Method and apparatus for processing signal

• US 8,468,025 B2
• Filed: 06/29/2011
• Issued: 06/18/2013
• Est. Priority Date: 12/31/2008
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Liu, Zexin, Miao, Lei, Chen, Longyin, Hu, Chen, Marcel Taddei, Herve, Zhang, Qing
• Primary Examiner(s): Saint Cyr, Leonard
• Application Number:
  US13/172,509
• Publication Number:
  US 20110320211A1
• Time in Patent Office: 720 Days
• Field of Search: None
• US Class Current: 704/500
• CPC Class Codes: G10L 19/0208 Subband vocoders
• CPC Class Codes: G10L 19/26 Pre-filtering or post-filtering
• CPC Class Codes: G10L 21/0208 Noise filtering

Abstract

A method and an apparatus for processing a signal are provided. The method includes: obtaining an energy average value of each sub-band for a current frame frequency-domain signal; obtaining a current frame modification coefficient of each sub-band for the current frame frequency-domain signal according to a spectral envelope and the energy average value of each sub-band; obtaining a weighted modification coefficient of each sub-band for the current frame frequency-domain signal by using the current frame modification coefficient and a relevant frame modification coefficient; and modifying the spectral envelope of each sub-band for the current frame frequency-domain signal by using the weighted modification coefficient.

Claims

1. A method for processing a signal, comprising:

obtaining an energy average value of each sub-band for a current frame frequency-domain signal;

obtaining a current frame modification coefficient of each sub-band for the current frame frequency-domain signal according to a spectral envelope and the energy average value of each sub-band;

obtaining a weighted modification coefficient of each sub-band for the current frame frequency-domain signal by using the current frame modification coefficient and a relevant frame modification coefficient, wherein the relevant frame modification coefficient comprises a modification coefficient of a sub-band for one or more previous frame frequency-domain signals; and

modifying the spectral envelope of each sub-band for the current frame frequency-domain signal by using the weighted modification coefficient.

2. The method for processing a signal according to claim 1, wherein before obtaining the current frame modification coefficient of each sub-band for the current frame frequency-domain signal according to the spectral envelope and the energy average value of each sub-band, the method further comprises determining that an energy average value of a low-band frequency-domain signal of the current frame frequency-domain signal is less than an energy average value of a high-band frequency-domain signal of the current frame frequency-domain signal.

3. The method for processing a signal according to claim 2, wherein obtaining the current frame modification coefficient of each sub-band for the current frame frequency-domain signal according to the spectral envelope and the energy average value of each sub-band comprises:

setting the current frame modification coefficient to be a first modification coefficient, if the spectral envelope of each sub-band for the current frame frequency-domain signal is less than a corresponding first spectral envelope threshold value, when the energy average value of the low-band frequency-domain signal is less than the energy average value of the high-band frequency-domain signal; and

setting the current frame modification coefficient to be a second modification coefficient, if the spectral envelope of each sub-band for the current frame frequency-domain signal is greater than a corresponding second spectral envelope threshold value, when the energy average value of the low-band frequency-domain signal is less than the energy average value of the high-band frequency-domain signal,

wherein the first modification coefficient is set to be φ

ranging in (0,

     1), and

wherein the second modification coefficient is set to be β

ranging in (1,

     2).

4. The method for processing a signal according to claim 1, wherein obtaining the weighted modification coefficient of each sub-band for the current frame frequency-domain signal by using the current frame modification coefficient and a relevant frame modification coefficient comprises performing a weight sum operation on the current frame modification coefficient and the relevant frame modification coefficient, and using an operation result as the weighted modification coefficient of each sub-band for the current frame frequency-domain signal.

5. The method for processing a signal according to claim 1, wherein modifying the spectral envelope of each sub-band for the current frame frequency-domain signal by using the weighted modification coefficient comprises linearly transforming the spectral envelope of each sub-band for the current frame frequency-domain signal with the weighted modification coefficient as a transform factor.

6. An apparatus for processing a signal, comprising:

an obtaining unit configured to obtain an energy average value of each sub-band for a current frame frequency-domain signal;

a current frame modification coefficient obtaining unit configured to obtain a current frame modification coefficient of each sub-band for the current frame frequency-domain signal according to a spectral envelope and the energy average value of each sub-band;

a weighted modification coefficient obtaining unit configured to obtain a weighted modification coefficient of each sub-band for the current frame frequency-domain signal by using the current frame modification coefficient and a relevant frame modification coefficient, wherein the relevant frame modification coefficient comprises a modification coefficient of a sub-band for one or more previous frame frequency-domain signals; and

a modifying unit configured to use a processor to modify the spectral envelope of each sub-band for the current frame frequency-domain signal by using the weighted modification coefficient.

7. The apparatus for processing a signal according to claim 6, further comprising a determining unit configured to determine that an energy average value of a low-band frequency-domain signal of the current frame frequency-domain signal is less than an energy average value of a high-band frequency-domain signal of the current frame frequency-domain signal.

8. The apparatus for processing a signal according to claim 7, wherein the determining unit comprises:

a signal dividing module configured to divide the current frame frequency-domain signal into the high-band frequency-domain signal and the low-band frequency-domain signal; and

a judging module configured to judge magnitudes of the energy average values of the low-band frequency-domain signal of the current frame frequency-domain signal and the high-band frequency-domain signal of the current frame frequency-domain signal.

9. The apparatus for processing a signal according to claim 8, wherein the weighted modification coefficient obtaining unit comprises:

a first modification coefficient obtaining sub-module configured to set the current frame modification coefficient to be a first modification coefficient, if the spectral envelope of each sub-band for the current frame frequency-domain signal is less than a corresponding first spectral envelope threshold value, when the energy average value of the low-band frequency-domain signal is less than the energy average value of the high-band frequency-domain signal; and

a second modification coefficient obtaining sub-module configured to set the current frame modification coefficient to be a second modification coefficient, if the spectral envelope of each sub-band for the current frame frequency-domain signal is higher than a corresponding second spectral envelope threshold value, when the energy average value of the low-band frequency-domain signal is less than the energy average value of the high-band frequency-domain signal,

wherein the first modification coefficient is set to be φ

ranging in (0,

     1); and

wherein the second modification coefficient is set to be β

ranging in (1,

     2).

10. A method for processing a signal, comprising:

obtaining an amplitude of at least one frequency-domain coefficient of a current frame frequency-domain signal;

obtaining at least one current frame modification coefficient corresponding to the at least one frequency-domain coefficient according to the amplitude of the at least one frequency-domain coefficient and an amplitude average value of the frequency-domain coefficients, wherein the amplitude average value of the frequency-domain coefficients is an amplitude average value of at least two consecutive frequency-domain coefficients in the current frame frequency-domain signal, and wherein the at least two consecutive frequency-domain coefficients include the at least one current frequency-domain coefficient;

obtaining a weighted modification coefficient of the current frame frequency-domain signal corresponding to the at least one frequency-domain coefficient by using the at least one current frame modification coefficient and a relevant frame modification coefficient, wherein the relevant modification coefficient comprises a modification coefficient of a sub-band for one or more previous frame frequency-domain signals; and

modifying the corresponding at least one frequency-domain coefficient of the current frame frequency-domain signal by using the weighted modification coefficient.

11. The method for processing a signal according to claim 10, wherein before obtaining the at least one current frame modification coefficient corresponding to the at least one frequency-domain coefficient according to the amplitude of the at least one frequency-domain coefficient and the amplitude average value of the frequency-domain coefficients of the current frame frequency-domain signal, the method further comprises determining whether an energy average value of a low-band frequency-domain signal of the current frame frequency-domain signal is less than an energy average value of a high-band frequency-domain signal of the current frame frequency-domain signal.

12. The method for processing a signal according to claim 11, wherein obtaining the at least one current frame modification coefficient corresponding to the at least one frequency-domain coefficient according to the amplitude of the at least one frequency-domain coefficient and the amplitude average value of the frequency-domain coefficients, wherein the amplitude average value of the frequency-domain coefficients is the amplitude average value of at least two consecutive frequency-domain coefficients in the current frame frequency-domain signal, and wherein the at least two consecutive frequency-domain coefficients include the at least one current frequency-domain coefficient, comprises:

setting the current frame modification coefficient to be a first modification coefficient, if the amplitude is less than a first frequency-domain coefficient threshold value determined according to the amplitude average value, when the energy average value of the low-band frequency-domain signal is less than the energy average value of the high-band frequency-domain signal; and

setting the current frame modification coefficient to be a second modification coefficient, if the amplitude of the frequency-domain coefficient of the current frame frequency-domain signal is higher than a second frequency-domain coefficient threshold value determined according to the amplitude average value, when the energy average value of the low-band frequency-domain signal is less than the energy average value of the high-band frequency-domain signal.

13. The method for processing a signal according to claim 10, wherein obtaining the weighted modification coefficient of the current frame frequency-domain signal corresponding to the at least one frequency-domain coefficient by using the at least one current frame modification coefficient and the relevant frame modification coefficient comprises:

performing a weight sum operation on the at least one current frame modification coefficient and the relevant frame modification coefficient; and

using an operation result as the weighted modification coefficient of the current frame frequency-domain signal corresponding to the at least one frequency-domain coefficient.

14. The method for processing a signal according to claim 10, wherein modifying the corresponding at least one frequency-domain coefficient of the current frame frequency-domain signal by using the weighted modification coefficient comprises linearly transforming the corresponding at least one frequency-domain coefficient of the current frame frequency-domain signal with the weighted modification coefficient as a transform factor.

15. The method for processing a signal according claim 10, wherein after modifying the corresponding at least one frequency-domain coefficient of the current frame frequency-domain signal by using the weighted modification coefficient, the method further comprises performing intra-frame smoothing processing in a frequency-domain axis on the frequency-domain signal.

16. An apparatus for processing a signal, comprising:

an obtaining unit configured to obtain an amplitude of at least one frequency-domain coefficient of a current frame frequency-domain signal;

a current frame modification coefficient obtaining unit configured to compare the amplitude of the at least one frequency-domain coefficient with an amplitude average value of the frequency-domain coefficients and obtain at least one current frame modification coefficient corresponding to the at least one frequency-domain coefficient, wherein the amplitude average value of the frequency-domain coefficients is an amplitude average value of at least two consecutive frequency-domain coefficients in the current frame frequency-domain signal, and wherein the at least two consecutive frequency-domain coefficients include the at least one current frequency-domain coefficient;

a weighted modification coefficient obtaining unit configured to obtain a weighted modification coefficient of the current frame frequency-domain signal corresponding to the at least one frequency-domain coefficient by using the at least one current frame modification coefficient and a relevant frame modification coefficient, wherein the relevant frame modification coefficient comprises a modification coefficient of one or more previous frame frequency-domain signals; and

a modifying unit configured to use a processor to modify the corresponding at least one frequency-domain coefficient of the current frame frequency-domain signal by using the weighted modification coefficient.

17. The apparatus for processing a signal according to claim 16, further comprising a determining unit configured to determine that an energy average value of a low-band frequency-domain signal of the current frame frequency-domain signal is less than an energy average value of a high-band frequency-domain signal of the current frame frequency-domain signal.

18. The apparatus for processing a signal according to claim 16, wherein the determining unit comprises:

a signal dividing module configured to divide the current frame frequency-domain signal into the high-band frequency-domain signal and the low-band frequency-domain signal; and

a judging module configured to judge magnitudes of the energy average values of the low-band frequency-domain signal of the current frame frequency-domain signal and the high-band frequency-domain signal of the current frame frequency-domain signal.

19. The apparatus for processing a signal according to claim 18, wherein the weighted modification coefficient obtaining unit comprises:

a first modification coefficient obtaining sub-module configured to set the current frame modification coefficient to be a first modification coefficient, if the amplitude is less than a first frequency-domain coefficient threshold value determined according to the amplitude average value, when the energy average value of the low-band frequency-domain signal is less than the energy average value of the high-band frequency-domain signal; and

a second modification coefficient obtaining sub-module configured to set the current frame modification coefficient to be a second modification coefficient, if the amplitude of the frequency-domain coefficient of the current frame frequency-domain signal is higher than a second frequency-domain coefficient threshold value determined according to the amplitude average value, when the energy average value of the low-band frequency-domain signal is less than the energy average value of the high-band frequency-domain signal.

20. The apparatus for processing a signal according to claim 16, further comprising a signal processing unit configured to perform intra-frame smoothing processing in a frequency-domain axis on the output frequency-domain signal after the corresponding at least one frequency-domain coefficient of the current frame frequency-domain signal is modified.