Apparatus and method for generating an enhanced signal using independent noise-filling

Patent metadata

Field	Value
Publication number	US-11705145-B2
Application number	US-202017098126-A
Country	US
Kind code	B2
Filing date	Nov 13, 2020
Priority date	Jul 28, 2014
Publication date	Jul 18, 2023
Grant date	Jul 18, 2023

Abstract

An apparatus for generating an enhanced signal from an input signal, wherein the enhanced signal has spectral values for an enhancement spectral region, the spectral values for the enhancement spectral regions not being contained in the input signal, includes a mapper for mapping a source spectral region of the input signal to a target region in the enhancement spectral region, the source spectral region including a noise-filling region; and a noise filler configured for generating first noise values for the noise-filling region in the source spectral region of the input signal and for generating second noise values for a noise region in the target region, wherein the second noise values are decorrelated from the first noise values or for generating second noise values for a noise region in the target region, wherein the second noise values are decorrelated from first noise values in the source region.

First claim

The invention claimed is:

1. An apparatus for generating an enhanced audio signal from an input audio signal, the apparatus comprising:
a mapper configured for mapping a source spectral region of the input audio signal to a target spectral region in an enhancement spectral region,
wherein the enhanced audio signal comprises spectral values for the enhancement spectral region, the spectral values for the enhancement spectral region not being comprised by the input audio signal,
wherein the mapper is configured to map the source spectral region so that a target spectral region frequency content of the target spectral region has frequency values being different from frequency values of a source region frequency content in the source spectral region; and
a noise filler configured for generating second noise values for a noise region in the target spectral region in the enhancement spectral region, wherein the second noise values are decorrelated from first noise values in the source spectral region of the input audio signal,
wherein at least one of the mapper and the noise filler comprises, at least partly, a hardware implementation.

2. The apparatus of claim 1 ,
wherein the input audio signal is an encoded audio signal comprising noise-filling parameters for the source spectral region of the input audio signal,
wherein the noise filler is configured for generating the first noise values using the noise-filling parameters and for generating the second noise values using an energy information on the first noise values.

3. The apparatus of claim 2 ,
wherein the noise filler is configured for:
identifying a noise-filling region comprising the first noise values in the input audio signal;
copying at least a region of the input audio signal to a source tile buffer, the region comprising the source spectral region, the source spectral region comprising the noise-filling region; and
replacing, in the source tile buffer, the first noise values as identified in the identifying the noise-filling region by decorrelated noise values; and

wherein the mapper is configured to map the source tile buffer comprising the decorrelated noise values to the target spectral region.

4. The apparatus of claim 1 ,
wherein the noise filler is configured for:
identifying a noise-filling region comprising the first noise values in the input audio signal;
copying at least a region of the input audio signal to a source tile buffer, the region comprising the source spectral region, the source spectral region comprising the noise-filling region; and
replacing, in the source tile buffer, the first noise values as identified in the identifying the noise-filling region by decorrelated noise values; and

wherein the mapper is configured to map the source tile buffer comprising the decorrelated noise values to the target spectral region.

5. The apparatus of claim 4 , wherein the noise filler is configured
to measure an energy information on the decorrelated noise values,
to measure an energy information on the first noise values, and
to scale the decorrelated noise values using a scaling value derived from the energy information on the decorrelated noise values and the energy information on the first noise values.

6. The apparatus of claim 4 ,
wherein the noise filler is configured to copy, in the copying operation, a complete spectral portion of the input audio signal or a complete spectral portion of the input audio signal above a noise-filling border frequency usable by the mapper to the source tile buffer and to perform the replacing operation on the full source tile buffer, or
wherein the noise filler is configured to copy, in the copying operation, only a spectral region of the input audio signal identified by one or more specific source identifiers for a source spectral region to be used by the mapper for an identified target spectral region, where an individual source tile buffer is used for each different individual mapping operation.

7. The apparatus of claim 1 ,
wherein the noise filler is configured for generating the second noise values subsequent to an operation of the mapper, or
wherein the noise filler is configured for generating the first and the second noise values subsequent to an operation of the mapper.

8. The apparatus of claim 1 , wherein the noise filler is configured
to perform noise-filling in spectral regions by generating the first noise values using a noise-filling operation and noise-filling parameters transmitted in the input audio signal as side information, and
to perform a noise-filling operation in the target spectral region to generate the second noise values using energy information on the first noise values.

9. The apparatus of claim 1 , further comprising:
an envelope adjuster configured for adjusting the second noise values in the enhancement spectral region using spectral envelope information comprised by the input audio signal as side information.

10. The apparatus of claim 1 ,
wherein the noise filler is configured to only use side information of the input audio signal to identify spectral positions for a noise-filling operation, or
wherein the noise filler is configured to analyze a time or spectral characteristic of the input audio signal with or without spectral values in the noise-filling region to identify spectral positions for the noise-filling operation.

11. The apparatus of claim 1 ,
wherein the noise filler is configured to identify noise positions using an identification vector comprising entries for spectral positions in the source spectral region only, or comprising entries for spectral positions in the source spectral region and in the target region.

12. The apparatus of claim 11 , wherein the noise filler is configured for calculating an energy information on noise values indicated by the identification vector,
calculating an energy information on inserted random values intended for the target spectral region,
calculating a gain factor for scaling the inserted random values, and
applying the gain factor to the inserted random values.

13. The apparatus of claim 1 ,
wherein the mapper is configured to perform a gap filling operation for generating the target region, the apparatus comprising:
a spectral domain audio decoder configured for generating a first decoded representation of a first set of first spectral portions, the decoded representation comprising a first spectral resolution;
a parametric decoder configured for generating a second decoded representation of a second set of second spectral portions comprising a second spectral resolution being lower than the first spectral resolution;
a frequency regenerator configured for regenerating a reconstructed second spectral portion comprising the first spectral resolution using a first spectral portion and spectral envelope information for the second spectral portion; and
a spectrum time converter configured for converting the first decoded representation in the reconstructed second spectral portion into a time representation,
wherein the mapper and the noise filler are at least partly comprised by the frequency regenerator.

14. The apparatus of claim 13 ,
wherein the spectral domain audio decoder is configured to output a sequence of decoded frames of spectral values, a decoded frame being the first decoded representation, wherein the frame comprises spectral values for the first set of spectral portions and zero indications for the second set of second spectral portions,
wherein the apparatus for decoding further comprises a combiner configured for combining spectral values generated by the frequency regen

Assignees

• Fraunhofer Ges Forschung

Inventors

• Disch Sascha
• Geiger Ralf
• Niedermeier Andreas
• Neusinger Matthias
• Schmidt Konstantin
• Wilde Stephan
• Schubert Benjamin
• Neukam Christian

Classifications

• G10L25/21

  the extracted parameters being power information · CPC title

• G10L21/038

  using band spreading techniques · CPC title

• G10L19/028 Primary

  Noise substitution, i.e. substituting non-tonal spectral components by noisy source (comfort noise for discontinuous speech transmission G10L19/012) · CPC title

• G10L19/0204 Primary

  using subband decomposition · CPC title

• G10L15/20

  Speech recognition techniques specially adapted for robustness in adverse environments, e.g. in noise, of stress induced speech (G10L21/02 takes precedence) · CPC title