SIGNAL PROCESSING METHOD AND APPARATUS FOR AMPLIFYING SPEECH SIGNALS

• US 20110184731A1
• Filed: 01/28/2011
• Published: 07/28/2011
• Est. Priority Date: 01/28/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: KIM, Jae-Hyun
• Granted Patent: US 8,949,116 B2
• Time in Patent Office: Days
• US Class Current: 704/205
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 21/038 using band spreading techniques

Abstract

A signal processing method is provided. The signal processing method includes extracting a first signal having a first frequency band from a sum signal of a left signal and a right signal, generating a second signal having a second frequency band by using the first signal, generating a third signal by using the first signal and the second signal, and applying a gain, generated by using a rate of a center signal included in the sum signal, to the third signal.

Claims

1. A signal processing method comprising:

extracting a first signal having a first frequency band from a sum signal of a left signal and a right signal;

generating a second signal having a second frequency band by using the first signal;

generating a third signal by using the first signal and the second signal; and

applying a gain, generated by using a rate of a center signal included in the sum signal, to the third signal.

2. The signal processing method of claim 1, wherein the generating of the second signal comprises:

generating harmonics for a fundamental wave by using the first signal as the fundamental wave; and

generating a signal included in the second frequency band among the harmonics as the second signal.

3. The signal processing method of claim 2, further comprising applying a weight filter to the second signal.

4. The signal processing method of claim 1, wherein the generating of the second signal comprises:

dividing the first signal into signals of N frequency bands and extracting a signal of an M^th frequency band from among the signals of the N frequency bands, N being a natural number greater than 2 and M being a natural number less than or equal to N;

generating harmonics by using the signal of the M^th frequency band as a fundamental wave;

extracting harmonics included in the M^th frequency band among N frequency bands included in the second frequency band from among the generated harmonics; and

generating the second signal by adding harmonics extracted from each of the N frequency bands included in the second frequency band when each of the signals of the N frequency bands of the first signal is used as a fundamental wave.

5. The signal processing method of claim 4, further comprising applying a weight filter to the second signal.

6. The signal processing method of claim 5, wherein the applying of the weight filter comprises applying a weight filter having a separate weight for each of the N frequency bands included in the second frequency band, and

wherein the weight filter has a small weight for a high-frequency band, the weight being a real number not less than 0 and not more than 1.

7. The signal processing method of claim 5, wherein the applying of the weight filter comprises applying a frequency weight filter having a small weight for a high frequency, the weight being a positive real number not more than 1.

8. The signal processing method of claim 5, wherein the generating of the third signal comprises:

time-delaying the first signal; and

generating the third signal by adding the second signal filtered by the weight filter to the time-delayed first signal.

9. The signal processing method of claim 1, wherein the applying of the gain comprises:

calculating a sum signal and a difference signal of the left signal and the right signal on each frame basis;

calculating a rate of the difference signal to the sum signal and calculating a rate of the center signal included in the sum signal by using the rate of the difference signal on a frame basis; and

generating a product of the rate of the center signal and K as a gain for each frame, where K is a positive real number.

10. The signal processing method of claim 9, wherein the calculating of the rate of the center signal comprises normalizing the rate of the difference signal included in the sum signal and subtracting the normalized rate from 1, to calculate the rate of the center signal.

11. The signal processing method of claim 9, wherein the applying of the gain comprises applying a gain obtained for each frame to the third signal on a frame basis.

12. The signal processing method of claim 1, further comprising:

time-delaying the left signal and the right signal; and

generating a new left signal and a new right signal by adding the signal to which the gain was applied to each of the time-delayed left signal and the time-delayed right signal.

13. The signal processing method of claim 1, wherein the second frequency band has frequency values greater than frequency values of the first frequency band.

14. The signal processing method of claim 1, wherein the second frequency band has a size that is twice the size of the first frequency band.

15. A signal processing apparatus comprising:

a first signal extracting unit which extracts a first signal which has a first frequency band from a sum signal of a left signal and a right signal;

a gain generating unit which generates a gain by using a rate of a center signal included in the sum signal; and

an extension signal generating unit which generates a second signal which has a second frequency band by using the first signal, generates a third signal by using the first signal and the second signal, and applies the gain to the third signal.

16. The signal processing apparatus of claim 15, wherein the extension signal generating unit generates harmonics for a fundamental wave by using the first signal as the fundamental wave, and generates a signal included in the second frequency band among the harmonics as the second signal.

17. The signal processing apparatus of claim 16, wherein the extension signal generating unit generates the second signal by applying a weight filter to the signal included in the second frequency band among the harmonics.

18. The signal processing apparatus of claim 15, wherein the extension signal generating unit comprises:

a filtering unit which divides the first signal into signals of N frequency bands and extracts a signal of an M^th frequency band from among the signals of the N frequency bands, N being a natural number greater than 2 and M being a natural number less than or equal to N; and

a harmonic generating unit which generates harmonics by using the signal of the M^th frequency band as a fundamental wave;

a weight filtering unit which extracts harmonics included in the M^th frequency band among N frequency bands included in the second frequency band from among the generated harmonics; and

a signal adding unit which generates the second signal by adding harmonics extracted from each of the N frequency bands included in the second frequency band when each of the signals of the N frequency bands of the first signal is used as a fundamental wave.

19. The signal processing apparatus of claim 18, wherein the weight filtering unit applies a weight filter to the extracted harmonics.

20. The signal processing apparatus of claim 19, wherein the weight filtering unit applies a weight filter which has a separate weight for each of the N frequency bands included in the second frequency band, and

wherein the weight filter has a small weight for a high-frequency band, the weight being a real number not less than 0 and not more than 1.

21. The signal processing apparatus of claim 19, wherein the weight filtering unit applies a frequency weight filter having a small weight for a high frequency, the weight being a positive real number not more than 1.

22. The signal processing apparatus of claim 19, wherein the extension signal generating unit further comprises a time delaying unit which time-delays the first signal, and the signal adding unit generates the third signal by adding the second signal filtered by the weight filter to the time-delayed first signal.

23. The signal processing apparatus of claim 15, wherein the gain generating unit calculates a sum signal and a difference signal of the left signal and the right signal on a frame basis, calculates a rate of the difference signal included in the sum signal, calculates a rate of the center signal included in the sum signal by using the rate of the difference signal on a frame basis, and generates a product of the rate of the center signal and K as a gain for each frame, K being a positive real number.

24. The signal processing apparatus of claim 23, wherein the gain generating unit normalizes the rate of the difference signal to the sum signal and subtracts the normalized rate from 1, to calculate the rate of the center signal.

25. The signal processing apparatus of claim 23, wherein the extension signal generating unit applies a gain obtained for each frame to the third signal on a frame basis.

26. The signal processing apparatus of claim 15, further comprising:

a left signal time delaying unit and a right signal time delaying unit which time-delays the left signal and the right signal, respectively; and

a stereo signal generating unit which generates a new left signal and a new right signal by adding the signal to which the gain was applied to the time-delayed left signal and the time-delayed right signal.

27. The signal processing apparatus of claim 15, wherein the second frequency band has frequency values greater than frequency values of the first frequency band.

28. The signal processing apparatus of claim 15, wherein the second frequency band has a size that is twice the size of the first frequency band.

29. A computer-readable recording medium having embodied thereon instructions that, when executed by a computer, causes the computer to perform a signal processing method, the signal processing method comprising:

extracting a first signal having a first frequency band from a sum signal of a left signal and a right signal;

generating a second signal having a second frequency band by using the first signal;

generating a third signal by using the first signal and the second signal; and

applying a gain, generated by using a rate of a center signal included in the sum signal, to the third signal.