Method for encoding multiple microphone signals into a source-separable audio signal for network transmission and an apparatus for directed source separation

• US 8,670,554 B2
• Filed: 04/20/2012
• Issued: 03/11/2014
• Est. Priority Date: 04/20/2011
• Status: Active Grant

• Current Assignee: Plantronics, Inc.
• Original Assignee: Aurenta, Inc.
• Inventors: Mukund, Shridhar K.
• Primary Examiner(s): ADDY, THJUAN KNOWLIN
• Application Number:
  US13/452,550
• Publication Number:
  US 20120269332A1
• Time in Patent Office: 690 Days
• Field of Search: 379/201.06, 379/406.01, 379/406.03, 379/406.06, 379/406.02, 381/92, 381/61, 381/94.1, 704/226, 704/231, 704/246, 704/200
• US Class Current: 379/406.01
• CPC Class Codes: G10L 2021/02161 Number of inputs available containing the signal or the noise to be suppressed
• CPC Class Codes: G10L 25/84 for discriminating voice from noise
• CPC Class Codes: H04R 2201/40 Details of arrangements for obtaining desired directional characteristic by combining a number of identical transducers covered by H04R1/40 but not provided for in any of its subgroups
• CPC Class Codes: H04S 2400/03 Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 H04S2400/01 takes precedence
• CPC Class Codes: H04S 3/006 in which a plurality of audio signals are transformed in a combination of audio signals and modulated signals, e.g. CD-4 systems

Abstract

A method is provided for encoding multiple microphone signals into a composite source-separable audio (SSA) signal, conducive for transmission over a voice network. The embodiments enable the processing of source separation of the target voice signal from its ambient sound to be performed at any point in the voice communication network, including the internet cloud. A multiplicity of processing is possible over the SSA signal, based on the intended voice application. The level of processing is adapted with the availability of the processing power at the chosen processing node in the network in one embodiment. An apparatus for separating out the target source voice from its ambient sound is also provided. The apparatus includes a directed source separation (DSS) unit, which processes the two virtual microphone signals in the SSA representation, to generate a new SSA signal including the enhanced target voice and the enhanced ambient noise.

Claims

1. A method for network transmission of voice, comprising:

combining two digital audio signals into a composite source separable audio (SSA) signal, each digital audio signal of the two digital audio signals representing an independent mixture of a target source voice and an ambient noise, wherein outputs of the plurality of microphones within the first group are summed together as a first output and the outputs of the plurality of microphones within the second group are summed together as a second output, thereby defining a first virtual microphone and a second virtual microphone, respectively, and wherein the combining process comprises interleaving the two audio signals to generate the composite SSA signal.

2. A method of claim 1, further comprising:

separating the two audio signals within the composite SSA signal into two mono audio signals by performing directed source separation (DSS).

3. A method of claim 1, wherein the two audio signals are analog signals and the combining process comprises delaying the second audio signal and summing the delayed second audio signal with the first audio signal to generate the composite SSA signal.

4. A method of claim 1, wherein the composite SSA signal is intelligible for human listening without requiring any further processing.

5. A method of claim 2, comprising:

performing a first ambient sound separation process for human listening intelligibility; and

performing a second ambient sound separation process for a machine voice application.

6. A method of claim 1, wherein a quality of ambient sound separation is traded off gracefully, depending on the availability of processing power.

7. A method of claim 1, wherein the separating is performed in an intermediate server in a network cloud.