Patent Description:
Conventionally, for example, Patent Document <NUM> below discloses an information processing apparatus including two microphones for collecting outside sound and converting the sound into sound signals, and a sound signal processing unit that applies processing including beamforming processing to the sound signals input from the microphones.

In a case where an earphone includes a microphone and transmits sound acquired by the microphone to the outside, the sound quality can be further improved as the number of microphones increases. However, when the number of microphones is increased, forming an effective microphone array while maintaining a small size of the earphone is difficult. It is difficult to mount a plurality of microphones on one of a pair of ear heads particularly in the ear heads highly demanded for a decrease in size. Patent Document <NUM> describes application of beamforming processing to the sound signals input from the two microphones, but wirelessly collecting the sound signals and applying the beamforming processing has not been assumed.

Therefore, further improvement of the quality of sound obtained by an earphone has been desired.

Prior art includes: <CIT>, <CIT>, <CIT> and <CIT>, each of which describe a prior art device.

As described above, according to the present disclosure, the quality of sound acquired by an earphone can be further improved.

Note that the above-described effect is not necessarily limited, and any of effects described in the present specification or another effect that can be grasped from the present specification may be exerted in addition to or in place of the above-described effect.

Favorable embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that, in the present specification and the drawings, redundant description of constituent elements having substantially the same functional configurations is omitted by giving the same reference numerals.

Note that the description will be given in the following order.

First, a configuration of an earphone system <NUM> according to an embodiment of the present disclosure will be described with reference to <FIG>. As illustrated in <FIG>, the system <NUM> includes an ear headset including a master-side earphone <NUM> and a slave-side earphone <NUM>. The master-side earphone <NUM> and the slave-side earphone <NUM> are separately configured and are inserted into respective ears of a user. As an example, it is assumed that the master-side earphone <NUM> is inserted into the right ear, and the slave-side earphone <NUM> is inserted into the left ear.

The master-side earphone <NUM> includes two microphones <NUM> and <NUM>. Furthermore, the master-side earphone <NUM> includes a communication unit <NUM>, an antenna <NUM>, a beamforming unit (sound quality improvement processing unit) <NUM>, a delay unit <NUM>, a control unit <NUM>, an external transmission unit <NUM>, and a power supply IC <NUM>.

Similarly, the slave-side earphone <NUM> includes two microphones <NUM> and <NUM>. Furthermore, the slave-side earphone <NUM> includes a communication unit <NUM>, an antenna <NUM>, an audio codec unit <NUM>, a control unit <NUM>, and a power supply IC <NUM>.

In the system <NUM> according to the present embodiment, sound acquired by the microphones <NUM> and <NUM> of the master-side earphone <NUM> and sound acquired by the microphones <NUM> and <NUM> of the slave-side earphone <NUM> are beamformed on the master side, and sound information is transmitted to an automatic speech recognition (ASR) engine or the like. At this time, high quality sound information with a high S/N ratio can be obtained as the number of microphones is larger. Therefore, according to the system <NUM> of the present embodiment, beamforming can be performed using the sound of the four microphones <NUM>, <NUM>, <NUM>, and <NUM>. Therefore, high quality sound with reduced noise can be obtained, and a success rate of sound recognition in the automatic speech recognition engine or the like can be increased, as compared with a case where beamforming is performed at each of the master-side earphone <NUM> and the slave-side earphone <NUM>. Furthermore, a total of four microphones can be dispersedly arranged in the master-side earphone <NUM> and the slave-side earphone <NUM>. Therefore, the earphones can be decreased in size as compared with a case where all the microphones are arranged in either the master-side earphone <NUM> or the slave-side earphone <NUM>.

Furthermore, the beamformed sound may be transmitted to an ear headset used by another person to make a voice call with the another person. Even in this case, a high quality voice call can be made.

The beamforming is performed by the beamforming unit <NUM> of the master-side earphone <NUM>. Therefore, the sound acquired by the microphones <NUM> and <NUM> of the slave-side earphone <NUM> is transmitted to the master-side earphone <NUM>. Although various methods can be used as a transmission method, the system <NUM> of the present embodiment sends the sound from the slave-side earphone <NUM> to the master-side earphone <NUM> using especially near field magnetic induction (NFMI) via the antennas <NUM> and <NUM>. Thus, the master-side earphone <NUM> can perform beamforming using the sound of the four microphones <NUM>, <NUM>, <NUM>, and <NUM>.

Note that, in the present embodiment, beamforming processing of causing a sound to have directionality is illustrated as processing of improving the quality of sound acquired by the plurality of microphones <NUM>, <NUM>, <NUM>, and <NUM>. However, sound quality improvement processing other than the beamforming processing may be performed. For example, processing of reducing wind noise of the sound acquired by the plurality of microphones <NUM>, <NUM>, <NUM>, and <NUM> or the like may be performed. Therefore, the beamforming unit <NUM> functions as a sound quality improvement processing unit in a broad sense.

When transmitting sound from the slave-side earphone <NUM> to the master-side earphone <NUM> using NFMI, an audio channel and a data channel can be used. Note that the audio channel is a wireless transmission path in which data arrival delay time is constant because data integrity is not guaranteed. Furthermore, the data channel is a wireless transmission path in which data integrity is guaranteed. In the data channel, information transmission time is affected by error correction or the like. In the present embodiment, the sound is transmitted from the slave-side earphone <NUM> to the master-side earphone <NUM> using the audio channel or the data channel. Hereinafter, the case where the audio channel is used and the case where the data channel is used will be respectively described.

First, the case of transmitting the sound from the slave-side earphone <NUM> to the master-side earphone <NUM> using the audio channel will be described on the basis of <FIG>. The microphones <NUM> and <NUM> of the slave-side earphone <NUM> acquire sound as pulse code modulation (PCM) data. The sound acquired by the microphones <NUM> and <NUM> of the slave-side earphone <NUM> is sent from the communication unit <NUM> of the slave-side earphone <NUM> to the communication unit <NUM> of the master-side earphone <NUM> using NFMI.

In the case of using the audio channel, the communication unit <NUM> and the communication unit <NUM> automatically compress and decompress sound data using an irreversible audio codec. As the irreversible audio codec, an audio codec such as ADPCM is used, for example. The communication unit <NUM> compresses the PCM data, and the communication unit <NUM> converts the compressed data into the PCM by decompression. Therefore, reversible compression and decompression of sound data is not performed by the control unit <NUM> and the control unit <NUM>, unlike the case of using the data channel to be described below. In the case of using the irreversible audio codec such as ADPCM, the sound quality may be slightly deteriorated.

In the master-side earphone <NUM>, the sound of the slave-side microphones <NUM> and <NUM> is sent from the communication unit <NUM> to the beamforming unit <NUM>. Meanwhile, the sound acquired by the microphones <NUM> and <NUM> of the master-side earphone <NUM> is also sent to the beamforming unit <NUM>. The sound acquired by the microphones <NUM> and <NUM> of the master-side earphone <NUM> is delayed by the delay unit <NUM> by a predetermined time. Thereby, beamforming can be optimally performed in consideration of a delay that occurs when the sound is transmitted from the slave-side earphone <NUM> to the master-side earphone <NUM>.

The beamforming unit <NUM> performs beamforming of four channels using the sound of the four microphones <NUM>, <NUM>, <NUM>, and <NUM>. The beamformed sound is sent to the external transmission unit <NUM>. The external transmission unit <NUM> transmits the beamformed sound to an external device, using a method such as Bluetooth (registered trademark), for example. Furthermore, the earphone system <NUM> can be directly connected to a network such as the Internet. In this case, the sound is directly transmitted from the external transmission unit <NUM> to an application such as an automatic speech recognition engine without passing through an external device.

As described above, in the case of using the audio channel, the sound data is sent along the one-dot chain line P1 illustrated in <FIG>. Note that the control unit <NUM> has a function to control all the configuration elements of the master-side earphone <NUM>. Similarly, the control unit <NUM> has a function to control all the configuration elements of the slave-side earphone <NUM>.

The external device is, for example, a device such as a smartphone or a personal computer (PC). When the external device receives the sound from the external transmission unit <NUM>, the sound is input to an application such as an automatic speech recognition engine, for example, and sound recognition is performed. Thereby, a search engine searches for desired information.

Next, the case of transmitting the sound from the slave-side earphone <NUM> to the master-side earphone <NUM> using the data channel will be described on the basis of <FIG>. Similarly to the case of using the audio channel, the microphones <NUM> and <NUM> of the slave-side earphone <NUM> acquire sound as PCM data. The sound acquired by the microphones <NUM> and <NUM> of the slave-side earphone <NUM> is sent to the control unit <NUM>. The control unit <NUM> encodes the sound and sends encoded sound data to the communication unit <NUM>. Then, the encoded sound data is sent from the communication unit <NUM> of the slave-side earphone <NUM> to the communication unit <NUM> of the master-side earphone <NUM> using NFMI.

The communication unit <NUM> of the master-side earphone <NUM> receives the encoded sound data and sends the encoded sound data to the control unit <NUM>. The control unit <NUM> decodes the encoded sound data and sends the decoded sound data to the beamforming unit <NUM>.

In the case of using the data channel, the encoding processing performed by the slave-side earphone <NUM> is reversible compression, and the master-side earphone <NUM> performs the decoding processing, and thus the master-side earphone <NUM> can restore the sound in an original sound state. Therefore, when the sound is sent from the slave-side earphone <NUM> to the master-side earphone, the sound quality is not deteriorated, and the sound can maintain the high quality original sound. Note that FLAC or the like can be used as a codec method, for example.

The beamforming unit <NUM> performs beamforming using the sound of the four microphones <NUM>, <NUM>, <NUM>, and <NUM>. Subsequent steps are similar to the steps in the case of using the audio channel. The beamformed sound is sent to the external transmission unit <NUM>. The external transmission unit <NUM> transmits the beamformed sound to an external device, using a method such as Bluetooth (registered trademark), for example.

As described above, in the case of using the data channel, the sound data is sent along the one-dot chain line P2 illustrated in <FIG>. Note that the control unit <NUM> has a function to control all the configuration elements of the master-side earphone <NUM>, in addition to performing the above-described decoding processing. Similarly, the control unit <NUM> controls all the configuration elements of the slave-side earphone <NUM>, in addition to performing the above-described encoding processing.

In the case of using the data channel, the microphones <NUM> and <NUM> of the slave-side earphone <NUM> and the microphones <NUM> and <NUM> of the master-side earphone <NUM> acquire sound at the same time.

Therefore, a timing signal indicating timing to start sound acquisition is sent from the master-side earphone <NUM> to the slave-side earphone <NUM> using the audio channel. A timing signal is sent using the audio channel. The slave-side earphone <NUM> starts sound acquisition at the time when receiving the timing signal. Since a delay time between the master and slave is a fixed value, the master-side earphone <NUM> starts sound acquisition after waiting for the delay time that is the fixed value. Thereby, the microphones <NUM> and <NUM> of the slave-side earphone <NUM> and the microphones <NUM> and <NUM> of the master-side earphone <NUM> can acquire sound at the same time.

<FIG> is a timing chart for describing delay processing performed by the master-side earphone <NUM>. <FIG> illustrates, from the top, the timing signal transmitted by the master-side earphone <NUM> to the slave-side earphone <NUM>, the timing signal received by the slave-side earphone <NUM>, and the timing signal at which the master-side earphone <NUM> starts sound acquisition.

As illustrated in <FIG>, when the master-side earphone <NUM> transmits the timing signal to the slave-side earphone <NUM> at time t1, the slave-side earphone <NUM> receives the timing signal at time t2. When the slave-side earphone <NUM> receives the timing signal at time t2, the slave-side earphone <NUM> starts sound acquisition at time t3 at which a predetermined time has elapsed. Note that the time from time t2 to time t3 is a time arising from a response time of hardware, and is a fixed value.

When a predetermined delay time T has elapsed after transmitting the timing signal at time t1, the master-side earphone <NUM> starts sound acquisition. The delay time T is determined in advance such that the timing at which the master-side earphone <NUM> acquires sound coincides with the time t3. Thereby, the timing of acquiring sound can be made coincide with each other between the master-side earphone <NUM> and the slave-side earphone <NUM>. Thereby, the sound from the slave-side earphone <NUM> to the master-side earphone <NUM> can be synchronized, and the master-side beamforming unit <NUM> can optimally perform beamforming.

Note that, for example, the sound acquisition (recording) by the microphones <NUM>, <NUM>, <NUM>, and <NUM> is performed for every fixed time (for every <NUM>, for example), and the sound data is beamformed and sent to the external transmission unit <NUM>. A transfer delay from the slave-side earphone <NUM> to the master-side earphone <NUM> is not a problem if after the sound data is sent to the external transmission unit <NUM>, the sound data is transferred from the slave-side earphone <NUM> to the master-side earphone <NUM> and the beamforming processing is completed during the next fixed time.

Note that, in the case of the audio channel, the delay time of the audio channel is a predetermined value, and thus the beamforming unit <NUM> of the master-side earphone <NUM> can perform beamforming in consideration of the delay time. Therefore, transmission of a timing signal from the master-side earphone <NUM> to the slave-side earphone <NUM> is not necessary.

Note that, in the present embodiment, the description has been made using the earphone system <NUM> including an ear headset including one master-side earphone <NUM> and one slave-side earphone <NUM> as an example. However, there may be a plurality of the slave-side earphones <NUM>, for example. Thereby, the number of microphones can be increased, and further improvement of the sound quality can be achieved.

As described above, according to the present embodiment, the sound acquired by the microphones <NUM> and <NUM> of the master-side earphone <NUM> and sound acquired by the microphones <NUM> and <NUM> of the slave-side earphone <NUM> are collected and beamformed on the master side. Therefore, the quality of the beamformed sound can be improved. Furthermore, since the plurality microphones can be dispersedly arranged on the master side and the slave side, downsizing of the master-side earphone <NUM> and the slave-side earphone <NUM> can be achieved.

Although the favorable embodiment of the present disclosure has been described in detail with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such examples. It is obvious that persons having ordinary knowledge in the technical field of the present disclosure can conceive various changes and alterations within the scope of the technical idea described in the claims, and it is naturally understood that these changes and alterations belong to the technical scope of the present disclosure.

Claim 1:
An earphone (<NUM>) that is one of earphones configuring an ear headset, the earphone comprising:
a sound acquisition unit (<NUM>, <NUM>) configured to acquire sound data;
a communication unit (<NUM>) configured to receive sound data from the other earphone by wireless communication; and
a sound quality improvement processing unit (<NUM>) configured to perform processing of improving sound quality of the sound data acquired by the sound acquisition unit and the sound data received from the other earphone;
wherein the communication unit receives the sound data from the other earphone using a data channel, the data channel being a wireless transmission path in which data integrity is guaranteed by performing error correction; wherein
the earphone transmits a timing signal indicating timing that the other earphone starts acquisition of the sound data using an audio channel, the audio channel being a wireless transmission path in which data integrity is not guaranteed, as error correction is not performed, and
the sound acquisition unit starts acquisition of the sound data after an elapse of a predetermined delay time from the transmission of the timing signal.