JP6984259B2 - Signal processing methods, signal processing devices, and information provision systems - Google Patents

Description

The present invention relates to a technique for processing an acoustic signal.

Acoustic communication using sound waves as a transmission medium has been conventionally proposed. For example, Patent Document 1 discloses a sound emitting system that mixes an acoustic signal representing various guidance sounds and a modulated signal representing the identification information of the guidance sound as an acoustic component and reproduces the sound from the sound emitting device.

Japanese Unexamined Patent Publication No. 2016-76201

In the technique of Patent Document 1, the frequency band of the modulated signal representing the identification information is set to the band on the high frequency side which is difficult for humans to hear. However, depending on the listener, the acoustic component of the modulated signal may be audible. In consideration of the above circumstances, it is an object of the present invention to make it difficult to hear the acoustic component representing the transmitted information.

In order to solve the above problems, in the signal processing method according to the preferred embodiment of the present invention, the computer specifies the volume of the first acoustic signal, and the volume of the modulated signal including the acoustic component representing the transmission information is specified. The second acoustic signal is generated by adjusting according to the adjusted volume and mixing the first acoustic signal and the adjusted modulated signal.
A signal processing device according to a preferred embodiment of the present invention includes a volume specifying unit that specifies the volume of a first acoustic signal, a signal generation unit that generates a modulated signal including an acoustic component representing transmission information, and the volume specifying unit. It includes a volume adjusting unit that adjusts the volume of the modulated signal according to the specified volume, and a mixing processing unit that mixes the first acoustic signal and the adjusted modulated signal.
The information providing system according to a preferred embodiment of the present invention includes a sound collecting unit that generates a first acoustic signal by collecting sound, a signal processing device that generates a second acoustic signal from the first acoustic signal, and the signal processing apparatus. The signal processing device includes a volume specifying unit for specifying the volume of the first acoustic signal and an acoustic component representing transmission information. A modulation processing unit that generates a modulation signal including the modulation processing unit, a volume adjustment unit that adjusts the volume of the modulation signal according to the volume specified by the volume specification unit, and a mixture of the first acoustic signal and the adjusted modulation signal. Includes a mixing processing unit.

It is a block diagram of the situation where the information provision system of 1st Embodiment is used. It is a block diagram which illustrates the structure of the information provision system. It is explanatory drawing of the operation which adjusts the volume of a modulated signal. It is a flowchart of the process executed by the control device of an information providing system. It is a block diagram exemplifying the configuration of a terminal device. It is explanatory drawing of the operation which adjusts the volume of a modulation signal in 2nd Embodiment.

<First Embodiment>
FIG. 1 is an explanatory diagram of a situation in which the information providing system 10 according to the first embodiment of the present invention is used. The status providing system of the first embodiment is a computer system installed in a transportation system such as a train or a bus and for providing information on the transportation system to the user Ua. The user Ua carries the terminal device 20 and uses the transportation system. The terminal device 20 is an information terminal such as a mobile phone or a smartphone. Although a plurality of users Ua can actually use the service of the information providing system 10, the following description focuses on one terminal device 20 for convenience.

The speaker (for example, a transportation staff member) Ub who operates the information providing system 10 pronounces a voice (hereinafter referred to as “guidance voice”) G for guiding the transportation system at any time. For example, a voice for notifying the user Ua of various information such as an operation status such as a train delay, a train arrival, precautions for getting on and off, or an emergency situation is pronounced as a guidance voice G. The information providing system 10 of the first embodiment transmits the identification information D corresponding to the guidance voice G pronounced by the speaker Ub to the terminal device 20. The identification information D is information for the terminal device 20 to present information related to the guidance voice G (hereinafter referred to as “related information”) to the user Ua. The terminal device 20 of the first embodiment presents a character string representing the utterance content of the guidance voice G to the user Ua as related information. Therefore, for example, a deaf person who has difficulty in listening to the guidance voice G can grasp the content of the guidance voice G.

<Information provision system 10>
FIG. 2 is a configuration diagram of the information providing system 10. As illustrated in FIG. 2, the information providing system 10 of the first embodiment includes a signal processing device 11, a sound collecting device 12, and a sound emitting device 13. For example, an information terminal such as a tablet terminal and a personal computer is used as the information providing system 10. In addition, for example, a display terminal for guidance such as an electric bulletin board installed in a transportation facility or an electronic signboard (for example, digital signage) installed in a commercial facility may be used as the information providing system 10. Further, the information providing system 10 is realized not only by a single device but also by a plurality of devices configured as separate bodies from each other.

The sound collecting device 12 (exemplification of the sound collecting unit) is an audio device (microphone) that collects ambient sound. Specifically, the sound collecting device 12 picks up the guidance voice G produced by the speaker Ub and generates an acoustic signal X (example of the first acoustic signal) representing the waveform of the guidance voice G. The illustration of the A / D converter that converts the acoustic signal X generated by the sound collecting device 12 from analog to digital is omitted for convenience. The speaker Ub pronounces a character string having a predetermined content as a guidance voice G. For example, referring to an announcement book containing a plurality of character strings for guidance, the speaker Ub pronounces a guidance voice G having contents according to the actual situation of transportation.

The signal processing device 11 generates an acoustic signal Y (an example of a second acoustic signal) from the acoustic signal X. The sound emitting device 13 (exemplification of the sound emitting unit) radiates the sound represented by the acoustic signal Y generated by the signal processing device 11 to the surroundings. For convenience, the illustration of the D / A converter that converts the acoustic signal Y generated by the signal processing device 11 from digital to analog is omitted.

As illustrated in FIG. 2, the signal processing device 11 includes a control device 31, a storage device 32, and an operation device 33. The control device 31 is composed of a processing circuit such as a CPU (Central Processing Unit), and controls each element of the information providing system 10 in an integrated manner. The storage device 32 stores a program executed by the control device 31 and various data used by the control device 31. For example, a known recording medium such as a semiconductor recording medium and a magnetic recording medium, or a combination of a plurality of types of recording media can be arbitrarily adopted as the storage device 32. The operation device 33 is an input device that receives an instruction from the speaker Ub.

The control device 31 has a plurality of functions (information generation unit 41, modulation processing unit 42, volume specifying unit 43,) for generating an acoustic signal Y from the acoustic signal X by executing a program stored in the storage device 32. The volume adjusting unit 44 and the mixing processing unit 45) are realized. A part of the functions of the control device 31 may be realized by a dedicated electronic circuit. For example, the modulation processing unit 42, the volume adjustment unit 44, and the mixing processing unit 34 are suitably realized by an electronic circuit dedicated to a specific signal processing. Further, the functions of the control device 31 may be distributed to a plurality of devices.

The information generation unit 41 generates information (transmission information) to be transmitted to the terminal device 20. The information generation unit 41 of the first embodiment generates identification information D (exemplification of transmission information) corresponding to the guidance voice G produced by the speaker Ub. The identification information D is information for identifying the guidance voice G. As described above, since the related information corresponds to the guidance voice G, the identification information D is also paraphrased as information for identifying the related information.

The speaker Ub pronounces the guidance voice G and instructs the signal processing device 11 to indicate the guidance voice G. Specifically, the speaker Ub selects the guidance voice G pronounced by himself / herself from a plurality of candidates by appropriately operating the operation device 33. The information generation unit 41 generates the identification information D corresponding to the guidance voice G instructed by the speaker Ub. For example, the identification information D of each guidance voice G is stored in the storage device 32, and the information generation unit 41 corresponds to the guidance voice G instructed by the speaker Ub among the plurality of identification information D stored in the storage device 32. The identification information D to be used is acquired from the storage device 32.

The modulation processing unit 42 generates a modulation signal M including an acoustic component representing the identification information D generated by the information generation unit 41. Specifically, the modulation processing unit 42 modifies the modulation signal by, for example, amplitude modulation or frequency modulation in which a carrier wave having a predetermined frequency is modulated by the identification information D, or modulation processing such as diffusion modulation of the identification information D using a diffusion code. Generate M. The frequency band of the acoustic component representing the identification information D is, for example, a frequency band that can be reproduced by the sound emitting device 13, and is a range exceeding the frequency band of the sound that the user Ua listens to in a normal environment (for example, 18 kHz or more). And 20 kHz or less). The sound in the frequency band exemplified above is basically a sound that is difficult for the user Ua to hear, but it may be audible depending on the user Ua.

As illustrated in FIG. 3, in the modulation signal M, the identification information D common to each of the plurality of periods m on the time axis is superimposed. Each period m before and after the phase may be continuous on the time axis or may be separated from each other at intervals. Further, as illustrated in FIG. 3, the volume of the modulated signal M is maintained at a predetermined value.

The volume specifying unit 43 of FIG. 2 specifies the volume V of the acoustic signal X generated by the sound collecting device 12. A known technique is arbitrarily adopted for specifying the volume V. The volume specifying unit 43 sequentially specifies the volume V of the acoustic signal X at a predetermined cycle (that is, at different time points of the acoustic signal X).

The volume adjusting unit 44 adjusts the volume of the modulated signal M according to the volume V specified by the volume specifying unit 43. Specifically, the volume adjusting unit 44 adjusts the volume of the modulated signal M so that the volume V of the acoustic signal X increases, the volume of the modulated signal M increases. That is, the volume of the acoustic component of the identification information D is also high during the period when the volume V of the guidance voice G is high, and the volume of the acoustic component of the identification information D is also low during the period when the volume V of the guidance voice G is low.

FIG. 3 shows a waveform of the modulated signal M and a waveform of the acoustic signal X after being adjusted by the volume adjusting unit 44. As can be understood from FIG. 3, the volume maintained at a predetermined value in the modulated signal M before adjustment is controlled to the same volume as the acoustic signal X in the modulated signal M after adjustment. The volume adjustment of the modulated signal M by the volume adjusting unit 44 is realized by an arithmetic process of multiplying the modulated signal M by a variable coefficient (gain) corresponding to the volume V. The volume adjusting unit 44 may be realized by a variable gain amplifier (VGA: Variable Gain Amplifier). Further, in reality, the modulated signal M is delayed on the time axis with respect to the acoustic signal X by the amount of time required for processing by the volume specifying unit 43 and the volume adjusting unit 44.

The mixing processing unit 45 generates an acoustic signal Y by mixing the acoustic signal X generated by the sound collecting device 12 and the modulated signal M adjusted by the volume adjusting unit 44. Specifically, the mixing processing unit 45 generates the acoustic signal Y by adding the acoustic signal X and the modulation signal M. The weighted sum of the acoustic signal X and the modulation signal M may be generated as the acoustic signal Y.

The acoustic signal Y generated by the mixing processing unit 45 is supplied to the sound emitting device 13. The sound emitting device 13 reproduces the sound represented by the acoustic signal Y. That is, the guidance voice G represented by the acoustic signal X and the acoustic component of the identification information D represented by the modulated signal M are reproduced from the sound emitting device 13. As can be understood from the above description, the sound emitting device 13 of the first embodiment functions as an acoustic device for reproducing the guidance voice G produced by the speaker Ub, and also has an acoustic sound wave as an air vibration as a transmission medium. It also functions as a transmitter that transmits the identification information D by communication. As illustrated in FIG. 3, since the common identification information D is superimposed on the plurality of periods m of the modulated signal M, the identification information D corresponding to the guidance voice G is repeatedly transmitted from the sound emitting device 13 to the surroundings. To.

FIG. 4 is a flowchart of the process executed by the control device 31 of the first embodiment. The process of FIG. 4 is started triggered by an instruction from the speaker Ub to the operation device 33. When the process of FIG. 4 is started, the information generation unit 41 generates the identification information D corresponding to the guidance voice G pronounced by the speaker Ub (S1). The modulation processing unit 42 generates a modulation signal M including the identification information D generated by the information generation unit 41 as an acoustic component (S2).

The volume specifying unit 43 specifies the volume V of the acoustic signal X supplied from the sound collecting device 12 (S3). It should be noted that the generation of the identification information D and the modulation signal M (S1, S2) and the specification of the volume V by the volume specifying unit 43 (S3) may be changed. For example, the volume specifying unit 43 may specify the volume V before the generation (S1) of the identification information D, or the volume specifying unit 43 may specify the volume V before the generation (S2) of the modulation signal M. ..

The volume adjusting unit 44 adjusts the volume of the modulated signal M according to the volume V specified by the volume specifying unit 43 (S4). The mixing processing unit 45 generates an acoustic signal Y by mixing the acoustic signal X generated by the sound collecting device 12 with the adjusted modulation signal M (S5). By supplying the acoustic signal Y to the sound emitting device 13, the identification information D is transmitted from the sound emitting device 13 by acoustic communication in parallel with the reproduction of the guidance voice G.

<Terminal device 20>
FIG. 5 is a block diagram illustrating the configuration of the terminal device 20. As illustrated in FIG. 5, the terminal device 20 of the first embodiment includes a control device 21, a storage device 22, a sound collecting device 23, and a display device 24. As described above, the terminal device 20 having the above-exemplified configuration is preferably realized by an information terminal such as a mobile phone or a smartphone. However, a display terminal for guidance such as an electric bulletin board installed in transportation facilities or an electronic signage (digital signage) installed in a commercial facility may be used as the terminal device 20.

The sound collecting device 23 is an acoustic device (microphone) that collects ambient sound. Specifically, the sound collecting device 23 collects the sound radiated from the sound emitting device 13 of the information providing system 10 and generates an acoustic signal Z representing the waveform of the sound. The acoustic signal Z may include the acoustic component of the identification information D. As understood from the above description, the sound collecting device 23 of the first embodiment is used for voice communication between the terminal devices 20 or voice recording at the time of moving image shooting, and also transmits sound waves as air vibration as a transmission medium. It also functions as a receiver for receiving the identification information D in the acoustic communication. The illustration of the A / D converter that converts the acoustic signal Z generated by the sound collecting device 23 from analog to digital is omitted for convenience.

The control device 21 is composed of a processing circuit such as a CPU (Central Processing Unit), and controls each element of the terminal device 20 in an integrated manner. The display device 24 is composed of, for example, a liquid crystal display panel, and displays various images under the control of the control device 21. The storage device 22 stores a program executed by the control device 21 and various data used by the control device 21. For example, a known recording medium such as a semiconductor recording medium and a magnetic recording medium, or a combination of a plurality of types of recording media can be arbitrarily adopted as the storage device 22. As illustrated in FIG. 5, the storage device 22 of the first embodiment stores related information R (R1, R2, ...) For each of the plurality of identification information D (D1, D2, ...). For the identification information D of any one guidance voice G, the related information R representing the pronunciation content of the guidance voice G is stored.

The control device 21 executes a program stored in the storage device 22 to execute a plurality of functions (information extraction unit 51 and presentation control unit 52) for executing processing related to the identification information D transmitted by the information providing system 10. To realize. A part of the functions of the control device 21 may be realized by a dedicated electronic circuit. Further, the functions of the control device 21 may be distributed to a plurality of devices.

The information extraction unit 51 extracts the identification information D from the acoustic signal Z generated by the sound collecting device 23. For example, the information extraction unit 51 performs filter processing for emphasizing the frequency band including the acoustic component of the identification information D in the acoustic signal Z and modulation processing for the identification information D (signal processing executed by the modulation processing unit 42). The identification information D is extracted by executing the corresponding demodulation process.

The presentation control unit 52 controls the display of information by the display device 24. The presentation control unit 52 of the first embodiment causes the display device 24 to display the related information R corresponding to the identification information D extracted by the information extraction unit 51. Specifically, the presentation control unit 52 acquires the related information R corresponding to the identification information D extracted by the information extraction unit 51 from the storage device 22, and causes the display device 24 to display the related information R.

As described above, in the first embodiment, since the volume of the modulated signal M is adjusted according to the volume V of the acoustic signal X mixed with the modulated signal M, the user uses the acoustic component representing the identification information D. It is possible for Ua to be difficult to hear. In the first embodiment, in particular, the volume of the modulated signal M is adjusted so that the volume V of the acoustic signal X is larger and the volume of the modulated signal M is higher. Therefore, the above-mentioned effect that the acoustic component of the identification information D can be difficult for the user Ua to hear is particularly remarkable. Further, since the volume of the modulated signal M increases during the period when the volume V of the acoustic signal X is large, there is an advantage that the identification information D can be easily extracted by the terminal device 20. On the other hand, since the volume of the modulated signal M decreases during the period when the volume V of the acoustic signal X is small, it is necessary for reproducing the acoustic signal X as compared with a configuration in which the modulated signal M is constantly reproduced at a high volume, for example. There is an advantage that the power consumption is reduced.

According to the first embodiment, even when the acoustic component of the identification information D is emitted as an acoustic sound in the audible range, it is difficult for the user Ua to hear it. Therefore, even when the low-performance sound emitting device 13 that cannot emit the sound of a very high frequency component (for example, 18 kHz or more and 20 kHz or less) that is difficult for the user Ua to hear is used, the user uses the acoustic component of the identification information D. The identification information D can be transmitted to the terminal device 20 by acoustic communication without having Ua listen to it. That is, according to the first embodiment, there is an advantage that the requirement for the performance (renewable band) required for the sound emitting device 13 is relaxed.

<Second Embodiment>
A second embodiment of the present invention will be described. For the elements whose actions or functions are the same as those of the first embodiment in each of the embodiments exemplified below, the reference numerals used in the description of the first embodiment will be diverted and detailed description of each will be omitted as appropriate.

FIG. 6 is a waveform diagram of the acoustic signal X and the modulated signal M in the second embodiment. As illustrated in FIG. 6, the volume adjusting unit 44 of the second embodiment adjusts the volume of the modulated signal M to a volume corresponding to the volume V of the acoustic signal X among a plurality of discrete volumes. Specifically, the volume adjusting unit 44 sets the volume of the modulated signal M to a large value when the volume V of the acoustic signal X exceeds a predetermined threshold value, and when the volume V of the acoustic signal X is below the threshold value. Sets the volume of the modulated signal M to a small value. That is, the volume of the modulated signal M is controlled binary depending on whether or not the volume V of the acoustic signal X exceeds the threshold value.

The same effect as that of the first embodiment is realized in the second embodiment. Further, in the second embodiment, since the volume of the modulated signal M is set to any of a plurality of volumes, the volume of the modulated signal M changes linearly with respect to the volume V of the acoustic signal X, as compared with the configuration. , The time variation of the volume of the modulated signal M is suppressed. Therefore, there is an advantage that the identification information D can be easily extracted by the terminal device 20 on the receiving side. In the above embodiment, the volume of the modulated signal M is controlled binary, but the volume of the modulated signal M may be controlled in multiple stages (three or more stages) according to the volume V of the acoustic signal X.

<Modification example>
Specific embodiments added to each of the above-exemplified embodiments will be illustrated below. Two or more embodiments arbitrarily selected from the following examples may be appropriately merged to the extent that they do not contradict each other.

(1) The volume adjusting unit 44 may adjust the volume of the modulated signal M in a range exceeding a predetermined lower limit value. That is, a lower limit value may be set for the volume of the modulated signal M after adjustment. For example, in the configuration of the first embodiment, when the volume V of the acoustic signal X is below the threshold value, the volume adjusting unit 44 sets the volume of the modulated signal M to a predetermined lower limit value. The lower limit of the volume of the modulated signal M is set to, for example, a predetermined positive number that is the lowest volume at which acoustic communication of the identification information D is possible and has little influence on the sense of hearing. That is, even when the volume V of the acoustic signal X is sufficiently lowered, the volume of the modulated signal M does not drop to zero (silenced state). According to the above configuration, even if the voice represented by the acoustic signal X is a voice that is intermittently or intermittently generated as in the guidance voice G (that is, even if a silent section is generated in the acoustic signal X), the identification information It is possible to continuously transmit D. That is, it is possible to reduce the possibility that the transmission of the identification information D is interrupted during the period when the volume of the acoustic signal X is low.

(2) In each of the above-described embodiments, the information generation unit 41 selects the identification information D instructed by the speaker Ub from a plurality of candidates, but the method for generating the identification information D is not limited to the above examples. For example, the identification information D is stored in the storage device 32 for each of the plurality of utterance contents, and the information generation unit 41 searches the storage device 32 for the identification information D corresponding to the utterance contents estimated by voice recognition for the acoustic signal X. You may. That is, the identification information D corresponding to the guidance voice G pronounced by the speaker Ub is generated.

(3) In each of the above-described embodiments, the sound pick-up device 12 picks up the voice of the speaker Ub to generate the acoustic signal X, but the method of generating the acoustic signal X is not limited to the above examples. For example, a plurality of acoustic signals X representing different guidance voices G are stored in the storage device 32, and the acoustic signal X selected by the speaker Ub in the operation with respect to the operating device 33 is specified (S3) at the volume V or the modulated signal M. It may be used for mixing with (S5).

(4) In each of the above-described embodiments, the related information R is displayed on the display device 24 of the terminal device 20, but the method of presenting the related information R to the user Ua of the terminal device 20 is not limited to the above examples. For example, it is also possible to present the related information R to the user Ua by reproducing the voice represented by the related information R. For example, a configuration in which the related information R represents a voice or a configuration in which a voice is generated by voice synthesis with respect to a character string represented by the related information R is assumed.

(5) In each of the above-described embodiments, the configuration in which the identification information D of the guidance voice G or the related information R is transmitted from the information providing system 10 to the terminal device 20 is illustrated, but the information providing system 10 transmits the identification information D to the terminal device 20. The information (transmission information) is not limited to the identification information D. For example, the related information R itself may be transmitted from the information providing system 10 to the terminal device 20 by acoustic communication.

(6) In each of the above-described embodiments, the related information R is stored in the storage device 22 of the terminal device 20, but the related information is stored in the distribution device that communicates with the terminal device 20 via, for example, a mobile communication network or a communication network such as the Internet. It is also possible to hold. The terminal device 20 transmits an information request including the identification information D received from the information providing system 10 to the distribution device. The distribution device searches for the related information R corresponding to the identification information D in the information request and transmits it to the requesting terminal device 20. The presentation control unit 52 of the terminal device 20 causes the display device 24 to display the related information R received from the distribution device.

(7) In each of the above-described embodiments, the information providing system 10 is used for guiding transportation, but the scene in which the information providing system 10 is used is not limited to the above examples. For example, facilities in which the information provision system 10 is installed include, for example, commercial facilities such as shopping malls or department stores, accommodation facilities such as inns or hotels, exhibition facilities such as museums or art galleries, tourist facilities such as historic sites or famous places, and facilities. An athletic facility such as a stadium or a gymnasium may be exemplified. The type of voice represented by the acoustic signal X is not limited to the voice for the purpose of guidance (guidance voice G), and is appropriately selected according to the situation in which the information providing system 10 is used. For example, the acoustic signal X representing the performance sound of various music such as background music may be reproduced.

(8) As understood from the above-mentioned examples of each form, a character string expressing the utterance content of the guidance voice G in the same language is a preferable example of the related information R, but a language different from the guidance voice G (hereinafter, "" It is also possible to present the related information R (referred to as "presentation language") to the user Ua. The presentation language is, for example, the language specified in the terminal device 20. For example, the storage device 22 of the terminal device 20 stores the related information R expressed in the presentation language for each of the plurality of identification information Ds. The presentation control unit 52 presents the related information R of the presentation language corresponding to the identification information D extracted by the information extraction unit 51 to the user Ua. The related information R expressed in a specific language (for example, the same language as the guidance voice G) may be converted into a character string in the presentation language by a known machine translation process and then presented to the user Ua. The related information R is not limited to the character string representing the utterance content of the guidance voice G. For example, information on products or coupons provided in various commercial facilities may be presented to user Ua as related information R. Further, for example, in a configuration in which the acoustic signal X represents the performance sound of music, information about the music (for example, a music name, a singer, an acquisition destination of music data, etc.) may be presented to the user Ua as related information R. ..

(9) The information providing system 10 according to each of the above-mentioned forms is realized by the cooperation between the control device 31 and the program as illustrated in each form. The program according to each of the above-described forms may be provided in a form stored in a computer-readable recording medium and installed in the computer. The recording medium is, for example, a non-transitory recording medium, and an optical recording medium (optical disc) such as a CD-ROM is a good example, but a known arbitrary such as a semiconductor recording medium or a magnetic recording medium. Can include recording media in the form of. The non-transient recording medium includes any recording medium other than the transient propagation signal (transitory, propagating signal), and does not exclude the volatile recording medium. It is also possible to provide the program to the computer in the form of distribution via a communication network.

(10) From the above-exemplified form, for example, the following configuration can be grasped.
<Aspect 1>
In the signal processing method according to the preferred embodiment (aspect 1) of the present invention, the computer specifies the volume of the first acoustic signal, and the volume of the modulated signal including the acoustic component representing the transmission information is set according to the specified volume. The second acoustic signal is generated by adjusting and mixing the first acoustic signal and the modulated modulation signal. In the above aspect, since the volume of the modulated signal is adjusted according to the volume of the first acoustic signal mixed with the modulated signal, it is possible to make it difficult to hear the acoustic component representing the transmission information.

<Aspect 2>
In the preferred example of the first aspect (aspect 2), the transmission information is the identification information corresponding to the sound represented by the first acoustic signal. According to the above aspect, the identification information corresponding to the sound represented by the first sound signal is notified to the surroundings. Therefore, for example, in the surrounding terminal device, it is possible to acquire the information corresponding to the identification information.

<Aspect 3>
In the preferred example of the first aspect or the second aspect (aspect 3), the volume of the modulated signal is adjusted so that the volume of the modulated signal becomes louder as the volume of the first acoustic signal becomes louder. In the above aspect, the louder the volume of the first acoustic signal, the louder the volume of the modulated signal, so that the effect of making it difficult to hear the acoustic component representing the transmission information is particularly remarkable.

<Aspect 4>
In the preferred example of Aspect 1 or Aspect 2 (Aspect 4), the volume of the modulated signal is adjusted to any of a plurality of volumes according to the volume of the first acoustic signal. In the above embodiment, since the modulated signal is adjusted to any of a plurality of volumes according to the volume of the first acoustic signal, the volume of the modulated signal is increased as the volume of the first acoustic signal is increased (first acoustic signal). The fluctuation of the volume of the modulated signal is suppressed as compared with the configuration in which the volume of the modulated signal changes linearly with respect to the volume of the signal). Therefore, there is an advantage that the identification information can be easily extracted on the receiving side.

<Aspect 5>
In any of the preferred examples (aspect 5) of aspects 1 to 4, the volume of the modulated signal is adjusted to a volume exceeding a predetermined lower limit value. In the above aspect, since the volume of the modulated signal is adjusted within a range exceeding a predetermined lower limit value, for example, even if the voice represented by the first acoustic signal is intermittently or intermittently generated, the transmission information is transmitted. It is possible to send continuously.

<Aspect 6>
The signal processing device according to a preferred embodiment (aspect 6) of the present invention includes a volume specifying unit for specifying the volume of the first acoustic signal, a signal generation unit for generating a modulated signal including an acoustic component representing transmission information, and the above-mentioned signal processing apparatus. It includes a volume adjusting unit that adjusts the volume of the modulated signal according to the volume specified by the volume specifying unit, and a mixing processing unit that mixes the first acoustic signal and the adjusted modulated signal. In the above aspect, since the volume of the modulated signal is adjusted according to the volume of the first acoustic signal mixed with the modulated signal, it is possible to make it difficult to hear the acoustic component representing the transmission information.

<Aspect 7>
The information providing system according to a preferred embodiment (aspect 7) of the present invention includes a sound collecting unit that generates a first acoustic signal by sound collection, a signal processing device that generates a second acoustic signal from the first acoustic signal, and a signal processing device. The signal processing device includes a sound emitting unit that emits the sound represented by the second acoustic signal generated by the signal processing device, and the signal processing device has a volume specifying unit that specifies the volume of the first acoustic signal and transmission information. A modulation processing unit that generates a modulation signal including a representative acoustic component, a volume adjustment unit that adjusts the volume of the modulation signal according to the volume specified by the volume specifying unit, and a first acoustic signal and the modulation after the adjustment. Includes a mixing processing unit that mixes with the signal.

10 ... Information providing system, 11 ... Signal processing device, 12 ... Sound collecting device, 13 ... Sound emitting device, 20 ... Terminal device, 21 ... Control device, 22 ... Storage device, 23 ... Sound collecting device, 24 ... Display device, 31 ... Control device, 32 ... Storage device, 33 ... Operation device, 41 ... Information generation unit, 42 ... Modulation processing unit, 43 ... Volume specification unit, 44 ... Volume adjustment unit, 45 ... Mixing processing unit, 51 ... Information extraction unit , 52 ... Presentation control unit.

Claims (6)

The computer
Identify the volume of the first acoustic signal,
When the volume of the first acoustic signal exceeds the threshold value, the volume of the first modulated signal including the acoustic component representing the transmission information is adjusted according to the volume of the first acoustic signal, and the volume of the first acoustic signal is increased. When the value is below the threshold value, the second modulation signal is generated by setting the transmission information to a lower limit value at which acoustic communication is possible.
A signal processing method for generating a second acoustic signal by mixing the first acoustic signal and the second modulated signal. The signal processing method according to claim 1, wherein the transmission information is identification information corresponding to the sound represented by the first acoustic signal. The signal processing method according to claim 1 or 2, wherein the volume of the first modulated signal is adjusted so that the volume of the second modulated signal becomes louder as the volume of the first acoustic signal becomes louder. The signal processing method according to any one of claims 1 to 3, wherein the volume of the first modulated signal is adjusted to any of a plurality of volumes according to the volume of the first acoustic signal. A volume specification unit that specifies the volume of the first acoustic signal,
A modulation processing unit that generates a first modulation signal including an acoustic component representing transmission information,
When the volume of the first acoustic signal exceeds the threshold value, the volume of the first modulated signal is adjusted according to the volume of the first acoustic signal, and when the volume of the first acoustic signal is lower than the threshold value, the said By setting the volume of the first modulated signal to the lower limit value at which acoustic communication of the transmission information is possible, the volume adjusting unit for generating the second modulated signal and
A signal processing device including a mixing processing unit that generates a second acoustic signal by mixing the first acoustic signal and the second modulation signal. A sound collecting unit that generates a first acoustic signal by collecting sound,
A signal processing device that generates a second acoustic signal from the first acoustic signal, and
It is provided with a sound emitting unit that emits the sound represented by the second acoustic signal generated by the signal processing device.
The signal processing device is
A volume specifying unit that specifies the volume of the first acoustic signal, and
A modulation processing unit that generates a first modulation signal including an acoustic component representing transmission information,
When the volume of the first acoustic signal exceeds the threshold value, the volume of the first modulated signal is adjusted according to the volume of the first acoustic signal, and when the volume of the first acoustic signal is lower than the threshold value, the said By setting the volume of the first modulated signal to the lower limit value at which acoustic communication of the transmission information is possible, the volume adjusting unit for generating the second modulated signal and
An information providing system including a mixing processing unit that generates the second acoustic signal by mixing the first acoustic signal and the second modulated signal.

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