JP7385531B2 - Acoustic communication system, acoustic transmitting device, acoustic receiving device, program and acoustic signal transmitting method - Google Patents

Description

The present invention relates to an acoustic communication system, an acoustic transmitting device, an acoustic receiving device, a program, and an acoustic signal transmitting method that transmit information embedded in acoustic signals such as sound waves.

As an acoustic communication system, a technique described in Patent Document 1 is known. The acoustic communication system described in Patent Document 1 includes an acoustic transmitting device that emits an acoustic signal in which identification information is embedded using an audio digital watermarking technique, and an acoustic device that collects (receives) the emitted acoustic signal with a microphone. A receiving device (mobile terminal) is provided. The acoustic receiving device extracts identification information from the acoustic signal and provides related information associated with the identification information to the user.

Japanese Patent Application Publication No. 2016-153906

By the way, in the sound electronic watermarking technology, identification information can be transmitted by embedding the identification information in an audio signal, but the amount of information that can be transmitted with one embedding is small, for example, on the order of several bits to 10-odd bits. Therefore, there is a problem that the application is limited to transmitting identification information. Therefore, there is a need to transmit data having a sufficiently larger amount of information than the unit amount of information per piece of embedded information using audio and digital watermarking technology.

Therefore, an acoustic communication system, an acoustic transmitter, an acoustic receiver, a program, and an acoustic Provide a signal transmission method.

Below, means for solving the above problems and their effects will be described.
(1) An acoustic communication system that solves the above problems includes an acoustic transmitting device having a sound emitting section that emits an acoustic signal in which embedded information is embedded, and an acoustic receiving device having a sound collecting section that collects the acoustic signal. an acoustic communication system comprising: a data dividing unit that divides the input original data into a plurality of small data; and a data division unit that divides the input original sound signal into a plurality of small data one by one. and an embedding section that causes the sound emitting section to emit an acoustic signal in which the embedded information is embedded in the original sound signal by embedding the embedded information as embedded information in the original sound signal, and the sound receiving device is configured such that the sound receiving device a data acquisition unit that extracts a plurality of embedded information from the acoustic signal and obtains a plurality of the small data from the plurality of embedded information; and a data acquisition unit that combines the plurality of small data to reconstruct the original data. and a data reconstruction unit.

According to this configuration, it is possible to transmit original data having a larger amount of information than the unit information amount per piece of embedded information embedded in the original sound signal using the audio digital watermarking technique. As a result, the applications of audio digital watermarking technology will expand.

(2) In the above acoustic communication system, the embedding section embeds a plurality of the embedding information into the original sound signal in the order in which the plurality of small data corresponding to the plurality of embedding information are arranged in the original data. , the data reconstruction unit may reconstruct the original data by combining the plurality of small data pieces in the order in which they were obtained.

According to this configuration, the acoustic receiving device can reconstruct the original data by combining the plurality of small pieces of data in the order in which the data reconstructing unit obtains them. For example, compared to a configuration in which order information specifying the order is added to the small data, the original data can be transmitted in a shorter time with a smaller number of divisions.

(3) In the above acoustic communication system, the acoustic transmitting device further includes an order information adding section that gives the small data order information specifying an order for reconstructing the original data, and the data reconstructing section The original data may be reconstructed by combining the plurality of small pieces of data in the order of the order information.

According to this configuration, even if the order in which the acoustic receiving device receives the small data is different from the order in which the original data is arranged due to noise in the acoustic signal, sound interruptions, small sound pressure, etc., the data reconstruction unit can By combining multiple small pieces of data in the order of order information, the original data can be correctly reconstructed.

(4) In the acoustic communication system, if the acoustic receiving device acquires a plurality of pieces of small data having the same order information and different values before all of the plurality of pieces of small data are collected, The data reconstruction unit saves the small data, and if an error is detected in the original data reconstructed using one of the plurality of small data, the data reconstruction unit reconstructs the other saved small data. The original data may be reconstructed using

According to this configuration, even if there is an error in the original data, the frequency at which correct original data can be quickly reconstructed increases without waiting for the acquisition of correct small data. Furthermore, even if necessary correct small data is not sent after an error is detected, the frequency with which correct original data can be reconstructed increases.

(5) In the acoustic communication system, the acoustic transmitting device includes an error detection code adding section that adds an error detection code to at least one of the plurality of small pieces of data, and the acoustic receiving device includes a plurality of small pieces of data. The data processing apparatus may include an error code detection unit that detects errors in the original data by comparing a calculated value obtained by performing a predetermined calculation using the data value with the value of the error detection code.

According to this configuration, errors in the reconstructed original data can be checked. Therefore, the frequency with which correctly reconstructed original data can be obtained increases.
(6) In the acoustic communication system, the acoustic transmitting device includes an encoding unit that encodes the small data into a spreading code, and the embedding unit embeds the embedded information in the original sound signal and acquires the data. The unit may include a decoding unit that decodes the embedded information extracted from the audio signal into the small data.

According to this configuration, since the embedded information is embedded in the original sound signal using a diffusion method, it is possible to suppress the influence on the audibility of the original sound as much as possible.
(7) The acoustic transmitting device in the acoustic communication system includes a data dividing unit that divides the input original data into a plurality of small data, and a data dividing unit that sequentially embeds the plurality of small data one by one in the input original sound signal. The audio recording device includes an embedding section that embeds embedded information as embedded information, and a sound emitting section that emits an acoustic signal in which embedded information is embedded in the original sound signal.

According to this configuration, the same effects as those of the acoustic transmitting device constituting the acoustic communication system can be obtained.
(8) The acoustic receiving device in the acoustic communication system includes a sound collection unit that collects the audio signal, and a plurality of embedded information that is extracted from the audio signal collected by the sound collection unit. A data acquisition unit that acquires a plurality of the small data pieces from the embedded information, and a data reconstruction unit that combines the plurality of small data pieces to reconstruct the original data.

According to this configuration, the same effects as those of the acoustic receiving device constituting the acoustic communication system can be obtained.
(9) A program to be executed by a computer included in the acoustic transmitting device, the program includes a data division unit that divides the input original data into a plurality of small data, and a data division unit that divides the input original sound signal into a plurality of the small data. By sequentially embedding the information one by one as embedded information, the embedded information functions as an embedding section that causes the sound emitting section to emit the acoustic signal embedded in the original sound signal.

According to this program, the same effects as the acoustic transmitter can be obtained by causing a computer to execute the program.
(10) A program to be executed by a computer included in the acoustic receiving device, the program to cause the computer to extract a plurality of the embedded information from the acoustic signal collected by the sound collection unit, The data acquisition unit functions as a data acquisition unit that acquires a plurality of small pieces of data from a data source, and a data reconstruction unit that combines a plurality of pieces of small data to reconstruct the original data.

According to this program, by causing a computer to execute the program, the same effects as those of the acoustic receiving device can be obtained.
(11) An acoustic signal transmission method that solves the above problem includes an acoustic transmitter having a sound emitting section that emits an acoustic signal in which embedded information is embedded, and an acoustic signal having a sound collecting section that collects the acoustic signal. A method for transmitting an acoustic signal in an acoustic communication system comprising a receiving device, wherein the acoustic transmitting device divides input original data into a plurality of small pieces of data, and the acoustic transmitting device divides the input original sound signal into a plurality of small pieces of data. By sequentially embedding the plurality of pieces of data one by one as embedded information, the embedded information causes the sound emitting unit to emit an acoustic signal embedded in the original sound signal, and the acoustic receiving device , extracting a plurality of the embedded information from the acoustic signal collected by the sound collection unit and acquiring a plurality of the small data from the plurality of embedded information, and combining the plurality of the small data to and reconstructing the original data. According to this acoustic signal transmission method, effects similar to those of an acoustic communication system can be obtained.

According to the present invention, data having an amount of information larger than the unit information amount per piece of embedded information embedded in an audio signal can be transmitted using the audio digital watermarking technique.

FIG. 1 is a schematic diagram showing an acoustic communication system according to an embodiment. FIG. 1 is a schematic diagram showing an acoustic communication system. FIG. 1 is a block diagram showing the configuration of an acoustic communication system. (a) to (c) are schematic diagrams illustrating division processing of original data. (a) to (c) are schematic diagrams illustrating reconstruction of original data. (a) to (c) are schematic diagrams illustrating division and reconstruction of original data in a modified example.

The acoustic communication system 10 of this embodiment will be described below with reference to FIGS. 1 to 5.
As shown in FIG. 1, the acoustic communication system 10 includes an acoustic transmitter 20 having a speaker 12 as an example of one or more sound emitting units, and information for receiving an acoustic signal AS emitted from the speaker 12. The terminal 15 includes an acoustic receiving device 30 built into the terminal 15. Embedded information SC (see FIG. 2) is embedded in the acoustic signal AS. The user carries the portable information terminal 15 with him when he moves. The acoustic receiving device 30 built into the information terminal 15 receives embedded information SC embedded in the acoustic signal AS. For example, a user uses the audio receiving device 30 of the information terminal 15 to receive an audio signal AS broadcast from a speaker 12 of a station, a shopping mall, a public facility, etc., which is mainly used for broadcasting. The information terminal 15 is, for example, a mobile phone, a smartphone, a notebook computer, or the like. The acoustic receiving device 30 acquires the provided information provided by the broadcaster based on the embedded information SC embedded in the acoustic signal AS. In this way, the user using the audio receiving device 30 can receive the information provided by the broadcasting entity.

The broadcasting entity is, for example, a person or business operator who broadcasts the audio signal AS, or a person or business operator who requests the broadcasting of the audio signal AS. The broadcasting entity may be a person who generates the audio signal AS himself or a business operator. The broadcasting entity does not have to be a person who generates the audio signal AS himself or a business operator. For example, broadcasting entities include businesses that operate stores, businesses that operate public transportation such as railways, businesses or organizations that operate learning facilities including schools, businesses that operate museums and exhibitions, businesses that operate swimming pools, etc. These include businesses that operate leisure facilities, businesses that operate accommodation facilities, and local governments that broadcast disaster warnings.

The provided information is information provided by the broadcaster to the user. The storage location of the provided information is not limited. In one example, the provision information is stored on a server on the Internet IN. In other examples, the provided information is stored in the acoustic receiving device 30. Examples of provided information are listed below. If the broadcasting entity is a business that operates a store, the provided information is detailed content of products in the store. When the broadcasting entity is a local government, the provided information is a map showing evacuation locations in the event of a disaster. When the broadcasting entity is a business that operates an exhibition, the provided information is information showing details of the exhibit. The provided information may be an announcement that is broadcast as an acoustic signal AS and translated into another language. When the broadcasting entity is a movie theater, the provided information may be subtitles of movie lines. The provided information may be link information (for example, URL: Uniform Resource Locator) indicating a location where detailed information is stored. In this embodiment, the provided information is provided as a URL on the Internet IN. The provided information may be displayed on the display section of the information terminal 15, emitted from headphones or earphones connected to the earphone jack of the information terminal 15, or emitted from the speaker of the information terminal 15. Good too.

The acoustic signal AS is a sound wave containing frequencies in the audible range. Embedded information SC is embedded in the audio signal AS as an audio digital watermark. The acoustic signal AS is broadcast from a broadcasting device. Examples of the acoustic signal AS include announcements, warnings, sound signs for the general public or visually impaired people, BGM (background music), explanatory sounds output at museums or exhibitions, and broadcast programs. The data length of one piece of embedded information SC embedded with an audio digital watermark is, for example, about 8 bits. In the present embodiment, the original data DS having a data length sufficiently longer than the data length of one embedded information SC is embedded into the acoustic signal AS emitted from the speaker 12 of the acoustic transmitting device 20 using a sound electronic watermark. It is transmitted to the acoustic receiving device 30 using a plurality of embedded information SC. Note that the data length of one embedded information SC is also referred to as the unit information amount of embedded information SC.

The original data DS in this embodiment may be, for example, the provided information itself or identification information associated with the provided information. If the original data DS is identification information that is linked to provided information provided by a broadcasting entity, it can be associated with a large number of provided information. The identification information as the original data DS and the provided information are associated on a one-to-one basis. Furthermore, in this embodiment, since the data length of the original data DS is long, the original data DS can be transmitted as the provided information itself using an audio and electronic watermark. As a result, the acoustic communication system 10 is not limited to the use of identification information, but has a wide range of uses.

As shown in FIG. 2, the acoustic transmitting device 20 includes a device main body 20A and a speaker 12 connected to the device main body 20A. The acoustic transmitting device 20 generates an acoustic signal Sas, which is a digital signal, by embedding embedded information SC in the original sound signal OS (see FIG. 3), and emits an acoustic signal AS based on the acoustic signal Sas from the speaker 12. . The acoustic signal AS is composed of an original sound signal OS consisting of voice or music, and a plurality of embedded information SC1, SC2, ..., SCn embedded as embedded information SC at predetermined time intervals with respect to the original sound in the original sound signal OS. configured. These embedded information SCk (k = 1, 2, ..., n) are not independent data, but are embedded small pieces of data obtained by dividing the long original data DS into multiple pieces. be. In this embodiment, the acoustic receiving device 30 combines a plurality of small data D1, D2, ..., Dn extracted by converting a plurality of embedded information SCk in the correct order to reconstruct one original data DS. .

The acoustic receiving device 30 includes a microphone 31 as an example of a sound collecting section. The acoustic receiving device 30 extracts a plurality of small pieces of data Dk embedded as embedded information SC from the acoustic signal AS picked up by the microphone 31. The acoustic receiving device 30 reconstructs the plurality of extracted small data Dk as one original data DS having a predetermined data length. Then, the acoustic receiving device 30 performs a predetermined operation based on the original data DS. This predetermined operation is an operation that cannot be obtained by the embedded information SC, which has a small amount of information, for example, about 8 bytes. For example, compared to a configuration in which the embedded information SC is used as identification information and the predetermined operation is to provide provided information associated with the identification information received by the acoustic receiving device 30, the degree of freedom in the predetermined operation is increased. Furthermore, the acoustic receiving device 30 can perform predetermined operations even without reference data that associates the identification information with the provided information.

Note that when the original data DS is divided and transmitted by being embedded in the audio signal AS as embedded information SC, at least one of the multiple pieces of data may be dropped due to audio interruptions, low volume, noise, etc. At the end of receiving all of the small data Dk of , the small data Dk that was dropped midway and failed to be received may be received. In this case, the order in which the small data Dk were received is different from the correct order when reconstructing the original data DS. The acoustic communication system 10 of this embodiment incorporates components for solving these problems.

With reference to FIG. 3, the configurations of the acoustic transmitter 20 and the acoustic receiver 30 will be described. In this embodiment, in order to distinguish between a sound signal caused by a sound wave transmitted in space and an electric signal, a sound wave is referred to as an acoustic signal AS, and an electric signal is referred to as an acoustic signal Sas. Further, the original sound signal OS is an electrical signal. Further, in the embedded information SC1, SC2, ..., SCn, what is embedded in the acoustic signal AS is a sound wave, and what is embedded in the acoustic signal Sas is an electric signal.

The audio transmitter 20 emits from the speaker 12 an audio signal AS in which a plurality of small pieces of data D1, D2, . The plurality of small pieces of data D1, D2, . . . , Dn are embedded in the audio signal AS as embedded information SC. The acoustic transmitting device 20 may be built into a broadcasting device that includes a speaker 12 that outputs the acoustic signal AS as a sound wave. On the other hand, the acoustic receiving device 30 is built into a portable information terminal 15 such as a smartphone. The acoustic receiving device 30 extracts the embedded information SC from the acoustic signal Sas picked up by the microphone 31, and internally reconstructs the original data DS from the plurality of small data Dk converted from the plurality of embedded information SC. Output. This acoustic receiving device 30 is configured as a device built into the information terminal 15, but may be configured as the information terminal 15 itself.

Hereinafter, with reference to FIG. 3, detailed configurations of the acoustic transmitter 20 and the acoustic receiver 30 will be described. First, the acoustic transmitter 20 will be explained.
The acoustic transmitter 20 includes a first input section 21 into which the original sound signal OS is input, and a second input section 22 into which the original data DS is input. This acoustic transmitting device 20 includes a first control section 23 that controls the acoustic transmitting device 20 in an integrated manner. The acoustic transmitting device 20 also includes a data dividing unit 24 that divides the original data DS into a plurality of small data D1, D2, ..., Dn, and one or additional of the plurality of small data D1, D2, ..., Dn. and an information adding section 25 that adds predetermined information to the small data. The information adding section 25 includes an order information adding section 25A and an error detection code adding section 25B. Furthermore, the acoustic transmitter 20 includes a spreading code generator 26, an encoding section 27, and an embedding section 28 having a function of convolving the embedding information SC into the original sound signal OS.

The order information assigning unit 25A assigns order information ND to each of the plurality of small data pieces D1, D2, . . . , Dn. Here, the order information ND is information indicating the order required to correctly reconstruct the plurality of small data D1, D2, . . . , Dn into one original data DS. The number of bits corresponding to the number of divisions N of the original data DS is assigned to the order information ND. For example, 1 bit is allocated for 2 divisions, 2 bits for 3 or 4 divisions, and 3 bits for 5 to 8 divisions. Note that as the number of divisions N increases, the number of bits allocated to the order information ND increases, and the number of bits allocated to the small data Dk decreases accordingly. Preferably, it is less than 1/2 of the total data length. However, the number of bits equal to or more than 1/2 of the total data length may be allocated to the order information ND.

The error detection code adding unit 25B checks at the transmission destination whether all of the plurality of small data D1, D2, ..., Dn are complete or whether the values of the plurality of small data D1, D2, ..., Dn have been correctly received. An error detection code used when making a determination in a certain acoustic receiving device 30 is provided. The error detection code adding unit 25B adds an error detection code to one of the plurality of small data D1, D2, . . . , Dn. The one piece of small data is, for example, the last small data Dn in the transmission order. For example, a checksum is used as the error detection code. Note that the acoustic transmitting device 20 of the present embodiment can receive all the small data D1, even if the acoustic receiving device 30 side fails to receive small data due to audio interruptions, low volume, noise, etc. of the acoustic signal AS. In order to more reliably receive D2, . Alternatively, an audio transmission method may be used in which a plurality of embedded information SC1, SC2, . . . , SCn is sequentially sent and this is repeated a plurality of times.

Further, the spreading code generator 26 generates a spreading code. The spreading code may be any code. For example, a PN sequence is used as the spreading code. The PN sequence is a sequence called a pseudo-noise sequence.

The encoding unit 27 encodes unit data IDk (where k=1, 2, . . . , n) consisting of small data Dk to which order information ND has been added, using a spreading code. The embedded information SC in which the unit data IDk is encoded is, for example, 8-bit information.

The embedding unit 28 embeds the embedding information SC into the audio signal AS by convolving the embedding information SC into the original sound signal OS. The original sound signal OS is, for example, an audio signal such as an announcement or a music signal such as BGM. The original sound signal OS of this example functions as a transmission medium (carrier wave) in which embedded information SC is embedded. Further, the original sound signal OS of this example has a frequency in the audible range. Note that the original sound signal OS may have a frequency in an inaudible range.

The method in which the embedding section 28 embeds the embedded information SC into the original sound signal OS, that is, the method in which the embedded information SC is convolved with the original sound signal OS and propagated, is an echo diffusion method or a spread spectrum method. The embedding method may be another method. Note that it is preferable to adopt a spreading method in which a PN sequence spreading code functions as a secret key in order to improve the confidentiality of the embedded information SC.

The acoustic transmitter 20 includes an electronic board on which a CPU, memory, and the like are mounted. A program for acoustic signal generation processing is stored in the memory. By executing the program read from the memory by the CPU, each section 23 to 28 made of software is configured within the acoustic transmitter 20. In other words, the program stored in the memory within the acoustic transmitter 20 causes the computer to function as each of the units 23-28. Specifically, the program stored in the memory in the acoustic transmitting device 20 causes the computer to function as the data dividing section 24, the order information adding section 25A, the spreading code generator 26, and the encoding section 27. Note that each of the units 23 to 28 may be configured by software and hardware, or may be configured by hardware.

Note that the computer functions as the data dividing unit 24, and the process of dividing the original data DS into a plurality of small data pieces D1, D2, . . . , Dn corresponds to an example of the data dividing step. In addition, the computer functions as the embedding unit 28 and sequentially embeds a plurality of small data D1, D2, ..., Dn one by one in the input original sound signal OS as the embedding information SC, so that the embedding information can be added to the original sound signal OS. The process of causing the speaker 12 to emit the audio signal AS embedded in the OS corresponds to an example of the embedding step.

Next, with reference to FIG. 3, the acoustic receiving device 30 will be described.
The acoustic receiving device 30 includes a microphone 31 that functions as an example of a sound collection unit that picks up an acoustic signal AS, and a receiving circuit (not shown) that converts the acoustic signal AS received by the microphone 31 into an acoustic signal Sas that is an electrical signal. Equipped with. Furthermore, the acoustic receiving device 30 includes a second control section 32 that controls the acoustic receiving device 30 in an integrated manner.

The acoustic receiving device 30 includes an extraction unit 33 that extracts embedded information SC from the acoustic signal Sas input from the receiving circuit. The acoustic receiving device 30 includes a decoding section 34 that decodes the embedded information SC. Furthermore, the acoustic receiving device 30 includes a data reconstruction section 35 and an error code detection section 36. The acoustic receiving device 30 also detects that the small data D1, D2, ..., Dn obtained by decoding the embedded information SC extracted by the extracting section 33 and the original data DS reconstructed by the data reconstructing section 35 are incorrect. If the data is normal with no error detected by the code detection section 36, it has an output section 38 that outputs this normal original data DS. Note that in this embodiment, the extraction section 33 and the decoding section 34 constitute an example of a data acquisition section.

The extraction unit 33 extracts the embedded information SC from the acoustic signal Sas using a method according to the diffusion method that the acoustic communication system 10 employs as a method for embedding the embedded information SC. When the embedding method is an echo diffusion method, the extraction unit 33 extracts the embedding information SC, which is spread in the time axis as an echo of the original sound included in the original sound signal OS, from the acoustic signal Sas. Specifically, the extraction unit 33 extracts the embedded information SC by performing cepstral transformation on the acoustic signal Sas. Further, when the embedding method is a spread spectrum method, the extraction unit 33 extracts the embedded information SC from the audio signal Sas by demodulating the embedded information SC that has been spread spectrum into the original sound signal OS. Further, when the embedding method is another method, the extraction unit 33 extracts the embedding information SC from the acoustic signal Sas using an extraction method corresponding to the other method.

The decoding unit 34 decodes the embedded information SC into unit data IDk. The decoding unit 34 decodes the embedded information SC into unit data IDk by performing despreading on the spreading adopted by the encoding unit 27 of the audio transmitting device 20. Specifically, the decoding unit 34 cross-correlates the embedded information SC with the same PN sequence as the PN sequence spread by the embedding unit 28, thereby converting the embedded information SC into unit data before encoding. Decode to IDk. The decoding unit 34 sends the decoded unit data IDk to the data reconstruction unit 35.

The data reconstruction unit 35 separates the unit data IDk into small data Dk and order information ND. For example, when the data reconstruction unit 35 finishes receiving a plurality of pieces of small data to which order information is attached from a value indicating the beginning (“start”) to a value indicating the last (“end”), the data reconstruction unit 35 receives N The pieces of small data D1, D2, . . . , Dn are combined in the order indicated by the order information ND. Thereby, the data reconstruction unit 35 reconstructs the plurality of small data D1, D2, . . . , Dn into one original data DS.

If the order of the order information ND is missing in the middle, the data reconstruction unit 35 adds the order information ND indicating the missing order even after receiving the order information ND indicating the final ("end"). Acceptance of unit data IDk is continued until small data Dk is obtained. Then, the data reconstruction unit 35 acquires the small data Dk to which order information ND indicating the order of omission has been added, and when all the plurality of small data D1, D2, ..., Dn are collected, these N small data D1, D2, ..., Dn are combined in the order indicated by the order information ND to generate original data DS, and the generated original data DS is sent to the next error code detection section 36.

The error code detection unit 36 detects the presence or absence of an error in the reconstructed value of the original data DS based on the error detection code ED added to the final small data Dn. When the error code detection section 36 detects an error in the value of the original data DS, it notifies the second control section 32 and the data reconstruction section 35 that there is an error. On the other hand, when the error code detection unit 36 confirms that there is no error in the value of the original data DS, it notifies the second control unit 32 and the data reconstruction unit 35 that there is no error, and also confirms that there is no error. The confirmed original data DS is output from the output unit 38.

When the second control unit 32 receives a notification from the error code detection unit 36 that there is an error, the second control unit 32 causes the extraction unit 33 to continue the extraction process of extracting the embedded information SC. When the data reconstruction unit 35 receives a notification that there is an error, it replaces the newly received small data Dk with the small data Dk in the order indicated by the order information, and each time it replaces the updated original data DS with an error. The data is sent to the code detection unit 36, and the error code detection unit 36 detects whether or not there is an error in the updated value of the original data DS. The original data DS is correctly updated until at least N pieces of small data are replaced.

The acoustic receiving device 30 includes an electronic board on which a CPU, memory, and the like are mounted. A program for acoustic signal reception processing is stored in the memory. By executing the program read from the memory by the CPU, each section 32 to 36 made of software is configured within the acoustic receiving device 30. In other words, the program stored in the memory within the acoustic receiving device 30 causes the computer to function as each of the units 32-36. Specifically, the program stored in the memory in the acoustic receiving device 30 causes the computer to function as the second control section 32, the extraction section 33, the decoding section 34, the data reconstruction section 35, and the error code detection section 36. Note that each of the units 32 to 36 may be configured by software and hardware, or may be configured by hardware.

When the digital watermark embedding method is an echo diffusion method, the embedding unit 28 convolves the original signal and the embedding information SC. Further, at the time of detection, the extraction unit 33 performs cepstral transformation on the signal of the embedded information SC embedded in the original signal. On the other hand, when using the spread spectrum method, the embedding unit 28 uses a PN sequence to spread the signal over an occupied band several ten times larger than the carrier wave before modulation. At the time of detection, the extraction unit 33 performs despreading and extracts the embedded information SC.

Note that the computer functions as a data acquisition unit including the extraction unit 33 and the decoding unit 34, and the process of acquiring the plurality of small data D1, D2, ..., Dn from the acoustic signal Sas corresponds to an example of the data acquisition step. . Further, the process in which the computer combines the plurality of small data pieces D1, D2, . . . , Dn to reconstruct the original data DS corresponds to an example of the data reconstruction step.

Next, the operation of the acoustic communication system 10 will be explained.
The user inputs the original data DS into the audio transmitter 20 and operates an operation section (not shown) to instruct transmission. When the acoustic transmitting device 20 receives a transmission instruction signal through a transmission instruction operation, it executes an acoustic signal transmission process. As shown in FIG. 4A, the original sound signal OS has a predetermined data length that is sufficiently longer than, for example, 8 bits, which is the information amount of one unit in which the embedded information SC is embedded. Further, the user inputs the original sound signal OS from the first input section 21 by operating the operation section. The original sound signal OS is an audio signal such as an announcement sound or a music signal such as BGM. First, in the acoustic transmitter 20, the data dividing section divides the original data DS into a plurality of small data D1, D2, . . . , Dn shown in FIG. 4(b). Each of the small data D1, D2, . . . , Dn has the same data length, for example, 6 bits. Note that small data having a data length other than 6 bits may be mixed. For example, since the final small data Dn is given an error detection code ED, 2 bits are required for the error detection code ED in addition to the order information ND. Therefore, the data length of the final small data Dn may be set to 4 bits.

Next, the order information adding unit 25A adds order information ND, for example, as a header, to each of the N pieces of small data D1, D2, . . . , Dn, as shown in FIG. 4(c). The order information adding unit 25A applies order information to each of the N pieces of small data D1, D2, ..., Dn in order from the beginning to the end ("end") of the original data DS. ND1, ND2,..., NDn are given. Further, the error detection code adding unit 25B adds an error detection code ED to the final small data Dn, as shown in FIG. 4(c). When N unit data IDk (k=1, 2, ..., n) are generated in this way, the encoding unit 27 converts the N unit data ID1, ID2, ..., IDn using, for example, a PN sequence. and encoded into embedded information SC1, SC2, ..., SCn.

Then, the embedding unit 28 generates an audio signal Sas in which the embedded information SC is embedded by convolving the original sound signal and the embedded information SC. A transmission circuit (not shown) emits an acoustic signal AS from the speaker 12 based on the acoustic signal Sas.

This acoustic signal AS is picked up by the microphone 31 of the acoustic receiving device 30. The acoustic receiving device 30 converts the acoustic signal AS picked up by the microphone 31 into an acoustic signal Sas using a receiving circuit. The extraction unit 33 that receives this acoustic signal Sas extracts the embedded information SC from the acoustic signal Sas. Next, the decoding unit 34 decodes the embedded information SCk into unit data IDk. In this way, a plurality of unit data ID1, ID2, . . . , IDn are sequentially input to the data reconstruction unit 35. The data reconstruction unit 35 separates the unit data IDk into small data Dk and order information ND. Then, when a plurality of unit data ID1, ID2, ..., IDn including the unit data ID1, IDn to which the first and last order information ND are given is input, N pieces of small data D1, D2, ..., Dn are given order information. By combining in the order indicated by ND, it is reconstructed into one original data DS.

At this time, even though the last unit data IDk has been input, if there is a missing number in the order information ND included in the unit data ID1, ID2, ..., IDn from the beginning to the one before the last. notifies the second control unit 32 of the information. In the example shown in FIG. 5(a), among (N-1) unit data ID1, ID3, ..., IDn from the first order information ND1 to the last order information NDn, the unit data ID2 that should be the second one is It's missing. The omission of the unit data ID2 is detected because the values of the (N-1) order information ND1, ND3, . . . , NDn are not continuous and there are missing numbers.

When receiving the notification of the dropped number, the second control unit 32 causes the extraction unit 33 to continue the extraction process. The data reconstruction unit 35 then checks the order information ND obtained by disassembling the input unit data IDk, and when the order information NDk indicating the missing number is obtained, the data reconstruction unit 35 disassembles the input unit data IDk and checks the order information ND. N pieces of small data D1, D2, . . . , Dn including data Dk are all assembled (FIG. 5(a)). The data reconstruction unit 35 rearranges the N pieces of small data D1, D2, ..., Dn into the correct order indicated by the order information ND1, ND2, ..., NDn, as shown in FIG. 5(b). Furthermore, the data reconstruction unit 35 combines the N pieces of small data D1, D2, ..., Dn in the correct order indicated by the order information ND1, ND2, ..., NDn, thereby creating the structure shown in FIG. 5(c). One source data DS shown is reconstructed.

Furthermore, the data reconstruction unit 35 may obtain the same number twice before obtaining the order information NDn indicating the last one. In this case, the data reconstruction unit 35 compares the values of the two pieces of small data Dk, Dk, and if the values are the same, leaves one in the reconstruction buffer and discards the other. On the other hand, if the values of the two small data Dk, Dk are different, one of the small data Dk is left in the reconstruction buffer, and the other small data Dk is stored in the temporary storage buffer. The data reconstruction unit 35 repeatedly performs such processing until all the unit data ID1, ID2, . . . , IDn from the beginning to the end are collected.

Furthermore, when the values of two pieces of small data Dk, Dk to which the same number is given to the order information NDk are different, the data reconstruction unit 35 acquires the amplitude of the original sound into which the respective pieces of small data Dk, Dk are diffused. The data reconstruction unit 35 may perform a process of comparing the amplitudes of the two original sounds corresponding to the two small data Dk, Dk, and leaving the small data Dk with the larger amplitude in the first buffer for reconstruction. . Alternatively, the data reconstruction unit 35 obtains the embedding strength α of the embedding information SCk, SCk embedded in the two small data Dk, Dk, and inserts the small data Dk corresponding to the one with the larger embedding strength α. A process of leaving the data in the first buffer for reconstruction may also be performed. Since the embedding strength α increases as the strength of the original sound increases, it can be said that the higher the embedding strength α, the higher the reception accuracy. Note that these data selection processes are employed when the embedding method to be employed allows extraction of the original sound and acquisition of the embedding strength α from the acoustic signal Sas.

When the data reconstruction unit 35 reconstructs the original data DS shown in FIG. Send to Department 36. The error code detection unit 36 checks the value of the original data DS based on the error detection code ED. A predetermined calculation according to the error code detection method is performed based on the value of the original data DS, and a value of the calculation result is obtained. The error code detection unit 36 compares the error detection code ED with the value of the calculation result, and if the two values match, it determines that the value of the original data DS is correct, and if the two values differ, it determines that the value of the original data DS is correct. It is determined that there is an error in the value. If there is an error in the value of the original data DS, the error code detection unit 36 notifies the second control unit 32 and the data reconstruction unit 35 of the error. The second control unit 32 that has received this notification causes the extraction unit 33 to continue the extraction process.

On the other hand, the data reconstruction unit 35 determines whether or not the unit data IDk is stored in the second buffer for temporary storage. The data reconstruction unit 35 reads the unit data IDk stored in the second buffer for temporary storage, and converts the small data Dk to which the order information NDk having the same value as the order information NDk was given to this new small data The original data DS is updated by exchanging it with the data Dk. Then, this updated original data DS is sent to the error code detection section 36.

The error code detection unit 36 checks the updated original data DS based on the error detection code ED, and if the value of the original data DS is correct, outputs the original data DS from the output unit 38. On the other hand, if the error code detection unit 36 determines that the value of the updated original data DS is also erroneous, the data reconstruction unit 35, which has received the notification of the error, stores the data in the second buffer for temporary storage. While there is unit data IDk, the small data Dk to which the order information NDk of the same value as the small data Dk taken out from other unit data IDk has been given is replaced with this new small data Dk to create the original data. Update DS. If the error code detection unit 36 determines that there is an error in the value of the original data DS even with this updated original data DS, the data reconstruction unit 35 converts the small data Dk extracted from the newly input unit data IDk. , the original data DS is updated by replacing the small data Dk with the small data Dk that has been given the same order information NDk as the order information NDk that was given to the small data Dk. The data reconstruction unit 35 repeats this process of updating the original data DS until the error code detection unit 36 determines that there is no error in the value of the original data DS. When the error code detection unit 36 determines that there is no error in the original data DS, the correctly reconstructed original data DS is output from the output unit 38.

The original data DS is sent from the output unit 38 to a processing unit within the information terminal 15, for example. A computer that executes a program installed on the information terminal 15 functions as a processing section. The processing unit displays characters or images based on the original data DS on the display unit, or causes audio based on the original data DS to be emitted from the earphone or speaker. Conventionally, since the unit information amount of the embedded information SC embedded using sound electronic watermarking technology is as small as about 8 bits, identification information is embedded and provided information such as a URL associated with the identification information is displayed on the information terminal 15 of the transmission destination. It has been used to display the provided information on the screen, or to emit the provided information through earphones or speakers. On the other hand, according to the present embodiment, the original data DS having a data length sufficiently larger than the unit information amount of the embedded information SC can be transmitted using audio digital watermarking technology, so that the above-mentioned identification information can be used. It is not limited and its uses are greatly expanded. Note that when the original data DS is used as identification information, the identification information can be associated with a very large number of pieces of provided information, and this also expands the applications of the audio and electronic watermarking technology. Note that the announcement voice or BGM based on the original sound signal OS may be output from the speaker or earphones (both not shown) of the information terminal 15, or may be discarded within the information terminal 15, depending on the user's settings. .

As described in detail above, according to this embodiment, the following effects can be obtained.
(1) The acoustic communication system 10 includes an acoustic transmitting device 20 having a speaker 12 and an acoustic receiving device 30 having a microphone 31. The acoustic transmitter 20 includes a data dividing unit 24 that divides the input original data DS into a plurality of small data D1, D2, ..., Dn, and a data division section 24 that divides the input original sound signal OS into a plurality of small data D1, D2, ..., Dn. The embedding unit 28 causes the speaker 12 to emit an acoustic signal AS in which the embedded information SC is embedded in the original sound signal OS by sequentially embedding the embedded information SC one by one. The acoustic receiving device 30 includes a data acquisition unit that extracts a plurality of embedded information SC from the acoustic signal AS picked up by the microphone 31 and obtains a plurality of small data D1, D2, ..., Dn from the plurality of embedded information SC. and a data reconstruction unit 35 that combines the plurality of small data D1, D2, . . . , Dn to reconstruct the original data DS. The data acquisition section includes an extraction section 33 and a decoding section 34. Therefore, by using the audio digital watermarking technique, it is possible to transmit the original data DS having a larger amount of information than the unit information amount per piece of embedded information SC embedded in the original audio signal OS. As a result, the applications of audio digital watermarking technology, for example, are expanded.

(2) The embedding unit 28 embeds the plurality of embedded information SC into the original sound signal OS in the order in which the plurality of small data D1, D2, ..., Dn corresponding to the plurality of embedded information SC are arranged in the original data DS. . The data reconstruction unit 35 reconstructs the original data DS by combining the plurality of small data D1, D2, . . . , Dn in the order in which they were acquired. Therefore, the acoustic receiving device 30 can reconstruct the original data DS by combining the plurality of small data pieces D1, D2, . For example, compared to a configuration in which order information specifying the order is given to the small data D1, D2, . . . , Dn, the original data DS can be transmitted in a shorter time with fewer divisions.

(3) The acoustic transmitting device 20 includes an order information adding unit 25A that adds order information ND specifying the order for reconstructing the original data DS to the small data D1, D2, . . . , Dn. The data reconstruction unit 35 reconstructs the original data DS by combining the plurality of small pieces of data D1, D2, . . . , Dn in the order of the order information ND1, ND2, . . . , NDn. Therefore, even if the order in which the acoustic receiving device 30 receives the small data Dk is different from the order in which the original data DS are arranged due to noise, sound interruption, small sound pressure, etc. in the acoustic signal AS, the data reconstruction unit 35 can correctly reconstruct the original data DS by combining a plurality of small pieces of data D1, D2, . . . , Dn in the order of order information ND1, ND2, . . . , NDn.

(4) If the acoustic receiving device 30 acquires a plurality of small data Dk having the same order information NDk and different values before all the plurality of small data D1, D2, ..., Dn are collected, Save data Dk. When an error is detected in the original data DS reconstructed using one of the plurality of small data Dk, the data reconstruction unit 35 reconstructs the original data DS using the other saved small data Dk. Rebuild. Therefore, even if there is an error in the reconstructed original data DS, the frequency with which the correct original data DS can be quickly reconstructed increases without waiting for the acquisition of the correct small data Dk. Furthermore, even if the required correct small data Dk is not sent after an error is detected, the frequency with which correct original data DS can be reconstructed increases.

(5) The acoustic transmitter 20 includes an error detection code adding section 25B that adds an error detection code ED to at least one of the plurality of small pieces of data D1, D2, . . . , Dn. The acoustic receiving device 30 detects errors in the original data DS by comparing the calculated value obtained by performing a predetermined calculation using the values of the plurality of small data D1, D2, ..., Dn and the value of the error detection code ED. It includes an error code detection section 36 that detects. Therefore, errors in the reconstructed original data DS can be checked. Therefore, the frequency with which correctly reconstructed original data DS can be obtained increases.

(6) The acoustic transmitter 20 includes an encoding unit 27 that encodes the small data D1, D2, ..., Dn into embedded information SC1, SC2, ..., SCn. The embedding unit 28 embeds the embedding information SC into the original sound signal OS. The acoustic receiving device 30 includes a decoding section 34 that decodes embedded information SC1, SC2, ..., SCn extracted from the acoustic signal Sas into small data D1, D2, ..., Dn. Therefore, since the embedded information SC is embedded in the original sound signal OS using a diffusion method, it is possible to suppress the influence on the audibility of the original sound as much as possible.

(7) Since the acoustic transmitter 20 includes the data dividing section 24, the embedding section 28, and the speaker 12, the plurality of small pieces of data D1, D2, ..., Dn obtained by dividing the original data DS are embedded into the original sound signal OS. The acoustic signal AS embedded as SC can be emitted from the speaker 12. Therefore, by using the acoustic transmitting device 20 as a part of the acoustic communication system 10, the above effect (1) can be obtained.

(8) Since the acoustic receiving device 30 includes the microphone 31, the data acquisition section, and the data reconstruction section 35, the embedded information SC1, SC2 extracted from the acoustic signal Sas obtained by collecting the acoustic signal AS with the microphone 31 , ..., SCn, and by combining them into one, the original data DS can be reconstructed. Therefore, by using the acoustic receiving device 30 as a part of the acoustic communication system 10, the above effect (1) can be obtained.

(9) The program included in the acoustic transmitting device 20 causes the computer to function as the data dividing section 24 and the embedding section 28. Therefore, by causing a computer to execute the program, the same effect as that of the acoustic transmitter 20 described in (7) above can be obtained.

(10) The program included in the acoustic receiving device 30 causes the computer to function as the data acquisition unit and the data reconstruction unit 35. Therefore, by causing a computer to execute the program, the same effect as the sound receiving device 30 described in (8) above can be obtained.

(11) The acoustic signal transmission method in the acoustic communication system 10 including the acoustic transmitting device 20 having the speaker 12 and the acoustic receiving device 30 having the microphone 31 includes a data division step, an embedding step, and a data acquisition step. , and a data reconstruction step. According to this acoustic signal transmission method, the same effects as the acoustic communication system 10 can be obtained.

The embodiment is not limited to the above, and may be modified in the following manner.
- It is not necessary to give order information ND to the plurality of small data D1, D2, . . . , Dn obtained by dividing the original data DS. For example, the data dividing unit 24 divides the original data DS shown in FIG. 6(a) into a plurality of small data D1, D2, ..., Dn as shown in FIG. 6(b), and each small data For example, an error detection code ED is added to the last small data Dn without adding order information NDk (FIG. 4(c)) to Dk. The embedding unit 28 embeds the embedding information SC1, SC2, . . . , SCn in the original sound signal OS in the order in which the small data D1, D2, . The extraction unit 33 extracts embedded information SC1, SC2, ..., SCn from the acoustic signal Sas, which is an electrical signal of the acoustic signal AS picked up by the microphone 31, in the order in which the small data D1, D2, ..., Dn are arranged. . The data reconstruction unit 35 combines the plurality of small data D1, D2, ..., Dn after the embedded information SC1, SC2, ..., SCn is decoded in the order of reception, as shown in FIG. 6(c). Rebuild the original data DS. As long as there are no sound breaks or noises in the audio signal AS, the original data DS can be correctly reconstructed.

- The unit information amount of the embedded information SC is not limited to 8 bits, but may be a predetermined number of bits less than or equal to 7 bits or a predetermined number of bits greater than or equal to 9 bits. For example, when used in an environment with good acoustic conditions, the unit information amount may be 16 bits or 32 bits. Furthermore, a unit information amount that can secure 8 bits or 16 bits may be set as the unit information amount of the small data Dk. For example, the order information NDk may be 3 bits, and the unit information amount of the unit data IDk combined with the small data Dk may be 11 bits or 19 bits.

・Masking using audio and digital watermarking technology is not limited to forward masking, but may also be backward masking.
・Sound electronic watermarking methods are not limited to diffusion methods such as echo diffusion method and spread spectrum method. For example, an echo method, a periodic phase modulation method, a phase multiplexing method, an amplitude modulation method, etc. may be used. Further, the spread spectrum method may be a direct spread method or a frequency hopping method.

- The order in which the embedded information SC1, SC2, ..., SCn is embedded is not limited to the configuration in which the same embedded information SCk (that is, the same small data Dk) is repeated multiple times, but all the embedded information SC1, SC2, ..., SCn (that is, small data D1, D2, . . . , Dn) may be sequentially transmitted once, and this may be repeated multiple times. According to this configuration, compared to a configuration in which the small data is transmitted multiple times (for example, 5 times), the acoustic receiving device 30 transmits all the small data D1, D2, ..., Dn early if there is no sound breakage or noise. The frequency with which you can receive messages will increase.

- The order in which the embedding unit 28 embeds the plurality of small data D1, D2, ..., Dn into the original sound signal OS as embedding information SC1, SC2, ..., SCn is limited to the order from the beginning of the original data. For example, the order of arrangement from the end of the original data may be used.

- The sound emitting unit is not limited to the speaker 12, and may be an earphone.
- Error detection codes are not limited to checksums, etc. Cyclic redundancy check (CRC), Hamming code, parity check, Adler-32, Luhn algorithm, check digit, Damm algorithm, Verhev algorithm, etc. may be used.

- The spreading code is not limited to a PN sequence (pseudo-noise sequence), but may be a Gold sequence or the longest sequence (M sequence) obtained by adding two types of PN sequences.

DESCRIPTION OF SYMBOLS 10...Acoustic communication system 12...Speaker as an example of a sound emitting part 20...Acoustic transmitter 21...1st input part 22...2nd input part 23...1st control part 24...Data division part 25...Information provision part 25A... Order information adding section 25B...Error detection code adding section 26...Spreading code generator 27...Encoding section 28...Embedding section 30...Acoustic receiving device 31...Microphone as an example of sound collecting section 32...Second control section 33...Data Extraction unit configuring an example of an acquisition unit 34...Decoding unit configuring an example of a data acquisition unit 35...Data reconstruction unit 36...Error code detection unit 38...Output unit AS...Acoustic signal Sas...Acoustic signal OS...Original sound signal SC , SC1 to SCn...Embedded information IN...Internet DS...Original data D1, D2,..., Dn, Dk...Small data ND, ND1, ND2,..., NDn...Order information ED...Error detection code ID1, ID2,..., IDn…Unit data

Claims (11)

An acoustic communication system comprising: an acoustic transmitting device having a sound emitting section that emits an acoustic signal in which embedded information is embedded; and an acoustic receiving device having a sound collecting section that collects the acoustic signal.
The acoustic transmitter includes:
a data division unit that divides the input original data into multiple small data;
an embedding unit that causes the sound emitting unit to emit an audio signal in which the embedded information is embedded by sequentially embedding the plurality of small data one by one as embedded information in the input original sound signal,
The acoustic receiving device includes:
a data acquisition unit that extracts a plurality of pieces of embedded information from the acoustic signal collected by the sound collection unit and acquires the plurality of small data from the plurality of pieces of embedded information;
a data reconstruction unit that reconstructs the original data by combining a plurality of the small data ,
The acoustic transmitting device further includes an order information adding unit that adds order information specifying an order for reconstructing the small data to the original data,
The data reconstruction unit is an acoustic communication system that reconstructs the original data by combining the plurality of small data pieces in the order of the order information. If the acoustic receiving device acquires a plurality of pieces of small data having the same order information and different values before all of the plurality of pieces of small data are collected, the acoustic receiving device stores the plurality of pieces of small data;
When an error is detected in the original data reconstructed using one of the plurality of small data, the data reconstruction unit reconstructs the original data using the other saved small data. The acoustic communication system according to claim 1 , wherein the acoustic communication system is reconstructed. The acoustic transmitting device includes an error detection code adding section that adds an error detection code to at least one of the plurality of small data,
The acoustic receiving device performs error code detection for detecting errors in the original data by comparing a calculated value obtained by performing a predetermined calculation using a plurality of values of the small data and a value of the error detection code. The acoustic communication system according to claim 1 or 2 , further comprising a section. When there is a omission in the order information, the data reconstruction unit requests the sending of the small data to which the order information is attached by notifying the missing order information, and the plurality of small data are The acoustic communication system according to any one of claims 1 to 3, wherein the original data is reconstructed when all the original data is collected. When the two pieces of small data having the same order information have different values, the data reconstruction unit uses one of the two pieces of small data that has a larger amplitude of the original sound or a larger embedding strength of the embedded information to reconstruct the data. The acoustic communication system according to any one of claims 1 to 4, wherein original data is reconstructed. The acoustic transmitting device includes an encoding unit that encodes the small data into embedded information,
The embedding unit embeds the embedding information into the original sound signal,
The acoustic communication system according to any one of claims 1 to 5, wherein the data acquisition unit includes a decoding unit that decodes the embedded information extracted from the acoustic signal into the small data. The acoustic transmitting device in the acoustic communication system according to any one of claims 1 to 6 ,
a data division unit that divides the input original data into multiple small data;
an order information adding unit that adds order information specifying an order for reconstructing the original data to the small data;
an embedding unit that sequentially embeds the plurality of small data one by one as embedding information into the input original sound signal;
An audio transmitting device comprising: a sound emitting unit that emits an audio signal in which the embedded information is embedded in the original sound signal. The acoustic receiving device in the acoustic communication system according to any one of claims 1 to 6 ,
a sound collection unit that collects the acoustic signal;
a data acquisition unit that extracts a plurality of the embedded information from the acoustic signal collected by the sound collection unit and acquires the plurality of small data from the plurality of embedded information;
An acoustic receiving device comprising: a data reconstruction unit that reconstructs the original data by combining a plurality of the small data pieces in the order of the order information . A program executed by a computer included in the acoustic transmitting device in the acoustic communication system according to any one of claims 1 to 6 ,
computer,
A data division unit that divides the input original data into multiple small data pieces,
an order information adding unit that adds order information to the small data specifying an order for reconstructing the original data;
an embedding unit that sequentially embeds the plurality of pieces of small data one by one as embedded information in the input original sound signal, and causes the sound emitting unit to emit a sound signal in which the embedded information is embedded in the original sound signal; A program to function as A program executed by a computer included in the acoustic receiving device in the acoustic communication system according to any one of claims 1 to 6 ,
computer,
a data acquisition unit that extracts the plurality of embedded information from the acoustic signal collected by the sound collection unit and obtains the plurality of small data from the plurality of embedded information;
A program for functioning as a data reconstruction unit that reconstructs the original data by combining a plurality of the small pieces of data in the order of the order information . An acoustic signal transmission method in an acoustic communication system comprising an acoustic transmitting device having a sound emitting section that emits an acoustic signal in which embedded information is embedded, and an acoustic receiving device having a sound collecting section that collects the acoustic signal. And,
a data dividing step in which the acoustic transmitting device divides the input original data into a plurality of small data;
an order information adding step in which the acoustic transmitting device adds order information to the small data specifying an order for reconstructing the original data;
The acoustic transmitting device sequentially embeds the plurality of small data pieces one by one in the input original sound signal as embedded information, thereby emitting the acoustic signal in which the embedded information is embedded in the original sound signal to the sound emitting section. An embedded step that makes a sound,
a data acquisition step in which the acoustic receiving device extracts a plurality of the embedded information from the acoustic signal collected by the sound collection unit and obtains the plurality of small data from the plurality of embedded information;
An acoustic signal transmission method comprising: a data reconstruction step of reconstructing the original data by combining a plurality of the small data in the order of the order information .