JP2015185950A - acoustic signal processing device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform acoustic communication with a particular device within a range where an acoustic signal reaches using the acoustic signal.SOLUTION: Acoustic signal generation means 101 generates an acoustic signal in which information is superposed on a particular frequency component. Storage means 102 stores data associating a ratio between before and after frequency shift of the acoustic signal with data representing moving speed as data on a frequency at which the acoustic signal is shifted. When the acoustic signal generation means 101 generates an acoustic signal, shifting means 103 shifts the frequency of the acoustic signal, i.e. the acoustic signal in which information is superposed on the particular frequency component, according to shift frequency data stored in the storage means 102. Output means 104 outputs the supplied acoustic signal, i.e. the acoustic signal whose frequency is shifted by the shifting means 103.

Description

  The present invention relates to a communication technique using an acoustic signal.

  There is a technique of communication using an acoustic signal (hereinafter referred to as “acoustic communication”). In Patent Document 1, an acoustic signal converted by an encoder driven at a reference frequency is transmitted, and the received acoustic signal is decoded using a decoder driven at a frequency different from the reference frequency, so that the transmission side and the reception side are decoded. An acoustic communication technique is disclosed in which normal signals can be transmitted and received even when there is a speed difference between the two sides.

JP 2004-048309 A

  When transmitting information by communication, there are cases where it is desired to transmit information only to a specific partner. In the case of acoustic communication, for example, it is a case where it is desired to perform acoustic communication using the acoustic signal only with a specific device among a plurality of devices within a range in which the acoustic signal reaches. In the technique of Patent Literature 1, even in such a case, all devices within the range where the acoustic signal can reach are targets for acoustic communication.

  Therefore, an object of the present invention is to perform acoustic communication using a specific device within a range where an acoustic signal can reach with the acoustic signal.

  In order to solve the above-described problems, the present invention provides an acoustic signal generation unit that generates an acoustic signal on which information is superimposed, a storage unit that stores data relating to a frequency at which the acoustic signal is shifted, and the acoustic signal generation unit. An acoustic signal comprising: a deviation unit that shifts the frequency of the generated acoustic signal according to data stored in the storage unit; and an output unit that outputs the acoustic signal whose frequency is shifted by the deviation unit as a sound wave. A processing device is provided.

  The present invention also provides a receiving means for receiving an acoustic signal on which information is superimposed, a storage means for storing data relating to a frequency for shifting the acoustic signal, and a frequency of the acoustic signal received by the receiving means. The shift means for shifting according to the data stored in the storage means, the extraction means for extracting the superposed information from the acoustic signal whose frequency is shifted by the shift means, and the extraction means Provided is an acoustic signal processing device including output means for outputting information.

  In the acoustic signal processing device, the data stored in the storage unit may be data in which data relating to the frequency before and after the deviation of the acoustic signal is associated with data relating to the moving speed.

  In the acoustic signal processing device, information determined for each of the plurality of frequency components is superimposed on the plurality of frequency components of the acoustic signal on which the information is superimposed, and the storage unit includes the plurality of frequency components. Data relating to a plurality of different frequencies before and after the shift and data relating to a plurality of movement speeds different for each of the plurality of frequency components, respectively, as data relating to a frequency at which the acoustic signal is shifted You may remember.

  In the acoustic signal processing device, the storage unit includes data representing a movement speed of 0 and data representing a movement speed other than 0 in the data relating to the plurality of movement speeds, and the movement speed is zero. Data in which data representing a deviation of the acoustic signal of 0 is associated with the data to be represented may be stored as data relating to the frequency at which the acoustic signal is displaced.

  Further, the present invention provides a computer that controls the acoustic signal processing device, an acoustic signal generating unit that generates an acoustic signal on which information is superimposed, a storage unit that stores data relating to a frequency at which the acoustic signal is shifted, Deviation means for shifting the frequency of the acoustic signal generated by the acoustic signal generation means according to the data stored in the storage means, and output means for outputting the acoustic signal whose frequency is shifted by the deviation means as a sound wave Provide a program to function as

  Further, the present invention provides a computer that controls the acoustic signal processing device, a receiving unit that receives an acoustic signal on which information is superimposed, a storage unit that stores data relating to a frequency at which the acoustic signal is shifted, and the receiving unit. The shift means for shifting the frequency of the acoustic signal received by the storage means according to the data stored in the storage means, and the extraction for extracting the superposed information from the acoustic signal whose frequency is shifted by the shift means And a program for functioning as output means for outputting information extracted by the extraction means.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to perform acoustic communication using the acoustic signal with the specific apparatus within the range which an acoustic signal reaches.

The block diagram which shows the structure of the acoustic communication system which concerns on embodiment of this invention. Block diagram showing the hardware configuration of the acoustic transmitter Block diagram showing the hardware configuration of the acoustic receiver The block diagram which shows the function structure of an acoustic transmitter and an acoustic receiver The figure for demonstrating the frequency of the output acoustic signal The figure for demonstrating the acoustic signal after a shift The figure which shows the example where information is not superimposed on the specific frequency component Sequence chart showing an example of the operation of the acoustic transmitter and the acoustic receiver The block diagram which shows the function structure of the acoustic transmitter of a modification, and an acoustic receiver. Sequence chart showing an example of operation of the acoustic transmission device and the acoustic reception device of the modification The figure which shows an example of the acoustic signal with which information was superimposed The figure which shows an example of a mode that the frequency of an acoustic signal is shifted The block diagram which shows an example of the hardware constitutions of the acoustic transmitter of a modification The block diagram which shows the function structure of the acoustic transmission apparatus of a modification.

<Configuration>
FIG. 1 is a block diagram showing the overall configuration of an acoustic communication system 1 according to an embodiment of the present invention. The acoustic communication system 1 includes an acoustic transmission device 10 and a plurality of acoustic reception devices 20. The acoustic transmission device 10 and the acoustic reception device 20 are both devices that perform processing related to acoustic signals, and are examples of the “acoustic signal processing device” of the present invention. The acoustic transmitter 10 outputs an acoustic signal on which information is superimposed as a sound wave. Each acoustic receiver 20 receives the acoustic signal output by the acoustic transmitter 10, extracts information superimposed on the acoustic signal from the received acoustic signal, and outputs the extracted information. As described above, the acoustic communication system 1 is a system that transmits information between apparatuses by communication using an acoustic signal (that is, acoustic communication).

  FIG. 2 is a diagram illustrating a hardware configuration of the acoustic transmission device 10. The acoustic transmission device 10 is a computer including a control unit 11, a storage unit 12, a sound wave output unit 13, and an interface 14. The control unit 11 includes an arithmetic device such as a CPU (Central Processing Unit) and a storage device such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit 12 is a large-capacity non-volatile storage unit such as a hard disk, and stores an acoustic signal and information superimposed on the acoustic signal in addition to a program. The CPU controls the operation of each unit of the acoustic transmission device 10 by executing a program stored in the ROM or the storage unit 12 using the RAM as a work area.

  The sound wave output unit 13 includes a speaker and an audio processing circuit (not shown), and is an output unit that outputs an acoustic signal read from the storage unit 12 and supplied by the control unit 11. The interface 14 inputs and outputs data to and from an external device through a wired connection via a USB (Universal Serial Bus) terminal or the like, or a wireless connection in accordance with a standard such as Bluetooth (registered trademark). Information superimposed on the acoustic signal may be input from an external device via the interface 14.

  FIG. 3 is a block diagram illustrating a hardware configuration of the acoustic receiver 20. The acoustic reception device 20 is a computer that includes a control unit 21, a storage unit 22, a communication unit 23, an operation unit 24, a display unit 25, and a sound wave reception unit 26. In the present embodiment, the case where the acoustic receiver 20 is a so-called smart phone will be described as an example. The acoustic receiving device 20 is not limited to a smart phone, and may be any device that can be carried by a user, such as a mobile phone, a tablet terminal, a PDA (Personal Digital Assistant), a mobile computer, or a game machine.

  The control unit 21 includes an arithmetic device such as a CPU and a storage device such as a ROM and a RAM. The storage unit 22 is a storage unit such as an EEPROM (Electronically Erasable and Programmable ROM) or a flash memory. The CPU controls the operation of each unit of the acoustic reception device 20 by executing a program stored in the ROM or the storage unit 22 using the RAM as a work area. The communication unit 23 includes an antenna and a communication circuit, and performs wireless communication with a base station of a mobile communication network.

  The operation unit 24 is an operation unit having operation elements such as keys and touch sensors, and supplies an operation signal corresponding to a user operation to the control unit 21. The control unit 21 performs processing according to the operation signal. The display unit 25 is a display unit including a liquid crystal panel and a liquid crystal driving circuit, and displays an image under the control of the control unit 21. The sound wave receiving unit 26 includes a microphone and a sound wave processing circuit (not shown), and is a receiving unit that receives an acoustic signal output from the acoustic transmission device 10. The sound wave receiving unit 26 supplies the received acoustic signal to the control unit 21.

<Overview>
The outline of the acoustic communication system 1 is as follows. The acoustic transmission device 10 is installed in a place visited by a user, such as a store, public facility, or street, for example, and is a sound on which information related to the installed location or information related to a product handled at the location is superimposed. Output a signal. Each acoustic receiving device 20 is carried by a user, and when the user passes near the place where the acoustic transmitting device 10 is installed, the acoustic receiving device 20 receives an acoustic signal output from the acoustic transmitting device 10. At this time, the acoustic communication system 1 does not transmit information to all the acoustic receiving devices 20 carried by the passing user, but transmits information to the acoustic receiving devices 20 carried by a specific user. The mechanism for this will be described below.

  FIG. 4 is a block diagram illustrating functional configurations of the acoustic transmission device 10 and the acoustic reception device 20. The acoustic transmission device 10 includes an acoustic signal generation unit 101, a storage unit 102, a shift unit 103, and an output unit 104. The acoustic reception device 20 includes a reception unit 201, an extraction unit 202, and an output unit 203. With. The acoustic signal generation unit 101 and the shift unit 103 are both realized by the controller 11 of the acoustic transmission device 10 executing a program, the storage unit 102 is realized by the storage unit 12, and the output unit 104 is a sound wave output. This is realized by the unit 13. The receiving unit 201 is realized by the sound wave receiving unit 26 of the acoustic receiver 20. The extraction unit 202 is realized by the control unit 21 executing a program and cooperating with the storage unit 22, and the output unit 203 is realized by the control unit 21 executing the program.

  The acoustic signal generation unit 101 reads an acoustic signal and information to be superimposed on the acoustic signal from the storage unit 12, and an acoustic signal in which the information is superimposed on a specific frequency component (hereinafter referred to as a specific frequency component) of the acoustic signal. Is generated. The acoustic signal generation unit 101 superimposes information on the acoustic signal by the following method, for example. The acoustic signal generation unit 101 generates a spreading code (pseudo noise code or the like), multiplies the spreading code by a data code representing information to be superimposed, and generates a spreading code modulated by the data code. Next, the acoustic signal generating unit 101 converts the value of each chip of the modulated spread code into a differential code by a process of replacing the absolute value with a value representing a change from the previous chip. Next, the acoustic signal generation unit 101 up-samples the converted differential code string, performs band limitation and waveform shaping, and then multiplies the carrier signal. The acoustic signal generation means 101 adjusts the gain of the modulation signal thus obtained, and adds and synthesizes the acoustic signal with the high frequency cut. Thereby, an acoustic signal on which information is superimposed is generated.

  Note that the method of superimposing information on an acoustic signal is not limited to this, and for example, information is superimposed using an OFDM (Orthogonal Frequency Division Multiplexing) modulation method as disclosed in JP 2007-104598 A. Alternatively, information may be superimposed by modulating the amplitude as disclosed in Japanese Patent Application Laid-Open No. 2006-251676. The acoustic signal generation unit 101 may superimpose information on the acoustic signal by any method as long as the information superimposed on the acoustic signal can be extracted. The acoustic signal generation means 101 includes an input means for inputting an acoustic signal and information to be superimposed on the acoustic signal from the outside, and generates an acoustic signal using the acoustic signal and information input by the input means. Also good.

  The storage means 102 stores data relating to the frequency at which the acoustic signal is shifted (hereinafter referred to as “shift frequency data”). The deviation frequency data stored in the storage means 102 includes, for example, data relating to frequencies before and after the deviation of the acoustic signal (hereinafter referred to as “data before and after deviation”) and data relating to the moving speed (hereinafter referred to as “moving speed data”). The associated data. The data before and after the shift is, for example, data indicating a ratio of the frequency of the acoustic signal before and after the shift (hereinafter referred to as “shift ratio”). The data before and after the shift may not indicate the shift ratio itself, for example, may indicate a frequency before the shift and a frequency after the shift, or may include a predetermined shift ratio and a sign. The code may be shown when the associated table is stored (A when the deviation ratio is 0.9, B when it is 0.8). In the latter case, the data before and after the shift indicates the shift ratio associated with the code indicated by the own data in the table.

  The moving speed data is data representing a predetermined moving speed in a predetermined unit (m / sec: meters per second, etc.), for example. As the predetermined moving speed, a moving speed when a person walks is determined. The moving speed data may not directly represent a predetermined moving speed. For example, the moving speed data is data that associates position information and time information by GPS (Global Positioning System) or the like (that is, from position information and time information). Data indicating the travel speed to be calculated), or a table in which a vehicle (a escalator at a department store, a cart, an attraction vehicle, etc.) with a predetermined travel speed is associated with a code is stored. Alternatively, it may be data indicating the code (that is, data indicating the moving speed of the vehicle corresponding to the code).

  When the acoustic signal generation unit 101 generates an acoustic signal on which information is superimposed, the shifting unit 103 stores the frequency of the acoustic signal, that is, the acoustic signal on which information is superimposed on a specific frequency component, stored in the storage unit 102. Shifting is performed according to the shift frequency data. The shift means 103 supplies the acoustic signal whose frequency is shifted to the output means (sound wave output unit 13), and the output means 104 outputs the supplied acoustic signal, that is, the shift means 103 shifts the frequency. An acoustic signal is output as a sound wave. The shift frequency data and moving speed data, and the method by which the shift means 103 shifts the frequency will be described below with reference to FIGS.

  FIG. 5 is a diagram for explaining the frequency of the output acoustic signal. FIG. 5 shows the relationship between the frequency of the acoustic signal and the sound pressure level when the horizontal axis is the frequency (Hz) and the vertical axis is the sound pressure level (dB). In FIG. 5A, the acoustic signal generated by the acoustic signal generation means 101, that is, the acoustic signal before the frequency is shifted (such an acoustic signal is hereinafter referred to as “the acoustic signal before deviation”). The relationship between the frequency and the sound pressure level of the acoustic signal A1 before deviation which is an example is shown. In this example, the pre-shift acoustic signal A1 is an acoustic signal having a frequency band from the frequency f1 to the frequency f2. Hereinafter, the frequency band of the pre-shift acoustic signal is referred to as “pre-shift band”. The sound pressure level of the pre-shift acoustic signal A1 is maximum at a frequency f3 that is between the frequency f1 and the frequency f2. The frequency f3 is a frequency that serves as a reference for the frequency component of the pre-shift acoustic signal A1, and is hereinafter referred to as a reference frequency f3.

  The acoustic receiving device 20 moves closer to or away from the acoustic transmitting device 10 by being carried by a moving user. When such an acoustic receiver 20 receives the pre-shifted acoustic signal A1 output from the acoustic transmitter 10, the relative speed of the acoustic transmitter 10 and the acoustic receiver 20 and the speed at which sound waves are transmitted through the air (sound speed). The Doppler effect according to the above occurs, and the frequency of the received acoustic signal shifts from the frequency of the acoustic signal A1 before shifting. Here, if the acoustic transmitter 10 does not move (that is, the speed is 0), the magnitude of the Doppler effect is the moving speed of the acoustic receiver 20 carried by the user, more specifically, the acoustic receiver 20. Of the moving speeds, the speed is determined according to the moving speed component and the sound speed on a straight line connecting the acoustic transmitter 10 and the acoustic receiver 20. In the following, in order to make the explanation easy to understand, it is assumed that the sound speed is constant and the acoustic receiver 20 moves on this straight line. Further, the speed in the direction away from the acoustic transmission device 10 is indicated by a positive value, and the speed in the direction approaching the acoustic transmission device 10 is indicated by a negative value.

  FIG. 5B shows acoustic signals A2 and A3, which are examples of acoustic signals after the frequency is shifted due to the Doppler effect. The acoustic signal A2 is an acoustic signal that is received when the acoustic receiver 20 is moving at a speed + V1 (that is, in a direction away from the acoustic transmitter 10), and has a lower frequency than the acoustic signal A1 before the shift. Thus, the acoustic signal has only a component having a frequency lower than that of the pre-shift band described above. The acoustic signal A3 is an acoustic signal that is received when the acoustic receiving device 20 is moving at the speed −V1 (that is, in a direction approaching the acoustic transmitting device 10), and is compared with the pre-shifting acoustic signal A1. The frequency is high, and the acoustic signal has only a component having a frequency higher than the pre-shift band.

  In this case, the reference frequency f3 of the acoustic signal A1 before shifting is shifted to the reference frequencies f4 and f5 in the acoustic signals A2 and A3, respectively. More specifically, in the acoustic signal A2, the frequency of the acoustic signal A1 before the shift is multiplied by a ratio Rv1 (Rv1 = (V0 + V1) ÷ V0, V0 is the speed of sound) corresponding to the speed + V1 (of the reference frequency f3). In this case, it is shifted to f3 × Rv1 = f4). In the acoustic signal A3, the frequency of the acoustic signal A1 before deviation is multiplied by a ratio Rv2 (RV2 = (V0−V1) ÷ V0) corresponding to the speed −V1 (in the case of the reference frequency f3, f3 × Rv2 = f5). ).

  The storage unit 102 stores, for example, shift frequency data in which movement speed data representing the speed + V and data before and after the shift indicating the shift ratio corresponding to the speed + V are associated with each other. The deviation ratio in this case is the ratio Rv1 described in FIG. In this case, the shift means 103 shifts the frequency of the acoustic signal to a frequency divided by the shift ratio Rv1 according to the stored shift frequency data. By performing the shift in this way, the shift ratio Rv1 represents the ratio before and after the shift of the frequency of the acoustic signal. The acoustic signal whose frequency is shifted by the shifting means 103 in this way is hereinafter referred to as “shifted acoustic signal”.

  FIG. 6 is a diagram for explaining the shifted acoustic signal. FIG. 6A shows the post-shift acoustic signal A4 in which the shift means 103 shifts the frequency of the pre-shift acoustic signal A1 to the frequency divided by the shift ratio Rv1. For example, the reference frequency f6 of the post-shift acoustic signal A4 has a value of reference frequency f3 ÷ shift ratio Rv1. Further, the post-shift acoustic signal A4 is an acoustic signal having only a frequency component higher than the pre-shift band (band from f1 to f2). The post-shift acoustic signal A4 is output by the sound wave output unit 13, and when the acoustic receiver 20 that moves at the speed + V1 receives the output post-shift acoustic signal A4, the frequency of the received acoustic signal A5 is As described in 5 (b), the frequency shifts to the frequency multiplied by the ratio Rv1 corresponding to the speed + V1 by the Doppler effect.

  Thereby, for example, the reference frequency f7 of the acoustic signal A5 becomes a frequency obtained by multiplying the reference frequency f6 of the shifted acoustic signal A4 by the ratio Rv1, and specifically, f7 = f6 × Rv1 = f3 ÷ Rv1 × Rv1 = f3. It becomes. This f3 is the same as the reference frequency of the pre-shift acoustic signal A1, that is, the frequency before the shift, that is, the frequency of the sound signal generated by the sound signal generating means 101.

  Thus, the frequency shift by the shift means 103 does not shift the frequency uniformly by a predetermined frequency or change the phase of the frequency, but divides the frequency by a predetermined ratio (the ratio). As well as multiplication by the reciprocal of. This is the same as the frequency shift caused by the Doppler effect, and the frequency shifted by the Doppler effect can be returned to the original frequency.

  When the moving speed data represents the speed −V, the storage unit 102 stores shift frequency data in which the moving speed data and the data before and after the shift indicating the shift ratio Rv2 are associated with each other. In this case, the shift means 103 shifts the frequency by dividing the frequency of the acoustic signal by the shift ratio Rv2 in accordance with the stored shift frequency data. When the acoustic receiving device 20 that moves at the speed −V1 receives the post-shifted acoustic signal output in this way, the frequency of the received acoustic signal A5 is multiplied by the ratio Rv2 corresponding to the speed −V1 due to the Doppler effect. Since it shifts, it becomes the frequency before the shift, that is, the frequency of the acoustic signal generated by the acoustic signal generation means 101.

  As described above, the storage unit 102 uses, as the shift frequency data, the moving speed data representing a predetermined moving speed such as + V and −V and the acoustic signal output from the own apparatus (acoustic transmitting apparatus 10) as the predetermined frequency. When the sound is received by the sound receiving device 20 moving at the moving speed, the frequency of the received sound signal, that is, the frequency of the sound signal whose frequency is shifted due to the Doppler effect, is generated by the sound signal generating unit 101. Data in which the data before and after the shift indicating the shift ratio that is the same as the frequency of the signal is associated is stored.

  As described above, the shifted acoustic signal whose frequency is shifted by the shifting unit 103 and output by the output unit 104 (sound wave output unit 13), that is, the acoustic signal on which the information is superimposed is, for example, Received by the receiving means 201. The extraction means 202 (control unit 21) of the acoustic receiver 20 extracts the superimposed information from the acoustic signal thus received. More specifically, when information is superimposed on a specific frequency component of the received acoustic signal, the extracting unit 202 extracts the information from the received acoustic signal. The storage unit 22 of the acoustic receiving device 20 stores band information indicating which frequency band the pre-shift band is, and the extraction unit 202 reads out the band information and the frequency indicated by the band information. Extract information from the band.

  When the acoustic receiver 20 is moving at the speed + V1, the wavelength of the received acoustic signal is shifted as shown in FIG. 6B due to the Doppler effect, so that the pre-shift band f1 to f2 Up to this point, all components of the acoustic signal A5 are included. That is, since the above information is superimposed on the specific frequency component in this case, the extraction unit 202 extracts the information from the acoustic signal A5. On the other hand, the extraction unit 202 does not extract information in the following cases.

  FIG. 7 is a diagram illustrating an example of an acoustic signal from which information is not extracted by the extraction unit 202. In FIG. 7, for example, the acoustic signal A6 when the acoustic receiver 20 that moves the shifted acoustic signal A4 illustrated in FIG. 6 at the speed −V1 is received is illustrated. In this case, as described with reference to FIG. 5, the frequency of the acoustic signal A6 is shifted so as to be higher than that of the post-shifting acoustic signal A4 due to the Doppler effect. Originally, the post-shift acoustic signal A4 is an acoustic signal having only a component having a frequency higher than that of the pre-shift band. Therefore, the acoustic signal A6 shifted to a higher frequency is also a component having a frequency higher than that of the pre-shift band. The acoustic signal has only the component and has no component in the band before the shift. Therefore, the acoustic signal A6 observed by the acoustic receiver 20 is an acoustic signal in which information is not superimposed on the specific frequency component, and the extraction unit 202 does not extract information from the acoustic signal A6.

  Further, FIG. 7 shows an acoustic signal A7 when the acoustic receiver 20 moving at a speed + V2 faster than the speed + V1 receives the post-shifting acoustic signal A4. In this example, the frequency shift due to the Doppler effect is greater than in the case of velocity + V1, and the acoustic signal A7 is an acoustic signal having only a component having a frequency lower than the pre-shift band. Therefore, the acoustic signal A7 observed by the acoustic receiver 20 is an acoustic signal in which information is not superimposed on the specific frequency component, and the control unit 21 does not extract information from the acoustic signal A7.

  The output means 203 of the acoustic receiver 20 outputs the information extracted from the acoustic signal by the extraction means 202 as described above. For example, the control unit 21 outputs the extracted information to the display unit 25. Note that the output destination of the information is not limited to the display unit 25, and may be an external device capable of communicating via the communication unit 23, for example, or may include an audio output unit that outputs sound. For example, the sound output means may be used. In any case, the output information may be transmitted to the user.

<Operation>
FIG. 8 is a sequence chart illustrating an example of operations of the acoustic transmission device 10 and the acoustic reception device 20. In FIG. 8, the predetermined movement speed used when the acoustic transmission device 10 shifts the frequency is the speed + V1 as in the above example, and the movement is performed at the speed + V1 within the range where the acoustic signal output from the acoustic transmission device 10 reaches. The case where the acoustic receiving device 20a that moves and the acoustic receiving device 20b that moves at a speed other than the speed + V1 are located will be described. First, the acoustic transmission device 10 shifts the frequency of the acoustic signal on which information is superimposed as described above (step S101), and outputs the shifted acoustic signal as a sound wave (step S102). The acoustic signals reach the acoustic receivers 20a and 20b, respectively.

  Next, the operation of the acoustic receiver 20a will be described. When the acoustic receiver 20a receives the acoustic signal output from the acoustic transmitter 10, the acoustic receiver 20a tries to extract information from the specific frequency component of the received acoustic signal (step S111), and there is information superimposed on the acoustic signal. If so, the superimposition information is extracted (step S112). Since the acoustic receiver 20a is moving at the predetermined speed + V1, the superposition information is extracted in step S112 and the superposition information is output (step S113). As described above, between the acoustic transmission device 10 and the acoustic reception device 20a, transmission of information by output and reception of an acoustic signal, that is, acoustic communication that is communication using the acoustic signal is performed.

  Next, the operation of the acoustic receiver 20b will be described. When the acoustic receiver 20b receives the acoustic signal output from the acoustic transmitter 10, the acoustic receiver 20b tries to extract information from the specific frequency component of the received acoustic signal (step S121). Since the acoustic receiver 20b is moving at a speed other than the predetermined movement speed of speed + V1, the superposition information cannot be extracted after step S121, and the operation ends. As described above, although the acoustic signal is output and received between the acoustic transmission device 10 and the acoustic reception device 20b, information is not transmitted and acoustic communication is not performed.

  In the present embodiment, the acoustic signals output from the acoustic transmission device 10 are received by the acoustic reception devices 20 within the reach of the acoustic signals. And only the specific apparatus of those acoustic receivers 20, in the above example, the apparatus moving at the speed + V1 extracts and outputs information from the received acoustic signal. Thus, according to this embodiment, it is possible to communicate with a specific device out of devices within a range where the acoustic signal can reach using the acoustic signal.

(Modification)
The above embodiment may be modified as follows. Moreover, you may implement embodiment and each modification in combination as needed.
(Modification 1)
In the embodiment, the acoustic transmission device 10 shifts the frequency of the acoustic signal, but the acoustic reception device 20 may shift the frequency of the acoustic signal. The configuration and operation in this case will be described with reference to FIGS.

FIG. 9 is a block diagram illustrating functional configurations of the acoustic transmission device 10 and the acoustic reception device 20 according to the present modification. The acoustic transmission device 10 includes an acoustic signal generation unit 101 and an output unit 104 illustrated in FIG. 4, and the acoustic reception device 20 includes a storage unit 204 and a shift unit 205 in addition to the units illustrated in FIG. 4. Yes. The storage unit 204 is realized by the storage unit 22, and the shift unit 205 is realized by the control unit 21 executing a program.
FIG. 10 is a sequence chart illustrating an example of operations of the acoustic transmission device 10 and the acoustic reception device 20 according to this modification. FIG. 10 also illustrates a case where the acoustic receiver 20a moves at a predetermined moving speed (for example, speed + V) and the acoustic receiver 20b moves at a speed other than the predetermined moving speed.

  In this modification, the output unit 104 of the acoustic transmission device 10 outputs the generated acoustic signal (step S131). More specifically, the acoustic signal is an acoustic signal in which information is superimposed on a specific frequency component, and the acoustic transmission device 10 outputs the acoustic signal as it is without shifting the frequency. When the acoustic receiver 20a receives the acoustic signal output from the acoustic transmitter 10, the acoustic receiver 20a shifts the frequency of the received acoustic signal (step S141). More specifically, the storage unit 204 of the acoustic receiver 20a stores deviation frequency data, and the deviation unit 205 stores the frequency of the acoustic signal received by the reception unit 201. The shift is performed according to the shift frequency data. The “frequency of the received acoustic signal” here means the frequency at the time of reception of the received acoustic signal, and does not mean the frequency at the time of transmission.

  Similar to the storage unit 102 described above, the storage unit 204 stores shift frequency data in which movement speed data and pre-shift data are associated with each other. In this example, the storage unit 204 stores shift frequency data in which movement speed data representing a speed + V, which is a predetermined movement speed, and data before and after the shift indicating the shift ratio Rv1 are associated with each other. In this case, the shift means 205 shifts the frequency of the received acoustic signal to a frequency divided by the shift ratio Rv1 according to the stored shift frequency data.

  Next, the extraction unit 202 of the acoustic receiver 20a attempts to extract information from the acoustic signal whose frequency is shifted by the shift unit 205 (step S142). As described above, since the acoustic receiving device 20a is moving at a predetermined moving speed, information is superimposed on the specific frequency component of the acoustic signal whose frequency is shifted, and the extracting unit 202 extracts the acoustic signal from the acoustic signal. Superimposition information is extracted (step S143). In this way, the extraction unit 202 extracts the superimposed information from the acoustic signal whose frequency is shifted by the shift unit 205. On the other hand, the acoustic receiving device 20b shifts the frequency of the acoustic signal in the same manner as the acoustic receiving device 20a (step S151) and tries to extract information (step S152), but the own device is at a speed other than the predetermined moving speed. Since it is moving, the operation is terminated without extracting the superimposition information.

  In this modification, since the acoustic receiver 20 performs a shift process for shifting the frequency, the processing load of the acoustic transmitter 10 can be reduced compared to the case where the acoustic transmitter 10 performs the shift process. . In addition, when the acoustic transmission device 10 performs the shift process, the predetermined moving speed is the same in any acoustic reception device 20, but in this modification, each acoustic reception device 20 individually performs the shift process. The predetermined moving speed can be varied for each acoustic receiver 20. For example, the acoustic transmission device 10 performs acoustic communication with the acoustic reception device 20a when leaving the own device with the speed + V1 set to a predetermined movement speed, while the acoustic reception device 20b moves the speed −V1 with a predetermined movement. For example, acoustic communication is performed when approaching the device at a speed.

(Modification 2)
In the embodiment, the frequency band of the output acoustic signal matches the frequency band on which information is superimposed, but the present invention is not limited to this.
FIG. 11 is a diagram illustrating an example of an acoustic signal on which information is superimposed in the present modification. FIG. 11 shows a graph showing the relationship between the frequency and the sound pressure level as in FIG. The acoustic signal A11 illustrated in FIG. 11 is an acoustic signal having a frequency component less than f1 and a frequency component greater than the frequency f2.

  In the acoustic signal A11, information is superimposed on the component A12 (portion indicated by hatching in the drawing) in the frequency band of the frequency f1 or higher and the frequency f2 or lower, and information is not superimposed on the other components. In this case, for example, a specific code is included in the superimposed information, and the control unit 21 (extraction means) of the acoustic reception device 20 performs a process of extracting information from the specific frequency component, and the code Is extracted, it is determined that information is superimposed on the specific frequency component. In this way, for example, information can be superimposed on the non-audible range component of the output acoustic signal, and communication using a human voice or the sound of music as the audible range component can be performed.

(Modification 3)
In the embodiment, the acoustic reception device 20 stores the band information indicating the pre-shift band, but the acoustic transmission device 10 may output the band information by superimposing the band information on the acoustic signal. In this case, the control unit 21 (extraction unit) of the acoustic receiver 20 performs a process of extracting information from the components of the entire acoustic signal, and extracts all the superimposed information. If the extracted information includes band information, the control unit 21 extracts information from the component of the pre-shift band indicated by the band information as in each of the above examples. In this modification, it is not necessary to previously store the band information in the acoustic receiver 20. Therefore, when the pre-shift band is changed, acoustic communication can be performed without distributing the band information indicating the post-change band, and the pre-shift band can be changed for each communication.

(Modification 4)
The “predetermined moving speed” described in the embodiment is a moving speed of the acoustic receiver 20 that enables acoustic communication by the output acoustic signal. In the embodiment, there is one type of information that is transmitted in a single way with the predetermined moving speed. However, there are a plurality of types of the predetermined moving speed, and different information may be transmitted for each predetermined moving speed. Information defined for each of the plurality of frequency components is superimposed on the plurality of frequency components of the acoustic signal on which information used in this case is superimposed. Then, the storage means (storage means 102 and 204) stores data in which a plurality of data before and after shift different for each of the plurality of frequency components and a plurality of movement speed data different for each of the plurality of frequency components are associated with each other. And stored as deviation frequency data. The shift means (shift means 103 and 205) shift each of the frequencies of the plurality of frequency components in accordance with the shift frequency data stored in this way.

  FIG. 12 is a diagram illustrating an example of how the frequency of the acoustic signal is shifted in the present modification. In FIG. 12A, the relationship between the frequency and the sound pressure level of the acoustic signal A20 output by the acoustic transmitter 10 is shown. The acoustic signal A20 has a frequency component A21 of the pre-shift band B1 from f11 to f12 and a frequency component A22 of the pre-shift band B2 from f13 to f14. Below, the case where the deviation means 103 of the acoustic transmitter 10 shifts a frequency is demonstrated. FIG. 12B shows a frequency component A23 (frequency component A21 before shift) and frequency component A24 (frequency component A22 before shift) whose frequency has been shifted by the shift means 103. . In this example, the shift means 103 shifts the frequency of the frequency component A21 using the speed + V1 as a predetermined moving speed (dividing the frequency by the ratio Rv1), and the frequency of the frequency component A22 is set to the predetermined speed -V1. The movement speed is shifted (frequency is divided by the ratio Rv2).

  FIG. 12C shows frequency components A25 and A26 included in the received acoustic signal when the acoustic signal is received by the acoustic receiver 20 moving at the speed + V1. The frequency components A25 and A26 are obtained by shifting the frequencies of the frequency components A23 and A24 by a ratio obtained by multiplying the ratio Rv1 by the Doppler effect at the speed + V1. In this case, information is extracted because the frequency component A25 is included in the pre-shift band B1, and no information is extracted because the frequency component A26 is not included in either of the pre-shift bands B1 and B2.

FIG. 12D shows frequency components A27 and A28 included in the received acoustic signal when the acoustic signal is received by the acoustic receiver 20 moving at the speed −V1. The frequency components A27 and A28 are obtained by shifting the frequencies of the frequency components A23 and A24 by a ratio obtained by multiplying the ratio Rv2 by the Doppler effect at the speed −V1. In this case, information is extracted because the frequency component A28 is included in the pre-shift band B2, and no information is extracted because the frequency component A27 is not included in either of the pre-shift bands B1 and B2.
In the above example, there are two predetermined moving speeds of speed + V1 and speed -V1, and different information is obtained for the acoustic receiver 20 moving at speed + V1 and the acoustic receiver 20 moving at speed -V1. Is transmitted. Thus, according to this modification, different information can be transmitted corresponding to a plurality of predetermined movement speeds.

(Modification 5)
In the embodiment, the acoustic transmission device 10 performs acoustic communication with the acoustic reception device 20 that moves at a predetermined moving speed. However, the acoustic transmission device 10 may perform acoustic communication with the acoustic reception device 20 that does not move. In that case, the deviation means (the deviation means 103 of the acoustic transmitter 10 and the deviation means 205 of the acoustic receiver 20) do not shift the frequency of the acoustic signal when the predetermined moving speed is zero. Thereby, the acoustic transmission device 10 performs acoustic communication with the stationary acoustic reception device 20 in which the Doppler effect does not occur. When such acoustic communication is used, for example, only a user who stops in front of a store can communicate information with the stationary acoustic reception device 20 possessed by the user to transmit information.

  In the above modification, when different information is transmitted for each of a plurality of predetermined movement speeds, the information may be transmitted by setting one of the movement speeds to zero. In this case, the storage means (storage means 102 and 204) stores a plurality of movement speed data and data before and after shift as shift frequency data. Each moving speed data includes data indicating that the moving speed is 0 or data indicating that the moving speed is other than 0. The data before and after the shift is associated with data indicating that the moving speed is 0, and indicates that the shift of the acoustic signal is 0. The data before and after the shift indicating that the shift of the acoustic signal is 0 is data indicating that the shift ratio is 1, for example.

  In this modification, when there is a user who moves at a predetermined moving speed other than 0, the information that is superposed by the acoustic reception device 20 of the user performing acoustic communication is output. For example, when the user stops with an interest in the information, the moving speed becomes 0. Therefore, acoustic communication corresponding to the moving speed of 0 is performed and different information is output. As described above, according to the present modification, information can be provided to a user who moves at a predetermined moving speed, and more detailed information and related information can be provided to a stationary user based on the information. .

(Modification 6)
The speed at which the specific acoustic receiver 20 moves may be set as a predetermined moving speed.
FIG. 13 is a block diagram illustrating an example of a hardware configuration of the acoustic transmission device according to the present modification. In FIG. 13, in addition to each part shown in FIG. 2, the acoustic transmission apparatus 10a provided with the imaging | photography part 15 is shown. The photographing unit 15 has a function as, for example, a video camera, photographs a video according to a user operation, and supplies video data indicating the video to the control unit 11.

  FIG. 14 is a block diagram illustrating an example of a functional configuration of the acoustic transmission device 10a according to the present modification. The deviation unit 103 of the acoustic transmission device 10 includes a measurement unit 105 that measures the moving speed of the acoustic reception device. The measuring unit 105 is realized by the control unit 11 executing a program. For example, the measuring unit 105 analyzes the video shot by the shooting unit 15 and specifies the position of the user shown in the video. The measuring unit 105 specifies a position at a predetermined time interval (for example, every second), and measures the moving speed of the user based on the change amount of the specified position. Since the acoustic receiver 20 carried by the user is moving at the same speed as the user, the measured moving speed of the user can be regarded as the moving speed of the acoustic receiver 20. Then, the shift means 103 shifts the frequency using the measured speed as a predetermined moving speed. Thereby, acoustic communication is performed between the acoustic receiver 20 and the acoustic transmitter 10 carried by the user whose moving speed is measured.

  In this modification, if the speed at which a user moves can be measured, information can be transmitted to the user by performing acoustic communication with the acoustic receiver 20 carried by the user. In addition, even when the moving speed of the user changes, it is possible to continue transmitting information to the user, and what is the acoustic receiving device 20 carried by a user moving at a speed different from that user? It is possible not to perform acoustic communication. Note that the method of measuring the moving speed of the user is not limited to the above. For example, the speed may be measured like a so-called speed gun using the reflected wave of the electromagnetic wave output from the acoustic transmitter 10. If the acoustic receiver 20 shifts the frequency, the acoustic receiver 20 is provided with positioning means such as GPS, and measures the moving speed of its own device based on the amount of change in the measured position. May be.

(Modification 7)
In the embodiment, the frequency of the generated acoustic signal is shifted and output, but the present invention is not limited to this. For example, when the acoustic signal generation unit 101 generates an acoustic signal on which information is superimposed, the acoustic signal generation unit 101 generates and superimposes an acoustic signal whose frequency is shifted according to the shifted frequency data stored in the storage unit 102. As for information, the time axis is expanded and contracted according to the degree to which the acoustic signal is shifted. Then, the acoustic signal generation unit 101 may superimpose information obtained by expanding and contracting the time axis on the shifted acoustic signal. In this case, the output unit 104 outputs the acoustic signal generated by the acoustic signal generation unit 101 as it is. The acoustic signal output in this way is an acoustic signal whose frequency is shifted as in the embodiment.

(Modification 8)
In the embodiment, the case where the sound speed is constant has been described. However, since the sound speed changes depending on the temperature and humidity, this change may be taken into consideration. When the sound speed changes, the magnitude of the Doppler effect also changes. For example, in the above example, the ratio Rv1 corresponding to the speed + V1 changes to Rv1 ′. If the frequency is shifted using the ratio Rv1 without taking the change into account, acoustic communication is not performed with the acoustic receiver that moves at a predetermined moving speed, and the sound moves at a speed slightly deviated from the predetermined moving speed. Acoustic communication is performed with the receiving device. That is, there is a difference between the moving speed (the predetermined moving speed described above) and the predetermined moving speed of the acoustic receiving device that enables acoustic communication based on the output acoustic signal.

  In this modification, for example, when the acoustic transmission device shifts the frequency, the acoustic transmission device includes a temperature sensor and a humidity sensor, and calculates the sound speed based on the detection results of those sensors. Then, when the sound receiving device receives the sound signal output from the device at the calculated sound speed, the sound transmitting device is configured to set a ratio at which the frequency of the received sound signal is shifted from the output frequency due to the Doppler effect. Using the obtained ratio, the frequency is shifted as in the above examples. As a result, the difference between the predetermined moving speed and the predetermined moving speed can be reduced when the sound speed changes due to changes in the temperature and humidity, compared to the case where the change in the sound speed is not taken into consideration.

(Modification 9)
The present invention can also be implemented in the form of a program for causing a computer to function. Such a program may be provided in a form recorded on a recording medium such as an optical disc, or may be provided in a form such that the program is downloaded to a computer via a network such as the Internet, and the program can be installed and used. Is possible.

  DESCRIPTION OF SYMBOLS 1 Acoustic communication system, 10 Acoustic transmitter, 20 Acoustic receiver, 11, 21 Control part, 12, 22 Storage part, 13 Sound wave output part, 14 Interface, 15 Imaging part, 23 Communication part, 24 Operation part, 25 Display part , 26 sound wave reception unit, 101 acoustic signal generation means, 102 storage means, 103 deviation means, 104 output means, 105 measurement means, 201 reception means, 202 extraction means, 203 output means, 204 storage means, 205 deviation means.

Claims (7)

Acoustic signal generation means for generating an acoustic signal on which information is superimposed;
Storage means for storing data relating to a frequency at which the acoustic signal is shifted;
Shift means for shifting the frequency of the acoustic signal generated by the acoustic signal generation means in accordance with data stored in the storage means;
An acoustic signal processing apparatus comprising: output means for outputting, as a sound wave, an acoustic signal whose frequency is shifted by the shifting means. Receiving means for receiving an acoustic signal on which information is superimposed;
Storage means for storing data relating to a frequency at which the acoustic signal is shifted;
Shift means for shifting the frequency of the acoustic signal received by the receiving means in accordance with data stored in the storage means;
Extraction means for extracting information superimposed from an acoustic signal whose frequency is shifted by the shift means;
An acoustic signal processing apparatus comprising: output means for outputting information extracted by the extraction means. The acoustic signal processing apparatus according to claim 1, wherein the data stored in the storage unit is data in which data relating to frequencies before and after deviation of the acoustic signal is associated with data relating to moving speed. Information defined for each of the plurality of frequency components is superimposed on the plurality of frequency components of the acoustic signal on which the information is superimposed,
The storage means includes data in which data related to a plurality of frequencies before and after the shift that differ for each of the plurality of frequency components and data related to a plurality of movement speeds that differ for each of the plurality of frequency components are associated with each other, The acoustic signal processing device according to any one of claims 1 to 3, wherein the acoustic signal processing device is stored as data relating to a frequency at which the acoustic signal is shifted. The storage means includes data indicating that the moving speed is 0 and data indicating that the moving speed is other than 0 in the data relating to the plurality of moving speeds, and the moving speed is 0. 5. The acoustic signal processing according to claim 4, wherein data in which data representing that the deviation of the acoustic signal is zero is associated with data representing the frequency as data relating to a frequency at which the acoustic signal is displaced. apparatus. A computer for controlling the acoustic signal processing device;
Acoustic signal generation means for generating an acoustic signal on which information is superimposed;
Storage means for storing data relating to a frequency at which the acoustic signal is shifted;
Shift means for shifting the frequency of the acoustic signal generated by the acoustic signal generation means in accordance with data stored in the storage means;
A program for causing the shift means to function as an output means for outputting an acoustic signal whose frequency is shifted as a sound wave. A computer for controlling the acoustic signal processing device;
Receiving means for receiving an acoustic signal on which information is superimposed;
Storage means for storing data relating to a frequency at which the acoustic signal is shifted;
Shift means for shifting the frequency of the acoustic signal received by the receiving means in accordance with data stored in the storage means;
Extraction means for extracting information superimposed from an acoustic signal whose frequency is shifted by the shift means;
A program for functioning as output means for outputting information extracted by the extraction means.

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