METHOD AND APPARATUS FOR PROCESSING SIGNAL

• US 20110320211A1
• Filed: 06/29/2011
• Published: 12/29/2011
• 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, HU, Chen, TADDEI, Herve Marcel, ZHANG, Qing, CHEN, Longyin
• Granted Patent: US 8,468,025 B2
• Time in Patent Office: Days
• 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; 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 the obtaining of 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 the obtaining of 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

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 the obtaining of 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 the modifying of 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; and

a modifying unit, configured 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

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 the at least two consecutive frequency-domain coefficients include the 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; 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 the obtaining of 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 the obtaining of 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 the at least two consecutive frequency-domain coefficients include the 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 the obtaining of 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 the modifying of 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 the modifying of 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 the at least two consecutive frequency-domain coefficients include the 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; and

a modifying unit, configured 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.