Audio processing in a portable listening device

• US 8,929,566 B2
• Filed: 01/20/2010
• Issued: 01/06/2015
• Est. Priority Date: 01/23/2009
• Status: Active Grant

• Current Assignee: Oticon A/S (William Demant Fonden)
• Original Assignee: Oticon A/S (William Demant Fonden)
• Inventors: Kaulberg, Thomas, Skovby, Lars
• Primary Examiner(s): Paul, Disler
• Application Number:
  US12/690,787
• Publication Number:
  US 20110019838A1
• Time in Patent Office: 1,812 Days
• Field of Search: 381/61, 381 98- 99, 381/312, 381/323, 381320-321, 704/500, 704/258
• US Class Current: 381/98
• CPC Class Codes: G10L 2021/065 Aids for the handicapped in understanding
• CPC Class Codes: G10L 21/038 using band spreading techniques
• CPC Class Codes: H04R 1/10 Earpieces; Attachments therefor ; Earphones; Monophonic headphones H04R1/28 takes precedence; stereophonic headphones H04R5/033
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 2460/03 Aspects of the reduction of energy consumption in hearing devices
• CPC Class Codes: H04R 25/43 Electronic input selection or mixing based on input signal analysis, e.g. mixing or selection between microphone and telecoil or between microphones with different directivity characteristics H04R25/407 takes precedence
• CPC Class Codes: H04R 25/505 using digital signal processing
• CPC Class Codes: H04R 25/554 using a wireless connection, e.g. between microphone and amplifier or using Tcoils
• CPC Class Codes: H04R 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S

Abstract

The invention relates to a method of processing an audio signal in a portable listening device, the audio signal comprising a low frequency part having an LF-bandwidth Δf_LF and a high-frequency part having a HF-bandwidth Δf_HF. The invention further relates to a listening device and to a listening system. The object of the present invention is to improve performance or save power in a portable listening device. The problem is solved in that the method comprises a) providing an audio input signal consisting of said low frequency part having an LF-bandwidth Δf_LF; b) performing at least one signal processing step on the low frequency part of the audio signal; and c) performing a bandwidth extension process on said low frequency part of the audio signal to generate said high-frequency _part of the audio signal, thereby generating or regenerating said audio output signal with a full bandwidth Δf_full comprising said LF-bandwidth Δf_LF and said HF-bandwidth Δf_HF. An advantage of this is that power consumption is reduced. The invention may e.g. be used for portable communication device, mobile telephones or listening devices, such as a hearing aids, ear protection devices, headsets, head phones, etc.

Claims

1. A method of reducing power consumption in a binaural listening system that processes an audio signal in a portable hearing aid of the binaural listening system, the audio signal comprising a low frequency part having an LF-bandwidth Δ

f_LF and a high-frequency part having a HF-bandwidth Δ

f_HF, the method comprising;

providing a first portable hearing aid and a second portable hearing aid;

receiving power in each of the first and second portable hearing aids from a local source of energy in each respective portable hearing aid;

providing an audio input signal consisting of said low frequency part having an LF-bandwidth Δ

f_LF to the second portable hearing aid;

performing signal processing on the low frequency part of the audio signal by the second portable hearing aid;

wirelessly transmitting the low frequency part from the second portable hearing aid to the first portable hearing aid;

receiving the transmitted low frequency part by the first portable hearing aid; and

performing a bandwidth extension process on said low frequency part of the audio signal by the first portable hearing aid to generate said high-frequency part of the audio signal, thereby generating or regenerating an audio output signal with a full bandwidth Δ

f_full comprising said LF-bandwidth Δ

f_LF and said HF-bandwidth Δ

f_HF, wherein

the LF-bandwidth Δ

f_LF constitutes 0.7 times or less of the full bandwidth Δ

f_full of the audio signal, and

the performing of said signal processing includes performing at least a majority of the processing steps of

introducing frequency dependent gain;

compression;

noise reduction;

feedback suppression; and

extraction of directionality information on the low frequency part of the audio signal.

2. A method according to claim 1 wherein the high-frequency part of the signal is generated by spectral band replication.

3. A method according to claim 1 wherein the LF-bandwidth and the HF-bandwidth together constitute the full bandwidth.

4. A method according to claim 1, wherein

the signal processing comprises all of the following signal processing steps:

(a) introducing frequency dependent gain,

(b) compression,

(c) noise reduction,

(d) feedback suppression, and

(e) extraction of directionality information.

5. A method according to claim 1, wherein

the low frequency part of the audio signal or a part thereof is picked up by a microphone of the portable hearing aid and

filtered by a low pass filter and/or digitized with an appropriate sample frequency.

6. A method according to claim 1, wherein

the full bandwidth audio signal is fed to an output transducer for presentation to a wearer of the first portable hearing aid.

11. The method according to claim 1, further comprising:

processing the audio signal based on a hearing profile of a hearing-impaired user of the binaural listening system.

7. A binaural listening system, comprising:

first and second portable hearing aids, each being configured to present an electrical output audio signal to a wearer of the hearing aid, the electrical output audio signal having a full bandwidth Δ

f_full comprising a low frequency part with LF-bandwidth Δ

_LF and a high frequency part with HF-bandwidth Δ

f_HF,

wherein

the second portable hearing aid includes

a local source of energy within the second portable hearing aid powering the second portable hearing aid,

a wireless transmitter for wirelessly transmitting the low frequency part of the electrical output audio signal with the bandwidth Δ

f_LF to the first portable hearing aid,

the first portable hearing aid includes

a wireless receiver for receiving said low frequency part of the electrical output audio signal,

a signal processor configured to process the low frequency part of the electrical output aidio signal and configured to provide a processed low bandwidth signal,

a local source of energy within said first portable hearing aid powering the first portable hearing aid, and

a bandwidth extension unit for constructing or re-generating the high-frequency part of the electrical output audio signal, the high-frequency part having the HF-bandwidth Δ

f_HF, and for forming the electrical output audio signal having the full bandwidth Δ

f_full based on or comprising said low frequency part having the LF-bandwidth Δ

f_LF and said high frequency part having the HF-bandwidth Δ

f_HF,

the LF-bandwidth Δ

f_LF constitutes 0.7 times or less of the full bandwidth Δ

f_full of the audio signal, and

said signal processor is configured to perform at least a majority of

introducing frequency dependent gain;

compression;

noise reduction;

feedback suppression; and

extraction of directionality information on the low frequency part of the audio signal.

8. A binaural listening system according to claim 7, wherein

the second portable hearing aid comprises:

an input transducer for converting an input sound to an electric input signal; and

a frequency limiting unit for generating said low frequency part having the LF-bandwidth Δ

f_LF for being wirelessly transmitted to the first portable hearing aid.

9. A binaural listening system according to claim 7, wherein

the second portable hearing aid comprises:

an electric interface for receiving a signal comprising an audio signal and providing an electric input signal, and

a frequency limiting unit for generating said low frequency part having the LF-bandwidth Δ

f_LF for being wirelessly transmitted to the first portable hearing aid from said electric input signal.

10. A binaural listening system according to claim 7, wherein

said wireless transmitter and receiver are adapted to provide an inductive coupling between the first and second portable hearing aids on which said transmission of said low frequency signal can be based, when said first and second portable hearing aids are located in an operational distance from each other.

12. The binaural listening system according to claim 7, wherein

the signal processor of the second portable hearing aid is further configured to process the audio signal based on a hearing profile of a hearing-impaired user of the binaural listening system.