Method and apparatus for determining a position of a microphone

• US 9,743,211 B2
• Filed: 03/18/2014
• Issued: 08/22/2017
• Est. Priority Date: 03/19/2013
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Harma, Aki Sakari
• Primary Examiner(s): Nguyen, Duc
• Assistant Examiner(s): Mohammed, Assad
• Application Number:
  US14/775,058
• Publication Number:
  US 20160029141A1
• Time in Patent Office: 1,253 Days
• CPC Class Codes: G01S 5/28 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: H04S 2400/01 Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
• CPC Class Codes: H04S 2400/11 Positioning of individual sound objects, e.g. moving airplane, within a sound field H04S2420/13 takes precedence
• CPC Class Codes: H04S 7/301 Automatic calibration of stereophonic sound system, e.g. with test microphone

Abstract

An apparatus comprises a receiver (203) receiving a multichannel signal comprising two channels for rendering by a first speaker (101) at a first position and a second speaker (103) at a second position respectively. A first signal generator (207) generates a correlated signal and a second signal generator (209) generates an uncorrelated signal from the multichannel signal, the signals comprising respectively correlated and uncorrelated signal components for the channels. A receiver (201) receives a microphone signal from the microphone (107). A first correlator (213) determines a first correlation signal from a correlation of the microphone signal and the correlated signal, and a second correlator (215) determines a second correlation signal from a correlation of the microphone signal and the uncorrelated signal. A position estimator (219) estimates a position of the microphone from the first and second correlation signals. For example, timings of peaks in the correlations signals may be used to determine propagation delays and thus distances from the speakers (101, 103).

Claims

1. An apparatus for determining a position of a microphone, the apparatus comprising:

a multi-channel signal receiver for receiving a multichannel signal comprising at least a first channel for rendering by a first speaker at a first position and a second channel for rendering by a second speaker at a second position;

a first signal generator for generating a first correlated signal from the multichannel signal, the first correlated signal comprising correlated signal components for the first channel and the second channel;

a second signal generator for generating a first uncorrelated signal from the multichannel signal, the first uncorrelated signal comprising signal components of the first channel not correlated with signal components of the second channel;

a microphone signal receiver for receiving a microphone signal from the microphone a first correlator for determining a first correlation signal from a correlation of the microphone signal and the first correlated signal;

a second correlator for determining a second correlation signal from a correlation of the microphone signal and the first uncorrelated signal; and

a position estimator for estimating the position of the microphone in response to the first correlation signal and the second correlation signal.

2. The apparatus of claim 1 further comprising:

a third signal generator to generate a second uncorrelated signal from the multichannel signal, the second uncorrelated signal comprising signal components of the second channel not correlated with signal components of the first channel;

a third correlator for determining a third correlation signal from a correlation of the microphone signal and the second uncorrelated signal; and

wherein the position estimator is configured to estimate the position of the microphone further in response to the third correlation signal.

3. The apparatus of claim 1 wherein the position estimator comprises:

a first estimator for generating a first arrival time estimate and a second arrival time estimate for sound from the first speaker and the second speaker to the microphone in response to the first correlation signal;

a second estimator configured to generate a third arrival time estimate for sound from the first speaker to the microphone in response to the first uncorrelated signal; and

wherein the position estimator is configured to estimate the position of the microphone in response to the first arrival time estimate, the second arrival time estimate and the third arrival time estimate.

4. The apparatus of claim 3 wherein the position estimator is configured to assign the first arrival time estimate to one of the first speaker and the second speaker in response to the third arrival time estimate.

5. The apparatus of claim 2 wherein the position estimator is configured to determine a combined arrival time estimate for sound of the first speaker from the third arrival time estimate and one of the first arrival time estimate and the second arrival time estimate, and to determine the position of the microphone to have a distance from the first speaker corresponding to the combined arrival time.

6. The apparatus of claim 5 wherein a relative weighting of the third arrival time and the one of the first arrival time estimate and the second arrival time estimate in generating the combined arrival time estimate depends on at least one of a correlation level estimate and a correlation noise estimate for at least one of the first correlation and the second correlation.

7. The apparatus of claim 3 wherein the first estimator is configured to detect a first peak and a second peak in the first correlation signal and to determine the first time of arrival estimate in response to a timing of the first peak and to determine the second time of arrival estimate in response to a timing of the second peak.

8. The apparatus of claim 3 wherein the first estimator is configured to perform a peak detection to detect a peak in the first correlation signal and to determine the first time of arrival estimate in response to a timing of the peak, wherein the peak detection is dependent on the second correlation signal.

9. The apparatus of claim 1 wherein the position estimator is configured to weigh the first correlation signal relative to the second correlation signal in response to at least one of:

a power measure of the first correlation signal relative to a power measure of the second correlation signal; and

a power measure for the first correlated signal relative to a measure level of the first uncorrelated signal.

10. The apparatus of claim 1 wherein the position estimator is configured to determine a probability of the position being in a region in response to at least one of a property of the first correlation signal in a first time interval and a property of the second correlation signal in a second time interval, the first and second time intervals corresponding to a sound propagation delay for sound from the first speaker to the region.

11. The apparatus of claim 10 wherein the property is a signal level measure.

12. The apparatus of claim 1 further comprising:

a divider which is configured to divide a first channel signal of the first channel into a plurality of time-frequency intervals;

a correlation estimator configured to generate a correlation measure for the first channel signal of the first channel and a second channel signal of the second channel for each time-frequency interval of the plurality of time-frequency intervals; and

wherein the first signal generator is configured to generate the first correlated signal by for each time frequency interval weighting a signal value of the first channel signal for the time frequency interval by a weight being a monotonically increasing function of the correlation measure for the time-frequency interval.

13. The apparatus of claim 12 wherein the second signal generator is configured to generate the first uncorrelated signal by for each time frequency interval weighting a signal value of the first channel signal for the time frequency interval by a weight being a monotonically decreasing function of the correlation measure for the time-frequency interval.

14. A method of determining a position of a microphone, the method comprising:

in an apparatus for determining a position of a microphone;

receiving via a multi-channel signal receiver, a multichannel signal comprising at least a first channel for rendering by a first speaker at a first position and a second channel for rendering by a second speaker at a second position;

generating via a first signal generator, a first correlated signal from the multichannel signal, the first correlated signal comprising correlated signal components for the first channel and the second channel;

generating via a second signal generator, a first uncorrelated signal from the multichannel signal, the first uncorrelated signal comprising signal components of the first channel not correlated with signal components of the second channel;

receiving a microphone signal from the microphone;

determining in a first correlator, a first correlation signal from a correlation of the microphone signal and the first correlated signal;

determining in a second correlator, a second correlation signal from a correlation of the microphone signal and the first uncorrelated signal; and

estimating in a position estimator, the position of the microphone in response to the first correlation signal and the second correlation signal.

15. A computer readable-readable storage media that is not a transitory propagating wave or signal, comprising computer program code adapted to perform a method of operating an apparatus for determining a position of a microphone, the method comprising the acts of:

in an apparatus for determining a position of a microphone;

receiving via a multi-channel signal receiver, a multichannel signal comprising at least a first channel for rendering by a first speaker at a first position and a second channel for rendering by a second speaker at a second position;

generating via a first signal generator, a first correlated signal from the multichannel signal, the first correlated signal comprising correlated signal components for the first channel and the second channel;

generating via a second signal generator, a first uncorrelated signal from the multichannel signal, the first uncorrelated signal comprising signal components of the first channel not correlated with signal components of the second channel;

receiving a microphone signal from the microphone;

determining in a first correlator, a first correlation signal from a correlation of the microphone signal and the first correlated signal;

determining in a second correlator, a second correlation signal from a correlation of the microphone signal and the first uncorrelated signal; and

estimating in a position estimator, the position of the microphone in response to the first correlation signal and the second correlation signal.