Method and device for spectral expansion for an audio signal

• US 10,622,005 B2
• Filed: 07/27/2018
• Issued: 04/14/2020
• Est. Priority Date: 01/15/2013
• Status: Active Grant

• Current Assignee: Staton Techiya, LLC
• Original Assignee: Staton Techiya, LLC
• Inventors: Usher, John, Ellis, Dan
• Primary Examiner(s): Abebe, Daniel
• Application Number:
  US16/047,612
• Publication Number:
  US 20180336914A1
• Time in Patent Office: 627 Days
• Field of Search: 704224
• CPC Class Codes: G10L 21/0388 Details of processing therefor
• CPC Class Codes: H04R 1/028 associated with devices performing functions other than acoustics, e.g. electric candles
• CPC Class Codes: H04R 1/1083 Reduction of ambient noise active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones
• CPC Class Codes: H04R 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10

Abstract

A method and device for automatically increasing the spectral bandwidth of an audio signal including generating a “mapping” (or “prediction”) matrix based on the analysis of a reference wideband signal and a reference narrowband signal, the mapping matrix being a transformation matrix to predict high frequency energy from a low frequency energy envelope, generating an energy envelope analysis of an input narrowband audio signal, generating a resynthesized noise signal by processing a random noise signal with the mapping matrix and the envelope analysis, high-pass filtering the resynthesized noise signal, and summing the high-pass filtered resynthesized noise signal with the input narrowband audio signal. Other embodiments are disclosed.

Claims

1. A system, comprising:

a wearable communications device, comprising;

an ambient microphone and an ear canal microphone;

a memory that stores instructions; and

a process that executes the instructions to perform operations, the operations comprising;

generating a mapping matrix, comprising;

simultaneously recording a sentence by the ambient microphone and by the ear canal microphone, wherein the ambient microphone captures a wideband signal and the ear canal microphone captures a narrowband signal;

performing, via the processor, a frequency transform on the wideband signal;

performing, via the processor, another frequency transform on the narrowband signal;

wherein the mapping matrix is based on an analysis of the frequency transform on the wideband signal and the frequency transform on the narrowband signal;

generating an energy envelope analysis of an input narrowband audio signal;

generating a resynthesized noise signal by processing a noise signal with the mapping matrix and the envelope analysis to provide the resynthesized noise signal;

high-pass filtering the resynthesized noise signal to provide a highpass filtered resynthesized noise signal; and

summing the high-pass filtered resynthesized noise signal with the input narrowband audio signal.

2. The system of claim 1, wherein the operations further comprise providing a signal to output the summed signal via a loudspeaker.

3. The system of claim 1, wherein providing a single comprises providing the signal via a voice telecommunications system.

4. The system of claim 1, wherein the ear canal microphone captures a sound exposure level within the ear canal.

5. The system of claim 1, wherein the mapping matrix is a transformation matrix predicting high frequency energy from a low frequency energy envelope.

6. The system of claim 1, wherein the frequency transform on the wideband signal transforms the wideband signal into a plurality of bands.

7. The system of claim 1, wherein the frequency transform on the narrowband signal transforms the narrowband signal into a plurality of bands.

8. The system of claim 1, wherein summing the high-pass filtered resynthesized noise signal with the input narrowband audio signal increases a spectral range of the input narrowband signal.

9. The system of claim 1, further comprising an earpiece that occludes an user'"'"'s ear canal.

10. The system of claim 1, wherein the wideband signal is a reference wideband signal.

11. The system of claim 1, wherein the narrowband signal is a reference narrowband signal.

12. A system, comprising:

a memory that stores instructions; and

a process that executes the instructions to perform operations, the operations comprising;

generating a mapping matrix, comprising;

receiving a wideband speech signal from an ambient microphone;

receiving a narrow band signal from a non-microphone source;

performing, via the processor, a frequency transform on the wideband signal;

performing, via the processor, another frequency transform on the narrowband signal;

wherein the mapping matrix is based on an analysis of the frequency transform on the wideband signal and the frequency transform on the narrowband signal;

generating an energy envelope analysis of an input narrowband audio signal;

generating a resynthesized noise signal by processing a noise signal with the mapping matrix and the envelope analysis to provide the resynthesized noise signal;

high-pass filtering the resynthesized noise signal to provide a highpass filtered resynthesized noise signal; and

summing the high-pass filtered resynthesized noise signal with the input narrowband audio signal.

13. The system of claim 12, wherein the non-microphone source comprises a wireless device.

14. The system of claim 12, wherein the wireless device provides the narrow band signal encoded via a codec.

15. The system of claim 12, wherein the operations further comprise outputting the summed signal with an ear canal receiver.

16. The system of claim 12, wherein the frequency transform on the wideband signal transforms the wideband signal into a plurality of bands.

17. The system of claim 12, wherein the frequency transform on the narrowband signal transforms the narrowband signal into a plurality of bands.

18. The system of claim 12, wherein generating a mapping matrix further comprises calculating an energy envelop with a logarithmic dB domain.

19. A system, comprising:

a memory that stores instructions; and

a process that executes the instructions to perform operations, the operations comprising;

generating a mapping matrix, comprising;

receiving a sentence recorded by an ambient microphone and by an ear canal microphone, wherein the ambient microphone captures a reference wideband signal and the ear canal microphone captures a reference narrowband signal;

performing, via the processor, a frequency transform on the reference wideband signal;

performing, via the processor, another frequency transform on the reference narrowband signal;

wherein the mapping matrix is based on an analysis of the frequency transform on the wideband signal and the frequency transform on the narrowband signal;

generating an energy envelope analysis of an input narrowband audio signal;

generating a resynthesized noise signal by processing a noise signal with the mapping matrix and the envelope analysis to provide the resynthesized noise signal;

high-pass filtering the resynthesized noise signal to provide a highpass filtered resynthesized noise signal; and

summing the high-pass filtered resynthesized noise signal with the input narrowband audio signal.

20. The system of claim 19, wherein the operations further comprise:

providing a signal to output the summed signal via a loudspeaker;

wherein providing a single comprises providing the signal via a voice telecommunications system.