced, a fully voiced, or a mixed voice segment.

Claims

16. A system for detecting rain noise from a voiced and unvoiced signal, comprising:

a time frequency transform logic that converts a time varying input signal into the frequency domain;

a background noise estimator coupled to the time frequency transform logic, the background noise estimator configured to measure the continuous noise that occurs near a receiver; and

a rain noise detector coupled to the background noise estimator, the rain noise detector configured to automatically identify and model a noise associated with rain.

17. The system of claim 16 further comprising a transient detector configured to disable the background noise estimator when a non-periodic transient signal is detected.

18. The system of claim 16 where the rain noise detector is configured to derive a correlation between a line and a portion of the input signal.

19. The system of claim 16 further comprising a signal discriminator coupled to the rain noise detector, the signal discriminator configured to identify the voice and the noise segments of the input signal.

20. The system of claim 16 further comprising a rain noise attenuator coupled to the rain noise detector, the rain noise attenuator configured to reduce the noise associated with the rain that is sensed by the receiver.

21. The system of claim 16 where the noise attenuator is configured to substantially remove the noise associated with the rain from the input signal.

22. The system of claim 16 further comprising a residual attenuator coupled to the background noise estimator operable to dampen signal power in a frequency range when a large increase in signal power is detected in the frequency range.

23. A system for suppressing rain noise from a voiced or unvoiced signal, comprising:

a time frequency transform logic that converts a time varying input signal into the frequency domain;

a background noise estimator coupled to the time frequency transform logic, the background noise estimator configured to measure the continuous noise that occurs near a receiver;

a rain noise detector means coupled to the background noise estimator, the rain noise detector configured to fit a line to a portion of an input signal; and

a rain noise attenuator coupled to the rain noise detector means, the rain noise attenuator being configured to remove a noise associated with rain that is sensed by the receiver.

24. A method of removing a noise associated with rain from an input signal comprising:

converting a time varying signal to a complex spectrum;

estimating a background noise;

detecting a noise associated with rain when a high correlation exists between a line and a portion of an input signal; and

dampening the noise associated with rain from the input signal.

25. The method of claim 24 where the act of estimating the background noise comprises estimating the background noise when a non-periodic transient is not detected.

26. The method of claim 24 where the act of removing the noise associated with rain comprises substantially removing a rain noise from the input signal.

27. A method of removing rain noise from an input signal comprising:

converting a time varying signal to a complex spectrum;

estimating a background noise;

detecting a rain noise when a high correlation exists between a line and a portion of an input signal; and

removing the rain noise from the input signal.

28. A signal-bearing medium having software that controls a detection of a noise associated with water falling through the air comprising:

a detector that converts sound waves into electrical signals;

a spectral conversion logic that converts the electrical signals from a first domain to a second domain; and

a signal analysis logic that models a portion of the sound waves that are associated with a rain.

1. A system for suppressing rain noise from a voiced or unvoiced signal, comprising:

a noise detector that detects and models a rain noise from an input signal; and

a noise attenuator electrically connected to the noise detector to substantially remove the rain noise from the input signal.

2. The system for suppressing rain noise of claim 1 where the noise detector models a portion of the input signal.

3. The system of claim 2 where the noise detector is configured to fit a line to a portion of the input signal.

4. The system of claim 1 where the noise detector is configured to model a rain event by calculating a correlation factor.

5. The system of claim 1 where the noise detector is configured to prevent the attributes of the modeled rain noise from exceeding a predefined value.

6. The system of claim 1 where the noise detector is configured to limit a rain noise correction when a vowel or a harmonic like structure is detected.

7. The system of claim 1 where the noise detector is configured to derive an average rain noise model and the average rain noise model is not updated when a voiced or a mixed voice signal is detected.

8. The system of claim 1 where the noise detector is configured to derive an average rain noise model that is derived by a weighted average of other modeled signals analyzed earlier in time.

9. The system of claim 1 where the noise attenuator is configured to substantially remove the rain noise and a continuous noise from the input signal.

10. The system of claim 1 further comprising a residual attenuator coupled to the noise detector and the noise attenuator to dampen signal power in a frequency range when a large increase in a signal power is detected in the frequency range.

11. The system of claim 1 further including an input device coupled to the noise detector, the input device configured to convert sound waves into analog signals.

12. The system of claim 1 further including a pre-processing system coupled to the noise detector, the pre-processing system configured to pre-condition the input signal before the rain noise detector processes it.

13. The system of claim 12 where the pre-processing system comprises first and second microphones spaced apart and configured to exploit a lag time of a signal that may arrive at the different microphones.

14. The system of claim 13 further comprising control logic that automatically selects a microphone and a channel that senses the least amount of noise in the input signal.

15. The system of claim 13 further comprising a second noise detector coupled to the noise detector and the first microphone.

29. The signal-bearing medium of claim 28 further comprising logic that derives a portion of a voiced signal masked by the noise.

30. The signal-bearing medium of claim 28 further comprising logic that attenuates portion of the sound waves.

31. The signal-bearing medium of claim 28 further comprising attenuator logic operable to limit a power in a selected frequency range.

32. The signal-bearing medium of claim 28 further comprising noise estimation logic that measures a continuous or ambient noise sensed by the detector.

33. The signal-bearing medium of claim 32 further comprising a transient logic that disables the estimation logic when an increase in power is detected.

34. The signal-bearing medium of claim 28 where the signal analysis logic is coupled to a vehicle.

35. The signal-bearing medium of claim 28 where the signal analysis logic models only the sound waves that are associated with the rain.

34-1. The signal-bearing medium of claim 28 where the signal analysis logic is coupled to an audio system.