Method for processing an audio signal in accordance with a room impulse response, signal processing unit, audio encoder, audio decoder, and binaural renderer

Patent metadata

Field	Value
Publication number	US-10433097-B2
Application number	US-201615003287-A
Country	US
Kind code	B2
Filing date	Jan 21, 2016
Priority date	Jul 22, 2013
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

A method for processing an audio signal in accordance with a room impulse response is described. The audio signal is separately processed with an early part and a late reverberation of the room impulse response, and the processed early part of the audio signal and the reverberated signal are combined. A transition from the early part to the late reverberation in the room impulse response is reached when a correlation measure reaches a threshold, the threshold being set dependent on the correlation measure for a selected one of the early reflections in the early part of the room impulse response.

First claim

The invention claimed is:

1. A method for processing an audio signal in accordance with a room impulse response, the method comprising:
separately processing, by a processing unit, the audio signal with an early part and a late reverberation of the room impulse response; and
combining, by a processing unit, the audio signal processed with the early part of the room impulse response and a reverberated signal,
wherein a transition from the early part to the late reverberation in the room impulse response is determined once a correlation measure reaches a threshold,
wherein the correlation measure describes with regard to the room impulse response a similarity of a decay in acoustic energy comprising an initial state and of the decay in acoustic energy starting at a time following the initial state over a predefined frequency range,
wherein the threshold is set dependent on the correlation measure for a selected one of the early reflections in the early part of the room impulse response,
wherein the selected one of the early reflections is the first reflection, and
wherein the processing unit comprises a hardware implementation.

2. The method of claim 1 , wherein determining the transition comprises:
determining a distribution of acoustic energy based on the room impulse response; and;
determining a plurality of correlation measures indicating for a plurality of portions of the determined distribution a correlation between the acoustic energy in the respective portion of the determined distribution and the acoustic energy at an initial state.

3. The method of claim 2 , wherein
determining the distribution comprises determining a time-frequency distribution of the acoustic energy, and
a portion of the distribution comprises a time block of a predefined length, the initial state being defined by the first one of a plurality of time blocks of the time-frequency distribution.

4. The method of claim 3 , wherein the room impulse response comprises a predefined effective length, and wherein determining the time-frequency distribution comprises calculating the FFT spectrum of the room impulse response using a window comprising a length corresponding to the effective length of the room impulse response.

5. The method of claim 2 , wherein determining the distribution comprises calculating the energy decay relief (EDR) from the room impulse response.

6. The method of claim 5 , wherein the EDR is calculated as follows:
E ( t ,ω)=|∫ t ∞ h (τ) e −jωτ dτ| 2

where
E(t,ω)=energy decay relief at frequency f starting a time t,
h(τ)=room impulse response,
ω=2πf.

7. The method of claim 1 , wherein the correlation measure is calculated as follows:

ρ
⁡

(
t
)

=

∑
ω

⁢

(

E
⁡

(

1
,
ω

)

-

E
_

⁡

(

1
,
ω

)

)

·

∑
ω

⁢

(

E
⁡

(

t
,
ω

)

-

E
_

⁡

(

t
,
ω

)

)

∑
ω

⁢

(

E
⁡

(

1
,
ω

)

-

E
_

⁡

(

1
,
ω

)

)

2

·

∑
ω

⁢

(

E
⁡

(

t
,
ω

)

-

Assignees

• Fraunhofer Ges Forschung

Inventors

• Fueg Simone
• Plogsties Jan

Classifications

• G01H7/00

  Measuring reverberation time {; room acoustic measurements} · CPC title

• G10K15/12 Primary

  using electronic time-delay networks · CPC title

• G10K15/08

  Arrangements for producing a reverberation or echo sound {(modifying acoustic properties to change reverberation time G10K11/002)} · CPC title

• H04S7/305 Primary

  Electronic adaptation of stereophonic audio signals to reverberation of the listening space (H04S7/301 takes precedence) · CPC title

• H04S3/004

  For headphones · CPC title