System and method for generating a separated signal by reordering frequency components

• US 8,898,056 B2
• Filed: 02/27/2007
• Issued: 11/25/2014
• Est. Priority Date: 03/01/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chan, Kwok-Leung, Visser, Erik
• Primary Examiner(s): He, Jialong
• Application Number:
  US12/281,245
• Publication Number:
  US 20090254338A1
• Time in Patent Office: 2,828 Days
• Field of Search: 704/205, 704/233
• US Class Current: 704/205
• CPC Class Codes: G10L 21/0272 Voice signal separating
• CPC Class Codes: H04L 25/03159 operating in the frequency domain H04L25/03165, H04L25/03178 take precedence

Abstract

The present invention relates to blind source separation. More specifically certain embodiments relate to the blind source separation using frequency domain processes. Aspects of the invention relate to methods and systems for receiving a set of frequency-domain first signals, and then separating the set of frequency-domain first signals into a set of frequency-domain second signals. The frequency-domain second signals may have a set of separated frequency-domain second signal elements corresponding to individual frequencies wherein each frequency-domain second signal element is assigned an identifier. The identifier may indicate which of the set of frequency-domain second signals includes the frequency-domain second signal element. Some aspects also include reordering the identifiers corresponding to at least one frequency to improve coherence of the frequency-domain second signals and to produce a set of frequency-domain third signals.

Claims

1. A signal separation method, implemented within an electronic system, comprising:

receiving, in an electronic system, a set of frequency-domain first signals, wherein each of the frequency-domain first signals comprises frequency-domain first signal elements corresponding to a plurality of frequencies, and wherein the set of frequency-domain first signals are derived from one or more of a plurality of signal sources;

separating, in an electronic system, the set of frequency-domain first signals into a set of frequency-domain second signals, wherein the set of frequency-domain second signals comprises a set of separated frequency-domain second signal elements corresponding to individual frequencies of the plurality of frequencies, and wherein each frequency-domain second signal element is assigned an identifier which indicates which of the set of frequency-domain second signals includes the frequency-domain second signal element, and

reordering, in an electronic system, the identifiers corresponding to at least one frequency to improve a coherence of the frequency-domain second signals by comparing each second signal element in the set of frequency domain second signals to another signal element to produce a set of frequency-domain third signals, wherein the improving the coherence of the frequency-domain second signals comprises;

optimizing the coherence of frequency-domain second signal elements corresponding to a first subset of frequencies; and

optimizing the coherence of frequency-domain second signal elements corresponding to a second subset of frequencies, wherein the second subset of frequencies includes more frequencies than the first subset of frequencies, and wherein the second subset of frequencies comprises the first subset of frequencies.

2. The method of claim 1, wherein the separating the set of frequency-domain first signals comprises a blind-source separation method.

3. The method of claim 2, wherein the blind-source separation method is applied to the frequency-domain first signal elements corresponding to individual frequencies.

4. The method of claim 1, wherein the coherence comprises a function that reflects the co-activity of signals at different frequencies.

5. The method of claim 1, wherein the improving the coherence of the frequency-domain second signals comprises optimizing the coherence of the frequency-domain second signals.

6. The method of claim 1, wherein the improving the coherence of the frequency-domain second signals comprises improving the coherence of a pair of adjacent frequency-domain second signal elements.

7. The method of claim 6, wherein the reordering the identifiers comprises reordering the identifiers corresponding to a plurality of frequencies, and wherein the reordering the identifiers further comprises sequentially reordering the identifiers from a low frequency of the plurality of frequencies to a high frequency of the plurality of frequencies.

8. The method of claim 6, wherein reordering the identifiers comprises reordering the identifiers corresponding to a plurality of frequencies, and wherein the reordering the identifiers further comprises improving the coherence between non-overlapping pairs of frequency-domain second signal elements.

9. The method of claim 1, further comprising transforming, in an electronic system, a set of time-domain input signals to produce the set of frequency-domain first signals.

10. The method of claim 9, wherein the time-domain input signals are acoustic signal mixtures.

11. The method of claim 10, wherein at least one of the acoustic signal mixtures comprises a speech signal.

12. The method of claim 1, further comprising inverse transforming a frequency-domain third signal of the set of frequency-domain third signals to produce a desired signal.

19. The method of claim 1, wherein the reordering the identifiers is done in pairs, wherein the second member of the pair is always fixed.

20. The method of claim 1, wherein the reordering the identifiers is done in pairs, wherein one member of the pair is always fixed.

13. A computer-implemented system for separating signals, comprising:

a receiver that is configured to receive a set of time-domain input signals;

a transformer module implemented in the system that is configured to transform the set of time-domain input signals to a set of frequency-domain first signals, wherein each of the frequency-domain first signals comprises frequency-domain first signal elements corresponding to a plurality of frequencies, and wherein the set of frequency-domain first signals comprises a plurality of signal sources;

a frequency-domain signal separator module implemented in the system that is configured to separate the set of frequency-domain first signals into a set of frequency-domain second signals, wherein the set of frequency-domain second signals comprises a set of separated frequency-domain second signal elements corresponding to individual frequencies of the plurality of frequencies, and wherein each frequency-domain second signal element is assigned an identifier which indicates which of the set of frequency-domain second signals includes the frequency-domain second signal element, and

a reordering module implemented in the system that is configured to reorder the identifiers corresponding to at least one frequency to improve a coherence of the frequency-domain second signals by comparing each second signal element in the set of frequency domain second signals to another signal element to produce a set of frequency-domain third signals, wherein the reordering module comprises;

a first module implemented in the system that is configured to determine a first subset of the frequency-domain second signal elements to be reordered by determining the corresponding frequency;

a second module implemented in the system that is configured to improve the coherence of frequency-domain second signal elements corresponding to a pre-determined frequency with frequency-domain second signal elements corresponding to a frequency adjacent to the pre-determined frequency; and

a third module implemented in the system that is configured to determine subsequent frequency-domain second signal elements to be reordered.

14. The system of claim 13, wherein the frequency-domain signal separator module is configured to separate the set of frequency-domain first signals by using an Independent Component Analysis method or Independent Vector Analysis method.

15. The system of claim 13, and

wherein the third module is further configured to determine subsequent frequency-domain second signal elements as those corresponding to a frequency adjacent to a frequency corresponding to previously reordered frequency-domain second signal elements.

16. The system of claim 13, further comprising an inverse transformer module that is configured to inversely transform a frequency-domain third signal of the set of frequency-domain third signals to produce a desired signal.

17. The system of claim 13, wherein the system comprises a headset.

18. The system of claim 13, wherein the system comprises a telephone.