Audio signal processing apparatus and method for modifying a stereo image of a stereo signal

Patent metadata

Field	Value
Publication number	US-10057702-B2
Application number	US-201715616654-A
Country	US
Kind code	B2
Filing date	Jun 7, 2017
Priority date	Apr 24, 2015
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

The disclosure relates to an audio signal processing apparatus for modifying a stereo image of a stereo signal. The apparatus includes a panning index modifier configured to apply a mapping function to at least all panning indexes of stereo signal time-frequency segments that are within a frequency bandwidth, a first panning gain determiner configured to determine modified panning gains for time-frequency signal segments of the first and second audio signal based on the modified panning indexes, and a re-panner configured to re-pan the stereo signal according to ratios between the modified panning gains and panning gains of the first and second audio signal that correspond to the modified panning gains in time and frequency.

First claim

What is claimed is:

1. An audio signal processing apparatus for modifying a stereo image of a stereo signal that includes first and second audio signals, the audio signal processing apparatus comprising:
a memory storing a computer program; and
a processor configured to execute the computer program to cause the audio signal processing apparatus to:
obtain panning indexes and panning gains, wherein the panning indexes characterize panning locations for stereo signal time-frequency segments and the panning gains characterize panning locations for time-frequency signal segments of the first and second audio signals;
apply a mapping function to at least all panning indexes of the stereo signal time-frequency segments that are within a frequency bandwidth, thereby providing modified panning indexes;
determine modified panning gains for time-frequency signal segments of the first and second audio signals based on the modified panning indexes; and
re-pan the stereo signal according to ratios between the modified panning gains and the panning gains of the first and second audio signals that correspond to the modified panning gains in time and frequency, thereby providing a re-panned stereo signal;

wherein the processor is further configured to execute the computer program to cause the audio signal processing apparatus to:
determine the at least all panning indexes based on comparing time-frequency signal segment values of the first and second audio signals that correspond in time and frequency; and
determine the panning gains for the time-frequency signal segments of the first and second audio signals based on the at least all panning indexes.

2. The audio signal processing apparatus of claim 1 , wherein applying the mapping function comprises applying a non-linear mapping function to the at least all panning indexes.

3. The audio signal processing apparatus claim 1 , wherein the mapping function is based on a sigmoid function.

4. The audio signal processing apparatus of claim 3 , wherein the mapping function is expressed as or based on:

Ψ
′

⁡

(

m
,
k

)

=

sign
⁡

(

Ψ
⁡

(

m
,
k

)

)

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1

1
+

e

-



Ψ
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(

m
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k

)



⁢
a

-
0.5

1

1
+

e

-
a

-
0.5

,

wherein Ψ(m,k) denotes a panning index, Ψ′(m,k) denotes a modified panning index, and a controls a mapping function curvature.

5. The audio signal processing apparatus of claim 1 , wherein applying the mapping function comprises applying a polynomial mapping function to the at least all panning indexes.

6. The audio signal processing apparatus of claim 1 , wherein re-panning the stereo signal comprises re-panning the stereo signal according to the following equations:

X
1
′

⁡

(

m
,
k

)

=

g
L
′

⁡

(

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,
k

)

g
L

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(

m
,
k

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⁢

X
1

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(

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,

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X
2
′

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(

m
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k

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=

Assignees

• Huawei Tech Co Ltd

Inventors

• Geiger Juergen
• Grosche Peter

Classifications

• H04S1/002 Primary

  Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution (control circuits for electronic adaptation of the sound field H04S7/30) · CPC title

• H04S7/00

  Indicating arrangements; Control arrangements, e.g. balance control · CPC title

• G10L21/02

  Speech enhancement, e.g. noise reduction or echo cancellation (reducing echo effects in line transmission systems H04B3/20; echo suppression in hands-free telephones H04M9/08) · CPC title

• H04S1/00 Primary

  Two-channel systems (H04S5/00, H04S7/00 take precedence) · CPC title