Control system and control method of loudspeaker in field domain

Abstract

The invention provides a control system and a control method of a loudspeaker in a field domain. The control method includes: outputting an audio signal by a first speaker corresponding to a first output power and a second speaker corresponding to a second output power; measuring, by the first microphone, a first volume and a first time delay corresponding to the audio signal; performing calculation of an optimization algorithm according to the first output power, the second output power, the first volume and the first time delay to obtain a first suggested output power corresponding to the first loudspeaker and a second suggested output power corresponding to the second loudspeaker; and configuring the first output power according to the first suggested output power, and configuring the second output power according to the second suggested output power.

Description

Technical Field

[0001] The present invention relates to a speaker control technology, and in particular to a control system and a control method of a speaker in a field. Background Art

[0002] Generally speaking, multiple speakers are installed in a large conference room to spread the speaker's voice to various locations in the conference room. Since the distance between each listener and the speaker may be different, the volume heard by each listener may also be different. As a result, some listeners may not be able to hear or hear the speaker's voice clearly. Therefore, how to make each listener in the conference room have a similar experience when listening to the speaker's speech is one of the important topics in this field. Summary of the invention

[0003] The invention provides a control system and a control method for a loudspeaker in a field, which can control the loudspeaker so that each audience in a conference room can hear the speaker's voice at a moderate volume.

[0004] A control system for a speaker in a field of the present invention comprises a first speaker, a second speaker, a first microphone and a controller. The first speaker corresponds to a first output power. The second speaker corresponds to a second output power. The controller is communicatively connected to the first speaker, the second speaker and the first microphone, wherein the controller is configured to perform: outputting an audio signal through the first speaker and the second speaker; measuring a first volume and a first time delay corresponding to the audio signal through the first microphone; performing calculation of an optimization algorithm according to the first output power, the second output power, the first volume and the first time delay to obtain a first recommended output power corresponding to the first speaker and a second recommended output power corresponding to the second speaker; and configuring the first output power according to the first recommended output power, and configuring the second output power according to the second recommended output power.

[0005] In one embodiment of the present invention, the optimization algorithm comprises a dynamic causal Bayesian optimization algorithm.

[0006] In one embodiment of the present invention, the objective function of the dynamic causal Bayesian optimization algorithm includes a mean square error between the reference volume and the first volume.

[0007] In one embodiment of the present invention, the control system further comprises a second microphone which is communicatively connected to the controller, wherein the second microphone obtains a sound wave corresponding to a second volume, and wherein the objective function of the dynamic causal Bayesian optimization algorithm comprises a mean square error between the second volume and the first volume.

[0008] In one embodiment of the present invention, the constraint conditions of the dynamic causal Bayesian optimization algorithm include an upper limit value and a lower limit value of the first recommended output power and an upper limit value and a lower limit value of the second recommended output power.

[0009] In an embodiment of the present invention, the first speaker outputs an audio signal at a first time point, and the first microphone receives the audio signal at a second time point, wherein the controller is further configured to execute: calculating a difference between the second time point and the first time point to obtain a first time delay.

[0010] In one embodiment of the present invention, the above-mentioned controller is further configured to perform: executing calculations of an optimization algorithm based on the first output power, the second output power, the first volume and the first time delay to obtain a recommended time delay corresponding to the first speaker; calculating the propagation delay based on the distance between the first speaker and the first microphone; subtracting the propagation delay from the recommended time delay to obtain a recommended output delay; and configuring the output delay of the first speaker according to the recommended output delay.

[0011] In one embodiment of the present invention, the controller is further configured to perform: outputting a first audio signal through a first speaker, and outputting a second audio signal through a second speaker; measuring a first propagation time of the first audio signal from the first speaker to the first microphone through a first microphone, and measuring a second propagation time of the second audio signal from the second speaker to the first microphone through the first microphone; generating first positioning information of the first microphone according to a first position of the first speaker, a first propagation time, a second position of the second speaker, and a second propagation time; and calculating a distance according to the first positioning information.

[0012] In one embodiment of the present invention, the first microphone comprises a first transceiver, and the controller is further configured to execute: transmitting at least one reference signal; receiving at least one reference signal through the first transceiver to measure the positioning parameters of the first microphone; and calculating the distance according to the positioning parameters.

[0013] In one embodiment of the present invention, the controller is further configured to: generate positioning information of the first microphone by executing ultra-wideband positioning method, enhanced cell identification code positioning method or arrival time difference measurement method according to the positioning parameters; and calculate the distance according to the positioning information of the first microphone.

[0014] The present invention provides a method for controlling a speaker in a field: an audio signal is output by a first speaker corresponding to a first output power and a second speaker corresponding to a second output power; a first volume and a first time delay corresponding to the audio signal are measured by a first microphone; an optimization algorithm is calculated based on the first output power, the second output power, the first volume and the first time delay to obtain a first recommended output power corresponding to the first speaker and a second recommended output power corresponding to the second speaker; and the first output power is configured according to the first recommended output power, and the second output power is configured according to the second recommended output power.

[0015] In one embodiment of the present invention, the optimization algorithm comprises a dynamic causal Bayesian optimization algorithm.

[0016] In one embodiment of the present invention, the objective function of the dynamic causal Bayesian optimization algorithm includes a mean square error between the reference volume and the first volume.

[0017] In one embodiment of the present invention, the control method further comprises: obtaining a sound wave corresponding to a second volume from a second microphone, wherein the objective function of the dynamic causal Bayesian optimization algorithm comprises a mean square error between the second volume and the first volume.

[0018] In one embodiment of the present invention, the constraints of the dynamic causal Bayesian optimization algorithm include an upper limit value and a lower limit value of the first recommended output power and an upper limit value and a lower limit value of the second recommended output power.

[0019] In an embodiment of the present invention, the first speaker outputs an audio signal at a first time point, and the first microphone receives the audio signal at a second time point, wherein the control method further comprises: calculating a difference between the second time point and the first time point to obtain a first time delay.

[0020] In one embodiment of the present invention, the above-mentioned control method further includes: executing an optimization algorithm to calculate according to the first output power, the second output power, the first volume and the first time delay to obtain a recommended time delay corresponding to the first speaker; calculating the propagation delay according to the distance between the first speaker and the first microphone; subtracting the propagation delay from the recommended time delay to obtain a recommended output delay; and configuring the output delay of the first speaker according to the recommended output delay.

[0021] In one embodiment of the present invention, the above-mentioned control method further includes: outputting a first audio signal through a first speaker, and outputting a second audio signal through a second speaker; measuring a first propagation time of the first audio signal from the first speaker to the first microphone through the first microphone, and measuring a second propagation time of the second audio signal from the second speaker to the first microphone through the first microphone; generating first positioning information of the first microphone according to a first position of the first speaker, a first propagation time, a second position of the second speaker, and a second propagation time; and calculating a distance according to the first positioning information.

[0022] In an embodiment of the present invention, the control method further comprises: transmitting at least one reference signal; receiving at least one reference signal through the first microphone to measure the positioning parameter of the first microphone; and calculating the distance according to the positioning parameter.

[0023] In one embodiment of the present invention, the control method further comprises: executing ultra-wideband positioning method, enhanced cell identification code positioning method or arrival time difference measurement method according to the positioning parameters to generate positioning information of the first microphone; and calculating the distance according to the positioning information of the first microphone.

[0024] Based on the above, the control system of the present invention can configure the output power or output delay of the loudspeaker so that the sound heard by each listener in the venue has a similar volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of a control system for a loudspeaker in a field is shown according to an embodiment of the present invention.

[0026] Figure 2 A flow chart of a method for controlling a loudspeaker in a field is shown according to an embodiment of the present invention.

[0027] Figure 3 A schematic diagram of a first scenario of a scene is shown according to an embodiment of the present invention.

[0028] Figure 4 A schematic diagram of a second scenario of a scene is shown according to an embodiment of the present invention.

[0029] Figure 5 A schematic diagram is shown according to an embodiment of the present invention showing that a scene changes from a first scenario to a third scenario.

[0030] Figure 6 A flow chart of a method for controlling a loudspeaker in a field is shown according to an embodiment of the present invention.

[0031] The reference numerals are described as follows:

[0032] 10: Control system

[0033] 100: Controller

[0034] 20: Field

[0035] 200: Speaker

[0036] 300: Microphone

[0037] 210, 310, 400: transceiver

[0038] S201, S202, S203, S204, S205, S601, S602, S603, S604: Steps DETAILED DESCRIPTION

[0039] In order to make the content of the present invention more understandable, the following embodiments are given as examples that the present invention can be implemented. In addition, wherever possible, the elements / components / steps with the same reference numerals in the drawings and embodiments represent the same or similar parts.

[0040] Figure 1 According to one embodiment of the present invention, a schematic diagram of a control system 10 for a speaker in a field is shown. The control system 10 may include a controller 100, N speakers 200, such as speaker #1, speaker #2, speaker #3, or speaker #N. N may be any positive integer greater than or equal to 2. In addition, the controller 10 may include M microphones 300, such as microphone #1, microphone #2, microphone #3, or microphone #M. M may be any positive integer. In one embodiment, the control system 10 may further include P transceivers 400, such as transceiver #1, transceiver #2, or transceiver #P. P may be any positive integer. In one embodiment, the control system 10 may be implemented by a multimedia server or a cloud server.

[0041] The controller 100 is, for example, a central processing unit (CPU), or other programmable general-purpose or special-purpose micro control unit (MCU), microprocessor, digital signal processor (DSP), programmable controller, application specific integrated circuit (ASIC), graphics processing unit (GPU), image signal processor (ISP), image processing unit (IPU), arithmetic logic unit (ALU), complex programmable logic device (CPLD), field programmable gate array (FPGA), or other similar components or combinations thereof. The controller 100 can be communicatively connected to the speaker 200, the microphone 300, or the transceiver 400.

[0042] The controller 100 may configure the speaker 200 so that the speaker 200 outputs an audio signal according to the output power and the output delay. The speaker 200 may be set at various locations in a field (e.g., a conference room). The microphone 300 is used to obtain or measure sound waves or audio signals. The microphone 300 is, for example, a portable device or microphone device held by a participant of the meeting, such as a microphone, a mobile phone, a tablet computer, or a laptop computer in a conference room. In this embodiment, it is assumed that microphone #1 (or the second microphone) is held by the speaker of the meeting, and other microphones such as microphone #2 (or the first microphone), microphone #3, or microphone #M are held by the audience of the meeting. In one embodiment, the speaker 200 may include a transceiver 210. The speaker 200 may transmit a wireless signal to the transceiver 400 or receive a wireless signal from the transceiver 400 via the transceiver 210.

[0043] The transceiver 400 may transmit and receive signals wirelessly or wiredly. The transceiver 400 may also perform operations such as low noise amplification, impedance matching, mixing, up or down frequency conversion, filtering, amplification, and the like. The communication protocols supported by the transceiver 400 may include, but are not limited to, ultra-wideband (UWB) communication protocol, global navigation satellite system (GNSS), location management function (LMF), or new radio positioning protocol annex (NRPPa).

[0044] In one embodiment, the microphone 300 may include a transceiver 310. The microphone 300 may transmit wireless signals to the transceiver 400 or receive wireless signals from the transceiver 400 via the transceiver 310.

[0045] Figure 2 According to an embodiment of the present invention, a flow chart of a method for controlling a loudspeaker in a field is shown, wherein the control method may be performed as follows: Figure 1 The control system 10 shown is implemented. In step S201, the controller 100 can obtain the positioning information of each speaker 200 and the positioning information of each microphone 300. The positioning information of the speaker 200 is, for example, the coordinates of the speaker 200 in the field. The positioning information of the microphone 300 is, for example, the coordinates of the microphone 300 in the field. Since the speakers in the field are usually set at fixed positions, the position information of the speaker 200 is predefined. However, in some cases, the speaker 200 can also move in the field, so the position information of the speaker 200 can also change dynamically. In order to obtain the positioning information of each speaker 200, the controller 100 can perform positioning on the speaker 200, and the speaker 200 transmits the positioning information to the controller 100 through the transceiver 210. That is, the controller 100 can obtain the positioning information of the speaker 200 from the speaker 200 through wireless communication technology. On the other hand, since the listener carrying the microphone 300 may move in the field, the positioning information of the microphone 300 can change dynamically. In order to obtain the positioning information of each microphone 300, the controller 100 can perform positioning on the microphone 300, and the microphone 300 transmits the positioning information to the controller 100 via the transceiver 310. In other words, the controller 100 can obtain the positioning information of the microphone 300 from the microphone 300 through wireless communication technology.

[0046] In one embodiment, the controller 100 may locate the microphone 300 according to the audio signals output by the plurality of speakers 200 to obtain first positioning information of the microphone 300, wherein the first positioning information includes, for example, the coordinates of the microphone 300 in the field. Specifically, the controller 100 may output a plurality of audio signals respectively corresponding to the plurality of speakers 200 through the plurality of speakers 200. The controller 100 may receive the audio signals output by each speaker 200 through the microphone 300, and measure the propagation time of the audio signals from each speaker 200 to the microphone 300. The controller 100 may generate the first positioning information of the microphone 300 according to the positions of each speaker 200 and each propagation time.

[0047] by Figure 3 For example, in order to obtain the positioning information of microphone #2, the controller 100 may output multiple audio signals through speaker #1 or speaker #2 respectively. The controller 100 may receive the audio signal from speaker #1 through microphone #2 and measure the propagation time of the audio signal from speaker #1 to microphone #2. On the other hand, the controller 100 may receive the audio signal from speaker #2 through microphone #2 and measure the propagation time of the audio signal from speaker #2 to microphone #2. The controller 100 may generate the first positioning information of microphone #2 according to the position of speaker #1, the propagation time from speaker #1 to microphone #2, the position of speaker #2 and the propagation time from speaker #2 to microphone #2, wherein the first positioning information includes, for example, the coordinates of microphone #2 in field 20. The controller 100 may calculate the distance between microphone 300 and speaker 200 according to the first positioning information and the positioning information of speaker 200.

[0048] In one embodiment, the controller 100 may locate the microphone 300 according to the electromagnetic wave signals output by the plurality of transceivers 400 to obtain the positioning parameters of the microphone 300, and calculate the second positioning information (or the third positioning information) according to the positioning parameters, wherein the second positioning information (or the third positioning information) includes, for example, the coordinates of the microphone 300 in the field. Specifically, the controller 100 may output a plurality of reference signals respectively corresponding to the plurality of transceivers 400 through the plurality of transceivers 400. The controller 100 may receive the reference signals output by each transceiver 400 through the transceiver 310 of the microphone 300 to measure the positioning parameters of the microphone 300. The controller 100 may perform the ultra-wideband positioning method according to the positioning parameters to generate the second positioning information of the microphone 300. On the other hand, the controller 100 may perform the enhanced cell identification (E-CID) positioning method or the observed time difference on arrival (OTDOA) method according to the positioning parameters to generate the third positioning information of the microphone 300. The above positioning parameters may include but are not limited to time of flight (TOF), two-way ranging, reference signal received power (RSRP), time of arrival (TOA), time difference of arrival (TDOA), time advanced (TADV), round trip time (RTT) or angle-of-arrival (AoA). The controller 100 may calculate the distance between the microphone 300 and the speaker 200 according to the second positioning information (or the third positioning information) and the positioning information of the speaker 200. In one embodiment, based on the same method as above, the controller 100 may locate the speaker 200 according to the electromagnetic wave signals output by the multiple transceivers 400 to obtain the positioning parameters of the speaker 200, and calculate the positioning information of the speaker 200 according to the positioning parameters, wherein the positioning information of the speaker 200, for example, includes the coordinates of the speaker 200 in the field.

[0049] In one embodiment, the controller 100 may calculate more accurate positioning information of the microphone 300 by comprehensively considering the first positioning information of the microphone 300 and the second positioning information (or third positioning information) generated according to the positioning parameters. For example, the controller 100 may perform data fusion, complementary positioning, hierarchical positioning, or a machine learning algorithm based on the first positioning information, the second positioning information, and the third positioning information to generate more accurate positioning information of the microphone 300. The controller 100 may calculate the distance between the microphone 300 and the speaker 200 based on the positioning information of the microphone 300 and the positioning information of the speaker 200.

[0050] In step S202 , the controller 100 may determine which of the plurality of microphones 300 is the speaker's microphone (ie, microphone # 1 ).

[0051] In one embodiment, the controller 100 may determine which of the multiple microphones 300 is microphone #1 based on the time point at which each microphone 300 receives the audio signal. The microphone 300 that receives the audio signal earliest may be determined by the controller 100 as microphone #1 corresponding to the speaker. Figure 3 For example, assume that microphone #1 belongs to the speaker, and microphone #2 and microphone #3 belong to the audience. When the speaker speaks at a first time point, microphone #1 can receive the sound waves containing the audio signal emitted by the speaker, and the controller 100 can output the audio signal obtained by microphone #1 through speaker #1 or speaker #2. Then, microphone #2 can receive the sound waves emitted by the speaker or the audio signal output from the speaker at a time point after the first time point, and microphone #3 can receive the sound waves emitted by the speaker or the audio signal output from the speaker at a time point after the first time point. Since the first time point at which microphone #1 receives the audio signal is earlier than the time point at which microphone #2 or microphone #3 receives the audio signal, the controller 100 can determine that microphone #1 corresponds to the speaker.

[0052] In one embodiment, the controller 100 may determine which of the multiple microphones 300 is microphone #1 based on the volume (or sound pressure) of the audio signal received by the multiple microphones 300, where the unit of volume is, for example, decibel (dB). The microphone 300 that receives the audio signal with the highest volume may be determined by the controller 100 as microphone #1 corresponding to the speaker. Figure 3For example, assume that microphone #1 belongs to the speaker, and microphone #2 and microphone #3 belong to the audience. When the speaker is speaking, the speaker is closer to microphone #1, resulting in the sound wave containing the audio signal received by microphone #1 having a larger volume. On the other hand, since the speaker is farther away from microphone #2 or microphone #3, the audio signal received by microphone #2 or microphone #3 has a smaller volume. Accordingly, the controller 100 can determine that microphone #1 corresponds to the speaker in response to the volume of the audio signal received by microphone #1 being greater than the volume of the audio signal received by microphone #2 or microphone #3.

[0053] In step S203, the controller 100 may obtain the output power SPK(i) of each speaker 200, the volume MIC(j) of the audio signal received by each microphone 300, and the time delay D(k) of each microphone 300. The output power SPK(i) represents the output power of the i-th speaker 200 (i.e., speaker #i) among the N speakers 200, and i=1-N. The volume MIC(j) represents the volume corresponding to the j-th microphone 300 (i.e., microphone #j) among the M microphones 300, and j=1-M, where index j=1 corresponds to the speaker (i.e., microphone #1), and index j=2-M corresponds to the audience (i.e., microphone #2 to microphone #M). The time delay D(k) represents the time delay of the k-th microphone 300 (i.e., microphone #k) among the M microphones 300, and k=2-M, where index k=2-M corresponds to the audience. Specifically, the controller 100 may control each speaker 200 to output an audio signal according to a predefined output power, and may measure the volume or time delay corresponding to the audio signal received by the microphone 300 through each microphone 300. In one embodiment, the time delay D(k) may be a vector, and the time delay D(k) may include the time delay between the kth microphone 300 and each speaker 200. For example, the time delay D(k)=[D(k,1)D(k,2)…D(k,N)], where D(k,1) corresponds to the time delay between the kth microphone 300 and the first speaker 200, D(k,2) corresponds to the time delay between the kth microphone 300 and the second speaker 200, and D(k,N) corresponds to the time delay between the kth microphone 300 and the Nth speaker 200.

[0054] In one embodiment, the time delay D(k) may include the difference between the time point at which each speaker 200 outputs an audio signal and the time point at which microphone #k receives the audio signal (i.e., the propagation delay between the speaker 200 and the microphone #k). For example, the time delay D(k) may be a vector and D(k)=[D(k,1)D(k,2)…D(k,N)], where D(k,1) is the difference between the time point at which the first speaker 200 outputs an audio signal and the time point at which the kth microphone 300 receives the audio signal, D(k,2) is the difference between the time point at which the second speaker 200 outputs an audio signal and the time point at which the kth microphone 300 receives the audio signal, and D(k,N) is the difference between the time point at which the Nth speaker 200 outputs an audio signal and the time point at which the kth microphone 300 receives the audio signal. Figure 3 For example, Figure 3 According to an embodiment of the present invention, a schematic diagram of a first scenario of a field 20 is shown. In the first scenario, a speaker and a microphone #1 carried by the speaker are located in the field 20. When the speaker speaks, the microphone #1 can obtain sound waves to transmit an audio signal corresponding to the sound waves to the controller 100, and the controller 100 can output the audio signal through the speaker #1 and the speaker #2 at time point t1. The microphone #2 can receive the audio signal from the speaker #1 at time point t2, and receive the audio signal from the speaker #2 at time point t3. The controller 100 can calculate the difference between the time point t2 and the time point t1 (i.e., t2-t1) and the difference between the time point t3 and the time point t1 (i.e., t3-t1), thereby obtaining the time delay D(2)=[D(2,1)D(2,2)] corresponding to microphone #2, where D(2,1) represents the time delay between microphone #2 and speaker #1, and D(2,2) represents the time delay between microphone #2 and speaker #2. In the same way, the controller 100 can obtain the time delay D(3)=[D(3,1)D(3,2)] corresponding to microphone #3, where D(3,1) represents the time delay between microphone #3 and speaker #1, and D(3,2) represents the time delay between microphone #3 and speaker #2.

[0055] In one embodiment, the controller 100 may calculate the propagation delay according to the distance between the speaker 200 and the microphone #k, and define the propagation delay as the time delay between the speaker 200 and the microphone #k, where the propagation delay is equal to the distance divided by the speed of sound (e.g., 340 m / s). Figure 4 For example, Figure 4According to an embodiment of the present invention, a schematic diagram of a second scenario of the field 20 is shown. In the second scenario, microphone #1 is not in the field 20, that is, the speaker may be conducting a remote meeting. When the speaker speaks, microphone #1 can obtain sound waves and transmit an audio signal corresponding to the sound waves to the controller 100 through the Internet. The controller 100 can output an audio signal to microphone #2 through speaker #1 and speaker #2. The controller 100 can calculate the propagation delay from speaker #1 to microphone #2 based on the distance between microphone #2 and speaker #1, and set the propagation delay to time delay D(2,1). The controller 100 can calculate the propagation delay from speaker #2 to microphone #2 based on the distance between microphone #2 and speaker #2, and set the propagation delay to time delay D(2,2). In this way, the controller 100 can obtain the time delay D(2)=[D(2,1)D(2,2)] corresponding to microphone #2. On the other hand, the controller 100 can output an audio signal to the microphone #3 through the speaker #1 and the speaker #2. The controller 100 can calculate the propagation delay from the speaker #1 to the microphone #3 according to the distance between the microphone #3 and the speaker #1, and set the propagation delay as the time delay D(3,1). The controller 100 can calculate the propagation delay from the speaker #2 to the microphone #3 according to the distance between the microphone #3 and the speaker #2, and set the propagation delay as the time delay D(3,2). In this way, the controller 100 can obtain the time delay D(3) = [D(3,1)D(3,2)] corresponding to the microphone #3. Accordingly, the transmission delay of the Internet can be prevented from seriously affecting the value of the time delay D(2) or D(3).

[0056] In step S204 , the controller 100 may perform calculations of an optimization algorithm according to the output power SPK(i) of each speaker 200 , the volume MIC(j) of the audio signal received by each microphone 300 , and the time delay D(k) of each microphone 300 , so as to obtain a recommended output power and a recommended output delay corresponding to each speaker 200 .

[0057] In one embodiment, the controller 100 may perform calculations using a dynamic causal Bayesian optimization (DCBO) algorithm to obtain the recommended output power and recommended output delay corresponding to each speaker 200, as shown in formula (1), where represents the objective function of the DCBO algorithm, SPK(i) represents the output power of speaker #i among the N speakers 200, MIC(j) represents the volume of microphone #j corresponding to the M microphones 300, D(k) represents the time delay of microphone #k among the M microphones 300, and T represents the reference volume (e.g., 70 dB). In one embodiment, formula (1) may further include constraints TH1 < SPK(i) < TH2 and TH3 < D(k) < TH4, where TH1 represents the lower limit value of the output power of the speaker 200 (e.g., the output power to make the speaker 200 output a sound of 20 decibels), TH2 represents the upper limit value of the output power of the speaker 200 (e.g., the output power to make the speaker 200 output a sound of 80 decibels), TH3 represents the lower limit value of the time delay of the speaker 200 (e.g., 0.01 seconds), and TH4 represents the upper limit value of the time delay of the speaker 200 (e.g., 0.08 seconds).

[0058]

[0059] The purpose of the objective function of formula (1) is to make the volume of the audio signal received by each microphone 300 as close as possible to the reference volume. The reference volume can be a custom value. In one embodiment, the reference volume T may be equal to the volume of the sound wave received by microphone #1, so that the volume of the sound heard by the listener is the same as the volume of the sound emitted by the speaker. The output power SPK(i)' that satisfies formula (1) is the recommended output power corresponding to speaker #i, and the time delay D(k)' that satisfies formula (1) is the recommended time delay corresponding to microphone #k. The recommended time delay D(k)' = [D(k,1)' D(k,2)'... D(k,N)'], where D(k,i)' represents the recommended time delay between microphone #k and speaker #i. The recommended time delay D(k,i)' may include the output delay of speaker #i itself plus the propagation delay P(i,k) between speaker #i and microphone #k. Accordingly, the controller 100 can calculate the recommended output delay RD(i) corresponding to speaker #i according to formula (2).

[0060] RD(i) = D(k,i)′ - P(i,k), k ∈ {2, 3,..., M}, i ∈ {1, 2,..., N}...(2)

[0061] With Figure 5For example, based on Equation (1), the controller 100 can generate a proposed delay time D(2)' = [D(2,1)' = 0.07 seconds, D(2,2)' = 0.04 seconds] corresponding to the microphone #2 and a proposed delay time D(3)' = [D(3,1)' = 0.06 seconds, D(3,2)' = 0.03 seconds] corresponding to the microphone #3 according to the output power SPK(1) of the speaker #1, the output power SPK(2) of the speaker #2, the time delay D(2) = [D(2,1) D(2,2)] of the microphone #2, and the time delay D(3) = [D(3,1) D(3,2)] of the microphone #3. If the propagation delay P(1,2) between the microphone #2 and the speaker #1 is 0.03 seconds, the controller 100 can calculate a proposed output delay RD(1) = D(2,1)' - P(1,2) = 0.04 seconds corresponding to the speaker #1 according to Equation (2). Optionally, if the propagation delay P(1,3) between the microphone #3 and the speaker #1 is 0.02 seconds, the controller 100 can calculate a proposed output delay RD(1) = D(3,1)' - P(1,3) = 0.04 seconds corresponding to the speaker #1 according to Equation (2). On the other hand, if the propagation delay P(2,2) between the microphone #2 and the speaker #2 is 0.02 seconds, the controller 100 can calculate a proposed output delay RD(2) = D(2,2)' - P(2,2) = 0.02 seconds corresponding to the speaker #2 according to Equation (2). Optionally, if the propagation delay P(2,3) between the microphone #3 and the speaker #2 is 0.01 seconds, the controller 100 can calculate a proposed output delay RD(2) = D(3,2)' - P(2,3) = 0.02 seconds corresponding to the speaker #2 according to Equation (2).

[0062] In one embodiment, the controller 100 can perform calculations based on the DCBO algorithm to further obtain a proposed input volume corresponding to each microphone 300, as shown in Equation (3), where represents the objective function of the DCBO algorithm, SPK(i) represents the output power of the speaker #i among the N speakers 200, MIC(j) represents the volume of the microphone #j corresponding to the M microphones 300, D(k) represents the time delay of the microphone #k among the M microphones 300, and T represents the reference volume. In one embodiment, Equation (3) can further include constraint conditions TH1 < SPK(i) < TH2 and TH3 < D(k) < TH4, where TH1 represents the lower limit value of the output power of the speaker 200, TH2 represents the upper limit value of the output power of the speaker 200, TH3 represents the lower limit value of the time delay of the speaker 200, and TH4 represents the upper limit value of the time delay of the speaker 200.

[0063]

[0064] The volume MIC(j)' that satisfies formula (3) is the recommended input volume corresponding to microphone #j. The controller 100 can control the sensitivity of microphone #j (unit: mV / Pa) according to the voltage (unit: millivolt (mV)) so that the volume of the audio signal received by microphone #j meets the recommended input volume.

[0065] In an embodiment, the controller 100 can perform calculations based on the DCBO algorithm to further obtain the recommended positions corresponding to each microphone 300 and each speaker 200, as shown in formula (4), where represents the objective function of the DCBO algorithm, SPK(i) represents the output power of speaker #i among the N speakers 200, MIC(j) represents the volume of microphone #j corresponding to the M microphones 300, D(k) represents the time delay of microphone #k among the M microphones 300, T represents the reference volume, C(i) represents the coordinates of speaker #i in the field 20, and c(j) represents the coordinates of microphone #j in the field 20. In an embodiment, formula (4) may further include the constraint conditions TH1 < SPK(i) < TH2 and TH3 < D(k) < TH4, where TH1 represents the lower limit value of the output power of the speaker 200, TH2 represents the upper limit value of the output power of the speaker 200, TH3 represents the lower limit value of the time delay of the speaker 200, and TH4 represents the upper limit value of the time delay of the speaker 200.

[0066]

[0067] The coordinate C(i)' that satisfies formula (4) is the recommended position corresponding to speaker #i, and the coordinate c(j)' that satisfies formula (4) is the recommended position corresponding to microphone #j. The organizer of the meeting can move the positions of each speaker 200 or microphone 300 in the field 20 according to the optimization result of formula (4).

[0068] In step S205, the controller 100 can configure the output power of the speaker 200 according to the recommended output power of the speaker 200 so that the audio signals heard by each listener have a similar volume. In an embodiment, the controller 100 can further configure the output delay of the speaker 200 according to the recommended output delay of the speaker 200 to reduce the interference of echo on the meeting and also make the audio volumes heard by the listeners similar.

[0069] The output power SPK(i), volume MIC(j) and time delay D(k) in formula (1) or formula (3) may change over time. For example, the output power SPK(i) may be affected by factors such as speaker aging, ambient humidity or voltage; the volume MIC(j) may be affected by factors such as microphone aging, ambient humidity or temperature; and the time delay D(k) may be affected by factors such as speaker aging, air temperature or air density. In order to maintain the best experience for conference participants, in one embodiment, the controller 100 may repeatedly execute the following as time changes. Figure 2 The process shown in FIG. 1 is used to dynamically configure the output power and output delay of the speaker 200. Figure 5 For example, Figure 5 According to an embodiment of the present invention, a schematic diagram of the scene 20 changing from the first scenario to the third scenario is shown. If the listener holding microphone #2 moves to a different position in the scene 20, the volume MIC(2) of the audio signal received by microphone #2 and the time delay D(2) of microphone #2 will change. Accordingly, the controller 100 can perform the calculation of the optimization algorithm according to the changed volume MIC(2) and time delay D(2), and then update the recommended output power and recommended output delay corresponding to each speaker 200.

[0070] Figure 6 According to an embodiment of the present invention, a flow chart of a method for controlling a loudspeaker in a field is shown, wherein the control method may be performed as follows: Figure 1 The control system 10 shown in FIG. 1 is implemented. In step S601, an audio signal is outputted by a first speaker corresponding to a first output power and a second speaker corresponding to a second output power. In step S602, a first volume and a first time delay corresponding to the audio signal are measured by a first microphone. In step S603, an optimization algorithm is calculated based on the first output power, the second output power, the first volume and the first time delay to obtain a first recommended output power corresponding to the first speaker and a second recommended output power corresponding to the second speaker. In step S604, the first output power is configured based on the first recommended output power, and the second output power is configured based on the second recommended output power.

[0071] In summary, the control system of the present invention can obtain the parameters of each speaker (e.g., output power) and each microphone (e.g., volume and time delay) in the field, optimize these parameters, and configure the output power and output delay of the speaker according to the optimization result. Therefore, the control system can make the sound heard by each listener in the field have a similar volume, and can reduce the interference of echo on the meeting, thereby improving the fluency and efficiency of the meeting.

Claims

1. A control system for a loudspeaker in a field, comprising: a first speaker corresponding to a first output power; a second speaker corresponding to a second output power; First microphone; as well as a controller communicatively connected to the first speaker, the second speaker, and the first microphone, wherein the controller is configured to perform: outputting an audio signal through the first speaker and the second speaker; measuring a first volume and a first time delay corresponding to the audio signal by the first microphone; Executing a calculation of an optimization algorithm according to the first output power, the second output power, the first volume, and the first time delay to obtain a first recommended output power corresponding to the first speaker and a second recommended output power corresponding to the second speaker; as well as The first output power is configured according to the first recommended output power, and the second output power is configured according to the second recommended output power.

2. The control system of claim 1, wherein the optimization algorithm comprises a dynamic causal Bayesian optimization algorithm. 3 . The control system of claim 2 , wherein an objective function of the dynamic causal Bayesian optimization algorithm comprises a mean square error between a reference volume and the first volume.

4. The control system of claim 2, further comprising: A second microphone is communicatively connected to the controller, wherein the second microphone obtains a sound wave corresponding to a second volume, wherein the objective function of the dynamic causal Bayesian optimization algorithm includes a mean square error between the second volume and the first volume.

5. The control system of claim 2, wherein the constraints of the dynamic causal Bayesian optimization algorithm include an upper limit value and a lower limit value of the first recommended output power and an upper limit value and a lower limit value of the second recommended output power.

6. The control system of claim 1, wherein the first speaker outputs the audio signal at a first time point, and the first microphone receives the audio signal at a second time point, wherein the controller is further configured to perform: The difference between the second time point and the first time point is calculated to obtain the first time delay.

7. The control system of claim 1, wherein the controller is further configured to perform: performing the calculation of the optimization algorithm according to the first output power, the second output power, the first volume, and the first time delay to obtain a recommended time delay corresponding to the first speaker; calculating a propagation delay based on a distance between the first speaker and the first microphone; subtracting the propagation delay from the proposed time delay to obtain a proposed output delay; and An output delay of the first speaker is configured according to the recommended output delay.

8. The control system of claim 7, wherein the controller is further configured to perform: outputting a first audio signal through the first speaker, and outputting a second audio signal through the second speaker; measuring, through the first microphone, a first propagation time of the first audio signal from the first loudspeaker to the first microphone, and measuring, through the first microphone, a second propagation time of the second audio signal from the second loudspeaker to the first microphone; generating first positioning information of the first microphone according to a first position of the first speaker, the first propagation time, a second position of the second speaker, and the second propagation time; as well as The distance is calculated according to the first positioning information.

9. The control system of claim 7, wherein the first microphone comprises a first transceiver, and the controller is further configured to perform: transmitting at least one reference signal; Receiving the at least one reference signal by the first transceiver to measure the positioning parameter of the first microphone; and The distance is calculated according to the positioning parameters.

10. The control system of claim 9, wherein the controller is further configured to perform: Executing an ultra-wideband positioning method, an enhanced cell identification code positioning method or an arrival time difference measurement method according to the positioning parameters to generate positioning information of the first microphone; and The distance is calculated according to the positioning information of the first microphone.

11. A method for controlling a loudspeaker in a field: Outputting an audio signal through a first speaker corresponding to a first output power and a second speaker corresponding to a second output power; measuring a first volume and a first time delay corresponding to the audio signal by a first microphone; Executing a calculation of an optimization algorithm according to the first output power, the second output power, the first volume, and the first time delay to obtain a first recommended output power corresponding to the first speaker and a second recommended output power corresponding to the second speaker; and The first output power is configured according to the first recommended output power, and the second output power is configured according to the second recommended output power.

12. The control method of claim 11, wherein the optimization algorithm comprises a dynamic causal Bayesian optimization algorithm. 13 . The control method of claim 12 , wherein an objective function of the dynamic causal Bayesian optimization algorithm comprises a mean square error between a reference volume and the first volume.

14. The control method according to claim 12, further comprising: A sound wave corresponding to a second volume is obtained from a second microphone, wherein an objective function of the dynamic causal Bayesian optimization algorithm includes a mean square error between the second volume and the first volume. 15 . The control method according to claim 12 , wherein the constraints of the dynamic causal Bayesian optimization algorithm include an upper limit value and a lower limit value of the first recommended output power and an upper limit value and a lower limit value of the second recommended output power.

16. The control method of claim 11, wherein the first speaker outputs the audio signal at a first time point, and the first microphone receives the audio signal at a second time point, wherein the control method further comprises: The difference between the second time point and the first time point is calculated to obtain the first time delay.

17. The control method according to claim 11, further comprising: performing the calculation of the optimization algorithm according to the first output power, the second output power, the first volume, and the first time delay to obtain a recommended time delay corresponding to the first speaker; calculating a propagation delay based on a distance between the first speaker and the first microphone; subtracting the propagation delay from the proposed time delay to obtain a proposed output delay; and An output delay of the first speaker is configured according to the recommended output delay.

18. The control method according to claim 17, further comprising: outputting a first audio signal through the first speaker, and outputting a second audio signal through the second speaker; measuring, through the first microphone, a first propagation time of the first audio signal from the first loudspeaker to the first microphone, and measuring, through the first microphone, a second propagation time of the second audio signal from the second loudspeaker to the first microphone; generating first positioning information of the first microphone according to a first position of the first speaker, the first propagation time, a second position of the second speaker, and the second propagation time; as well as The distance is calculated according to the first positioning information.

19. The control method according to claim 17, further comprising: transmitting at least one reference signal; Receiving the at least one reference signal through the first microphone to measure the positioning parameter of the first microphone; as well as The distance is calculated according to the positioning parameters.

20. The control method of claim 19, further comprising: Execute an ultra-wideband positioning method, an enhanced cell identification code positioning method or an arrival time difference measurement method according to the positioning parameters to generate positioning information of the first microphone; as well as The distance is calculated according to the positioning information of the first microphone.

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