Method and device for signal separation of a mixed signal

• US 6,934,397 B2
• Filed: 09/23/2002
• Issued: 08/23/2005
• Est. Priority Date: 09/23/2002
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Madievski, Anton, Thomson, Mark
• Primary Examiner(s): Pendleton, Brian T.
• Application Number:
  US10/252,274
• Publication Number:
  US 20040057585A1
• Time in Patent Office: 1,065 Days
• Field of Search: 381/92, 381/71.1, 381/94.1, 704/200, 704/226, 348/14.01
• US Class Current: 381/94.1
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

A method (20) and electronic device (1) for signal separation of mixed signals provided by sensors (11,13), the mixed signals resulting from the sensors (11,13) detecting respective mixed waveforms comprising a plurality of source waveforms originating from waveform generating sources mixed in a mixing environment (10). The method (20) and device (1), in use, provide for configuring (22) communication between a processor (3) and a plurality of the sensors (11,13) in the mixing environment (10), the configuring being effected dynamically depending upon variations in the number of sensors (11,13) in the environment. At a receiving step (23) the processor (3) receives respective mixed signals from the sensors (11,13) and a step of determining (24) un-mixing parameters for the environment based on the number of sensors (11,13) is then effected. Thereafter, a step of applying selectively (35) applies the un-mixing parameters to at least one of said mixed signals to thereby separate at least one of the mixed signals and provide at least one output source signal associated with one of the sensors (11,13), the output source signal being indicative of an unmixed one of the source waveforms.

Claims

1. A method for signal separation of mixed signals provided by sensors, the mixed signals resulting from the sensors detecting respective mixed waveforms comprising a plurality of source waveforms originating from waveform generating sources mixed in a mixing environment, the method including the steps of:

configuring communication between a processor and a plurality of the sensors in the mixing environment, the configuring being effected dynamically depending upon variations in the number of sensors in the environment, wherein said processor repeatedly checks for the presence of sensors in the mixing environment to effect the configuring communication between said processor and sensors that are detected in the environment;

receiving, by said processor, respective said mixed signals from the sensors;

determining un-mixing parameters for the environment based on the number of sensors; and

applying selectively said un-mixing parameters to at least one of said mixed signals to thereby separate said at least one of said mixed signals and provide at least one output source signal associated with one of the sensors, the output source signal being indicative of an unmixed one of said source waveforms.

2. A method as claimed in claim 1, wherein the repeatedly checking for the presence of sensors is characterized by at least some of the sensors repeatedly sending a presence signal to the processor.

3. A method as claimed in claim 2, wherein the step of configuring communication is further characterized by the processor repeatedly updating a presence list of sensors in the environment, the presence list being indicative of the sensors in the environment that are in communication with the processor.

4. A method as claimed in claim 1, wherein, the step of determining un-mixing parameters is effected by Blind Signal Separation.

5. A method as claimed in claim 4, wherein y, the Blind Signal Separation is effected by solving an equation [W, D]=eig(X X^T, R), where X is a N×

T mixed signal matrix containing T samples of N sensor readings of mixed signals (N being the number of sensors in the environment that were configured in the step of configuring 22); and

eig is an the generalised eigenvalue procedure that is defined as [V, D]=eig(A, B) for A.V=B.V.D, i.e. V jointly diagonalises A and B, and R is a matrix based on assumptions imposed on the source signals.

6. A method as claimed in claim 1, wherein, the step of applying selectively is characterized by separating the mixed signals to provide a said output source signal for each of said sensors.

7. A method as claimed in claim 1, wherein the step of applying selectively is effected by the output source signals being separated all at once by use of an equation S=W^TX, where S is a matrix of the output source signals.

8. A method as claimed in claim 1, wherein the step of applying selectively is effected by the output source signals being separated individually as a product of particular row of the matrix W^T and column of the matrix X.

9. A method as claimed in claim 1, wherein, after the step of applying selectively there is a further step of transmitting said at least one output source signal.

10. An electronic device for signal separation of mixed signals provided by sensors operatively coupled to the device, the mixed signals resulting from the sensors detecting respective mixed waveforms comprising a plurality of source waveforms originating from waveform generating sources mixed in a mixing environment, the electronic device comprising

a processor having a memory coupled thereto, the memory storing operating code for the processor;

a sampler for receiving the mixed signals from the sensors, the sampler being coupled to the processor, wherein in use the operating code effects the steps of;

configuring communication between the processor and plurality of the sensors in the mixing environment, the configuring being effected dynamically depending upon variations in the number of sensors in the environment by said processor repeatedly checking for the presence of sensors in the mixing environment to effect the configuring communication between said processor and sensors that are detected in the environment;

receiving, by said processor, respective said mixed signals from the sensors;

determining un-mixing parameters for the environment based on the number of sensors; and

applying selectively said un-mixing parameters to at least one of said mixed signals to thereby separate said at least one of said mixed signals and provide at least one output source signal associated with one of the sensors, the output source signal being indicative of an unmixed one of said source waveforms.

11. An electronic device as claimed in claim 10, wherein the device effects the step of determining un-mixing parameters by Blind Signal Separation.

12. An electronic device as claimed in claim 11, wherein the device effects Blind Signal Separation by solving an equation [W, D]=eig(X X^T, R), where X is a N×

T mixed signal matrix containing T samples of N sensor readings of mixed signals (N being the number of sensors in the environment that were configured in the step of configuring 22); and

eig is an the generalised eigenvalue procedure that is defined as [V, D]=eig(A, B) for A.V=B. V. D,i.e. V jointly diagonalises A and B, and R is a matrix based on assumptions imposed on the source signals.

13. An electronic device as claimed in claim 10, wherein the device effects the step of applying selectively by separating the mixed signals to provide a said output source signal for each of said sensors.

14. An electronic device as claimed in claim 10, wherein, the device effects the step of applying selectively by the output source signals being separated all at once by use of an equation S=W^TX, where S is a matrix of the output source signals.

15. An electronic device as claimed in claim 10, wherein the device effects the step of applying selectively by the output source signals being separated individually as a product of particular row of the matrix W^T and column of the matrix X.

16. An electronic device as claimed in claim 10, wherein device has a transmitter for transmitting said at least one output source signal.

17. A method as claimed in claim 10, wherein the repeatedly checking for the presence of sensors is characterized by at least some of the sensors repeatedly sending a presence signal to the processor.

18. A method as claimed in claim 10, wherein the step of configuring communication is further characterized by the processor repeatedly updating a presence list of sensors in the environment, the presence list being indicative of the sensors in the environment that are in communication with the processor.