Speakerphone self calibration and beam forming
First Claim
1. A system comprising:
- a set of microphones;
memory configured to store program instructions;
a processor configured to read and execute the program instructions from the memory, wherein the program instructions are executable by the processor to;
(a) receive an input signal corresponding to each of the microphones;
(b) transform the input signals into the frequency domain to obtain respective input spectra;
(c) operate on the input spectra with a set of virtual beams to obtain respective beam-formed spectra, wherein each of the virtual beams is associated with a corresponding frequency range and a corresponding subset of the input spectra, wherein each of the virtual beams operates on portions of input spectra of the corresponding subset of input spectra which have been band limited to the corresponding frequency range, wherein the virtual beams include one or more low end beams and one or more high end beams, wherein each of the low end beams is a beam of a corresponding integer order, wherein each of the high end beams is a delay-and-sum beam;
(d) compute a linear combination of the beam-formed spectra to obtain a resultant spectrum; and
(e) inverse transform the resultant spectrum to obtain a resultant signal.
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Abstract
A communication system includes a set of microphones, a speaker, memory and a processor. The processor is configured to operate on input signals from the microphones to obtain a resultant signal representing the output of a virtual microphone which is highly directed in a target direction. The processor also is configured for self calibration. The processor may provide an output signal for transmission from the speaker. The output signal may be a noise signal, or, a portion of a live conversation. The processor captures one or more input signals in response to the output signal transmission uses the output signal and input signals to estimate parameters of the speaker and/or microphone.
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Citations
28 Claims
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1. A system comprising:
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a set of microphones;
memory configured to store program instructions;
a processor configured to read and execute the program instructions from the memory, wherein the program instructions are executable by the processor to;
(a) receive an input signal corresponding to each of the microphones;
(b) transform the input signals into the frequency domain to obtain respective input spectra;
(c) operate on the input spectra with a set of virtual beams to obtain respective beam-formed spectra, wherein each of the virtual beams is associated with a corresponding frequency range and a corresponding subset of the input spectra, wherein each of the virtual beams operates on portions of input spectra of the corresponding subset of input spectra which have been band limited to the corresponding frequency range, wherein the virtual beams include one or more low end beams and one or more high end beams, wherein each of the low end beams is a beam of a corresponding integer order, wherein each of the high end beams is a delay-and-sum beam;
(d) compute a linear combination of the beam-formed spectra to obtain a resultant spectrum; and
(e) inverse transform the resultant spectrum to obtain a resultant signal. - View Dependent Claims (2, 3, 5, 6)
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4. A system comprising:
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a set of microphones;
memory configured to store program instructions;
a processor configured to read and execute the program instructions from the memory, wherein the program instructions are executable by the processor to;
(a) receive an input signal from each of the microphones;
(b) operate on the input signals with a set of virtual beams to obtain respective beam-formed signals, wherein each of the virtual beams is associated with a corresponding frequency range and a corresponding subset of the input signals, wherein each of the virtual beams operates on versions of the input signals of the corresponding subset of input signals which have been band limited to the corresponding frequency range, wherein the virtual beams include one or more low end beams and one or more high end beams, wherein each of the low end beams is a beam of a corresponding integer order, wherein each of the high end beams is a delay-and-sum beam;
(c) compute a linear combination of the beam-formed signals to obtain a resultant signal.
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7. A system comprising:
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a microphone;
a speaker;
memory configured to store program instructions;
a processor configured to read and execute the program instructions from the memory, wherein the program instructions are executable by the processor to;
(a) output a stimulus signal for transmission from the speaker;
(b) receive an input signal from the microphone;
(c) compute a midrange sensitivity and a lowpass sensitivity for a spectrum of the input signal;
(d) subtract the midrange sensitivity from the lowpass sensitivity to obtain a speaker-related sensitivity;
(e) perform an iterative search for current values of parameters of an input-output model for the speaker using the input signal spectrum, a spectrum of the stimulus signal, the speaker-related sensitivity;
(f) update averages of the parameters of the speaker input-output model using the current values obtained in (e);
wherein the parameter averages of the speaker input-output model are usable to perform echo cancellation on other input signals. - View Dependent Claims (8, 9, 10)
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11. A system comprising:
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a microphone;
a speaker;
memory configured to store program instructions;
a processor configured to read and execute the program instructions from the memory, wherein the program instructions are executable by the processor to;
(a) provide an output signal for transmission from the speaker, wherein the output signal carries live signal information from a remote source;
(b) receive an input signal from the microphone;
(c) compute a midrange sensitivity and a lowpass sensitivity for a spectrum of the input signal;
(d) subtract the midrange sensitivity from the lowpass sensitivity to obtain a speaker-related sensitivity;
(e) perform an iterative search for current values of parameters of an input-output model for the speaker using the input signal spectrum, a spectrum of the output signal, the speaker-related sensitivity;
(f) update averages of the parameters of the speaker input-output model using the current values obtained in (e);
wherein the parameter averages of the speaker input-output model are usable to perform echo cancellation on other input signals. - View Dependent Claims (12, 13, 14)
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15. A method comprising:
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(a) receiving an input signal from each microphone in set of microphones;
(b) transforming the input signals into the frequency domain to obtain respective input spectra;
(c) operating on the input spectra with a set of virtual beams to obtain respective beam-formed spectra, wherein each of the virtual beams is associated with a corresponding frequency range and a corresponding subset of the input spectra, wherein each of the virtual beams operates on portions of input spectra of the corresponding subset of input spectra which have been band limited to the corresponding frequency range, wherein the virtual beams include one or more low end beams and one or more high end beams, wherein each of the low end beams is a beam of a corresponding integer order, wherein each of the high end beams is a delay-and-sum beam;
(d) computing a linear combination of the beam-formed spectra to obtain a resultant spectrum; and
(e) inverse transforming the resultant spectrum to obtain a resultant signal. - View Dependent Claims (16, 17)
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18. A method comprising:
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(a) receiving an input signal from each microphone in a set of microphones;
(b) operating on the input signals with a set of virtual beams to obtain respective beam-formed signals, wherein each of the virtual beams is associated with a corresponding frequency range and a corresponding subset of the input signals, wherein each of the virtual beams operates on versions of the input signals of the corresponding subset of input signals which have been band limited to the corresponding frequency range, wherein the virtual beams include one or more low end beams and one or more high end beams, wherein each of the low end beams is a beam of a corresponding integer order, wherein each of the high end beams is a delay-and-sum beam; and
(c) computing a linear combination of the beam-formed signals to obtain a resultant signal. - View Dependent Claims (19, 20)
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21. A method comprising:
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(a) outputting a stimulus signal for transmission from a speaker;
(b) receiving an input signal from a microphone;
(c) computing a midrange sensitivity and a lowpass sensitivity for a spectrum of the input signal;
(d) subtracting the midrange sensitivity from the lowpass sensitivity to obtain a speaker-related sensitivity;
(e) performing an iterative search for current values of parameters of an input-output model for the speaker using the input signal spectrum, a spectrum of the stimulus signal, the speaker-related sensitivity;
(f) updating averages of the parameters of the speaker input-output model using the current values obtained in (e);
wherein the parameter averages of the speaker input-output model are usable to perform echo cancellation on other input signals. - View Dependent Claims (22, 23, 24)
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25. A method comprising:
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(a) providing an output signal for transmission from a speaker, wherein the output signal carries live signal information from a remote source;
(b) receiving an input signal from a microphone;
(c) computing a midrange sensitivity and a lowpass sensitivity for a spectrum of the input signal;
(d) subtracting the midrange sensitivity from the lowpass sensitivity to obtain a speaker-related sensitivity;
(e) performing an iterative search for current values of parameters of an input-output model for the speaker using the input signal spectrum, a spectrum of the output signal, the speaker-related sensitivity;
(f) updating averages of the parameters of the speaker input-output model using the current values obtained in (e);
wherein the parameter averages of the speaker input-output model are usable to perform echo cancellation on other input signals. - View Dependent Claims (26, 27, 28)
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Specification