MICROPHONE APPARATUS

Abstract

The present disclosure relates to a microphone apparatus and an associated computer implemented method. The microphone apparatus comprising a main microphone array, an adaptive beamformer, a fixed beamformer, and an analyzer. The analyzer is configured to determine a first relative score based on the output of the fixed beamformer and the adaptive beamformer. The first relative score indicating a difference between the adaptive beamformer and the fixed beamformer.

Claims

1. A microphone apparatus, comprising: a main microphone array, an adaptive beamformer, a fixed beamformer, and an analyzer, wherein the main microphone array comprises a first microphone adapted to provide a first input audio signal representing sound at a first microphone inlet, a second microphone adapted to provide a second input audio signal representing sound at a second microphone inlet, wherein the first microphone inlet is spatially separated from the second microphone inlet, and wherein the main microphone array is configured to: provide a main input vector comprising the first and the second input audio signal as components, wherein the adaptive beamformer is configured to: based on the main input vector, provide a first directional audio signal, wherein the directional sensitivity of the first directional audio signal is chosen to optimize a speech quality, wherein the fixed beamformer is configured to: based on the main input vector, provide a second directional audio signal, wherein the directional sensitivity of the second directional audio signal is predetermined, and wherein the analyzer is configured to: based on the first directional audio signal and the second directional audio signal, determine a first relative score indicating a difference between the first directional audio signal and the second directional audio signal, wherein the first relative score gives information regarding misalignment in directional sensitivity between the adaptive beamformer and the fixed beamformer, and output the first relative score for controlling further processing of the first and the second input audio signal or for determining a dispositioning of the microphone apparatus.

2. A microphone apparatus according to claim 1, wherein the first microphone and the second microphone are omnidirectional microphones.

3. A microphone apparatus according to claim 1, wherein the directional sensitivity of the second directional audio signal is predetermined based on an intended position of the first microphone and/or the second microphone.

4. A microphone apparatus according to claim 1, further comprising, a speech detector configured to: based on the main input vector, provide a speech probability signal indicating a probability of speech in the first and/or second input audio signal, and, wherein the adaptive beamformer is further configured to: based on the speech probability signal and the main input vector, provide the first directional audio signal,

5. A microphone apparatus according to claim 1, further comprising a signal path selector, and wherein the analyzer is further configured to: compare the first relative score to a first threshold, and provide a first pass signal if the first relative score exceeds a first threshold, and wherein the signal path selector is configured to, in response to the first pass signal being provided: pass on the first directional audio signal for further processing to provide an audio signal to be transmitted, and stop the second directional audio signal from being further processed.

6. A microphone apparatus according to claim 1, further comprising a signal path selector, and wherein the analyzer is further configured to: compare the first relative score to a first threshold, and provide a second pass signal if the first relative score does not exceed a first threshold, and wherein the signal path selector is configured to, in response to the second pass signal being provided: pass on the second directional audio signal for further processing to provide an audio signal to be transmitted, and stop the first directional audio signal from being further processed.

7. A microphone apparatus according to claim 6, where wherein the adaptive beamformer is further configured to: go from an active mode to a passive mode in response to the analyzer providing the second pass signal.

8. A microphone apparatus according to claim 5, wherein the analyzer is further configured to: determine an initial speech quality parameter, wherein the initial speech quality parameter is associated with the first audio input, the second audio input, or a combination of the first audio input and the second audio input, determine a first speech quality parameter, wherein the first speech quality parameter is associated with the first directional audio signal, determine a second speech quality parameter, wherein the second speech quality parameter is associated with the second directional audio signal, determine a first difference between the first speech quality parameter and the initial speech quality parameter, determine a second difference between the second speech quality parameter and the initial speech quality parameter, based on the first difference and the second difference, determine the first relative score

9. A microphone apparatus according to claim 1, wherein the microphone apparatus is a headset comprising: a movable boom arm, wherein the first microphone inlet and/or the second microphone inlet are arranged on the boom arm.

10. A microphone apparatus according to claim 1, wherein analyzer is further configured to: compare the first relative score to a first threshold, and provide a misposition signal if the first relative score exceeds the first threshold, output the misposition signal as a user notification for notifying the user regarding a misposition of the first microphone inlet and/or the second microphone inlet.

11. A microphone apparatus according to claim 9, wherein the microphone apparatus further comprises a misposition indicator, wherein the misposition indicator is configured to: receive the misposition signal, and provide a user stimulus for indicating the misposition of the first microphone inlet and/or the second microphone inlet in response to receiving the misposition signal.

12. A computer implemented method comprising the steps of: receiving a main input vector comprising as components a first input audio signal representing sound at a first microphone inlet and a second input audio signal representing sound at a second microphone inlet, wherein the first microphone inlet is spatially separated from the second microphone inlet, based on the main input vector, providing a first directional audio signal, wherein the directional sensitivity of the first directional audio signal is chosen to optimize a speech quality, based on the main input vector, providing a second directional audio signal, wherein the directional sensitivity of the second directional audio signal is predetermined, based on the first directional audio signal and the second directional audio signal, determining a first relative score indicating a difference between the first directional audio signal and the second directional audio signal, wherein the first relative score gives information regarding misalignment in directional sensitivity between the adaptive beamformer and the fixed beamformer, and outputting the first relative score for controlling further processing of the first and the second input audio signal or for determining a mispositioning of the microphone apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0134] The disclosure will be explained in more detail below together with preferred embodiments and with reference to the drawings in which:

[0135] FIG. 1 shows a schematic block diagram of an embodiment of a microphone apparatus according to the present disclosure.

[0136] FIG. 2 shows a schematic block diagram of another embodiment of a microphone apparatus according to the present disclosure.

[0137] FIG. 3 shows an example of a speech mask outputted by a speech detector according to the present disclosure.

[0138] FIG. 4 shows a schematic block diagram of yet another embodiment of a microphone apparatus according to the present disclosure.

[0139] FIG. 5 shows a schematic block diagram of an embodiment of a microphone apparatus according to the present disclosure.

[0140] FIG. 6 shows a schematic block diagram of an embodiment of a microphone apparatus according to the present disclosure.

[0141] The figures are schematic and simplified for clarity, and they just show details essential to understanding the disclosure, while other details may be left out. Where practical, like reference numerals and/or labels are used for identical or corresponding parts.

DETAILED DESCRIPTION OF THE DRAWINGS

[0142] The detailed description given herein and the specific examples indicating preferred embodiments of the disclosure are intended to enable a person skilled in the art to practice the disclosure and should thus be regarded mainly as an illustration of the disclosure. The person skilled in the art will be able to readily contemplate applications of the present disclosure as well as advantageous changes and modifications from this description without deviating from the scope of the disclosure. Any such changes or modifications mentioned herein are meant to be non-limiting for the scope of the disclosure. An aspect or an advantage described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced in any other embodiments even if not so illustrated, or if not so explicitly described.

[0143] Referring initially to FIG. 1 depicting a schematic block diagram of an embodiment of a microphone apparatus 1 according to the present disclosure. The microphone apparatus 1 comprises a main microphone array 10, an adaptive beamformer 20, a fixed beamformer 30, and an analyzer 40. The microphone apparatus 1 may be a headset with or without a boom arm, a pair of earbuds, a speaker phone or other audio devices. The main microphone array 10 comprises a first microphone 11 adapted to provide a first input audio signal representing sound at a first microphone inlet, a second microphone 12 adapted to provide a second input audio signal representing sound at a second microphone inlet. The first microphone inlet is spatially separated from the second microphone inlet. The main microphone array 10 is configured to capture sounds created by a sound source external to the microphone apparatus, e.g., the main microphone array 10 may capture a user signal 3 created by a user 2 of the microphone apparatus 1, the first input audio signal and the second input audio signal may then be the user signal 2 as captured by the first microphone 11 and the second microphone 12. The main microphone array 10 is configured to provide a main input vector comprising the first and the second input audio signal as components. The main input vector is provided as a digital signal. The first microphone 11 and the second microphone 12 are omnidirectional microphones.

[0144] The main input vector is received by the adaptive beamformer 20 from the main microphone array 10. The adaptive beamformer 20 is configured to, based on the main input vector, provide a first directional audio signal. The directional sensitivity of the first directional audio signal is chosen to optimize a speech quality.

[0145] The main input vector is received by the fixed beamformer 30 from the main microphone array 10. The fixed beamformer 30 is configured to, based on the main input vector, provide a second directional audio signal. The directional sensitivity of the second directional audio signal is predetermined. The directional sensitivity of the second directional audio signal is predetermined based on an intended position of the first microphone 11 and/or the second microphone 12.

[0146] The analyzer 40 receives the first directional audio signal from the adaptive beamformer 20, and receives the second directional audio from the fixed beamformer 30. The analyzer is configured to, based on the first directional audio signal and the second directional audio signal, determine a first relative score indicating a difference between the first directional audio signal and the second directional audio signal. The analyzer 40 then outputs the first relative score. The first relative score may be outputted for further processing the microphone apparatus and/or be outputted to devices external to the microphone apparatus. The analyzer 40 may determine the first relative score by determining a first audio parameter associated with the first directional audio signal and a second audio parameter associated with the second directional audio signal and compare the first audio parameter to the second audio parameter to determine the first relative score. The comparison between the first audio parameter and the second audio parameter may be to determine a difference between the first audio parameter and the second audio parameter.

[0147] The main microphone array 10, the adaptive beamformer 20, the fixed beamformer 30, and the analyzer 40 may all form part of a digital signal processor of the microphone apparatus 1. The main microphone array 10 may comprise an analog to digital converter configured to convert the audio signals picked up by the first microphone 11 and the second microphone 12 into digital signals.

[0148] Referring now to FIGS. 2 and 3, where FIG. 2 depicts a schematic block diagram of an embodiment of a microphone apparatus 1 according to the present disclosure, and FIG. 3 depicts an example of a speech mask 51 outputted by a speech detector 50 according to the present disclosure. The microphone apparatus of FIG. 2 differs from that of FIG. 1 in that it further comprises a speech detector 50. The speech detector 50 is configured to receive the main input vector from the main microphone array 10. The speech detector 50 is configured to, based on the main input vector, provide a speech probability signal indicating a probability of speech in the first and/or second input audio signal. Preferably, either the first microphone or the second microphone are picked as a reference microphone and the speech probability signal is provided based on the chosen reference microphone. The speech probability signal may be provided as a speech mask 51 as shown in FIG. 3.

[0149] The adaptive beamformer 20 receives the speech probability signal from the speech detector 50. The adaptive beamformer 20 is configured to, based on the speech probability signal and the main input vector, provide the first directional audio signal. The adaptive beamformer may determine a covariance matrix based on the speech probability signal and the main input vector and determine one or more beamforming weights based on the covariance matrix.

[0150] Referring now to FIG. 4 depicting a schematic block diagram of an embodiment of a microphone apparatus 1 according to the present disclosure. The embodiment of FIG. 4 differs from the depicted in FIG. 2 in that the main input vector is transmitted from the main microphone array 10 to the analyzer 40, and the speech probability signal is transmitted from the speech detector 50 to the analyzer 40.

[0151] The analyzer 40 in the present embodiment is further configured to determine an initial speech quality parameter. The initial speech quality parameter may be associated with the first audio input, the second audio input, or a combination of the first audio input and the second audio input. However, in the present embodiment the first microphone 11 is defined as a reference microphone and the initial speech quality parameter is determined based on the first input audio signal provided by the first microphone 11. The initial speech quality parameter is determined as a signal to noise ratio in the first input audio signal. Where the signal is determined as the power of the first audio input in a speech active region, and the noise is determined as the power of the first audio input in a speech inactive region. The analyzer 40 is configured to determine the speech active region and the speech inactive region based on the speech probability signal, e.g., the speech probability signal may be a speech mask 51 as depicted on FIG. 3, where the speech active region and the speech inactive regions may be directly determined based on the speech mask 51. The analyzer 40 is further configured to determine the first speech quality parameter by receiving the first directional audio signal. The analyzer 40 then determines a signal to noise ratio, where the signal is determined as the power of the first directional audio signal in the speech active regions, and the noise is determined as the power of the first directional audio signal in the speech inactive region. The analyzer 40 is further configured to determine the second speech quality parameter by receiving the second directional audio signal. The analyzer 40 then determines a signal to noise ratio, where the signal is determined as the power of the second directional audio signal in the speech active regions, and the noise is determined as the power of the second directional audio signal in the speech inactive region.

[0152] The analyzer 40 then determines a first difference between the first speech quality parameter and the initial speech quality parameter. The first difference may be viewed as giving a measure for the improvement or degradation in speech quality after the fixed beamformer has processed the main input vector. The analyzer 40 further determines a second difference between the second speech quality parameter and the initial speech quality parameter. The second difference may be viewed as giving a measure for the improvement or degradation in speech quality after the adaptive beamformer has processed the main input vector.

[0153] Based on the first difference and the second difference, the analyzer 40 is further configured to determine the first relative score. The first relative score is determined by determining the difference between the first difference and the second difference, the first difference may then be expressed as a dB difference between the first difference and the second difference.

[0154] Referring now to FIG. 5 which depicts a schematic block diagram of an embodiment of a microphone apparatus 1 according to the present disclosure. The microphone apparatus of FIG. 5 differs from that of FIG. 1 in that it further comprises a signal path selector 60. The signal path selector 60 is configured to pass on a signal 61 for further processing. The signal path selector 60 is configured to receive the first directional audio signal from the adaptive beamformer 20. The signal path selector 60 is configured to receive the second directional audio signal from the fixed beamformer 30. The signal path selector 60 is configured to receive a first pass signal or a second pass signal from the analyzer 40. The analyzer 40 is configured to compare the first relative score to a first threshold. The first threshold being set as a fixed value of 1 dB. The analyzer 40 is configured to provide the first pass signal if the first relative score exceeds the first threshold. The analyzer 40 is configured to provide the second pass signal if the first relative score does not exceed the first threshold. In response to receiving the first pass signal, the signal path selector 60 is configured to pass on the first directional audio signal for further processing, and stop the second directional audio signal from being further processed. In response to receiving the second pass signal, the signal path selector 60 is configured to pass on the second directional audio signal for further processing, and stop the first directional audio signal from being further processed. The adaptive beamformer is further configured to receive the second pass signal, and in response to receiving the second pass signal go from an active mode to a passive mode.

[0155] Lastly, referring to FIG. 6 which depicts a schematic block diagram of an embodiment of a microphone apparatus 1 according to the present disclosure. The microphone apparatus 1 depicted in FIG. 6 is a combination of the microphone apparatus 1 depicted in FIGS. 4 and 5, hence, the microphone apparatus of FIG. 6 comprises both a speech detector 50 and a signal path selector 60. The microphone apparatus 1 further comprises a misposition indicator 70. The analyzer 40 is further configured to compare the first relative score to the first threshold. The analyzer 40 is further configured to provide a misposition signal if the first relative score exceeds the first threshold. The analyzer 40 is further configured to provide a misposition signal if the first relative score exceeds the first threshold. The analyzer 40 is further configured to output the misposition signal as a user notification for notifying the user 2 regarding a misposition of the first microphone inlet and/or the second microphone inlet. The misposition indicator 70 is configured to receive the misposition signal and provide a user stimulus for indicating the misposition of the first microphone inlet and/or the second microphone inlet in response to receiving the misposition signal.

[0156] The disclosure is not limited to the embodiments disclosed herein, and the disclosure may be embodied in other ways within the subject-matter defined in the following claims. As an example, features of the described embodiments may be combined arbitrarily, e.g., in order to adapt devices according to the disclosure to specific requirements.

[0157] Any reference numerals and labels in the claims are intended to be non-limiting for the scope of the claims.