System for bandwidth extension of narrow-band speech
View Patent ↗A method applies a parametric approach to bandwidth extension but does not require training. The method computes narrowband linear predictive coefficients from a received narrowband speech signal, computes narrowband partial correlation coefficients using recursion, computes M nb area coefficients from the partial correlation coefficient, and extracts M wb area coefficients using interpolation. Wideband parcors are computed from the M wb area coefficients and wideband LPCs are computed from the wideband parcors. The method further comprises synthesizing a wideband signal using the wideband LPCs and a wideband excitation signal, highpass filtering the synthesized wideband signal to produce a highband signal, and combining the highband signal with the original narrowband signal to generate a wideband signal.
1. A method comprising:
computing, via a processor, linear predictive coefficients from a received signal;
recursively computing partial correlation coefficients based on the linear predictive coefficients;
computing narrow area coefficients from the partial correlation coefficients;
computing wide area coefficients via interpolation of the narrow area coefficients; and
synthesizing a wideband signal using the wide area coefficients.
2. The method of claim 1 , wherein the interpolation of the narrow area coefficients comprises one of a fractal interpolation scheme and a cubic spline interpolation scheme.
3. The method of claim 1 , wherein the received signal is a narrowband signal.
4. The method of claim 1 , wherein computing linear predictive coefficients is based on a narrowband sampling rate.
5. The method of claim 4 , wherein the interpolation of the narrow area coefficients comprises changing the wide area coefficients from the narrowband sampling rate to a wideband sampling rate.
6. The method of claim 1 , wherein the interpolation of the narrow area coefficients comprises use of a zero-order polynomial.
7. The method of claim 1 , wherein recursively computing partial correlation coefficients comprises using Step-Down back-recursion.
8. A system comprising:
a processor; and
a computer-readable storage medium having instructions stored which, when executed by the processor, cause the processor to perform operations comprising:
computing linear predictive coefficients from a received signal;
recursively computing partial correlation coefficients based on the linear predictive coefficients;
computing narrow area coefficients from the partial correlation coefficients;
computing wide area coefficients via interpolation of the narrow area coefficients; and
synthesizing a wideband signal using the wide area coefficients.
9. The system of claim 8 , wherein the interpolation of the narrow area coefficients comprises one of a fractal interpolation scheme and a cubic spline interpolation scheme.
10. The system of claim 8 , wherein the received signal is a narrowband signal.
11. The system of claim 8 , wherein computing linear predictive coefficients is based on a narrowband sampling rate.
12. The system of claim 11 , wherein the interpolation of the narrow area coefficients comprises changing the wide area coefficients from the narrowband sampling rate to a wideband sampling rate.
13. The system of claim 8 , wherein the interpolation of the narrow area coefficients comprises use of a zero-order polynomial.
14. The system of claim 8 , wherein recursively computing partial correlation coefficients comprises using Step-Down back-recursion.
15. A computer-readable storage device having instructions stored which, when executed by a computing device, cause the computing device to perform operations comprising:
computing linear predictive coefficients from a received signal;
recursively computing partial correlation coefficients based on the linear predictive coefficients;
computing narrow area coefficients from the partial correlation coefficients;
computing wide area coefficients via interpolation of the narrow area coefficients; and
synthesizing a wideband signal using the wide area coefficients.
16. The computer-readable storage device of claim 15 , wherein the interpolation of the narrow area coefficients comprises one of a fractal interpolation scheme and a cubic spline interpolation scheme.
17. The computer-readable storage device of claim 15 , wherein the received signal is a narrowband signal.
18. The computer-readable storage device of claim 15 , wherein computing linear predictive coefficients is based on a narrowband sampling rate.
19. The computer-readable storage device of claim 18 , wherein the interpolation of the narrow area coefficients comprises changing the wide area coefficients from the narrowband sampling rate to a wideband sampling rate.
20. The computer-readable storage device of claim 15 , wherein the interpolation of the narrow area coefficients comprises use of a zero-order polynomial.