Communication device, communication method, and communication program

Abstract

A communication device (100) is provided with: a first addition unit (5) that adds reproduction sound to communication voice of a remote speaker and outputs the communication voice to a speaker (1), said communication voice having the reproduction sound added thereto; and an acoustic echo canceller (3) for cancelling the echo component of the call voice included in the input signal acquired by the microphone (2) for picking up the surrounding sound, using the call voice as a reference signal.

Description

Technical Field

[0001] The present disclosure relates to a technology for amplifying a given reproduced sound to surroundings and conducting a conversation between a person in the surroundings and a remote speaker. Background Art

[0002] For example, the speech detection unit of the acoustic echo canceller device with amplification function shown in Patent Document 1 detects the level of a received signal from a far end, and outputs a signal to stop coefficient correction to the coefficient correction unit when the level of the received signal is below a certain level. Thus, the coefficient correction unit corrects the coefficient of the echo canceller only when a received signal above the certain level is input.

[0003] For example, the voice communication device of Patent Document 2 has a function of resetting the acoustic echo cancellation function (adaptive filter) by remote operation. This makes it possible to confirm whether the voice data sent from the terminal is normally reproduced at the other terminal during voice communication via the communication network.

[0004] However, in the above-mentioned conventional technology, it is difficult for the remote speaker to confirm whether the reproduced sound is amplified, and further improvement is required.

[0005] Prior Art Literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 63-79449

[0008] Patent Document 2: Japanese Patent No. 5245884 Summary of the invention

[0009] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a technology that can eliminate acoustic echo generated by amplifying a call voice of a remote speaker and enable the remote speaker to confirm whether the reproduced sound is amplified.

[0010] The communication device involved in the present disclosure is a communication device that amplifies a given reproduced sound for the surroundings and conducts communication between a person in the surroundings and a remote speaker, and comprises: a first adding unit that adds the reproduced sound to the call voice of the remote speaker and outputs the call voice to which the reproduced sound is added to a speaker; and an acoustic echo canceller that uses the call voice as a reference signal to cancel the echo component of the call voice contained in the input signal acquired by a microphone that picks up surrounding sounds.

[0011] According to the present disclosure, it is possible to eliminate the acoustic echo generated by amplifying the call voice of the remote speaker, and the remote speaker can confirm whether the reproduced sound is amplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a diagram showing the configuration of a communication system in Embodiment 1 of the present disclosure.

[0013] Figure 2 1 is a block diagram showing a detailed structure of the acoustic echo canceller in Embodiment 1 of the present disclosure.

[0014] Figure 3 This is a flowchart for explaining the operation of the communication device in Embodiment 1 of the present disclosure.

[0015] Figure 4 This is a diagram showing the configuration of a communication system in Embodiment 2 of the present disclosure.

[0016] Figure 5 This is a flowchart for explaining the operation of the communication device in Embodiment 2 of the present disclosure.

[0017] Figure 6 This is a diagram showing the configuration of a communication system in Embodiment 3 of the present disclosure.

[0018] Figure 7 This is a flowchart for explaining the operation of the communication device in Embodiment 3 of the present disclosure.

[0019] Figure 8 This is a diagram showing the structure of a communication system in Embodiment 4 of the present disclosure.

[0020] Fig. 9 This is a flowchart for explaining the operation of the communication device in Embodiment 4 of the present disclosure.

[0021] Fig.10 This is a diagram showing the structure of a communication system in Embodiment 5 of the present disclosure.

[0022] Fig.11 This is a diagram showing the relationship between the strength (Power) of the filter coefficient and the first suppression gain when the reproduced sound is detected in the fifth embodiment.

[0023] Fig.12 This is the first flowchart for explaining the operation of the communication device in Embodiment 5 of the present disclosure.

[0024] Fig.13 This is the second flowchart for explaining the operation of the communication device in Embodiment 5 of the present disclosure.

[0025] Fig.14This is a diagram showing the structure of a communication system in Embodiment 6 of the present disclosure.

[0026] Fig.15 This is a diagram showing the relationship between the echo cancellation amount and the first suppression gain when reproduced sound is detected in the sixth embodiment.

[0027] Fig.16 This is a diagram showing the structure of a communication system in Embodiment 7 of the present disclosure.

[0028] Fig.17 This is a flowchart for explaining the operation of the communication device in Embodiment 7 of the present disclosure.

[0029] Fig.18 This is a diagram showing the structure of a communication system in Embodiment 8 of the present disclosure.

[0030] Fig.19 This is a diagram showing the structure of a communication system in Embodiment 9 of the present disclosure.

[0031] Fig. 20 This is a diagram showing the structure of a communication system in Embodiment 10 of the present disclosure.

[0032] Fig.21 This is a diagram showing the structure of a communication system in Embodiment 11 of the present disclosure.

[0033] Fig. 22 This is a diagram showing the configuration of a vehicle including the communication device and the remote monitoring device in the first embodiment.

[0034] Fig.23 This is a diagram showing another configuration of the vehicle including the communication device in the first embodiment and the remote monitoring device. DETAILED DESCRIPTION

[0035] (Knowledge that forms the basis of this disclosure)

[0036] In the past, there was a transport system in which a vehicle that drives autonomously and is driven by remote control transports goods. In this transport system, a remote monitor remotely controls the movement of the vehicle, but the remote monitor and the recipient of the goods need to communicate. The vehicle is equipped with a speaker, a microphone, and an acoustic echo canceller, and the recipient of the goods has a voice-amplified conversation with the remote monitor. The speaker amplifies the remote monitor's voice, and the microphone picks up the recipient's voice. The acoustic echo canceller eliminates the echo component of the remote monitor's voice contained in the input signal acquired by the microphone.

[0037] In addition, the vehicle amplifies the reproduced sounds such as "start" and "reverse" to call the attention of the surrounding people. After the remote monitor instructs to amplify the reproduced sounds, the vehicle starts to move. Therefore, the remote monitor needs to confirm that the reproduced sounds are amplified from the vehicle and that the amplification of the reproduced sounds has ended.

[0038] However, in the above-mentioned Patent Document 1, when the speaker amplifies the received signal and the reproduced sound at the far end, not only the received signal that is bypassed from the speaker to the microphone is removed, but also the reproduced sound that is bypassed from the speaker to the microphone is removed as an acoustic echo. Therefore, the remote monitor cannot hear the reproduced sound, and it is difficult to confirm whether the reproduced sound is normally amplified.

[0039] In the above-mentioned patent document 2, since the filter coefficient is reset, the echo from the speaker to the microphone is not removed by the echo cancellation unit, and the terminal can confirm that the voice is amplified in the other party's terminal. However, as the update of the filter coefficient of the echo cancellation unit progresses, the echo from the speaker to the microphone is removed. Therefore, depending on the length of the reproduced sound, there is a concern that it is impossible to confirm that the amplification of the reproduced sound has been completed.

[0040] In addition, in the above-mentioned patent document 2, both the voice signal of this terminal and the reproduced sound are sent from the terminal on the other side, so the reproduced sound is superimposed on the voice signal of this terminal, and the reproduced sound cannot be heard, which causes a concern that it is impossible to confirm whether the reproduced sound is amplified normally.

[0041] In order to solve the above problems, the following technology is disclosed.

[0042] (1) A communication device according to one embodiment of the present invention is a communication device that amplifies a given reproduced sound for the surroundings and conducts a communication between a person in the surroundings and a remote speaker, and comprises: a first adding unit that adds the reproduced sound to the communication voice of the remote speaker and outputs the communication voice to which the reproduced sound is added to a speaker; and an acoustic echo canceller that uses the communication voice as a reference signal to cancel an echo component of the communication voice contained in an input signal acquired by a microphone that picks up surrounding sounds.

[0043] According to this structure, the conversation voice of the remote speaker is input into the acoustic echo canceller as a reference signal, and the reproduced sound is not input into the acoustic echo canceller as a reference signal. Therefore, the echo component of the conversation voice added to the reproduced sound that is transmitted from the speaker to the microphone is eliminated by the acoustic echo canceller, but the echo component of the reproduced sound is not eliminated and is output to the remote speaker side.

[0044] Therefore, it is possible to eliminate the acoustic echo generated by amplifying the call voice of the remote speaker, and the remote speaker can confirm whether the reproduced sound is amplified.

[0045] (2) The communication device described in (1) above may further include a reproduced sound detection unit for detecting the presence of the reproduced sound, wherein the acoustic echo canceller stops updating the filter coefficients of the adaptive filter when the reproduced sound detection unit detects the reproduced sound.

[0046] According to this configuration, when a reproduced sound is detected, the filter coefficient of the adaptive filter is not updated, so that only the echo component of the call speech of the remote speaker can be eliminated with high accuracy.

[0047] (3) The communication device described in (1) or (2) above may further include a first volume adjustment unit that adjusts the volume of the reproduced sound and outputs the reproduced sound with the adjusted volume to the first adder.

[0048] According to this configuration, the reproduced sound and the call voice with the volume adjusted are output from the speaker, so that the person located around the speaker can reliably hear the reproduced sound.

[0049] (4) The communication device described in any one of (1) to (3) above may further include an automatic gain control unit that automatically adjusts the volume of an output signal from the acoustic echo canceller.

[0050] According to this configuration, the volume of the output signal from the acoustic echo canceller is automatically adjusted, so that the volume of the echo of the reproduced sound and the volume of the speech of the near-end speaker located around the microphone can be coordinated, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0051] (5) The communication device described in (2) above may further include: a suppression gain setting unit for setting a first suppression gain for suppressing the volume of the output signal from the acoustic echo canceller when the reproduced sound is detected by the reproduced sound detection unit, and for setting a second suppression gain for not suppressing the volume of the output signal from the acoustic echo canceller when the reproduced sound is not detected by the reproduced sound detection unit; and a variable amplifier for multiplying the output signal from the acoustic echo canceller by the first suppression gain or the second suppression gain set by the suppression gain setting unit.

[0052] According to this configuration, when the reproduced sound is detected, the first suppression gain to be multiplied by the output signal from the acoustic echo canceller is set so that the volume of the echo of the reproduced sound heard on the far-end speaker side and the volume of the speech of the near-end speaker become the same. Thus, the volume of the echo of the reproduced sound and the volume of the speech of the near-end speaker located around the microphone can be coordinated, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0053] (6) The communication device described in (1) above may further include: a volume suppression unit for suppressing the volume of the reproduced sound; and a second adding unit for adding the reproduced sound whose volume is suppressed by the volume suppression unit to the communication voice, wherein the acoustic echo canceller uses the output signal from the second adding unit as a reference signal to cancel the echo components of the communication voice and the reproduced sound whose volume is suppressed contained in the input signal acquired by the microphone.

[0054] According to this configuration, the volume of the reproduced sound output from the speaker is different from the volume of the reproduced sound input to the acoustic echo canceller as a reference signal, so that a part of the echo component of the reproduced sound is output without being cancelled by the acoustic echo canceller, so that the remote speaker can confirm whether the reproduced sound is amplified.

[0055] (7) The communication device described in (6) above may further include a reproduced sound detection unit that detects the presence of the reproduced sound, and when the reproduced sound detection unit detects the reproduced sound, the acoustic echo canceller stops updating the filter coefficients of the adaptive filter.

[0056] According to this configuration, when a reproduced sound is detected, the filter coefficient of the adaptive filter is not updated, so that only the echo component of the call speech of the remote speaker can be eliminated with high accuracy.

[0057] (8) The communication device described in (7) above may further include: a suppression gain setting unit for estimating an echo cancellation amount of the acoustic echo canceller when the reproduced sound is detected by the reproduced sound detection unit, and setting a first suppression gain for suppressing the volume of an output signal from the acoustic echo canceller based on the estimated echo cancellation amount, and for setting a second suppression gain for not suppressing the volume of the output signal from the acoustic echo canceller when the reproduced sound is not detected by the reproduced sound detection unit; and a variable amplifier for multiplying the output signal from the acoustic echo canceller by the first suppression gain or the second suppression gain set by the suppression gain setting unit.

[0058] According to this configuration, when the reproduced sound is detected, the first suppression gain to be multiplied by the output signal from the acoustic echo canceller is set according to the echo cancellation status of the acoustic echo canceller so that the volume of the echo of the reproduced sound heard on the far-end speaker side and the volume of the speech of the near-end speaker become the same. Thus, the volume of the echo of the reproduced sound and the volume of the speech of the near-end speaker located around the microphone can be coordinated, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0059] (9) In the communication device described in (8) above, the suppression gain setting unit may calculate the strength of the filter coefficient, and estimate the echo cancellation amount based on the calculated strength of the filter coefficient.

[0060] According to this configuration, when the filter coefficient is not updated and the strength of the filter coefficient is small, the echo cancellation amount becomes small, and the volume of the echo of the reproduced sound output from the acoustic echo canceller becomes large. Therefore, before the update of the filter coefficient is advanced and the strength of the filter coefficient becomes large, the echo component of the reproduced sound is suppressed by the first suppression gain. As a result, the volume of the echo of the reproduced sound and the volume of the speech of the near-end speaker located around the microphone can be coordinated, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0061] (10) In the communication device described in (8) above, the suppression gain setting unit may estimate the echo cancellation amount based on a level of the input signal from the microphone to the acoustic echo canceller and a level of an output signal from the acoustic echo canceller.

[0062] According to this configuration, for example, the echo cancellation amount indicates the ratio of the level of the input signal input from the microphone to the acoustic echo canceller to the level of the output signal from the acoustic echo canceller. When the acoustic echo canceller does not cancel the echo, the echo cancellation amount becomes 1, and the volume of the echo of the reproduced sound output from the acoustic echo canceller becomes larger. Therefore, before the acoustic echo canceller fully cancels the echo, the echo component of the reproduced sound is suppressed by the first suppression gain. As a result, the volume of the echo of the reproduced sound can be coordinated with the volume of the speech of the near-end speaker located around the microphone, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0063] (11) In the communication device described in (1) above, the acoustic echo canceller may use the output signal from the first adding unit as a reference signal to cancel the echo components of the call voice and the reproduced sound contained in the input signal acquired by the microphone, and the communication device may also include a second adding unit that adds the reproduced sound to the output signal from the acoustic echo canceller.

[0064] According to this configuration, the echo component of the reproduced sound that is bypassed from the speaker to the microphone is removed by the acoustic echo canceller. Then, the reproduced sound is added to the output signal from the acoustic echo canceller from which the echo component of the reproduced sound is removed, and the output signal to which the reproduced sound that does not pass through the acoustic echo path is added is output to the remote speaker side. Therefore, the remote speaker can confirm the clear reproduced sound that is not an acoustic echo.

[0065] (12) The communication device described in (11) above may further include: a second volume adjustment unit for adjusting the volume of the reproduced sound, wherein the second adding unit adds the reproduced sound whose volume is adjusted by the second volume adjustment unit to the output signal from the acoustic echo canceller.

[0066] According to this configuration, the volume of the reproduced sound added to the output signal from the acoustic echo canceller is adjusted, so that the volume of the reproduced sound can be coordinated with the volume of the speech of the near-end speaker located around the microphone, and both the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0067] (13) In the communication device described in any one of (1) to (3) above, it may also include: a switch that switches between an on state in which the call voice is input as the reference signal to the acoustic echo canceller and an off state in which the call voice is not input as the reference signal to the acoustic echo canceller based on a control signal indicating whether the call voice is sent back to the remote side, and when the control signal indicating that the call voice is sent back to the remote side is input, the switch is switched to the off state.

[0068] According to this configuration, when a control signal indicating that the call voice is sent back to the remote side is input, the switch is switched to an OFF state in which the call voice is not input as a reference signal to the acoustic echo canceller. Therefore, the call voice is not removed by the acoustic echo canceller, and the remote speaker can confirm that his or her call voice is amplified on the other side.

[0069] (14) In the communication device described in any one of the above (1) to (3), it may also further include: a third adding unit, which adds the call voice to the output signal from the acoustic echo canceller; and a third volume adjustment unit, which adjusts the volume of the call voice input to the third adding unit based on a control signal indicating whether the call voice is sent back to the remote side, wherein the third volume adjustment unit adjusts the call voice to the volume that can be heard by the remote speaker when the control signal indicating that the call voice is sent back to the remote side is input, and adjusts the call voice to the volume that cannot be heard by the remote speaker when the control signal indicating that the call voice is not sent back to the remote side is input.

[0070] According to this configuration, when a control signal indicating that the call voice is to be sent back to the remote side is input, the call voice is adjusted to a volume that the remote speaker can hear. Therefore, the call voice adjusted to a volume that the remote speaker can hear by the third volume adjustment unit is added to the output signal from the acoustic echo canceller, so the remote speaker can confirm that his or her call voice is amplified on the other party side.

[0071] (15) The communication device described in (11) or (12) above may further include: a switch that switches between an on state in which the output signal from the first adding unit is input as the reference signal to the acoustic echo canceller, and an off state in which the output signal from the first adding unit is not input as the reference signal to the acoustic echo canceller, based on a control signal indicating whether the call voice is sent back to the remote side, wherein the switch is switched to the off state when the control signal indicating that the call voice is sent back to the remote side is input.

[0072] According to this configuration, when a control signal indicating that the call voice is to be sent back to the remote side is input, the switch is switched to an OFF state in which the output signal from the first adding unit is not input as a reference signal to the acoustic echo canceller. Therefore, the call voice is not removed by the acoustic echo canceller, and the remote speaker can confirm that his or her call voice is amplified on the other party side.

[0073] (16) In the communication device described in (11) or (12) above, it may also include: a third adding unit for adding the call voice to the output signal from the second adding unit; and a third volume adjustment unit for adjusting the volume of the call voice input to the third adding unit based on a control signal indicating whether the call voice is sent back to the remote side, wherein the third volume adjustment unit adjusts the call voice to the volume that can be heard by the remote speaker when the control signal indicating that the call voice is sent back to the remote side is input, and adjusts the call voice to the volume that cannot be heard by the remote speaker when the control signal indicating that the call voice is not sent back to the remote side is input.

[0074] According to this configuration, when a control signal indicating that the call voice is to be sent back to the remote side is input, the call voice is adjusted to a volume that the remote speaker can listen to. Therefore, the call voice adjusted to a volume that the remote speaker can listen to by the third volume adjustment unit is added to the output signal from the second adding unit, so the remote speaker can confirm that his or her call voice is amplified on the other party side.

[0075] (17) In the communication device described in any one of (1) to (16) above, it may also include: a storage unit that pre-stores a plurality of reproduced sounds; a communication unit that receives reproduction information specifying a reproduced sound to be output from the plurality of reproduced sounds from a remote communication device; and a reading unit that reads the reproduced sound specified by the reproduction information from the storage unit.

[0076] According to this configuration, it is possible to read out the reproduced sound stored in the communication device and output the read reproduced sound from the speaker.

[0077] (18) The communication device described in any one of (1) to (16) above may further include a communication unit that receives the reproduced sound transmitted from a remote communication device.

[0078] According to this configuration, it is possible to receive the reproduced sound from the remote communication device and output the received reproduced sound from the speaker.

[0079] In addition, the present disclosure can be implemented not only as a communication device having the characteristic structure as described above, but also as a communication method that performs characteristic processing corresponding to the characteristic structure of the communication device. In addition, it can also be implemented as a computer program that enables a computer to perform the characteristic processing included in such a communication method. Therefore, in the following other methods, the same effect as the above-mentioned communication device can be achieved.

[0080] (19) Another embodiment of the present disclosure relates to a communication method in which a given reproduced sound is amplified for the surroundings and a communication is conducted between a person in the surroundings and a remote speaker. The communication method adds the reproduced sound to the communication voice of the remote speaker, outputs the communication voice to which the reproduced sound is added to a speaker, and uses the communication voice as a reference signal to eliminate an echo component of the communication voice contained in an input signal acquired by a microphone that picks up surrounding sounds.

[0081] (20) Another embodiment of the present disclosure relates to a call program for amplifying a given reproduced sound for a surrounding area and for conducting a call between a person in the surrounding area and a remote speaker, wherein the call program causes a computer to function as a first adder and an acoustic echo canceller, wherein the first adder adds the reproduced sound to the call speech of the remote speaker and outputs the call speech to which the reproduced sound is added to a speaker; and the acoustic echo canceller uses the call speech as a reference signal to cancel the echo component of the call speech contained in an input signal acquired by a microphone that picks up surrounding sounds.

[0082] (21) Another embodiment of the present disclosure relates to a non-transitory computer-readable recording medium having a call program recorded thereon, which records a call program for amplifying a given reproduced sound with respect to surroundings and for conducting a call between a person located in the surroundings and a remote speaker, wherein the non-transitory computer-readable recording medium enables a computer to function as a first adding unit and an acoustic echo canceller, wherein the first adding unit adds the reproduced sound to the call speech of the remote speaker and outputs the call speech to which the reproduced sound is added to a speaker; and the acoustic echo canceller uses the call speech as a reference signal to cancel an echo component of the call speech contained in an input signal acquired by a microphone that picks up surrounding sounds.

[0083] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, the embodiments described below all illustrate a specific example of the present disclosure. The numerical values, shapes, constituent elements, steps, the order of steps, etc. shown in the following embodiments are examples, and the main purpose is not to limit the present disclosure. In addition, for the constituent elements in the following embodiments that are not recorded in the independent claims representing the highest concept, they are described as arbitrary constituent elements. In addition, it is also possible to combine the various contents in all embodiments.

[0084] (Implementation method 1)

[0085] Figure 1 This is a diagram showing the configuration of a communication system in Embodiment 1 of the present disclosure.

[0086] The communication system is mounted on a vehicle. The vehicle is, for example, an electric robot, an electric car, an electric truck, or an electric drone. For example, the vehicle moves within a given area to carry the user's goods. The vehicle is monitored by a remote monitor. The vehicle drives autonomously and is driven by remote control.

[0087] Figure 1 The illustrated communication system includes a speaker 1 , a microphone 2 , a call audio input unit 21 , a reproduced sound input unit 22 , a call audio output unit 23 , and a communication device 100 .

[0088] The communication device 100 amplifies a given reproduced sound to the surroundings, and communicates between a person in the surroundings and a remote monitor. The remote monitor is an example of a remote speaker. The reproduced sound is a voice such as "start" and "reverse" to call attention to the surrounding people. For example, when the vehicle starts to move, the reproduced sound is amplified.

[0089] The call voice input unit 21 outputs the remote call voice of the remote monitoring party received from the remote monitoring device (not shown) on the receiving side to the call device 100 .

[0090] The reproduced sound input unit 22 outputs the reproduced sound to the communication device 100 .

[0091] The speaker 1 amplifies the remote call voice of the remote monitor and amplifies the reproduced sound. Here, when the voice output from the speaker 1 is picked up by the microphone 2, the voice uttered by the speaker on the receiving side is reproduced with a delay, and a so-called acoustic echo is generated from the speaker on the receiving side. Therefore, the acoustic echo canceller 3 described later suppresses the acoustic echo signal included in the input signal output from the microphone 2.

[0092] The microphone 2 collects surrounding sounds. The microphone 2 collects the voice of a near-end speaker (sender). The microphone 2 outputs an input signal representing the collected voice to the communication device 100 .

[0093] The communication device 100 includes an acoustic echo canceller 3, a first amplifier 4, a first adder 5, and a reproduced sound detector 6. In addition, the communication device 100 may include at least one of a speaker 1 and a microphone 2.

[0094] The acoustic echo canceller 3 cancels the echo component of the remote call voice contained in the input signal acquired by the microphone 2, using the remote call voice of the remote monitor as a reference signal. The remote call voice xf(j) is input to the acoustic echo canceller 3 as a reference signal, and the input signal y(j) from the microphone 2 is input to the acoustic echo canceller 3. The acoustic echo canceller 3 removes the acoustic echo caused by the remote call voice that is amplified from the speaker 1 and enters the microphone 2. The acoustic echo canceller 3 outputs an echo-removed signal e(j) obtained by removing the echo component of the remote call voice xf(j) from the input signal y(j) acquired by the microphone 2. The detailed structure of the acoustic echo canceller 3 will be described later.

[0095] The first amplifier 4 controls the volume of the reproduced sound so that the reproduced sound can be heard in the required sound amplification area. The first amplifier 4 is an example of a first volume adjustment unit. The first amplifier 4 adjusts the volume of the reproduced sound and outputs the reproduced sound with the adjusted volume to the first adder 5.

[0096] The first adder 5 adds the reproduced sound output from the first amplifier 4 to the remote call voice output from the call voice input unit 21. The first adder 5 adds the reproduced sound to the remote call voice of the remote speaker and outputs the call voice to which the reproduced sound is added to the speaker 1.

[0097] The remote call voice xf(j) is a reference signal of the acoustic echo canceller 3. The first amplifier 4 multiplies the reproduced sound xr(j) by a given gain G1. The gain G1 is predetermined according to the environment in which the call device 100 is used. The gain G1 is a value greater than 0. The first adder 5 adds G1·xr(j) to the remote call voice xf(j). The speaker 1 amplifies xf(j)+G1·xr(j). In addition, the acoustic echo canceller 3 estimates the impulse response H from the speaker 1 to the microphone 2.

[0098] The reproduced sound detection unit 6 detects the presence or absence of the reproduced sound xr(j). The reproduced sound detection unit 6 calculates the amplitude level xr of the reproduced sound xr(j) by performing short-time averaging of the amplitude as shown in the following equation (1): ～ (j) The reproduced sound detection unit 6 determines the amplitude level xr ～ (j) Whether it is greater than the threshold.

[0099] xr ～ (j)=B·|xr(j)|+(1-B)·xr ～ (j-1)……(1)

[0100] In the above formula (1), |xr(j)| is the absolute value of the reproduced sound xr(j), and xr ～(j) is the short-time average value of the absolute value of the reproduced sound xr(j), j is the time, and B is the update gain (0 <B<1)。

[0101] The reproduced sound detection unit 6 determines that there is a reproduced signal when the amplitude level is greater than the threshold value, and determines that there is no reproduced signal when the amplitude level is less than the threshold value.

[0102] When the reproduced sound detection unit 6 does not detect the reproduced sound, the acoustic echo canceller 3 estimates the impulse response from the speaker 1 to the microphone 2. When the reproduced sound detection unit 6 detects the reproduced sound, the acoustic echo canceller 3 stops estimating the impulse response from the speaker 1 to the microphone 2. That is, when the reproduced sound detection unit 6 detects the reproduced sound, the acoustic echo canceller 3 stops updating the filter coefficients of the adaptive filter.

[0103] The call audio output unit 23 outputs the echo-removed signal e(j) output from the acoustic echo canceller 3 as the near-end call audio.

[0104] In addition, the call voice input unit 21, the reproduced sound input unit 22, and the call voice output unit 23 are connected to a communication unit (not shown). The communication unit sends the near-end call voice to the remote monitoring device (not shown) on the receiving side via the network, and receives the remote call voice from the remote monitoring device (not shown) on the receiving side via the network. In addition, the communication unit receives the reproduced sound from the remote monitoring device (not shown) on the receiving side via the network. The network is, for example, the Internet.

[0105] Figure 2 1 is a block diagram showing a detailed structure of the acoustic echo canceller 3 in Embodiment 1 of the present disclosure.

[0106] The acoustic echo canceller 3 includes an adaptive filter 31 , a subtracting unit 32 , and a filter coefficient updating unit 33 .

[0107] The adaptive filter 31 generates an estimated echo yhat(j) by convolving the filter coefficient HHAT(j) and the reference signal sequence Xf(j).

[0108] The subtracting unit 32 removes the echo component of the remote call speech xf(j) included in the input signal y(j) by subtracting the estimated echo yhat(j) from the input signal y(j) from the microphone 2. The subtracting unit 32 outputs an echo-removed signal e(j) obtained by removing the echo component from the input signal y(j).

[0109] The filter coefficient updating unit 33 updates the filter coefficient HHAT(j) using the echo-eliminated signal e(j) output from the subtracting unit 32 and the reference signal sequence Xf(j).

[0110] The input signal y(j) output from the microphone 2 is expressed by the following equation (2) using the input signal sequence Xf(j)+G1·Xr(j) of the speaker 1 and the impulse response H of the acoustic echo path from the speaker 1 to the microphone 2 .

[0111] y(j)=H*(Xf(j)+G1·Xr(j))……(2)

[0112] In the above formula (2), Xf(j), Xr(j) and H are represented by the following formulas (3), (4) and (5). In the above formula (2), * represents a convolution operation.

[0113] Xf(j)=xf(j),xf(j-1),…,xf(j-N+1)…(3)

[0114] Xr(j)=xr(j),xr(j-1),…,xr(j-N+1)…(4)

[0115] H=h(0),h(1),…,h(N-1)…(5)

[0116] In the above-mentioned equations (3), (4), and (5), N represents the filter tap length.

[0117] Here, the number of taps of the impulse response H is set to be the same as the number of taps of the filter coefficient HHAT(j) of the acoustic echo canceller 3. In fact, the impulse response decays over time. Therefore, if the acoustic echo canceller 3 can sufficiently remove the acoustic echo, there is no problem in practical terms that the number of taps of the impulse response H and the number of taps of the filter coefficient HHAT(j) are considered to be the same.

[0118] Furthermore, the estimated echo yhat(j) generated by the adaptive filter 31 is expressed by the following equation (6).

[0119] yhat(j)=HHAT(j)*Xf(j)……(6)

[0120] In addition, HHAT(j) in the above-mentioned formula (6) is represented by the following formula (7).

[0121] HHAT(j)=hhat(j,0),hhat(j,1),…,hhat(j,N-1)…(7)

[0122] Furthermore, the echo-free signal e(j) output from the subtraction unit 32 is expressed by the following equation (8).

[0123] e(j)=y(j)-yhat(j)

[0124] =H*(Xf(j)+G1·Xr(j))-HHAT(j)*Xf(j)

[0125] =(H-HHAT(j))*Xf(j)+G1·H*Xr(j)……(8)

[0126] When the reproduced sound detection unit 6 has not detected the reproduced sound, the filter coefficient HHAT(j) updated by the filter coefficient update unit 33 is expressed by the following equation (9).

[0127] HHAT(j+1)=HHAT(j)+Δ·Xf(j)……(9)

[0128] In addition, Δ in the above-mentioned formula (9) is expressed by the following formula (10).

[0129] Δ=α·e(j) / ||Xf(j)||......(10)

[0130] In the above-mentioned formula (10), ||Xf(j)|| represents the norm of Xf(j), and is represented by the following formula (11). In addition, α represents a gain (0≤α≤1).

[0131] ||Xf(j)||=xf(j) 2 +xf(j-1) 2 +... + xf (j-N + 1) 2 …… (11)

[0132] In the above-mentioned formula (9), the normalized mean least squares algorithm is used as the algorithm for updating the coefficients, but other algorithms may be used as the algorithm for updating the coefficients.

[0133] When the reproduced sound detection unit 6 detects the reproduced sound, the filter coefficient HHAT(j) whose updating is stopped by the filter coefficient updating unit 33 is expressed by the following equation (12).

[0134] HHAT(j+1)=HHAT(j)……(12)

[0135] In addition, the entire frequency band is processed in the above equations (2) to (12), but the entire frequency band can also be processed by dividing it into multiple bands. In addition, the above equations (2) to (12) are processed in the time domain, but they can also be processed in the frequency domain.

[0136] Regarding the filter coefficient HHAT(j) of the acoustic echo canceller 3, if the impulse response H of the actual acoustic echo path can be accurately estimated, HHAT(j)≈H. When the reproduced sound sequence Xr(j)=0, the reference signal of the acoustic echo canceller 3 is Xf(j). In the above equation (8), when HHAT(j)≈H and Xr(j)=0, e(j)≈0 is obtained for the echo-removed signal e(j) output from the acoustic echo canceller 3. Therefore, the echo can be removed.

[0137] Next, the operation of the communication device 100 in the first embodiment of the present disclosure will be described.

[0138] Figure 3 This is a flowchart for explaining the operation of the communication device 100 in the first embodiment of the present disclosure.

[0139] First, in step S1, the acoustic echo canceller 3 and the first adder 5 acquire the remote call voice output from the call voice input unit 21. The call voice input unit 21 outputs the remote call voice received from the remote monitoring device (not shown) on the receiving side to the acoustic echo canceller 3 and the first adder 5. The acoustic echo canceller 3 acquires only the remote call voice as a reference signal.

[0140] Next, in step S2, the first amplifier 4 acquires the reproduced sound output from the reproduced sound input unit 22. The reproduced sound input unit 22 outputs the reproduced sound received from the remote monitoring device (not shown) on the receiving side to the first amplifier 4.

[0141] Next, in step S3 , the first amplifier 4 adjusts the volume of the reproduced sound. The first amplifier 4 multiplies the reproduced sound by a predetermined gain G1. The first amplifier 4 outputs the reproduced sound of which the volume has been adjusted to the first adder 5 .

[0142] Next, in step S4 , the first adder 5 adds the reproduced sound whose volume has been adjusted by the first amplifier 4 to the long-distance call voice.

[0143] Next, in step S5, the first adder 5 outputs the long-distance call voice to which the reproduced sound is added to the speaker 1. The speaker 1 amplifies the long-distance call voice to which the reproduced sound is added.

[0144] Next, in step S6, the acoustic echo canceller 3 acquires an input signal from the microphone 2. At this time, the microphone 2 picks up surrounding sounds and outputs the input signal to the acoustic echo canceller 3. The input signal includes the voice of the near-end speaker and the far-end call voice to which the reproduced sound from the speaker 1 that enters the microphone 2 is added.

[0145] Next, in step S7 , the reproduced sound detection unit 6 detects the presence or absence of the reproduced sound.

[0146] Next, in step S8, the reproduced sound detection unit 6 determines whether the reproduced sound is detected. Here, if it is determined that the reproduced sound is not detected (No in step S8), the process moves to step S10. The reproduced sound detection unit 6 outputs a detection result signal det indicating whether the reproduced sound is detected to the acoustic echo canceller 3.

[0147] On the other hand, when it is determined that the reproduced sound is detected (YES in step S8 ), in step S9 , the acoustic echo canceller 3 stops updating the filter coefficients of the adaptive filter 31 .

[0148] Next, in step S10 , the acoustic echo canceller 3 uses the remote call voice as a reference signal to cancel the echo component of the remote call voice included in the input signal acquired by the microphone 2 .

[0149] Next, in step S11, the acoustic echo canceller 3 outputs an echo-removed signal obtained by removing the echo component of the remote call voice from the input signal. The acoustic echo canceller 3 outputs the echo-removed signal to the call voice output unit 23. The call voice output unit 23 transmits the echo-removed signal output from the acoustic echo canceller 3 as the near-end call voice to a remote monitoring device (not shown) on the receiving side.

[0150] In this way, the conversation voice of the remote speaker is input as a reference signal to the acoustic echo canceller 3, and the reproduced sound is not input as a reference signal to the acoustic echo canceller 3. Therefore, the echo component of the conversation voice is canceled by the acoustic echo canceller 3 after the reproduced sound from the speaker 1 is added to the conversation voice after being bypassed to the microphone 2, but the echo component of the reproduced sound is not canceled and is output to the remote speaker side. Therefore, the acoustic echo generated by amplifying the conversation voice of the remote speaker can be eliminated, and the remote speaker can confirm whether the reproduced sound is amplified.

[0151] according to Figure 1 In the structure of the present invention, the remote call speech xf(j) is input to the acoustic echo canceller 3 as the reference signal sequence Xf(j) while being amplified by the speaker 1. The remote call speech xf(j) is bypassed from the speaker 1 to the microphone 2. The adaptive filter 31 in the acoustic echo canceller 3 generates an estimated echo yhat(j) by convolving the reference signal sequence Xf(j) and the estimated filter coefficient HHAT(j). By subtracting the generated estimated echo yhat(j) from the input signal y(j) output from the microphone 2, the echo component based on the remote call speech xf(j) is removed from the input signal y(j).

[0152] On the other hand, after the volume of the reproduced sound xr(j) is adjusted by the first amplifier 4, it is added to the remote call voice xf(j) by the first adder 5. The reproduced sound xr(j) added to the remote call voice xf(j) is amplified from the speaker 1 and picked up by the microphone 2. The reproduced sound xr(j) is not included in the reference signal sequence Xf(j) of the acoustic echo canceller 3. Therefore, the estimated echo yhat(j) does not include the echo component H*G1·Xr(j) of the reproduced sound. Therefore, the echo component of the reproduced sound xr(j) is not removed by the acoustic echo canceller 3 and is sent to the remote monitoring device. In other words, although the echo component of the remote call voice xf(j) is removed, the echo component of the reproduced sound xr(j) is not removed, so the remote monitor can hear the acoustic echo of the reproduced sound xr(j).

[0153] In the first embodiment, the communication device 100 may not include the reproduced sound detection unit 6. In the first embodiment, the communication device 100 may not include the first amplifier 4.

[0154] (Implementation method 2)

[0155] For example, the volume of the reproduced sound used to attract the attention of people in the vicinity of the vehicle is sometimes set to be loud so that the people in the vicinity can hear it reliably. In this case, there is a concern that the volume of the reproduced sound picked up by the microphone 2 is louder than the volume of the speech of the near-end speaker in the vicinity. In addition, when the distance between the speaker 1 and the microphone 2 is close, the volume of the reproduced sound picked up by the microphone 2 becomes even louder. In the communication device 100 of embodiment 1, there is a concern that the volume of the reproduced sound is louder than the volume of the speech of the near-end speaker in the vicinity, and it is difficult to hear both the echo of the reproduced sound and the speech due to the volume difference between the two sounds. Therefore, the communication device of embodiment 2 automatically adjusts the gain so that the volume of the echo removal signal output from the acoustic echo canceller 3 does not exceed the threshold.

[0156] Figure 4 This is a diagram showing the configuration of a communication system in Embodiment 2 of the present disclosure.

[0157] Figure 4 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, and a communication device 101. In Embodiment 2, the same components as those in Embodiment 1 are denoted by the same reference numerals and their description is omitted.

[0158] The communication device 101 includes an acoustic echo canceller 3 , a first amplifier 4 , a first adder 5 , a reproduced sound detector 6 , and an automatic gain control unit 7 . Figure 4The communication device 101 shown is relative to Figure 1 The communication device 100 shown in the figure has an additional automatic gain control unit 7 between the acoustic echo canceller 3 and the communication voice output unit 23. The other structures are the same as those of the present invention. Figure 1 In addition, the communication device 101 may include at least one of the speaker 1 and the microphone 2 .

[0159] The acoustic echo canceller 3 outputs the echo-removed signal to the automatic gain control unit 7 .

[0160] The automatic gain control unit 7 automatically adjusts the volume of the output signal from the acoustic echo canceller 3. The automatic gain control unit 7 automatically adjusts the gain so that the magnitude of the input signal is within a given range. When the volume of the input signal is greater than the given range, the automatic gain control unit 7 reduces the amplitude of the input signal, thereby matching the volume of the echo of the reproduced sound with the volume of the spoken voice of the near-end speaker. As a result, both the echo of the reproduced sound and the spoken voice of the near-end speaker can be easily heard at the far end side.

[0161] Next, the operation of the communication device 101 in the second embodiment of the present disclosure will be described.

[0162] Figure 5 This is a flowchart for explaining the operation of the communication device 101 in Embodiment 2 of the present disclosure.

[0163] Figure 5 The processing of steps S21 to S30 shown in FIG. Figure 3 The processes in steps S1 to S10 are the same, and thus description thereof will be omitted.

[0164] Next, in step S31, the automatic gain control unit 7 automatically adjusts the volume of the echo-removed signal output from the acoustic echo canceller 3. The automatic gain control unit 7 automatically adjusts the gain so that the volume of the echo-removed signal is within a given range.

[0165] Next, in step S32, the automatic gain control unit 7 outputs the echo-removed signal with the volume adjusted. The automatic gain control unit 7 outputs the echo-removed signal with the volume adjusted to the call voice output unit 23. The call voice output unit 23 transmits the echo-removed signal output from the automatic gain control unit 7 as the near-end call voice to a remote monitoring device (not shown) on the receiving side.

[0166] In this way, the volume of the output signal from the acoustic echo canceller 3 is automatically adjusted. Therefore, the volume of the echo of the reproduced sound and the volume of the speech of the near-end speaker located around the microphone 2 can be coordinated, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0167] In the second embodiment, the communication device 101 may not include the reproduced sound detection unit 6. In the second embodiment, the communication device 101 may not include the first amplifier 4.

[0168] (Implementation method 3)

[0169] In the third embodiment, similarly to the second embodiment, the volume difference between the echo of the reproduced sound at the far end and the speech voice of the near end speaker is reduced.

[0170] Figure 6 This is a diagram showing the configuration of a communication system in Embodiment 3 of the present disclosure.

[0171] Figure 6 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, and a communication device 102. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and their description is omitted.

[0172] The communication device 102 includes an acoustic echo canceller 3 , a first amplifier 4 , a first adder 5 , a reproduced sound detector 6 , a suppression gain setting unit 8 , and a variable amplifier 9 . Figure 6 The communication device 102 shown is relative to Figure 1 The communication device 100 shown in the figure further comprises a suppression gain setting unit 8 and a variable amplifier 9. The other structures are similar to those of FIG. Figure 1 In addition, the communication device 102 may include at least one of the speaker 1 and the microphone 2 .

[0173] When the reproduced sound detection unit 6 detects the reproduced sound, the suppression gain setting unit 8 sets a first suppression gain for suppressing the volume of the output signal from the acoustic echo canceller 3. When the reproduced sound detection unit 6 does not detect the reproduced sound, the suppression gain setting unit 8 sets a second suppression gain for not suppressing the volume of the output signal from the acoustic echo canceller 3.

[0174] When the reproduction sound is detected by the reproduction sound detection unit 6, the suppression gain setting unit 8 sets the suppression gain Gsup(j) of the variable amplifier 9 to the first suppression gain Gsup0 of the suppression signal. In addition, when the reproduction sound is not detected by the reproduction sound detection unit 6, the suppression gain setting unit 8 sets the suppression gain Gsup(j) of the variable amplifier 9 to the second suppression gain Gsup1 that does not suppress the signal. The first suppression gain Gsup0 is a predetermined value in the range of 0 < Gsup0 < 1. The second suppression gain Gsup1 is 1. The value of the first suppression gain Gsup0 is preset so that the volume of the echo of the reproduction sound heard on the remote side and the volume of the speech of the near-end speaker become the same.

[0175] The variable amplifier 9 multiplies the output signal from the acoustic echo canceller 3 by the first suppression gain or the second suppression gain set by the suppression gain setting unit 8.

[0176] Next, the operation of the communication device 102 in Embodiment 3 of the present disclosure will be described.

[0177] Figure 7 It is a flowchart for explaining the operation of the communication device 102 in Embodiment 3 of the present disclosure.

[0178] Figure 7 The processes of steps S41 to S49 shown are the same as Figure 3 the processes of steps S1 to S9 shown, so the description is omitted.

[0179] Next, in step S50, the suppression gain setting unit 8 sets the first suppression gain Gsup0 for suppressing the volume of the output signal from the acoustic echo canceller 3 to the variable amplifier 9.

[0180] On the other hand, when it is determined that the reproduction sound is not detected (No in step S48), in step S51, the suppression gain setting unit 8 sets the second suppression gain Gsup1 that does not suppress the volume of the output signal from the acoustic echo canceller 3 to the variable amplifier 9. The second suppression gain Gsup1 is 1.

[0181] Figure 7 The process of step S52 shown is the same as Figure 3 the process of step S10 shown, so the description is omitted.

[0182] Next, in step S53, the variable amplifier 9 multiplies the echo cancellation signal output from the acoustic echo canceller 3 by the first suppression gain or the second suppression gain set by the suppression gain setting unit 8.

[0183] Next, in step S54, the variable amplifier 9 outputs the echo-removed signal multiplied by the first suppression gain or the second suppression gain. The variable amplifier 9 outputs the echo-removed signal to the call voice output unit 23. The call voice output unit 23 transmits the echo-removed signal output from the variable amplifier 9 as the near-end call voice to a remote monitoring device (not shown) on the receiving side.

[0184] In this way, when the reproduced sound is detected, the first suppression gain to be multiplied by the output signal from the acoustic echo canceller 3 is set so that the volume of the echo of the reproduced sound heard on the far-end speaker side and the volume of the speech of the near-end speaker become the same. As a result, the volume of the echo of the reproduced sound and the volume of the speech of the near-end speaker located around the microphone 2 can be coordinated, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0185] In addition, in the third embodiment, the communication device 102 may not include the first amplifier 4 .

[0186] (Implementation method 4)

[0187] In the present fourth embodiment, similarly to the second embodiment, the volume difference between the echo of the reproduced sound at the far end and the speech voice of the near end speaker is reduced.

[0188] Figure 8 This is a diagram showing the structure of a communication system in Embodiment 4 of the present disclosure.

[0189] Figure 8 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, and a communication device 103. In the fourth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and their description is omitted.

[0190] The communication device 103 includes an acoustic echo canceller 3A, a first amplifier 4 , a first adder 5 , a reproduced sound detector 6 , a second amplifier 10 , and a second adder 11 . Figure 8 The communication device 103 shown is relative to Figure 1 The communication device 100 shown in the figure further comprises a second amplifier 10 and a second adding unit 11. The other structures are similar to those of the Figure 1 In addition, the communication device 103 may include at least one of the speaker 1 and the microphone 2 .

[0191] The second amplifier 10 suppresses the volume of the reproduced sound. The second amplifier 10 is an example of a volume suppression unit. The second amplifier 10 multiplies the output signal G1·xr(j) from the first amplifier 4 by a given gain G2 (0 < G2 < 1). The second amplifier 10 controls the amplitude of the output signal from the first amplifier 4.

[0192] The second adder 11 adds the reproduced sound with the volume suppressed by the second amplifier 10 to the remote call voice. The second adder 11 adds the remote call voice xf(j) to the output signal G1·G2·xr(j) from the second amplifier 10. The second adder 11 produces the reference signal xf(j) + G1·G2·xr(j) for the acoustic echo canceller 3A.

[0193] The acoustic echo canceller 3A uses the output signal from the second adder 11 as a reference signal to cancel the echo components of the remote call voice and the reproduced sound with the suppressed volume included in the input signal acquired by the microphone 2.

[0194] When the update of the filter coefficient HHAT(j) of the acoustic echo canceller 3A is advanced, the impulse response H of the acoustic echo path from the speaker 1 to the microphone 2 can be accurately estimated, and in the state where the echo of the remote call voice xf(j) has been removed, when the reproduced sound xr(j) is reproduced, the output signal G1·G2·xr(j) from the second amplifier 10 is added to the remote call voice xf(j) through the second adder 11.

[0195] The input signal y(j) output from the microphone 2 is represented by the above formula (2) using the input signal sequence Xf(j) + G1·Xr(j) of the speaker 1 and the impulse response H of the acoustic echo path from the speaker 1 to the microphone 2.

[0196] As shown in the following formula (13), the acoustic echo canceller 3A convolves the estimated filter coefficient HHAT(j) with the output signal sequence Xf(j) + G1·G2·Xr(j) of the second adder 11 to produce the estimated echo yhat(j).

[0197] yhat(j) = HHAT(j) * (Xf(j) + G1·G2·Xr(j))... (13)

[0198] In addition, the echo cancellation signal e(j) output from the acoustic echo canceller 3A is represented by the following formula (14).

[0199] e(j) = y(j) - yhat(j)

[0200] =H*(Xf(j)+G1·Xr(j))-HHAT(j)*(Xf(j)+G1·G2·Xr(j))

[0201] = (H-HHAT(j))*(Xf(j)+G1·Xr(j))+G1·(1-G2)·HHAT(j)*Xr(j)……(14)

[0202] In the above-mentioned equation (14), when HHAT(j)=H, the echo-removed signal e(j) output from the acoustic echo canceller 3A is expressed by the following equation (15).

[0203] e(j)=G1·(1-G2)·H*Xr(j)......(15)

[0204] As shown in the above-mentioned equations (14) and (15), although the echo corresponding to the amount G1·G2 of the long-distance call voice xf(j) and the reproduced sound xr(j) is removed by the acoustic echo canceller 3A, the echo component G1·(1-G2)·H*Xr(j) corresponding to the amount G1·(1-G2) is not removed and is output from the acoustic echo canceller 3A.

[0205] When there is a reproduced sound, the signal amplified from the speaker 1 is xf(j)+G1·xr(j), and the reference signal is xf(j)+G1·G2·xr(j). The signal amplified from the speaker 1 is different from the reference signal, so if the filter coefficient HHAT(j) is updated, the filter coefficient cannot be updated correctly. Therefore, similarly to the first embodiment, when the reproduced sound xr(j) is detected by the reproduced sound detection unit 6, the acoustic echo canceller 3A stops updating the filter coefficient HHAT(j). When the reproduced sound xr(j) is not detected, the acoustic echo canceller 3A updates the filter coefficient.

[0206] Furthermore, the volume of the echo component G1·(1-G2)·H*Xr(j) of the reproduced sound included in the echo-removed signal e(j) output from the acoustic echo canceller 3A can be controlled to be equal to the volume of the speech of the near-end speaker by adjusting the gain G2 of the second amplifier 10. As a result, both the speech of the near-end speaker and the reproduced sound can be easily heard in the remote monitoring device.

[0207] Next, the operation of the communication device 103 in Embodiment 4 of the present disclosure will be described.

[0208] Fig. 9 This is a flowchart for explaining the operation of the communication device 103 in Embodiment 4 of the present disclosure.

[0209] Fig. 9The processing of steps S61 to S65 shown in FIG. Figure 3 The processes in steps S1 to S5 shown are the same, and thus description thereof will be omitted.

[0210] Next, in step S66 , the second amplifier 10 multiplies the output signal (G1·xr(j)) from the first amplifier 4 by a given gain G2. The second amplifier 10 outputs the reproduced sound (G1·G2·xr(j)) multiplied by the gains G1 and G2 to the second adder 11 .

[0211] Next, in step S67, the second adder 11 adds the output signal from the second amplifier 10 to the long-distance call speech. The second adder 11 outputs the long-distance call speech (xf(j)+G1·G2·xr(j)) to which the output signal from the second amplifier 10 is added as a reference signal to the acoustic echo canceller 3A.

[0212] Fig. 9 The processing of steps S68 to S71 shown in FIG. Figure 3 The processes in steps S6 to S9 are the same, and thus their description is omitted.

[0213] Next, in step S72, the acoustic echo canceller 3A uses the remote call voice after the reproduced sound whose volume is suppressed by the gains G1 and G2 as a reference signal to cancel the echo components of the remote call voice and the reproduced sound multiplied by the gains G1 and G2 contained in the input signal acquired by the microphone 2.

[0214] Next, in step S73, the acoustic echo canceller 3A outputs an echo-removed signal obtained by removing the echo components of the remote end call voice and the reproduced sound multiplied by the gains G1 and G2 from the input signal. The acoustic echo canceller 3A outputs the echo-removed signal to the call voice output unit 23. The call voice output unit 23 transmits the echo-removed signal output from the acoustic echo canceller 3A as the near-end call voice to a remote monitoring device (not shown) on the receiving side.

[0215] In this way, the volume of the reproduced sound output from the speaker 1 is different from the volume of the reproduced sound input to the acoustic echo canceller 3A as a reference signal, so that a part of the echo component of the reproduced sound is not eliminated by the acoustic echo canceller 3A and is output, so that the remote speaker can confirm whether the reproduced sound is amplified.

[0216] In Embodiments 2 and 3, the suppression gain is changed depending on whether or not there is a reproduced sound. Therefore, in Embodiments 2 and 3, there is a concern that the background noise may change due to the change in the suppression gain. In Embodiments 2 and 3, when the reproduced sound is reproduced simultaneously with the input of the speech voice of the near-end speaker, there is a concern that the speech voice of the near-end speaker may be suppressed due to the change in the suppression gain. In contrast, in Embodiment 4, when the reproduced sound is reproduced simultaneously with the input of the speech voice of the near-end speaker, the output of the acoustic echo canceller 3A is not suppressed, so the background noise does not change, and there is an advantage that the speech voice of the near-end speaker is not suppressed.

[0217] (Implementation method 5)

[0218] In the fourth embodiment, the volume of the reproduced sound included in the output of the acoustic echo canceller 3A is appropriately controlled when the acoustic echo canceller 3A can sufficiently remove the echo. In contrast, in the fifth embodiment, the volume of the reproduced sound included in the output of the acoustic echo canceller 3A is appropriately controlled even when the acoustic echo canceller 3A cannot remove the echo.

[0219] Fig.10 This is a diagram showing the structure of a communication system in Embodiment 5 of the present disclosure.

[0220] Fig.10 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, and a communication device 104. In Embodiment 5, the same components as those in Embodiments 1 to 4 are denoted by the same reference numerals and their description is omitted.

[0221] The communication device 104 includes an acoustic echo canceller 3A, a first amplifier 4 , a first adder 5 , a reproduced sound detector 6 , a variable amplifier 9 , a second amplifier 10 , a second adder 11 , and a suppression gain setting unit 81 . Fig.10 The communication device 104 is shown relative to Figure 8 The communication device 103 shown in the figure further comprises a suppression gain setting unit 81 and a variable amplifier 9. The other structures are similar to those of FIG. Figure 8 In addition, the communication device 104 may include at least one of the speaker 1 and the microphone 2 .

[0222] When the reproduced sound is detected by the reproduced sound detection unit 6, the suppression gain setting unit 81 estimates the echo cancellation amount of the acoustic echo canceller 3A. The suppression gain setting unit 81 calculates the strength of the filter coefficient, and estimates the echo cancellation amount based on the calculated strength of the filter coefficient. The suppression gain setting unit 81 calculates a first suppression gain for suppressing the volume of the output signal from the acoustic echo canceller 3A based on the estimated echo cancellation amount, and sets the calculated first suppression gain.

[0223] Furthermore, when the reproduced sound detection unit 6 has not detected the reproduced sound, the suppression gain setting unit 81 sets the second suppression gain for not suppressing the volume of the output signal from the acoustic echo canceller 3A.

[0224] The variable amplifier 9 multiplies the output signal from the acoustic echo canceller 3A by the first suppression gain or the second suppression gain set by the suppression gain setting unit 81 .

[0225] When the reproduced sound detection unit 6 detects the reproduced sound, the suppression gain setting unit 81 calculates an estimated value (||HHAT(j)||) of the echo cancellation amount of the acoustic echo canceller 3A using the filter coefficient HHAT(j) of the acoustic echo canceller 3A. 1 / 2 / Pwrh0. ||HHAT(j)|| represents the norm of HHAT(j), which is expressed by the following equation (16). Pwrh0 represents the square root of the total intensity of the impulse response of the acoustic echo path (||H||) 1 / 2 ). Then, the suppression gain setting unit 81 sets the suppression gain Gsup(j) of the variable amplifier 9 to the first suppression gain Gsup0 based on the estimated value of the echo canceling amount.

[0226] ||HHAT(j)||=hhat(j,0) 2 +hhat(j,1) 2 + ... + hhat(j, N-1) 2 …… (16)

[0227] When the reproduced sound detection unit 6 does not detect the reproduced sound, the suppression gain setting unit 81 sets the suppression gain Gsup(j) of the variable amplifier 9 to the second suppression gain Gsup1 that does not suppress the signal. The second suppression gain Gsup1 is 1.

[0228] The variable amplifier 9 suppresses the output signal of the acoustic echo canceller 3A by the first suppression gain Gsup0 or the second suppression gain Gsup1 set by the suppression gain setting unit 81 .

[0229] Specifically, when the reproduced sound is detected by the reproduced sound detection unit 6, the suppression gain setting unit 81 sets the first suppression gain Gsup0 according to the following formula (17).

[0230] Gsup0 = min((1 - G2) / (1 - G2·(||HHAT(j)||) 1 / 2 / Pwrh0), 1)......(17)

[0231] In addition, in formula (17), min(a, b) represents selecting the smaller one of a and b. G1 represents the gain of the first amplifier 4 (0 < G1), G2 represents the gain of the second amplifier 10 (0 < G2 ≤ 1), and j represents the time.

[0232] Fig.11 is a diagram showing the relationship between the strength of the filter coefficient and the first suppression gain when the reproduced sound is detected in Embodiment 5.

[0233] As the update of the filter coefficient HHAT(j) of the acoustic echo canceller 3A progresses, ||HHAT(j)|| gradually increases, and the first suppression gain Gsup0 approaches 1. On the other hand, in a state where the filter coefficient HHAT(j) of the acoustic echo canceller 3A is not updated at all, that is, in a state where ||HHAT(j)|| = 0, the first suppression gain Gsup0 becomes 1 - G2, and the echo component of the reproduced sound is suppressed in the variable amplifier 9. At this time, the volume of the echo of the reproduced sound on the remote side becomes the same as the volume of the echo of the reproduced sound when the acoustic echo canceller 3A has sufficiently removed the echo. If the acoustic echo canceller 3A has sufficiently cancelled the echo, the first suppression gain Gsup0 becomes 1. This is the same state as in Embodiment 4. In Embodiment 5, it is possible to control the suppression gain of the reproduced sound according to the echo removal situation of the acoustic echo canceller 3A, and make the reproduced sound and the speech of the nearby speaker have the same volume on the remote side regardless of the echo cancellation amount of the acoustic echo canceller 3A.

[0234] Next, the operation of the communication device 104 in Embodiment 5 of the present disclosure will be described.

[0235] Fig.12 is the first flowchart for explaining the operation of the communication device 104 in Embodiment 5 of the present disclosure, Fig.13 is the second flowchart for explaining the operation of the communication device 104 in Embodiment 5 of the present disclosure.

[0236] Fig.12 and Fig.13 The processing of steps S81 to S91 shown is the same as the processing of steps S61 to S71 shown in Fig. 9 Therefore, the description is omitted.

[0237] Next, in step S92 , the suppression gain setting unit 81 calculates the strength of the filter coefficient of the acoustic echo canceller 3A, and estimates the echo cancellation amount of the acoustic echo canceller 3A based on the calculated strength of the filter coefficient.

[0238] Next, in step S93 , the suppression gain setting unit 81 calculates a first suppression gain Gsup0 for suppressing the volume of the output signal from the acoustic echo canceller 3A based on the estimated echo cancellation amount, and sets the calculated first suppression gain Gsup0 to the variable amplifier 9 .

[0239] On the other hand, when it is determined that the reproduced sound is not detected (No in step S90), in step S94, the suppression gain setting unit 81 sets the second suppression gain Gsup1 for not suppressing the volume of the output signal from the acoustic echo canceller 3A to the variable amplifier 9. The second suppression gain Gsup1 is 1.

[0240] Fig.13 The processing of step S95 shown is the same as Fig. 9 The processing of step S72 shown is the same, so the description is omitted. Fig.13 The processing of step S96 and step S97 shown in FIG. Figure 7 The processes of step S53 and step S54 are the same, so the description thereof is omitted.

[0241] In this way, when the reproduced sound is detected, the first suppression gain to be multiplied by the output signal from the acoustic echo canceller 3A is set according to the echo cancellation status of the acoustic echo canceller 3A so that the volume of the echo of the reproduced sound heard on the far-end speaker side becomes the same as the volume of the speech of the near-end speaker. Thus, the volume of the echo of the reproduced sound and the volume of the speech of the near-end speaker located around the microphone 2 can be coordinated, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0242] In addition, when the filter coefficient is not updated and the strength of the filter coefficient is small, the echo cancellation amount becomes small, and the volume of the echo of the reproduced sound output from the acoustic echo canceller 3A becomes large. Therefore, before the update of the filter coefficient is advanced and the strength of the filter coefficient becomes large, the echo component of the reproduced sound is suppressed by the first suppression gain. As a result, the volume of the echo of the reproduced sound and the volume of the speech of the near-end speaker located around the microphone 2 can be coordinated, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0243] (Implementation method 6)

[0244] The suppression gain setting unit 81 in the fifth embodiment estimates the echo cancellation amount based on the strength of the filter coefficient of the acoustic echo canceller 3A. In contrast, the suppression gain setting unit in the sixth embodiment estimates the echo cancellation amount based on the level of the input signal input from the microphone 2 to the acoustic echo canceller 3A and the level of the output signal from the acoustic echo canceller 3A.

[0245] Fig.14 This is a diagram showing the structure of a communication system in Embodiment 6 of the present disclosure.

[0246] Fig.14 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, and a communication device 105. In Embodiment 6, the same components as those in Embodiments 1 to 5 are denoted by the same reference numerals and their description is omitted.

[0247] The communication device 105 includes an acoustic echo canceller 3A, a first amplifier 4 , a first adder 5 , a reproduced sound detector 6 , a variable amplifier 9 , a second amplifier 10 , a second adder 11 , and a suppression gain setting unit 82 . Fig.14 The communication device 105 shown in the figure is provided with a suppression gain setting unit 82 instead of Fig.10 The suppression gain setting unit 81 of the communication device 104 shown in FIG. Fig.10 In addition, the communication device 105 may include at least one of the speaker 1 and the microphone 2 .

[0248] When the reproduced sound is detected by the reproduced sound detection unit 6, the suppression gain setting unit 82 estimates the echo cancellation amount of the acoustic echo canceller 3A. The suppression gain setting unit 82 estimates the echo cancellation amount based on the level of the input signal input to the acoustic echo canceller 3A from the microphone 2 and the level of the output signal from the acoustic echo canceller 3A. The suppression gain setting unit 82 calculates a first suppression gain for suppressing the volume of the output signal from the acoustic echo canceller 3A based on the estimated echo cancellation amount, and sets the calculated first suppression gain.

[0249] Furthermore, when the reproduced sound detection unit 6 has not detected the reproduced sound, the suppression gain setting unit 82 sets the second suppression gain for not suppressing the volume of the output signal from the acoustic echo canceller 3A.

[0250] When the reproduction sound is not detected by the reproduction sound detection unit 6, the suppression gain setting unit 82 estimates the echo cancellation amount can(j) based on the ratio of the level of the input signal of the acoustic echo canceller 3A to the level of the output signal of the acoustic echo canceller 3A. When the reproduction sound is not detected by the reproduction sound detection unit 6, the suppression gain setting unit 82 calculates the echo cancellation amount can(j) based on the following formula (18).

[0251] can(j)=min(e ～ (j) / y ～ (j), 1)……(18)

[0252] In addition, in the above formula (18), e ～ (j) represents the short-time average value of the absolute value of the echo cancellation signal e(j), and y ～ (j) represents the short-time average value of the absolute value of the input signal y(j). min(a, b) represents selecting the smaller one of a and b, and j represents the time. The short-time average value of the input signal y(j) of the acoustic echo canceller 3A: y ～ (j) and the short-time average value e ～ (j) of the output signal e(j) are calculated by the same method as xr ～ (j) in the above formula (1).

[0253] In addition, when the reproduction sound is detected by the reproduction sound detection unit 6, the suppression gain setting unit 82 holds the previously estimated echo cancellation amount. When the reproduction sound is detected by the reproduction sound detection unit 6, the suppression gain setting unit 82 calculates the echo cancellation amount can(j) based on the following formula (19).

[0254] can(j)=can(j - 1)……(19)

[0255] When the reproduction sound is detected by the reproduction sound detection unit 6, the suppression gain setting unit 82 calculates the first suppression gain Gsup0 based on the following formula (20), and sets the suppression gain Gsup(j) of the variable amplifier 9 to the calculated first suppression gain Gsup0.

[0256] Gsup0=(1 - G2) / (1 - G2 + G2·can(j))……(20)

[0257] In addition, in the above formula (20), G1 represents the gain of the first amplifier 4 (0 < G1), G2 represents the gain of the second amplifier 10 (0 < G2 ≤ 1), and j represents the time.

[0258] When the reproduced sound detection unit 6 does not detect the reproduced sound, the suppression gain setting unit 82 sets the suppression gain Gsup(j) of the variable amplifier 9 to the second suppression gain Gsup1 that does not suppress the signal. The second suppression gain Gsup1 is 1.

[0259] Fig.15 This is a diagram showing the relationship between the echo cancellation amount and the first suppression gain when reproduced sound is detected in the sixth embodiment.

[0260] When the reproduced sound detection unit 6 does not detect the reproduced sound, echo suppression is not performed, and therefore the suppression gain Gsup(j) of the variable amplifier 9 is 1 (second suppression gain Gsup1 ).

[0261] When the reproduced sound detection unit 6 detects the reproduced sound and the acoustic echo canceller 3A does not completely cancel the echo, the echo cancellation amount can(j) becomes 1 and the first suppression gain Gsup0 becomes minimum. At this time, the first suppression gain Gsup0 becomes 1-G2.

[0262] On the other hand, when the reproduced sound detection unit 6 detects the reproduced sound and the acoustic echo canceller 3A sufficiently cancels the echo, the echo cancellation amount can(j) becomes small. When can(j)≈0, the first suppression gain Gsup0 becomes 1.

[0263] The sixth embodiment differs from the fifth embodiment only in the calculation process of the suppression gain, and the other processes are the same as those of the fifth embodiment. Therefore, the description of the operation of the communication device 105 in the sixth embodiment is omitted.

[0264] According to the sixth embodiment, for example, the echo cancellation amount indicates the ratio of the level of the input signal input from the microphone 2 to the acoustic echo canceller 3A to the level of the output signal from the acoustic echo canceller 3A. When the acoustic echo canceller 3A does not cancel the echo, the echo cancellation amount becomes 1, and the volume of the echo of the reproduced sound output from the acoustic echo canceller 3A becomes larger. Therefore, before the acoustic echo canceller 3A fully cancels the echo, the echo component of the reproduced sound is suppressed by the first suppression gain. Thus, the volume of the echo of the reproduced sound and the volume of the speech of the near-end speaker located around the microphone 2 can be coordinated, and both the echo of the reproduced sound and the speech of the near-end speaker can be easily heard on the far-end speaker side.

[0265] (Implementation method 7)

[0266] In the first embodiment, only the remote call speech is input as a reference signal to the acoustic echo canceller 3. In contrast, in the seventh embodiment, the remote call speech with the reproduced sound added thereto is input as a reference signal to the acoustic echo canceller, and the reproduced sound is added to the output signal from the acoustic echo canceller.

[0267] Fig.16 This is a diagram showing the structure of a communication system in Embodiment 7 of the present disclosure.

[0268] Fig.16 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, and a communication device 106. In Embodiment 7, the same components as those in Embodiment 1 are denoted by the same reference numerals and their description is omitted.

[0269] The communication device 106 includes an acoustic echo canceller 3B, a first amplifier 4, a first adder 5, a third amplifier 12, and a third adder 13. The communication device 106 may include at least one of a speaker 1 and a microphone 2.

[0270] The first adder 5 adds the remote call voice and the output signal G1·xr(j) from the first amplifier. The first adder 5 adds the reproduced sound to the remote call voice of the remote speaker, and outputs the call voice to which the reproduced sound is added to the speaker 1 and the acoustic echo canceller 3B. The output signal xf(j)+G1·xr(j) from the first adder 5 is a reference signal for the acoustic echo canceller 3B. The output signal from the first adder 5 is also amplified from the speaker 1.

[0271] The acoustic echo canceller 3B uses the output signal from the first adding unit 5 as a reference signal to cancel the echo components of the call voice and the reproduced sound contained in the input signal acquired by the microphone 2. The acoustic echo canceller 3B removes not only the echo component of the remote call voice but also the echo component of the reproduced sound. The remote call voice xf(j) to which the reproduced sound G1·xr(j) with the volume adjusted is added is input to the acoustic echo canceller 3B as a reference signal, and the input signal y(j) from the microphone 2 is input to the acoustic echo canceller 3B. The acoustic echo canceller 3B removes the acoustic echo that is amplified from the speaker 1 and enters the microphone 2.

[0272] The third amplifier 12 multiplies the reproduced sound by a given gain G3. The third amplifier 12 adjusts the volume of the reproduced sound and outputs the reproduced sound with the adjusted volume to the third adder 13. The third amplifier 12 is an example of a second volume adjuster. The gain G3 of the third amplifier 12 is determined so that the speech voice of the near-end speaker and the reproduced sound become equal on the far-end side.

[0273] The third adding unit 13 adds the output signal from the third amplifier 12 and the output signal from the acoustic echo canceller 3B. The third adding unit 13 adds the reproduced sound to the output signal from the acoustic echo canceller 3B. The third adding unit 13 is an example of the second adding unit. The third adding unit 13 adds the reproduced sound whose volume is adjusted by the third amplifier 12 to the output signal from the acoustic echo canceller 3B.

[0274] As in the first embodiment, the long-distance call voice xf(j) is amplified from the speaker 1 and picked up as an echo component by the microphone 2, but the echo component is removed by the acoustic echo canceller 3B. Also, unlike the first embodiment, the echo component of the reproduced sound xr(j) is removed by the acoustic echo canceller 3B.

[0275] The reproduced sound G1·G3·xr(j) whose volume is adjusted by the third amplifier 12 is added to the echo-removed signal e(j) output from the acoustic echo canceller 3B by the third adder 13, and e(j)+G1·G3·xr(j) is sent to the remote end. Therefore, the reproduced sound can be confirmed at the remote end.

[0276] In the first embodiment, the echo of the reproduced sound obtained by amplifying the sound from the speaker 1 and picking up the sound by the microphone 2 is sent to the remote side, but in the seventh embodiment, the reproduced sound G1·G3·xr(j) obtained by multiplying the reproduced sound G1·xr(j) input to the speaker 1 by the gain G3 of the third amplifier 12 is sent to the remote side. Therefore, there is an effect that a clear reproduced sound without an echo can be confirmed at the remote side without passing through the acoustic echo path.

[0277] Next, the operation of the communication device 106 in Embodiment 7 of the present disclosure will be described.

[0278] Fig.17 This is a flowchart for explaining the operation of the communication device 106 in Embodiment 7 of the present disclosure.

[0279] Fig.17 The processing of steps S101 to S102 shown in FIG. Figure 3 The processes of step S1 to step S2 shown are the same, and thus description thereof will be omitted.

[0280] Next, in step S103, the first amplifier 4 adjusts the volume of the reproduced sound. The first amplifier 4 multiplies the reproduced sound by a given gain G1. The gain G1 is predetermined according to the environment in which the communication device 100 is used. The first amplifier 4 outputs the reproduced sound with the adjusted volume to the first adder 5 and the third amplifier 12.

[0281] Fig.17 The processing of step S104 shown in FIG. Figure 3 The processing of step S4 shown is the same, so the description is omitted.

[0282] Next, in step S105, the first adder 5 outputs the remote call voice with the reproduced sound added thereto to the speaker 1 and the acoustic echo canceller 3B. The speaker 1 amplifies the remote call voice with the reproduced sound added thereto. The acoustic echo canceller 3B uses the remote call voice with the reproduced sound added thereto as a reference signal.

[0283] Fig.17 The processing of step S106 shown in FIG. Figure 3 The processing of step S6 shown is the same, so the description is omitted.

[0284] Next, in step S107 , the acoustic echo canceller 3B uses the long-distance call voice to which the reproduced sound is added as a reference signal to cancel the echo components of the long-distance call voice and the reproduced sound included in the input signal acquired by the microphone 2 .

[0285] Next, in step S108, the third amplifier 12 adjusts the volume of the reproduced sound output from the first amplifier 4 after multiplication by the gain G1. The third amplifier 12 multiplies the output signal from the first amplifier 4 by a given gain G3. The gain G3 is predetermined so that the speech voice of the near-end speaker and the reproduced sound become equal on the far-end side. The third amplifier 12 outputs the reproduced sound with the adjusted volume to the third adder 13.

[0286] Next, in step S109, the third adding unit 13 adds the reproduced sound output from the third amplifier 12 to the echo-removed signal output from the acoustic echo canceller 3B. The third adding unit 13 adds the reproduced sound G1·G3·xr(j) whose volume is adjusted by the first amplifier 4 and the third amplifier 12 to the echo-removed signal e(j) from the acoustic echo canceller 3B.

[0287] Next, in step S110, the third adding unit 13 outputs the echo-removed signal to which the reproduced sound is added to the call voice output unit 23. The call voice output unit 23 transmits the echo-removed signal to which the reproduced sound is added output from the third adding unit 13 to a remote monitoring device (not shown) on the receiving side as the near-end call voice.

[0288] In this way, the echo component of the reproduced sound that is bypassed from the speaker 1 to the microphone 2 is removed by the acoustic echo canceller 3B. Then, the reproduced sound is added to the output signal from the acoustic echo canceller 3B from which the echo component of the reproduced sound has been removed, and the output signal to which the reproduced sound that does not pass through the acoustic echo path is added is output to the remote speaker side. Therefore, the remote speaker can confirm the clear reproduced sound that is not an acoustic echo.

[0289] In addition, in the seventh embodiment, the communication device 106 may not include the first amplifier 4 and the third amplifier 12 .

[0290] (Implementation method 8)

[0291] In the case of a remote conference or remote speech, there is a need for the remote speaker to confirm that his or her own voice is amplified on the other side. Therefore, the communication device of embodiment 8 amplifies the remote communication voice from the speaker 1 and sends the remote communication voice picked up by the microphone 2 back to the remote communication device on the receiving side.

[0292] Fig.18 This is a diagram showing the structure of a communication system in Embodiment 8 of the present disclosure.

[0293] Fig.18 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, a control signal input unit 24, and a communication device 107A. In Embodiment 8, the same components as those in Embodiment 1 are denoted by the same reference numerals and their description is omitted.

[0294] The control signal input unit 24 outputs a control signal indicating whether to send the remote call voice back to the remote side to the call device 107A. The control signal is sent by the remote call device (not shown) on the receiving side. The control signal input unit 24 is connected to a communication unit (not shown). The communication unit receives the control signal from the remote monitoring device on the receiving side via the network. The remote monitoring device receives an input from the remote speaker regarding whether to send the remote call voice back to the remote side.

[0295] The communication device 107A includes an acoustic echo canceller 3 , a first amplifier 4 , a first adder 5 , a reproduced sound detector 6 , and a reference switch 14 . Fig.18 The communication device 107A shown is relative to Figure 1 The communication device 100 shown in FIG. 1 has a reference switch 14 added between the communication voice input unit 21 and the acoustic echo canceller 3. The other structures are similar to those of FIG. 1 . Figure 1 In addition, the communication device 107A may include at least one of the speaker 1 and the microphone 2 .

[0296] The reference switching switch 14 switches between an on state in which the remote call voice is input as a reference signal to the acoustic echo canceller 3 and an off state in which the remote call voice is not input as a reference signal to the acoustic echo canceller 3, based on a control signal indicating whether to send the remote call voice back to the remote side. The on / off state of the reference switching switch 14 is switched according to a control signal input from the control signal input unit 24. Normally, the reference switching switch 14 is set to be on.

[0297] When a control signal indicating that the remote call voice is sent back to the remote side is input, the reference switch 14 is switched to the off state. That is, when the remote speaker confirms that the remote call voice is amplified on the other party side, the control signal input unit 24 obtains a control signal for setting the reference switch 14 to the off state. Then, the reference switch 14 is set to the off state.

[0298] When the reference switching switch 14 is set to on, the remote call voice is removed by the acoustic echo canceller 3. In this case, the remote speaker cannot hear the remote call voice that is amplified on the other party side. On the other hand, when the reference switching switch 14 is set to off, the remote call voice is not removed by the acoustic echo canceller 3. In this case, the remote speaker can hear the remote call voice that is amplified on the other party side.

[0299] When the reference changeover switch 14 is set to OFF, 0 is input as a reference signal of the acoustic echo canceller 3 instead of the long-distance call speech xf(j). Thus, updating of coefficients of the adaptive filter of the acoustic echo canceller 3 is stopped.

[0300] As described above, when a control signal indicating that the remote call voice is sent back to the remote side is input, the reference switch 14 is switched to an OFF state in which the remote call voice is not input as a reference signal to the acoustic echo canceller. Therefore, the remote call voice is not removed by the acoustic echo canceller 3, and the remote speaker can confirm that his or her own call voice is amplified on the other side.

[0301] (Implementation method 9)

[0302] The communication device of the ninth embodiment is similar to the communication device of the eighth embodiment. The speaker 1 amplifies the remote communication voice and the remote communication voice picked up by the microphone 2 is sent back to the remote communication device on the receiving side.

[0303] Fig.19 This is a diagram showing the structure of a communication system in Embodiment 9 of the present disclosure.

[0304] Fig.19 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, a control signal input unit 24, and a communication device 107B. In Embodiment 9, the same components as those in Embodiment 1 are denoted by the same reference numerals and their description is omitted.

[0305] The control signal input unit 24 outputs a control signal indicating whether to send the remote call voice back to the remote speaker to the call device 107B. The control signal is sent by the remote call device (not shown) on the receiving side. The control signal input unit 24 is connected to a communication unit (not shown). The communication unit receives the control signal from the remote monitoring device on the receiving side via the network. The remote monitoring device receives an input from the remote speaker regarding whether to send the remote call voice back to the remote side.

[0306] The communication device 107B includes an acoustic echo canceller 3 , a first amplifier 4 , a first adder 5 , a reproduced sound detector 6 , a fourth amplifier 15 , and a fourth adder 16 . Fig.19 The communication device 107B shown is relative to Figure 1 The communication device 100 shown in FIG. 1 has a fourth adding unit 16 added between the acoustic echo canceller 3 and the communication voice output unit 23, and a fourth amplifier 15 added between the communication voice input unit 21 and the fourth adding unit 16. The other structures are similar to those of FIG. 1 . Figure 1 In addition, the communication device 107B may include at least one of the speaker 1 and the microphone 2 .

[0307] The fourth amplifier 15 adjusts the volume of the remote call voice input to the fourth adder 16 based on the control signal indicating whether to send the remote call voice back to the remote side. The fourth amplifier 15 is an example of the third volume adjustment unit. The fourth amplifier 15 adjusts the volume of the remote call voice from the call voice input unit 21 based on the control signal input from the control signal input unit 24. When the control signal indicating that the remote call voice is sent back to the remote side is input, the fourth amplifier 15 adjusts the remote call voice to a volume that the remote speaker can hear. In addition, when the control signal indicating that the remote call voice is not sent back to the remote side is input, the fourth amplifier 15 adjusts the remote call voice to a volume that the remote speaker cannot hear.

[0308] The fourth amplifier 15 changes the gain according to the control signal input from the control signal input unit 24. When the control signal is an instruction to send the remote call voice back to the remote side, the fourth amplifier 15 multiplies the remote call voice from the call voice input unit 21 by a given gain G4. The gain G4 is predetermined so that the speech voice of the near-end speaker and the remote call voice become equal on the remote side. When the control signal is an instruction not to send the remote call voice back to the remote side, the fourth amplifier 15 multiplies the remote call voice from the call voice input unit 21 by 0 to mute the remote call voice.

[0309] The fourth adding unit 16 adds the output signal from the fourth amplifier 15 and the output signal from the acoustic echo canceller 3. The fourth adding unit 16 is an example of the third adding unit. When a control signal indicating that the remote call voice is sent back to the remote side is input, the fourth adding unit 16 adds the remote call voice amplified by the fourth amplifier 15 to the output signal from the acoustic echo canceller 3. When a control signal indicating that the remote call voice is not sent back to the remote side is input, the fourth adding unit 16 does not add the remote call voice to the output signal from the acoustic echo canceller 3.

[0310] In this way, when a control signal indicating that the remote call voice is sent back to the remote side is input, the call voice is adjusted to a volume that the remote speaker can hear. Therefore, the remote call voice adjusted to a volume that the remote speaker can hear by the fourth amplifier 15 is added to the output signal from the acoustic echo canceller 3, so the remote speaker can confirm that his or her call voice is amplified on the other side.

[0311] (Implementation 10)

[0312] The communication device of Embodiment 10, like the communication devices of Embodiments 8 and 9, amplifies the remote communication voice from the speaker 1 and sends the remote communication voice picked up by the microphone 2 back to the remote communication device on the receiving side.

[0313] Fig. 20 This is a diagram showing the structure of a communication system in Embodiment 10 of the present disclosure.

[0314] Fig. 20 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, a control signal input unit 24, and a communication device 108A. In the tenth embodiment, the same reference numerals are used for the same structures as those in the first and seventh embodiments, and the description thereof is omitted.

[0315] The control signal input unit 24 outputs a control signal indicating whether to send the remote call voice back to the remote side to the call device 108A. The control signal is sent by the remote call device (not shown) on the receiving side. The control signal input unit 24 is connected to a communication unit (not shown). The communication unit receives the control signal from the remote monitoring device on the receiving side via the network. The remote monitoring device receives an input from the remote speaker regarding whether to send the remote call voice back to the remote side.

[0316] The communication device 108A includes an acoustic echo canceller 3B, a first amplifier 4 , a first adder 5 , a third amplifier 12 , a third adder 13 , and a reference changeover switch 14 . Fig. 20The communication device 108A shown is relative to Fig.16 The communication device 106 shown in the figure has a reference switch 14 added between the first adding unit 5 and the acoustic echo canceller 3B. Fig.16 In addition, the communication device 108A may include at least one of the speaker 1 and the microphone 2 .

[0317] The reference switching switch 14 switches between an on state in which the output signal from the first adding unit 5 is input as a reference signal to the acoustic echo canceller 3B, and an off state in which the output signal from the first adding unit 5 is not input as a reference signal to the acoustic echo canceller 3B, based on a control signal indicating whether to send the remote call voice back to the remote side. The on / off state of the reference switching switch 14 is switched in accordance with a control signal input from the control signal input unit 24. Normally, the reference switching switch 14 is set to be on.

[0318] When a control signal indicating that the remote call voice is sent back to the remote side is input, the reference switch 14 is switched to the off state. That is, when the remote speaker confirms that the remote call voice is amplified on the other party side, the control signal input unit 24 obtains a control signal for setting the reference switch 14 to the off state. Then, the reference switch 14 is set to the off state.

[0319] When the reference switching switch 14 is set to on, the output signal xf(j)+G1·xr(j) from the first adding unit 5 is removed by the acoustic echo canceller 3B. In this case, the remote speaker cannot hear the remote call voice that has been amplified on the other side. On the other hand, when the reference switching switch 14 is set to off, the output signal xf(j)+G1·xr(j) from the first adding unit 5 is not removed by the acoustic echo canceller 3B. In this case, the remote speaker can hear the remote call voice that has been amplified on the other side.

[0320] When the reference switch 14 is set to OFF, 0 is input as the reference signal of the acoustic echo canceller 3B instead of the output signal xf(j)+G1·xr(j) from the first adder 5. Thus, updating of coefficients of the adaptive filter of the acoustic echo canceller 3B is stopped.

[0321] As described above, when a control signal indicating that the remote call voice is sent back to the remote side is input, the reference switch 14 is switched to an OFF state in which the output signal from the first adder 5 is not input as a reference signal to the acoustic echo canceller 3B. Therefore, the remote call voice is not removed by the acoustic echo canceller 3B, and the remote speaker can confirm that his or her call voice is amplified on the other side.

[0322] (Implementation 11)

[0323] The communication device of Embodiment 11 is similar to the communication devices of Embodiments 8 to 10 in that the remote communication voice is amplified from the speaker 1 and the remote communication voice picked up by the microphone 2 is sent back to the remote communication device on the receiving side.

[0324] Fig.21 This is a diagram showing the structure of a communication system in Embodiment 11 of the present disclosure.

[0325] Fig.21 The communication system shown includes a speaker 1, a microphone 2, a call voice input unit 21, a reproduced sound input unit 22, a call voice output unit 23, a control signal input unit 24, and a communication device 108B. In Embodiment 11, the same reference numerals are used for the same structures as those in Embodiments 1 and 7, and the description thereof is omitted.

[0326] The control signal input unit 24 outputs a control signal indicating whether to send the remote call voice back to the remote side to the call device 108B. The control signal is sent by the remote call device (not shown) on the receiving side. The control signal input unit 24 is connected to a communication unit (not shown). The communication unit receives the control signal from the remote monitoring device on the receiving side via the network. The remote monitoring device receives an input from the remote speaker regarding whether to send the remote call voice back to the remote side.

[0327] The communication device 108B includes an acoustic echo canceller 3B, a first amplifier 4 , a first adder 5 , a third amplifier 12 , a third adder 13 , a fourth amplifier 15 , and a fourth adder 16 . Fig.21 The communication device 108B shown is relative to Fig.16 The communication device 106 shown in FIG. 1 has a fourth adding unit 16 added between the third adding unit 13 and the communication voice output unit 23, and a fourth amplifier 15 added between the communication voice input unit 21 and the fourth adding unit 16. The other structures are similar to those of FIG. Fig.16 In addition, the communication device 108B may include at least one of the speaker 1 and the microphone 2 .

[0328] The fourth amplifier 15 adjusts the volume of the remote call voice input to the fourth adder 16 based on the control signal indicating whether to send the remote call voice back to the remote side. The fourth amplifier 15 is an example of the third volume adjustment unit. The fourth amplifier 15 adjusts the volume of the remote call voice from the call voice input unit 21 based on the control signal input from the control signal input unit 24. When the control signal indicating that the remote call voice is sent back to the remote side is input, the fourth amplifier 15 adjusts the call voice to a volume that the remote speaker can hear. In addition, when the control signal indicating that the remote call voice is not sent back to the remote side is input, the fourth amplifier 15 adjusts the call voice to a volume that the remote speaker cannot hear.

[0329] The fourth amplifier 15 changes the gain according to the control signal input from the control signal input unit 24. When the control signal is an instruction to send the remote call voice back to the remote side, the fourth amplifier 15 multiplies the remote call voice from the call voice input unit 21 by a given gain G4. The gain G4 is predetermined so that the speech voice of the near-end speaker and the remote call voice become equal on the remote side. When the control signal is an instruction not to send the remote call voice back to the remote side, the fourth amplifier 15 multiplies the remote call voice from the call voice input unit 21 by 0 to mute the remote call voice.

[0330] The fourth adding unit 16 adds the output signal from the fourth amplifier 15 and the output signal e(j)+G1·G3·xr(j) from the third adding unit 13. The fourth adding unit 16 is an example of the third adding unit. When a control signal indicating that the remote call voice is sent back to the remote side is input, the fourth adding unit 16 adds the remote call voice amplified by the fourth amplifier 15 to the output signal from the third adding unit 13. When a control signal indicating that the remote call voice is not sent back to the remote side is input, the fourth adding unit 16 does not add the remote call voice to the output signal from the third adding unit 13.

[0331] In this way, when a control signal indicating that the remote call voice is sent back to the remote side is input, the remote call voice is adjusted to a volume that the remote speaker can hear. Therefore, the remote call voice adjusted to a volume that the remote speaker can hear by the fourth amplifier 15 is added to the output signal from the third adding unit 13, so the remote speaker can confirm that his or her own call voice is amplified on the other side.

[0332] Next, the configurations of a vehicle and a remote monitoring device including the communication device 100 according to the first embodiment will be described.

[0333] Fig. 22This is a diagram showing the configuration of a vehicle 201 including the communication device 100 according to the first embodiment and a remote monitoring device 202 .

[0334] The vehicle 201 includes a speaker 1, a microphone 2, a call device 100, and a communication unit 110. Fig. 22 In the embodiment, the same components as those of the first embodiment are denoted by the same reference numerals and their description is omitted. In addition, vehicle 201 may include any one of communication devices 101 to 108B of the second to eleventh embodiments instead of communication device 100 of the first embodiment.

[0335] The communication unit 110 includes a call audio input unit 21 , a reproduced sound input unit 22 , and a call audio output unit 23 .

[0336] The communication unit 110 receives the remote call voice of the remote monitor transmitted by the remote monitoring device 202. The communication unit 110 outputs the received remote call voice to the communication device 100. The communication unit 110 transmits the near-end call voice output from the communication device 100 to the remote monitoring device 202. The near-end call voice is a voice signal including the call voice of the near-end speaker and the echo of the reproduced sound, and the echo component of the remote call voice is removed. The communication unit 110 receives the reproduced sound transmitted by the remote monitoring device 202. The communication unit 110 outputs the received reproduced sound to the communication device 100. In addition, the communication device 100 may also include the communication unit 110.

[0337] The vehicle 201 is connected to the remote monitoring device 202 so as to be able to communicate with each other via a network 203. The network 203 is, for example, the Internet or a mobile phone network.

[0338] The remote monitoring device 202 includes a microphone 41, an operation unit 42, a speaker 43, a storage unit 210, a reading unit 211, and a communication unit 212. The remote monitoring device 202 is an example of a remote communication device.

[0339] The microphone 41 collects the voice of the remote monitor. The microphone 212 outputs the remote call voice representing the collected voice to the communication unit 212.

[0340] The operation unit 42 is, for example, a keyboard, a mouse, or a touch panel, and receives input operations from a remote monitor. The operation unit 42 receives selection of a reproduced sound to be output to the outside of the vehicle 201 from among a plurality of reproduced sounds by the remote monitor.

[0341] Furthermore, the operation unit 42 may receive input of control information for remotely controlling the vehicle 201. The remote monitor uses the operation unit 42 to move the vehicle 201.

[0342] The storage unit 210 stores a plurality of reproduced sounds in advance.

[0343] The reading unit 211 reads out the reproduced sound selected by the operation unit 42 from among the plurality of reproduced sounds stored in the storage unit 210 .

[0344] The communication unit 212 transmits the long-end call voice output from the microphone 41 to the vehicle 201. The communication unit 212 receives the near-end call voice transmitted from the vehicle 201 and outputs it to the speaker 43. The communication unit 212 transmits the reproduced sound read by the reading unit 211 to the vehicle 201.

[0345] The speaker 43 amplifies the near-end conversation voice transmitted from the vehicle 201 side.

[0346] like Fig. 22 As shown, the communication device 100 may also acquire the reproduced sound transmitted from the remote monitoring device 202 .

[0347] Fig.23 This is a diagram showing another configuration of a vehicle 201A and a remote monitoring device 202A including the communication device 100 according to the first embodiment.

[0348] The vehicle 201A includes a speaker 1, a microphone 2, a communication device 100, a storage unit 111, a communication unit 112, and a reading unit 113. Fig.23 In the embodiment, the same components as those of the first embodiment are denoted by the same reference numerals and their description is omitted. In addition, the vehicle 201A may include any one of the communication devices 101 to 108B of the second to eleventh embodiments instead of the communication device 100 of the first embodiment.

[0349] The storage unit 111 stores a plurality of reproduced sounds in advance.

[0350] The communication unit 112 includes a call audio input unit 21 and a call audio output unit 23 .

[0351] The communication unit 112 receives the remote call voice of the remote monitor transmitted by the remote monitoring device 202A. The communication unit 112 outputs the received remote call voice to the communication device 100. The communication unit 112 transmits the near-end call voice output from the communication device 100 to the remote monitoring device 202A. The near-end call voice is a voice signal including the call voice of the near-end speaker and the echo of the reproduced sound, and the echo component of the remote call voice is removed. The communication unit 112 receives the reproduction information specifying the reproduced sound to be output among the plurality of reproduced sounds from the remote monitoring device 202A.

[0352] The reading unit 113 reads out the reproduced sound specified by the reproduction information received by the communication unit 112 from the storage unit 111. The reading unit 113 outputs the read reproduced sound to the communication device 100. The reading unit 113 includes the reproduced sound input unit 22.

[0353] Furthermore, the communication device 100 may include a storage unit 111 , a communication unit 112 , and a reading unit 113 .

[0354] The vehicle 201A is connected to the remote monitoring device 202A so as to be able to communicate with each other via a network 203. The network 203 is, for example, the Internet.

[0355] The remote monitoring device 202A includes a microphone 41, an operation unit 42, a speaker 43, and a communication unit 213. The remote monitoring device 202A is an example of a remote communication device. Fig.23 The microphone 41 and the speaker 43 are shown with Fig. 22 The microphone 41 and the loudspeaker 43 shown are identical.

[0356] The operation unit 42 is, for example, a keyboard, a mouse, or a touch panel, and receives input operations from a remote monitor. The operation unit 42 receives selection of a reproduced sound to be output to the outside of the vehicle 201A from among a plurality of reproduced sounds by the remote monitor.

[0357] The communication unit 213 transmits the long-end call voice output from the microphone 41 to the vehicle 201A. The communication unit 213 receives the near-end call voice transmitted from the vehicle 201A and outputs it to the speaker 43. The communication unit 213 transmits the reproduction information specifying the reproduced sound selected by the operation unit 42 and output from the vehicle 201A among the plurality of reproduced sounds to the vehicle 201A.

[0358] like Fig.23 As shown, the communication device 100 may also acquire the reproduced sound pre-stored in the vehicle 201A or the communication device 100 .

[0359] In addition, in each of the above-mentioned embodiments, each component may also be constituted by dedicated hardware, or implemented by executing a software program suitable for each component. Each component may also be implemented by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. In addition, the program may also be implemented by another independent computer system by recording the program on a recording medium and transferring it or by transferring the program via a network.

[0360] Part or all of the functions of the device involved in the embodiments of the present disclosure are typically implemented as LSI (Large Scale Integration) as an integrated circuit. They can be monolithic individually or monolithic to include part or all. In addition, integrated circuitization is not limited to LSI, and can also be implemented by a dedicated circuit or a general-purpose processor. It is also possible to use an FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connection and setting of the circuit unit inside the LSI.

[0361] Furthermore, a part or all of the functions of the apparatus according to the embodiment of the present disclosure may be realized by executing a program by a processor such as a CPU.

[0362] In addition, all the numbers used above are exemplified in order to specifically describe the present disclosure, and the present disclosure is not limited to the exemplified numbers.

[0363] In addition, the order of executing each step shown in the above flowchart is an illustrative order for specifically explaining the present disclosure, and an order other than the above may be used within the scope of obtaining the same effect. In addition, part of the above steps may also be executed simultaneously (in parallel) with other steps.

[0364] Industrial Applicability

[0365] The technology disclosed herein can eliminate the acoustic echo generated by amplifying the conversation voice of a remote speaker, and the remote speaker can confirm whether the reproduced sound has been amplified. Therefore, it is useful as a technology for amplifying a given reproduced sound for the surroundings and conducting a conversation between a person in the surroundings and the remote speaker.

Claims

1. A communication device that amplifies a given reproduced sound to a surrounding area and enables a communication between a person in the surrounding area and a remote speaker, comprising: a first adding unit that adds the reproduced sound to the call speech of the remote speaker and outputs the call speech to which the reproduced sound is added to a speaker; and The acoustic echo canceller uses the call voice as a reference signal to cancel an echo component of the call voice included in an input signal acquired by a microphone that collects surrounding sounds.

2. The communication device according to claim 1, wherein: The communication device further comprises: a reproduced sound detection unit for detecting the presence or absence of the reproduced sound; The acoustic echo canceller stops updating of filter coefficients of an adaptive filter when the reproduced sound is detected by the reproduced sound detection unit.

3. The communication device according to claim 1 or 2, wherein: The communication device further includes a first volume adjustment unit that adjusts the volume of the reproduced sound and outputs the reproduced sound with the adjusted volume to the first adder.

4. The communication device according to claim 1 or 2, wherein: The communication device further includes an automatic gain control unit that automatically adjusts the volume of an output signal from the acoustic echo canceller.

5. The communication device according to claim 2, wherein: The communication device also has: a suppression gain setting unit for setting a first suppression gain for suppressing the volume of the output signal from the acoustic echo canceller when the reproduced sound is detected by the reproduced sound detection unit, and for setting a second suppression gain for not suppressing the volume of the output signal from the acoustic echo canceller when the reproduced sound is not detected by the reproduced sound detection unit; and The variable amplifier multiplies the output signal from the acoustic echo canceller by the first suppression gain or the second suppression gain set by the suppression gain setting unit.

6. The communication device according to claim 1, wherein: The communication device also has: a volume suppressing unit that suppresses the volume of the reproduced sound; and a second adding unit that adds the reproduced sound whose volume is suppressed by the volume suppressing unit to the call voice; The acoustic echo canceller cancels the echo components of the call voice and the reproduced sound with suppressed volume included in the input signal acquired by the microphone, using the output signal from the second adding unit as a reference signal.

7. The communication device according to claim 6, wherein: The communication device further comprises: a reproduced sound detection unit for detecting the presence or absence of the reproduced sound; The acoustic echo canceller stops updating of filter coefficients of an adaptive filter when the reproduced sound is detected by the reproduced sound detection unit.

8. The communication device according to claim 7, wherein: The communication device also has: a suppression gain setting unit for estimating an echo cancellation amount of the acoustic echo canceller when the reproduced sound is detected by the reproduced sound detection unit, setting a first suppression gain for suppressing the volume of an output signal from the acoustic echo canceller based on the estimated echo cancellation amount, and for not suppressing the volume of the output signal from the acoustic echo canceller when the reproduced sound is not detected by the reproduced sound detection unit; and The variable amplifier multiplies the output signal from the acoustic echo canceller by the first suppression gain or the second suppression gain set by the suppression gain setting unit.

9. The communication device according to claim 8, wherein: The suppression gain setting unit calculates the strength of the filter coefficient, and estimates the echo cancellation amount based on the calculated strength of the filter coefficient.

10. The communication device according to claim 8, wherein: The suppression gain setting unit estimates the echo cancellation amount based on a level of the input signal input from the microphone to the acoustic echo canceller and a level of an output signal from the acoustic echo canceller.

11. The communication device according to claim 1, wherein: The acoustic echo canceller uses the output signal from the first adding unit as a reference signal to cancel the echo components of the call voice and the reproduced sound included in the input signal acquired by the microphone. The communication device further includes a second adding unit that adds the reproduced sound to an output signal from the acoustic echo canceller.

12. The communication device according to claim 11, wherein: The communication device further comprises: a second volume adjustment unit for adjusting the volume of the reproduced sound; The second adding section adds the reproduced sound whose volume is adjusted by the second volume adjusting section to the output signal from the acoustic echo canceller.

13. The communication device according to claim 1 or 2, wherein: The communication device further comprises: a switch for switching between an on state in which the communication voice is input as the reference signal to the acoustic echo canceller and an off state in which the communication voice is not input as the reference signal to the acoustic echo canceller, based on a control signal indicating whether the communication voice is sent back to the remote side; When the control signal indicating that the call voice is to be sent back to the remote side is input, the switch is switched to the OFF state.

14. The communication device according to claim 1 or 2, wherein: The communication device also has: a third adding unit that adds the call voice to the output signal from the acoustic echo canceller; and The third volume adjustment unit adjusts the volume of the call voice input to the third adding unit based on a control signal indicating whether to send the call voice back to the remote side. The third volume adjustment unit adjusts the call voice to the volume that the remote speaker can hear when the control signal indicating that the call voice is sent back to the remote side is input, and adjusts the call voice to the volume that the remote speaker cannot hear when the control signal indicating that the call voice is not sent back to the remote side is input.

15. The communication device according to claim 11 or 12, wherein: The communication device further comprises: a switch, which switches between an on state in which the output signal from the first adding unit is input as the reference signal to the acoustic echo canceller, and an off state in which the output signal from the first adding unit is not input as the reference signal to the acoustic echo canceller, based on a control signal indicating whether the communication voice is sent back to the remote side. When the control signal indicating that the call voice is to be sent back to the remote side is input, the switch is switched to the OFF state.

16. The communication device according to claim 11 or 12, wherein: The communication device also has: a third adding unit that adds the call voice to the output signal from the second adding unit; and The third volume adjustment unit adjusts the volume of the call voice input to the third adding unit based on a control signal indicating whether to send the call voice back to the remote side. The third volume adjustment unit adjusts the call voice to the volume that the remote speaker can hear when the control signal indicating that the call voice is sent back to the remote side is input, and adjusts the call voice to the volume that the remote speaker cannot hear when the control signal indicating that the call voice is not sent back to the remote side is input.

17. The communication device according to claim 1 or 2, wherein: The communication device also has: A storage unit that stores a plurality of reproduced sounds in advance; a communication unit that receives, from the remote communication device, reproduction information that specifies a reproduced sound to be output among the plurality of reproduced sounds; and The reading unit reads the reproduced sound specified by the reproduction information from the storage unit.

18. The communication device according to claim 1 or 2, wherein: The communication device further includes a communication unit that receives the reproduced sound transmitted from a remote communication device.

19. A communication method, in a communication device, which amplifies a given reproduced sound to surroundings and conducts a communication between a person in the surroundings and a remote speaker, the communication method comprising: adding the reproduced sound to the conversation voice of the remote speaker, and outputting the conversation voice to which the reproduced sound is added to a speaker; The call speech is used as a reference signal to cancel an echo component of the call speech included in an input signal acquired by a microphone that collects surrounding sounds.

20. A communication program for amplifying a given reproduced sound to a surrounding area and for making a communication between a person in the surrounding area and a remote speaker, the communication program causing a computer to function as a first adder and an acoustic echo canceller. the first adding unit adds the reproduced sound to the call speech of the remote speaker, and outputs the call speech to which the reproduced sound is added to a speaker, The acoustic echo canceller uses the call voice as a reference signal to cancel an echo component of the call voice included in an input signal acquired by a microphone that collects surrounding sounds.

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