Shielding sound generation device, shielding sound generation method, and program

Abstract

A shielded sound generation device (100) is provided with: an acquisition unit (110) that acquires a pickup signal generated by pickup of a microphone (11); a detection unit (120) that detects, on the basis of the pickup signal, a noise level in a pickup space in which the microphone (11) is disposed; and a first generation unit (140) that generates a first shielded sound signal from the noise level. A second generation unit (150) that generates, on the basis of the noise level, a second shielded sound signal having a sound pressure higher than that of the first shielded sound signal in a frequency band higher than the first frequency; a synthesis unit (160) that synthesizes the first shielded sound signal and the second shielded sound signal to generate a synthesized shielded sound signal; and an output unit (170) that outputs the synthesized shielding sound signal to a speaker that emits sound to the sound emission space.

Description

Technical Field

[0001] The present disclosure relates to a masking sound generating device, a masking sound generating method, and a program. Background Art

[0002] Patent Document 1 discloses a technique for emitting two types of masking sounds in order to reduce the noise or discomfort felt by listeners.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-154125 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The present disclosure provides a masking sound generating device and the like that can generate a sound signal for providing a comfortable sound environment for people using a space.

[0008] Means for solving problems

[0009] A masking sound generating device according to one embodiment of the present invention comprises: an acquisition unit for acquiring a sound pickup signal generated by sound pickup by a microphone; a detection unit for detecting, based on the sound pickup signal, a noise level of a sound pickup space in which the microphone is arranged; a first generation unit for generating a first masking sound signal according to the noise level; a second generation unit for generating, according to the noise level, a second masking sound signal having a sound pressure greater than that of the first masking sound signal in a frequency band higher than the first frequency; a synthesis unit for synthesizing the first masking sound signal and the second masking sound signal to generate a synthesized masking sound signal; and an output unit for outputting the synthesized masking sound signal to a speaker that emits sound into a sound emission space.

[0010] In addition, a method for generating a masked sound according to one embodiment of the present invention is performed by a computer, wherein a sound pickup signal generated by sound pickup by a microphone is obtained; based on the sound pickup signal, a noise level of a sound pickup space in which the microphone is arranged is detected; according to the noise level, a first masked sound signal is generated; according to the noise level, a second masked sound signal having a sound pressure greater than that of the first masked sound signal in a frequency band higher than the first frequency is generated; the first masked sound signal and the second masked sound signal are synthesized; and the synthesized masked sound signal is output to a speaker that emits sound into a sound emission space.

[0011] In addition, these overall or specific methods can also be implemented by non-volatile recording media such as integrated circuits, computer programs, or computer-readable CD-ROMs, and can also be implemented by any combination of devices, methods, integrated circuits, computer programs, and non-volatile recording media.

[0012] Effects of the Invention

[0013] The masking sound generating device and the like in the present disclosure can generate a sound signal for providing a comfortable sound environment for people using a space. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a diagram for explaining a space to which the masking sound generating system according to the first embodiment is applied.

[0015] Figure 2 This is a diagram showing an example of use of the masking sound generating system according to the first embodiment.

[0016] Figure 3 This is a block diagram showing an example of the hardware configuration of the masking sound generating device according to the first embodiment.

[0017] Figure 4 This is a block diagram showing an example of the functional configuration of the masking sound generating device according to the first embodiment.

[0018] Figure 5 This is a schematic diagram showing an example of the sound pressure frequency characteristics of the sound signals of the first sound source data and the second sound source data.

[0019] Figure 6 This is a table schematically showing a method of generating the first masking sound signal and the second masking sound signal according to the stage of the noise level according to the first embodiment.

[0020] Fig. 7A This is a diagram schematically showing the sound pressure frequency characteristics of the first masking sound signal and the second masking sound signal when the noise level is smaller than the threshold value Th1.

[0021] Figure 7B This is a diagram schematically showing the sound pressure frequency characteristics of the first masking sound signal and the second masking sound signal when the noise level is greater than or equal to the threshold value Th1 and less than the threshold value Th2.

[0022] Figure 7C This is a diagram schematically showing the sound pressure frequency characteristics of the first masking sound signal and the second masking sound signal when the noise level is greater than or equal to the threshold value Th2 and less than the threshold value Th3.

[0023] Fig.7D1 is a diagram schematically showing the sound pressure frequency characteristics of the first masking sound signal and the second masking sound signal when the noise level is equal to or greater than the threshold value Th3.

[0024] Figure 8 This is a flowchart showing an example of a masking sound generating method performed by the masking sound generating device according to the first embodiment.

[0025] Fig. 9 This is a diagram showing an example of use of the masking sound generating system according to the second embodiment.

[0026] Fig.10 This is a block diagram showing an example of the functional configuration of the masking sound generating device according to the second embodiment.

[0027] Fig.11 This is a table schematically showing a method of generating the first masking sound signal and the second masking sound signal according to the stage of the noise level according to the second embodiment.

[0028] Fig.12 This is a flowchart showing an example of a masking sound generating method performed by the masking sound generating device according to the second embodiment.

[0029] Fig.13 This is a flowchart showing an example of a method for determining actions by the determination unit. DETAILED DESCRIPTION

[0030] (Knowledge that is the basis of this disclosure)

[0031] In the technique of Patent Document 1, the second masking sound that mitigates the effect of the first masking sound on hearing is generated before the first masking sound is generated, thereby reducing the noise or discomfort felt by the listener who hears the first masking sound.

[0032] However, in the prior art as described above, when two types of masking sounds are emitted into a space used by people, the masking sounds are generated without considering the sound pressure (noise level) of the sound (noise) that affects the sound environment of the space, so there is a problem that it is difficult to provide a sufficiently comfortable sound environment. For example, when the noise level is greater than a certain threshold, if the sound pressure of the masking sound is increased in order to reduce the impact of the noise on people, there is a concern that the masking sound itself will become a sound that annoys people.

[0033] The present inventors have made arduous studies and, in order to provide a comfortable sound environment for people, have invented a masking sound generating device, a masking sound generating method and a program as described below.

[0034] The masking sound generating device involved in the first embodiment of the present invention comprises: an acquisition unit, which acquires a sound pickup signal generated by sound pickup by a microphone; a detection unit, which detects the noise level of the sound pickup space where the microphone is arranged based on the sound pickup signal; a first generation unit, which generates a first masking sound signal according to the noise level; a second generation unit, which generates a second masking sound signal having a sound pressure greater than that of the first masking sound signal in a frequency band higher than the first frequency according to the noise level; a synthesis unit, which synthesizes the first masking sound signal and the second masking sound signal to generate a synthesized masking sound signal; and an output unit, which outputs the synthesized masking sound signal to a speaker that emits sound into a sound emission space.

[0035] Thus, the first masking sound signal and the second masking sound signal are generated according to the noise level so as to achieve the optimal equivalent noise level, thereby effectively reducing the effect of the noise in the sound collection space on the person. Thus, a sound signal for providing a comfortable sound environment for the person using the sound emission space can be generated.

[0036] A masking sound generating device according to a second aspect of the present disclosure is the masking sound generating device according to the first aspect, wherein the first generating unit generates the first masking sound signal so that the maximum frequency becomes lower as the noise level becomes higher.

[0037] If the first masking sound based on the first masking sound signal is adjusted to have a sound pressure greater than a predetermined value, the sound in the high-frequency band is likely to cause unpleasantness to people. Therefore, by generating the first masking sound signal so that the highest frequency is lower when the noise level is higher, the sound that causes adverse effects to people can be cut off. In this way, masking sound that can reduce unpleasantness to people can be generated.

[0038] A masking sound generating device according to a third aspect of the present disclosure is the masking sound generating device according to the first aspect, wherein the second generating unit generates the second masking sound signal so that the lowest frequency becomes higher as the noise level becomes higher.

[0039] The second masking sound based on the second masking sound signal has a characteristic frequency band on the high frequency side. If the sound pressure is adjusted to be larger according to the noise level, the frequency band on the low frequency side that has almost no characteristics is also emphasized. Therefore, by generating the second masking sound signal so that the lowest frequency is higher when the noise level is higher, the frequency band on the high frequency side with characteristics can be retained. In this way, a sound signal for providing a comfortable sound environment for people using the sound release space can be generated.

[0040] A masking sound generating device according to a fourth aspect of the present disclosure is the masking sound generating device according to the second aspect, wherein the second generating unit generates the second masking sound signal so that the lowest frequency becomes larger as the noise level becomes larger.

[0041] The second masking sound based on the second masking sound signal has a characteristic frequency band on the high frequency side. If the sound pressure is adjusted to be larger according to the noise level, the frequency band on the low frequency side, which has almost no characteristics, is also emphasized. Therefore, by generating the second masking sound signal so that the lowest frequency is higher when the noise level is higher, the frequency band on the high frequency side with characteristics can be retained. In addition, since the frequency band on the high frequency side of the first masking sound signal is cut off, the frequency band on the high frequency side can be filled with the second masking sound signal. Thus, a sound signal can be generated for providing a more comfortable sound environment for people using the sound release space.

[0042] The masking sound generating device involved in the 5th mode of the present disclosure is a masking sound generating device involved in the 4th mode. When the noise level is above the first threshold, the first generating unit generates the first masking sound signal so that all its frequency bands are cut off, and the second generating unit generates the second masking sound signal so that it becomes an equivalent noise level corresponding to the noise level and the frequency band lower than the first frequency is cut off.

[0043] If the first masking sound based on the first masking sound signal is adjusted to have a sound pressure greater than a specified value, the sound in the frequency band on the high-frequency side is likely to cause discomfort to people. Therefore, by generating the first masking sound signal so that it is cut off in all frequency bands (that is, the sound pressure in all frequency bands is 0) when the noise level is greater than the first threshold, the sound that has a negative impact on people can be cut off. In addition, the second masking sound based on the second masking sound signal has characteristics in the frequency band on the high-frequency side. If the sound pressure is adjusted to be larger according to the noise level, the frequency band on the low-frequency side that has almost no characteristics is also emphasized. Therefore, by generating the second masking sound signal so that the lowest frequency is higher when the noise level is greater, the frequency band on the high-frequency side with characteristics can be retained. In this way, a sound signal for providing a comfortable sound environment to people who use the sound release space can be generated.

[0044] The masking sound generating device involved in the 6th mode of the present disclosure is a masking sound generating device involved in the 4th mode or the 5th mode. When the noise level is greater than a second threshold value that is smaller than the first threshold value and less than the first threshold value, the first generating unit generates the first masking sound signal so as to make it an equivalent noise level corresponding to the noise level, and the second generating unit generates the second masking sound signal so as to make it an equivalent noise level corresponding to the noise level.

[0045] Thus, the first masking sound signal and the second masking sound signal are generated according to the noise level so as to achieve the optimal equivalent noise level, thereby effectively reducing the effect of the noise in the sound collection space on the person. Thus, a sound signal for providing a comfortable sound environment for the person using the sound emission space can be generated.

[0046] The masking sound generating device involved in the 7th embodiment of the present disclosure is a masking sound generating device involved in the 6th embodiment. When the noise level is greater than the third threshold value that is greater than the second threshold value and less than the first threshold value, and less than the first threshold value, the first generating unit generates the first masking sound signal so that a frequency band higher than the second frequency is cut off, and the second generating unit generates the second masking sound signal so that a frequency band lower than the first frequency is cut off.

[0047] If the first masking sound based on the first masking sound signal is adjusted to have a sound pressure greater than a specified value, the sound in the frequency band on the high-frequency side is likely to cause discomfort to people. Therefore, by generating a first masking sound signal in which a frequency band higher than the second frequency is cut off when the noise level is greater than the second threshold, it is possible to cut off the sound that has a negative impact on people. In addition, the second masking sound based on the second masking sound signal has characteristics in the frequency band on the high-frequency side. If the sound pressure is adjusted to be larger according to the noise level, the frequency band on the low-frequency side that has almost no characteristics is also emphasized. Therefore, by generating a second masking sound signal in which a frequency band lower than the first frequency is cut off, it is possible to retain the characteristic frequency band on the high-frequency side. In this way, it is possible to generate a sound signal for providing a comfortable sound environment to people who use the sound emission space.

[0048] The masking sound generating device involved in the 8th mode of the present disclosure is a masking sound generating device involved in any one of the 4th to 7th modes. When the noise level is less than the second threshold, the first generating unit generates the first masking sound signal so that it becomes an equivalent noise level corresponding to the second threshold, and the second generating unit generates the second masking sound signal so that it becomes an equivalent noise level corresponding to the second threshold.

[0049] Thus, when the noise level is less than the second threshold, the first masking sound signal and the second masking sound signal are generated so as to be an equivalent noise level corresponding to the second threshold, so that the first masking sound signal and the second masking sound signal can be generated according to the noise level so as to be an optimal equivalent noise level. Thus, a sound signal for providing a comfortable sound environment for a person using the sound emission space can be generated.

[0050] The masking sound generating device involved in the 9th mode of the present disclosure is a masking sound generating device involved in any one of the 1st to 8th modes, and further includes a determination unit for determining an action performed by one or more persons in the sound emission space, wherein the first generation unit generates the first masking sound signal so that when the determination unit determines that the action is rest, the equivalent noise level is greater than when the determination unit determines that the action is intellectual activity, and the second generation unit generates the second masking sound signal so that when the determination unit determines that the action is rest, the equivalent noise level is greater than when the determination unit determines that the action is intellectual activity.

[0051] It is known that when a person is resting, he or she can rest more efficiently when the sound pressure of the masking sound is greater than when the person is engaged in intellectual activity. Therefore, by making the equivalent noise level of the masking sound signal generated during rest greater than the equivalent noise level of the masking sound signal generated during intellectual activity, a person can rest more effectively.

[0052] The masking sound generating device involved in the 10th embodiment of the present disclosure is the masking sound generating device involved in the 9th embodiment, wherein the first generating unit generates the first masking sound signal so that when the determination unit determines that the action is an intellectual activity performed by more than two persons, the equivalent noise level becomes larger than the case where the determination unit determines that the action is an intellectual activity performed by one person, and the second generating unit generates the second masking sound signal so that when the determination unit detects that the action is an intellectual activity performed by more than two persons, the equivalent noise level becomes larger than the case where the determination unit determines that the action is an intellectual activity performed by one person.

[0053] It is known that when multiple people perform intellectual activities, people can perform intellectual activities more efficiently when the sound pressure of the masking sound is greater than when the intellectual activities are performed by one person. Therefore, by making the equivalent noise level of the masking sound signal generated in the intellectual activities of multiple people greater than the equivalent noise level of the masking sound signal generated in the intellectual activities of one person, people can perform intellectual activities more efficiently.

[0054] The masking sound generating device according to the 11th aspect of the present disclosure is the masking sound generating device according to any one of the 1st to 10th aspects, further comprising the microphone and the speaker, wherein the microphone is arranged on the opposite side of the speaker to the direction in which the speaker emits sound.

[0055] The masking sound generating device involved in the 12th aspect of the present disclosure is a masking sound generating device involved in any one of the 1st to 11th aspects, wherein the first masking sound signal is a sound signal for masking noise, and the second masking sound signal is a sound signal for modifying the first masking sound based on the first masking sound signal.

[0056] The masking sound generation method involved in the 13th mode of the present disclosure is executed by a computer, wherein a sound pickup signal generated by sound pickup by a microphone is obtained; based on the sound pickup signal, the noise level of the sound pickup space where the microphone is configured is detected; according to the noise level, a first masking sound signal is generated; according to the noise level, a second masking sound signal having a sound pressure greater than that of the first masking sound signal in a frequency band higher than the first frequency is generated; the first masking sound signal and the second masking sound signal are synthesized; and the synthesized masking sound signal is output to a speaker that emits sound into a sound emission space.

[0057] Thus, the first masking sound signal and the second masking sound signal are generated according to the noise level so as to achieve the optimal equivalent noise level, thereby effectively reducing the effect of the noise in the sound collection space on the person. Thus, a sound signal for providing a comfortable sound environment for the person using the sound emission space can be generated.

[0058] A program according to a fourteenth aspect of the present disclosure is a program for causing a computer to execute the masking sound generating method according to the thirteenth aspect.

[0059] In addition, these overall or specific methods can also be implemented by devices, integrated circuits, computer programs or non-volatile recording media such as computer-readable CD-ROMs, and can also be implemented by any combination of devices, integrated circuits, computer programs and non-volatile recording media.

[0060] Hereinafter, the embodiments are described in detail with reference to the accompanying drawings as appropriate. In which, an overly detailed description is sometimes omitted. For example, a detailed description of a known matter or a repeated description of a substantially identical structure is sometimes omitted. This is to avoid the following description from becoming too lengthy so that it is easy for those skilled in the art to understand.

[0061] In addition, the inventor provides the drawings and the following description in order to enable those skilled in the art to fully understand the present disclosure, and it is not intended that the subject matter described in the claims be limited thereby.

[0062] (Implementation Method 1)

[0063] [1-1. Structure]

[0064] <Overview of the sound shielding system>

[0065] Figure 1 This is a diagram for explaining a space to which the masking sound generating system according to the first embodiment is applied. Figure 2 : is a diagram showing an example of using the masking sound generating system according to the first embodiment. Figure 2 This is a diagram showing the masking sound generating system 1 as viewed from above.

[0066] Figure 1 and Figure 2 Indicates the first space 201 and the second space 202 separated by the partition 13. On the partition 13 arranged at the boundary between the first space 201 and the second space 202, the speaker device 12 is arranged toward the first space 201, and the microphone 11 is arranged toward the second space 202. The first space 201 is, for example, a space for people to work (work space) and can be used by more than one person. The second space 202 is, for example, a space shared by multiple unspecified people such as a lobby for people to come and go or take a break. The first space 201 is an example of a sound emission space. The second space 202 is an example of a sound collection space.

[0067] Figure 2 The masking sound generating system 1 includes a masking sound generating device 100 , a microphone 11 , and a speaker device 12 .

[0068] The microphone 11 is arranged on the side of the partition 13 close to the second space 202. The microphone 11 picks up the sound generated in the second space 202 and outputs a picked-up signal. In addition, the microphone 11 is not limited to being arranged on the partition 13 as long as it can pick up the sound generated in the second space 202. It can also be arranged on the ceiling of the second space 202, on the wall arranged in the second space 202, on the floor of the second space 202, or on a table, chair, etc. arranged in the second space 202.

[0069] The speaker device 12 is arranged on the side of the partition 13 close to the first space 201. The speaker device 12 outputs a sound (masked sound) for making the sound generated in the second space 202 difficult to be heard by people in the first space 201. Here, the sound generated in the second space 202 is, for example, a conversation among users using the second space 202, the sound caused by the action, the working sound of the equipment configured in the second space 202, etc. The conversation among users using the second space 202 may be a conversation between multiple users using the second space 202, or a conversation between a user using the second space 202 and a user outside the second space 202 through a voice call using a communication terminal. In addition, the speaker device 12 may also include a speaker array composed of a plurality of speaker units arranged in a specific direction, and may be capable of controlling directivity in a specific direction.

[0070] Furthermore, the microphone 11 and the speaker device 12 may be arranged such that the microphone 11 is not likely to pick up the sound output by the speaker device 12 by adjusting the position or orientation thereof. Furthermore, the microphone 11 and the speaker device 12 may be arranged such that the volume of the speaker device 12 or the sensitivity of the microphone 11 is adjusted such that the microphone 11 is not likely to pick up the sound output by the speaker device 12. The microphone 11 and the speaker device 12 may be arranged such that the microphone 11 is not likely to pick up the sound output by the speaker device 12, and may not be arranged on the partition plate 13.

[0071] The masking sound generating device 100 acquires the detection result from the microphone 11 , and generates the masking sound to be output from the speaker device 12 based on the acquired detection result.

[0072] <Hardware configuration of masking sound generating device>

[0073] Next, the specific configuration of the masking sound generating device 100 will be described.

[0074] Figure 3 This is a block diagram showing an example of the hardware configuration of the masking sound generating device according to the first embodiment.

[0075] like Figure 3 As shown, the masking sound generating device 100 includes a processor 101, a main memory 102, a storage device 103, and a communication IF (Interface) 104 as a hardware configuration. The masking sound generating device 100 may further include an input IF (Interface) 105 and a display 106.

[0076] The processor 101 is a processor that executes a program stored in the storage device 103 or the like.

[0077] The main memory 102 is a volatile storage area used to temporarily store data generated during the process performed by the processor 101, or used as a work area when the processor 101 executes a program, or used to temporarily store data received by the communication IF 104. The data generated during the process performed by the processor 101 includes, for example, a masking sound signal which is a masking sound signal generated by the processor 101. The data received by the communication IF 104 includes, for example, a sound signal obtained from the microphone 11.

[0078] The storage device 103 is a nonvolatile storage device that stores various data such as programs. The storage device 103 stores, for example, various data generated as a result of processing performed by the processor 101. In addition, the storage device 103 stores sound source data for generating masking sounds.

[0079] The communication IF104 is a communication interface for transmitting data with external devices such as smart phones, tablet computers, PCs (Personal Computers), and servers. The communication IF104 may be, for example, an interface for wireless communication such as a wireless LAN interface or a Bluetooth (registered trademark) interface. The communication IF104 may also be an interface for wired communication such as a USB (Universal Serial Bus) or a wired LAN interface. In addition, the communication IF104 is not limited to the above case, and may also be a communication interface for transmitting data with external devices via a communication network. The communication IF104 receives a pickup signal from the microphone 11, for example.

[0080] The input IF 105 is an interface for accepting input from a person. The input IF 105 may be a pointing device such as a mouse, a touch pad, a touch panel, or a trackball, or may be a keyboard.

[0081] The display 106 is a device that displays at least a part of the processing results performed by the processor 101. The display 106 is, for example, a liquid crystal display, an organic EL display, or the like.

[0082] Figure 4 This is a block diagram showing an example of the functional configuration of the masking sound generating device according to the first embodiment.

[0083] like Figure 4 As shown, the masking sound generating device 100 includes an acquiring unit 110 , a detecting unit 120 , a storing unit 130 , a first generating unit 140 , a second generating unit 150 , a synthesizing unit 160 , and an output unit 170 .

[0084] The acquisition unit 110 acquires a sound collection signal generated by sound collection by the microphone 11. The acquisition unit 110 acquires in real time the sound collection signal sequentially generated by the microphone 11. The acquisition unit 110 is realized by, for example, the communication IF 104 or the like.

[0085] The detection unit 120 detects the noise level (equivalent noise level) of the second space 202 where the microphone 11 is arranged based on the sound pickup signal. Specifically, the detection unit 120 determines the size of the sound represented by the sound pickup signal by analyzing the sound pickup signal based on the sound pickup signal, thereby detecting the noise level of the second space 202. The size of the sound represented by the sound pickup signal may be, for example, the amplitude at the peak of the sound waveform in a predetermined period of the sound pickup signal. When there are multiple peaks in the predetermined period, the size of the sound represented by the sound pickup signal may be the maximum value of the amplitudes of the multiple peaks or the average value. The predetermined period is, for example, a period from a predetermined time earlier than the current time (i.e., the latest time when the sound pickup signal is generated) to the current time. The predetermined time represents a time interval, and may be, for example, a time of less than 100 seconds. In addition, the size of the sound represented by the sound pickup signal may be the amplitude of an envelope formed by connecting the tangents of the peaks of the sound waveform of the sound pickup signal at the current time, or may be the maximum value in the predetermined period or the average value. The detection unit 120 detects the noise level of the second space 202 in real time, and outputs the detection result to the first generation unit 140 and the second generation unit 150. The detection unit 120 is implemented by the processor 101 executing a program stored in the storage device 103 using the main memory 102, for example.

[0086] The storage unit 130 stores sound source data. The sound source data includes first sound source data used to generate a first masking sound signal generated by the first generation unit 140, and second sound source data used to generate a second masking sound signal generated by the second generation unit 150. The first sound source data and the second sound source data may be sound source data prepared in advance.

[0087] Figure 5 This is a schematic diagram showing an example of the sound pressure frequency characteristics of the sound signals of the first sound source data and the second sound source data.

[0088] The sound signal of the first sound source data is a sound signal for masking noise, such as colored noise including white noise. The sound signal of the second sound source data has a sound pressure greater than that of the sound signal of the first sound source data in a frequency band higher than the frequency f2 (first frequency). In addition, the sound signal of the second sound source data has a sound pressure less than that of the sound signal of the first sound source data in a frequency band lower than the frequency f3 (third frequency) lower than the frequency f2 (first frequency). For example, the sound pressure frequency characteristic of the sound signal of the second sound source data in which the noise in the sound signal is reduced by taking the time average value thereof may have a sound pressure greater than that of the sound signal of the first sound source data in a frequency band higher than the first frequency, and a sound pressure less than that of the sound signal of the first sound source data in a frequency band lower than the third frequency. The sound signal of the second sound source data is a sound signal for modifying the first masking sound based on the first masking sound signal, such as an ambient sound pre-collected in nature. In addition, the sound source data prepared in advance may also be data representing a sound pre-collected by the microphone 11.

[0089] Furthermore, the storage unit 130 is realized by, for example, the storage device 103 .

[0090] Furthermore, the sound source data may not be sound source data prepared in advance, but may be sound source data acquired from an external device via a network by the acquisition unit 110 . The sound source data acquired from the external device by the acquisition unit 110 is stored in the storage unit 130 .

[0091] The first generation unit 140 processes the sound signal of the first sound source data according to the noise level detected by the detection unit 120, thereby generating a first masking sound signal. Specifically, the first generation unit 140 generates the first masking sound signal so that the highest frequency of the first masking sound signal is lower when the noise level is higher. The first masking sound signal is, for example, a sound signal of white noise having a sound pressure frequency characteristic whose sound pressure is included in a prescribed sound pressure range in the entire frequency band. A specific example of the first masking sound signal is described later. The first generation unit 140 is implemented, for example, by the processor 101 executing a program stored in the storage device 103 using the main memory 102.

[0092] The second generation unit 150 processes the sound signal of the second sound source data according to the noise level detected by the detection unit 120, thereby generating a second masking sound signal. The second masking sound signal has a sound pressure greater than that of the first masking sound signal in a frequency band higher than the first frequency. Specifically, the second generation unit 150 generates the second masking sound signal so that the lowest frequency of the second masking sound signal is higher when the noise level is higher. A specific example of the second masking sound signal is described later. The second generation unit 150 is implemented, for example, by the processor 101 using the main memory 102 to execute a program stored in the storage device 103.

[0093] The synthesizing unit 160 synthesizes the first masking sound signal and the second masking sound signal to generate a synthesized masking sound signal. The synthesizing unit 160 is implemented, for example, by the processor 101 executing a program stored in the storage device 103 using the main memory 102 .

[0094] The output unit 170 outputs the synthesized masking sound signal generated by the synthesizing unit 160 to the speaker device 12. The output unit 170 is implemented by the communication IF 104, for example.

[0095] The speaker device 12 includes an amplifier 21 and a speaker 22. The synthesized masking sound signal output from the masking sound generating device 100 is amplified in the amplifier 21, and the speaker 22 is driven by the amplified sound signal. The speaker 22 emits sound based on the amplified sound signal to the first space 201. In addition, the speaker device 12 may not include the amplifier 21. For example, the amplifier 21 may be configured in the masking sound generating device 100, or may be configured in a device different from the masking sound generating device 100. In addition, the amplifier 21 may be a device that is separate from the masking sound generating device 100 and the speaker device 12, and is connected to the masking sound generating device 100 and the speaker device 12.

[0096] <First masking sound signal and second masking sound signal>

[0097] Next, use Figure 6 and Figure 7A to Figure 7D Specific examples of the first masking sound signal generated by the first generating unit 140 and the second masking sound signal generated by the second generating unit 150 will be described.

[0098] Figure 6 This is a table schematically showing a method of generating the first masking sound signal and the second masking sound signal according to the stage of the noise level according to the first embodiment. Fig. 7A This is a diagram schematically showing the sound pressure frequency characteristics of the first masking sound signal and the second masking sound signal when the noise level is smaller than the threshold value Th1. Figure 7B This is a diagram schematically showing the sound pressure frequency characteristics of the first masking sound signal and the second masking sound signal when the noise level is greater than or equal to the threshold value Th1 and less than the threshold value Th2. Figure 7C This is a diagram schematically showing the sound pressure frequency characteristics of the first masking sound signal and the second masking sound signal when the noise level is greater than or equal to the threshold value Th2 and less than the threshold value Th3. Fig.7D 1 is a diagram schematically showing the sound pressure frequency characteristics of the first masking sound signal and the second masking sound signal when the noise level is equal to or greater than the threshold value Th3.

[0099] As described above, the first generation unit 140 and the second generation unit 150 each generate the first masking sound signal and the second masking sound signal according to the noise level of the second space 202. If the noise levels are different, the first masking sound signal and the second masking sound signal are generated by different methods. For example, the first masking sound signal and the second masking sound signal are generated by different methods at four stages of noise levels. The four stages of noise levels are (1) less than the threshold Th1, (2) greater than the threshold Th1 and less than the threshold Th2, (3) greater than the threshold Th2 and less than the threshold Th3, and (4) greater than the threshold Th3. In addition, the threshold Th1 is smaller than the threshold Th2, and the threshold Th2 is smaller than the threshold Th3. The threshold Th1 is, for example, 33 dB, which is an example of the second threshold. The threshold Th2 is, for example, 40 dB, which is an example of the third threshold. The threshold Th3 is, for example, 50 dB, which is an example of the first threshold. Specific examples of the threshold Th1 , the threshold Th2 , and the threshold Th3 are not limited to those described above, and may be values ​​obtained by adding or subtracting 1 to 3 dB from the above-described specific examples, for example.

[0100] (1) Use Figure 6 and Fig. 7A The following describes a case where the noise level is less than the threshold value Th1. In this case, the first generation unit 140 adjusts the sound pressure of the sound signal of the first sound source data so that it becomes an equivalent noise level NL1 (i.e., a fixed equivalent noise level) corresponding to the threshold value Th1, thereby generating a first masking sound signal. Specifically, the first generation unit 140 applies a gain to the sound signal of the first sound source data to adjust the amplitude of the sound signal (amplify or attenuate it), thereby adjusting the sound pressure of the sound signal of the first sound source data so that the equivalent noise level of the obtained sound signal becomes the equivalent noise level NL1. For example, the equivalent noise level NL1 is a value obtained by subtracting 1 dB from the threshold value Th1 (e.g., 32 dB). As described above, the equivalent noise level NL1 is a target value of the sound pressure when the first generation unit 140 adjusts the sound pressure of the sound signal of the first sound source data when the noise level is less than the threshold value Th1.

[0101] The equivalent noise level is an average value of energy in a sound of a sound signal whose sound pressure (noise level) varies, and is a time average value of the total energy of the sound within a certain period of time.

[0102] In this case, the second generation unit 150 adjusts the sound pressure of the sound signal of the second sound source data to an equivalent noise level NL1 corresponding to the threshold value Th1, similarly to the first generation unit 140, thereby generating a second masking sound signal. Specifically, the second generation unit 150 applies a gain to the sound signal of the second sound source data to adjust the amplitude of the sound signal (amplify or attenuate it), thereby adjusting the sound pressure of the sound signal of the second sound source data so that the equivalent noise level of the obtained sound signal becomes the equivalent noise level NL1. In this way, the equivalent noise level NL1 is a target value of the sound pressure when the second generation unit 150 adjusts the sound pressure of the sound signal of the second sound source data when the noise level is less than the threshold value Th1.

[0103] In case (1), the first generation unit 140 does not cut off a specific frequency band of the sound signal of the first sound source data, that is, the first generation unit 140 generates the first masking sound signal using the entire frequency band of the sound signal of the first sound source data. Similarly, the second generation unit 150 does not cut off a specific frequency band of the sound signal of the second sound source data, that is, the second generation unit 150 generates the second masking sound signal using the entire frequency band of the sound signal of the second sound source data.

[0104] In the case of (1), the equivalent noise level NL1 corresponding to the threshold value Th1, which is the target value when the first generation unit 140 and the second generation unit 150 generate the first masking sound signal and the second masking sound signal, is not limited to the value obtained by subtracting 1 dB from the threshold value Th1, but may be a value obtained by subtracting 1 to 3 dB from the threshold value Th1, or may be a value obtained by multiplying the threshold value Th1 by a ratio less than 1. That is, the equivalent noise level NL1 only needs to be a value smaller than the threshold value Th1. In addition, the equivalent noise level NL1 may be a value greater than the threshold value Th1.

[0105] (2) Use Figure 6 and Figure 7BThe following describes a case where the noise level is greater than the threshold value Th1 and less than the threshold value Th2. In this case, the first generation unit 140 adjusts the sound pressure of the sound signal of the first sound source data so that it becomes an equivalent noise level NL2 corresponding to the noise level, thereby generating a first masking sound signal. Specifically, the first generation unit 140 applies a gain to the sound signal of the first sound source data to adjust the amplitude of the sound signal (amplify or attenuate it), thereby adjusting the sound pressure of the sound signal of the first sound source data so that the equivalent noise level of the obtained sound signal becomes the equivalent noise level NL2. For example, the equivalent noise level NL2 is the same sound pressure as the noise level. In this way, the equivalent noise level NL2 is the target value of the sound pressure when the first generation unit 140 adjusts the sound pressure of the sound signal of the first sound source data when the noise level is greater than the threshold value Th1 and less than the threshold value Th2.

[0106] In this case, similarly to the first generation unit 140, the second generation unit 150 adjusts the sound pressure of the sound signal of the second sound source data so that it becomes an equivalent noise level NL2 corresponding to the noise level, thereby generating a second masking sound signal. Specifically, the second generation unit 150 applies a gain to the sound signal of the second sound source data to adjust the amplitude of the sound signal (amplify or attenuate it), thereby adjusting the sound pressure of the sound signal of the second sound source data so that the equivalent noise level of the obtained sound signal becomes the equivalent noise level NL2. In this way, the equivalent noise level NL2 is a target value of the sound pressure when the second generation unit 150 adjusts the sound pressure of the sound signal of the second sound source data when the noise level is greater than the threshold value Th1 and less than the threshold value Th2.

[0107] In case (2), the first generation unit 140 does not cut off a specific frequency band of the sound signal of the first sound source data, that is, the first generation unit 140 generates the first masking sound signal using the entire frequency band of the sound signal of the first sound source data. Similarly, the second generation unit 150 does not cut off a specific frequency band of the sound signal of the second sound source data, that is, the second generation unit 150 generates the second masking sound signal using the entire frequency band of the sound signal of the second sound source data.

[0108] (3) Use Figure 6 and Figure 7CThe following describes a case where the noise level is greater than the threshold value Th2 and less than the threshold value Th3. In this case, the first generation unit 140 adjusts the sound pressure of the sound signal of the first sound source data so that it becomes an equivalent noise level NL3 corresponding to the noise level, thereby generating a first masking sound signal. Specifically, the first generation unit 140 applies a gain to the sound signal of the first sound source data to adjust the amplitude of the sound signal (amplify or attenuate it), thereby adjusting the sound pressure of the sound signal of the first sound source data so that the equivalent noise level of the obtained sound signal becomes the equivalent noise level NL3. For example, the equivalent noise level NL3 is the same sound pressure as the noise level. As such, the equivalent noise level NL3 is the target value of the sound pressure when the first generation unit 140 adjusts the sound pressure of the sound signal of the first sound source data when the noise level is greater than the threshold value Th2 and less than the threshold value Th3.

[0109] In this case, the second generation unit 150 adjusts the sound pressure of the sound signal of the second sound source data to an equivalent noise level NL3, similarly to the first generation unit 140, thereby generating a second masking sound signal. Specifically, the second generation unit 150 applies a gain to the sound signal of the second sound source data to adjust the amplitude of the sound signal (amplify or attenuate it), thereby adjusting the sound pressure of the sound signal of the second sound source data so that the equivalent noise level of the obtained sound signal becomes the equivalent noise level NL3. As described above, the equivalent noise level NL3 is a target value of the sound pressure when the second generation unit 150 adjusts the sound pressure of the sound signal of the second sound source data when the noise level is greater than the threshold value Th2 and less than the threshold value Th3.

[0110] In addition, in the case of (3), the first generation unit 140 generates the first masking sound signal so that the frequency band higher than the frequency f1 is cut off. For example, the frequency f1 is 5 kHz, and the first generation unit 140 cuts off the frequency band higher than 5 kHz from the sound signal of the first sound source data to generate the first masking sound signal. The frequency f1 is an example of the second frequency. In addition, the frequency f1 is not limited to 5 kHz, as long as it is a frequency included in 1 kHz to 5 kHz. In addition, in this case, the second generation unit 150 generates the second masking sound signal so that the frequency band lower than the frequency f2 is cut off. For example, the frequency f2 is 1 kHz, and the second generation unit 150 cuts off the frequency band lower than 1 kHz from the sound signal of the second sound source data to generate the second masking sound signal. The frequency f2 is an example of the first frequency. In addition, the frequency f2 is not limited to 1 kHz, as long as it is a frequency included in 0.1 kHz to 2 kHz.

[0111] (4) Use Figure 6 and Fig.7DThe following describes a case where the noise level is above the threshold value Th3. In this case, the first generation unit 140 adjusts the sound pressure of the sound signal of the first sound source data so that it is truncated in all frequency bands (that is, the sound pressure becomes 0 in all frequency bands), thereby generating a first masked sound signal. That is, the first generation unit 140 generates a sound signal with all frequency bands truncated as the first masked sound signal. In other words, the first generation unit 140 generates a silent sound signal as the first masked sound signal. In addition, in this case, the second generation unit 150 adjusts the sound pressure of the sound signal of the second sound source data so that it becomes an equivalent noise level NL4 corresponding to the noise level, thereby generating a second masked sound signal. For example, the equivalent noise level NL4 is the same sound pressure as the noise level. Specifically, the second generator 150 applies a gain to the sound signal of the second sound source data to adjust the amplitude of the sound signal (amplify or attenuate it), thereby adjusting the sound pressure of the sound signal of the second sound source data so that the equivalent noise level of the obtained sound signal becomes the equivalent noise level NL4. As described above, the equivalent noise level NL4 is a target value of the sound pressure when the second generator 150 adjusts the sound pressure of the sound signal of the second sound source data when the noise level is greater than or equal to the threshold value Th3.

[0112] The second generation unit 150 generates the second masking sound signal so that the frequency band lower than the frequency f2 is cut off. For example, the second generation unit 150 generates the second masking sound signal by cutting off the frequency band lower than 1 kHz from the sound signal of the second sound source data.

[0113] As described in the case of the four stages (1) to (4), as the first masking sound signal, compared with the cases (1) and (2), in the case of (3), the frequency band higher than the frequency f1 is cut off, and in the case of (4), all the frequency bands are cut off. That is, the first masking sound signal is generated so that the highest frequency becomes lower when the noise level is higher.

[0114] In addition, as described in the case of the four stages (1) to (4), as the second masking sound signal, the frequency band lower than the frequency f2 is cut off in the cases (3) and (4) compared with the cases (1) and (2). That is, the second masking sound signal is generated so that the lowest frequency becomes higher when the noise level is higher.

[0115] [1-2. Action]

[0116] Next, the operation of the masking sound generating device 100 according to the first embodiment will be described.

[0117] Figure 8 This is a flowchart showing an example of a masking sound generating method performed by the masking sound generating device according to the first embodiment.

[0118] First, the acquisition unit 110 acquires a sound collection signal generated by sound collection by the microphone 11 ( S11 ).

[0119] Next, the detection unit 120 detects the noise level of the second space 202 where the microphone 11 is arranged based on the picked-up sound signal ( S12 ).

[0120] Next, the first generator 140 processes the sound signal of the first sound source data according to the noise level detected by the detector 120, thereby generating a first masking sound signal (S13). Figure 6 and Figure 7A to Figure 7D As described above, the first masking sound signal is generated.

[0121] Next, the second generation unit 150 processes the sound signal of the second sound source data according to the noise level detected by the detection unit 120, thereby generating a second masking sound signal (S14). Figure 6 and Figure 7A to Figure 7D As described above, the second masking sound signal is generated.

[0122] In addition, the order of step S13 and step S14 is not limited to the above case, and step S14 may be performed before step S13, or step S13 and step S14 may be performed in parallel.

[0123] Next, the synthesizing unit 160 synthesizes the first masking sound signal and the second masking sound signal (S15), thereby generating a synthesized masking sound signal.

[0124] Next, the output unit 170 outputs the synthesized masking sound signal to the speaker device 12 ( S16 ). As a result, the speaker device 12 emits the synthesized masking sound based on the synthesized masking sound signal toward the first space 201 .

[0125] [1-3. Effects, etc.]

[0126] The masking sound generating device 100 according to the present embodiment includes an acquisition unit 110, a detection unit 120, a first generation unit 140, a second generation unit 150, a synthesis unit 160, and an output unit 170. The acquisition unit 110 acquires a sound pickup signal generated by sound pickup by the microphone 11. The detection unit 120 detects the noise level of the second space 202 in which the microphone 11 is arranged based on the sound pickup signal. The first generation unit 140 generates a first masking sound signal according to the noise level. The second generation unit 150 generates a second masking sound signal having a greater sound pressure than the first masking sound signal in a frequency band higher than the first frequency according to the noise level. The synthesis unit 160 synthesizes the first masking sound signal and the second masking sound signal. The output unit 170 outputs the synthesized masking sound signal to the speaker device 12.

[0127] Thus, the first masking sound signal and the second masking sound signal are generated according to the noise level so as to achieve the optimal equivalent noise level. Therefore, by emitting the synthetic masking sound based on the synthetic masking sound signal from the speaker device 12 to the first space 201, the influence of the noise of the second space 202 on the person using the first space 201 can be effectively reduced. Thus, a sound signal for providing a comfortable sound environment for the person using the first space 201 can be generated.

[0128] In addition, in the masking sound generating device 100 according to the present embodiment, the first generating unit 140 generates the first masking sound signal so that the highest frequency becomes lower when the noise level is higher. If the first masking sound based on the first masking sound signal is adjusted so that the sound pressure is greater than a predetermined value, the sound in the frequency band on the high-frequency side is likely to cause unpleasantness to people. Therefore, by generating the first masking sound signal so that the highest frequency becomes lower when the noise level is higher, it is possible to cut off the sound that has a bad influence on people. In this way, it is possible to generate a masking sound that can reduce the unpleasantness caused to people.

[0129] In addition, in the masking sound generating device 100 involved in the present embodiment, the second generating unit 150 generates the second masking sound signal so that the lowest frequency is higher when the noise level is higher. The second masking sound based on the second masking sound signal has a characteristic in the frequency band on the high frequency side. If the sound pressure is adjusted to be larger according to the noise level, the frequency band on the low frequency side that has almost no characteristics is also emphasized. Therefore, by generating the second masking sound signal so that the lowest frequency is higher when the noise level is higher, the frequency band on the high frequency side with characteristics can be retained. In addition, since the frequency band on the high frequency side of the first masking sound signal is cut off, the frequency band on the high frequency side can be filled with the second masking sound signal. In this way, a sound signal for providing a more comfortable sound environment to people using the first space 201 can be generated.

[0130] In addition, in the masking sound generating device 100 involved in this embodiment, when the noise level is greater than the threshold value Th3 (first threshold value), the first generating unit 140 generates the first masking sound signal so that all frequency bands are cut off, and the second generating unit 150 generates the second masking sound signal so that it becomes an equivalent noise level corresponding to the noise level and the frequency band lower than the first frequency is cut off.

[0131] If the first masking sound based on the first masking sound signal is adjusted to have a sound pressure greater than a specified value, the sound in the frequency band on the high-frequency side is likely to cause discomfort to people. Therefore, by generating the first masking sound signal so that it is cut off in all frequency bands (that is, the sound pressure of all frequency bands is 0) when the noise level is greater than the threshold Th3 (the first threshold), the sound that has a negative impact on people can be cut off. In addition, the second masking sound based on the second masking sound signal has characteristics in the frequency band on the high-frequency side. If the sound pressure is adjusted to be larger according to the noise level, the frequency band on the low-frequency side that has almost no characteristics is also emphasized. Therefore, by generating the second masking sound signal so that the lowest frequency is higher when the noise level is greater, the frequency band on the high-frequency side with characteristics can be retained. In this way, a sound signal for providing a comfortable sound environment to people using the first space 201 can be generated.

[0132] In addition, in the masking sound generating device 100 involved in this embodiment, when the noise level is greater than or equal to the threshold value Th1 (second threshold value) and less than the threshold value Th3 (first threshold value), the first generating unit 140 generates the first masking sound signal so that it becomes an equivalent noise level corresponding to the noise level, and the second generating unit 150 generates the second masking sound signal so that it becomes an equivalent noise level corresponding to the noise level.

[0133] Thus, the first masking sound signal and the second masking sound signal are generated according to the noise level so as to be the optimal equivalent noise level, thereby effectively reducing the influence of the noise on the person in the second space 202. Thus, a sound signal for providing a comfortable sound environment for the person using the first space 201 can be generated.

[0134] In addition, in the masking sound generating device 100 involved in this embodiment, when the noise level is greater than or equal to the threshold value Th2 (third threshold value) and less than the threshold value Th3 (first threshold value), the first generating unit 140 generates the first masking sound signal so that the frequency band higher than the frequency f1 (second frequency) is cut off, and the second generating unit 150 generates the second masking sound signal so that the frequency band lower than the frequency f2 (first frequency) is cut off.

[0135] If the first masking sound based on the first masking sound signal is adjusted to have a sound pressure greater than a specified value, the sound in the frequency band on the high-frequency side is likely to cause discomfort to people. Therefore, by generating a first masking sound signal in which a frequency band higher than frequency f1 (second frequency) is cut off when the noise level is greater than the threshold Th1 (second threshold), it is possible to cut off the sound that has a negative impact on people. In addition, the second masking sound based on the second masking sound signal has a characteristic frequency band on the high-frequency side. If the sound pressure is adjusted to be larger according to the noise level, the frequency band on the low-frequency side that has almost no characteristics is also emphasized. Therefore, by generating a second masking sound signal in which a frequency band lower than frequency f2 is cut off, the frequency band on the high-frequency side with characteristics can be retained. In this way, a sound signal for providing a comfortable sound environment to people using the first space 201 can be generated.

[0136] In addition, in the masking sound generating device 100 involved in this embodiment, when the noise level is less than the threshold value Th1 (second threshold value), the first generating unit 140 generates the first masking sound signal so that it becomes the equivalent noise level corresponding to the threshold value Th1 (second threshold value), and the second generating unit 150 generates the second masking sound signal so that it becomes the equivalent noise level corresponding to the threshold value Th1 (second threshold value).

[0137] Thus, when the noise level is less than the threshold value Th1 (second threshold value), the first masking sound signal and the second masking sound signal are generated so as to become an equivalent noise level corresponding to the threshold value Th1 (second threshold value), so that the first masking sound signal and the second masking sound signal can be generated according to the noise level so as to become an optimal equivalent noise level. Thus, a sound signal for providing a comfortable sound environment for a person using the first space 201 can be generated.

[0138] (Implementation Method 2)

[0139] The masking sound generating system 1A according to the second embodiment is different from the masking sound generating system 1 according to the first embodiment in that the masking sound generating device 100A determines the behavior of a person in the first space 201 using the image of the first space 201 photographed by the camera 14, and generates the first masking sound signal and the second masking sound signal in consideration of the determined behavior of the person. Hereinafter, the masking sound generating system 1A according to the second embodiment will be mainly described in terms of the configuration different from the masking sound generating system 1 according to the first embodiment. In addition, the same reference numerals are attached to the same configuration as the masking sound generating system 1 according to the first embodiment, and the description thereof will be omitted.

[0140] [2-1. Structure]

[0141] Fig. 9 : is a diagram showing an example of using the masking sound generating system according to Embodiment 2. Fig. 9This is a diagram showing the masking sound generating system 1A as viewed from above.

[0142] The masking sound generating system 1A further includes a camera 14 and a microphone 15 arranged in the first space 201. The camera 14 and the microphone 15 are arranged, for example, on a table arranged in the first space 201. In addition, the camera 14 is not limited to being arranged on the table, and can be arranged on the ceiling of the first space 201 or on the wall of the first space 201 as long as it can photograph the first space 201. In addition, the camera 14 can be arranged in the second space 202 as long as it can photograph the first space 201. Similarly, the microphone 15 is not limited to being arranged on the table, and can be arranged on the ceiling of the first space 201 or on the wall of the first space 201 as long as it can pick up sounds in the first space 201. In addition, the microphone 15 can be arranged in the second space 202 as long as it can pick up sounds in the first space 201.

[0143] The camera 14 is, for example, a camera capable of global (panoramic) or hemispherical photography, and can photograph one or more people located around the table. The camera 14 only needs to be able to photograph the entire first space 201, and may not be a camera capable of global (panoramic) or hemispherical photography. The camera 14 may also be composed of a combination of multiple cameras. The image signal obtained by the camera 14 is, for example, an image signal of a dynamic image. The camera 14 outputs the image signal obtained by photographing the first space 201 to the masking sound generating device 100A in real time.

[0144] The microphone 15 and the microphone 11 may be of the same type or of different types.

[0145] In addition, since the hardware configuration of the masking sound generating device 100A is the same as that of the masking sound generating device 100 according to the first embodiment, the description thereof will be omitted.

[0146] Fig.10 This is a block diagram showing an example of the functional configuration of the masking sound generating device according to the second embodiment.

[0147] like Fig.10 As shown, the masking sound generating device 100A is different from the masking sound generating device 100 in that it further includes the functions of a determination unit 180, an acquisition unit 110A, a first generation unit 140A, and a second generation unit 150A.

[0148] The acquisition unit 110A acquires a sound pickup signal from the microphone 11 , acquires an image signal captured by the camera 14 from the camera 14 , and acquires a sound pickup signal of sound picked up by the microphone 15 from the microphone 15 .

[0149] The determination unit 180 determines an action performed by one or more persons in the first space 201 (hereinafter referred to as "person's action"). Specifically, the determination unit 180 analyzes the image signal of the first space 201 obtained from the camera 14 and the sound signal obtained from the microphone 15, thereby determining whether the action of the person in the first space 201 is rest or intellectual activity. In addition, intellectual activity refers to a person's thinking activity, which is different from physical activities such as exercise. Intellectual activities include activities that are not accompanied by the movement of the human body. In addition, when the action of the person is an intellectual activity, the determination unit 180 further determines whether the intellectual activity is an intellectual activity performed by two or more persons or an intellectual activity performed by one person. An intellectual activity performed by two or more persons is, for example, a meeting. An intellectual activity performed by one person is, for example, working alone. For example, the determination unit 180 detects the line of sight of the person reflected in the image represented by the image signal, and determines whether the action of the person is rest, meeting, or working alone based on the detected line of sight. The determination unit 180 determines the action of the person in real time and outputs its determination result to the first generation unit 140A and the second generation unit 150A. The details of the method of determining the action performed by one or more persons by the determination unit 180 will be described later. The determination unit 180 is implemented, for example, by the processor 101 executing a program stored in the storage device 103 using the main memory 102 .

[0150] The first generation unit 140A not only has the function of the first generation unit 140 of the first embodiment, but also generates the first masking sound signal so that it becomes an equivalent noise level corresponding to the action determined by the determination unit 180 to be performed by one person. Specifically, the first generation unit 140A generates the first masking sound signal so that when the determination unit 180 determines that the action of the person is resting, it becomes an equivalent noise level larger than when the determination unit 180 determines that the action is an intellectual activity. In addition, the first generation unit 140A generates the first masking sound signal so that when the determination unit 180 determines that the action of the person is an intellectual activity performed by two or more people (i.e., a meeting), it becomes an equivalent noise level larger than when the determination unit 180 determines that the action is an intellectual activity of one person (i.e., working alone).

[0151] The second generation unit 150A not only has the function of the second generation unit 150 of the first embodiment, but also generates a second masking sound signal so that it becomes an equivalent noise level corresponding to the action determined by the determination unit 180 to be performed by one person. Specifically, the second generation unit 150A generates the second masking sound signal so that when the determination unit 180 determines that the action of the person is resting, it becomes an equivalent noise level greater than when the determination unit 180 determines that the action is an intellectual activity. In addition, the second generation unit 150A generates the second masking sound signal so that when the determination unit 180 determines that the action of the person is an intellectual activity performed by two or more people (i.e., a meeting), it becomes an equivalent noise level greater than when the determination unit 180 determines that the action is an intellectual activity of one person (i.e., working alone).

[0152] <First masking sound signal and second masking sound signal>

[0153] Next, use Fig.11 A specific example of the first masking sound signal generated by the first generation unit 140A and the second masking sound signal generated by the second generation unit 150A will be described.

[0154] Fig.11 This is a table schematically showing a method of generating the first masking sound signal and the second masking sound signal according to the stage of the noise level according to the second embodiment.

[0155] like Fig.11 As shown, in the case where (1) to (3) is less than the threshold value Th3, the first masking sound signal and the second masking sound signal are generated in different ways not only according to the noise level but also according to the action of the person. Specifically, when the action of the person is working alone, the first masking sound signal and the second masking sound signal are generated in the same way as in Implementation 1. The first masking sound signal and the second masking sound signal are generated when the action of the person is a meeting, so that they become the equivalent noise level obtained by adding the first sound pressure difference (for example, 1 dB) to the first masking sound signal and the second masking sound signal when the action of the person is working alone. The first masking sound signal and the second masking sound signal are generated when the action of the person is resting, so that they become the equivalent noise level obtained by adding the second sound pressure difference (for example, 3 dB) to the first masking sound signal and the second masking sound signal when the action of the person is working alone. In addition, the second sound pressure difference is greater than the first sound pressure difference.

[0156] Specifically, when (1) is less than the threshold value Th1, the equivalent noise level NL11 as the target value of the sound pressure of the first masking sound signal and the second masking sound signal when the human action is a meeting is a value obtained by adding the first sound pressure difference to the equivalent noise level NL1 as the target value of the sound pressure of the first masking sound signal and the second masking sound signal when the human action is working alone. The equivalent noise level NL12 as the target value of the sound pressure of the first masking sound signal and the second masking sound signal when the human action is resting is a value obtained by adding the second sound pressure difference to the equivalent noise level NL1.

[0157] In addition, when (2) is greater than or equal to the threshold value Th1 and less than the threshold value Th2, the equivalent noise level NL21 as the target value of the sound pressure of the first masking sound signal and the second masking sound signal when the human action is a meeting is a value obtained by adding the first sound pressure difference to the equivalent noise level NL2 as the target value of the sound pressure of the first masking sound signal and the second masking sound signal when the human action is working alone. The equivalent noise level NL22 as the target value of the sound pressure of the first masking sound signal and the second masking sound signal when the human action is resting is a value obtained by adding the second sound pressure difference to the equivalent noise level NL2.

[0158] In addition, when (3) is greater than or equal to the threshold value Th2 and less than the threshold value Th3, the equivalent noise level NL31 as the target value of the sound pressure of the first masking sound signal and the second masking sound signal when the human action is a meeting is a value obtained by adding the first sound pressure difference to the equivalent noise level NL3 as the target value of the sound pressure of the first masking sound signal and the second masking sound signal when the human action is working alone. The equivalent noise level NL32 as the target value of the sound pressure of the first masking sound signal and the second masking sound signal when the human action is resting is a value obtained by adding the second sound pressure difference to the equivalent noise level NL3.

[0159] In addition, when (4) the noise level is equal to or greater than the threshold value Th3, since the noise level is large and the sound pressure of the second masking sound signal is sufficiently large, the first masking sound signal and the second masking sound signal are each generated by the same method as in the case of Embodiment 1 regardless of the behavior of the person. In this case, the target values ​​of the sound pressures of the first masking sound signal and the second masking sound signal become the equivalent noise level NL4.

[0160] [2-2. Action]

[0161] Next, the operation of the masking sound generating device 100A according to the second embodiment will be described.

[0162] Fig.12 This is a flowchart showing an example of a masking sound generating method performed by the masking sound generating device according to the second embodiment.

[0163] Here, step S21 , step S22 , step S27 , and step S28 are respectively the same as step S11 , step S12 , step S15 , and step S16 in the first embodiment, and thus description thereof is omitted.

[0164] After step S22 , the acquisition unit 110A acquires a video signal generated by imaging by the camera 14 ( S23 ).

[0165] Next, the determination unit 180 determines the behavior of the person in the first space 201 ( S24 ).

[0166] Next, the first generation unit 140A processes the sound signal of the first sound source data according to the noise level detected by the detection unit 120 and the human action determined by the determination unit 180, thereby generating a first masking sound signal (S25). Fig.11 The first masking sound signal is generated as described above.

[0167] Next, the second generation unit 150A processes the sound signal of the second sound source data according to the noise level detected by the detection unit 120 and the human action determined by the determination unit 180, thereby generating a second masking sound signal (S26). Fig.11 The second masking sound signal is generated as described above.

[0168] In addition, the order of steps S21, S22 and steps S23, S24 is not limited to the above case, and steps S23, S24 may be performed before steps S21, S22, or steps S21, S22 and steps S23, S24 may be performed in parallel.

[0169] In addition, the order of step S25 and step S26 is not limited to the above case, and step S25 may be performed before step S26, or step S25 and step S26 may be performed in parallel.

[0170] By performing step S28 , the speaker device 12 emits the synthesized masking sound based on the synthesized masking sound signal toward the first space 201 .

[0171] Next, use Fig.13 A specific example of the method of determining the action in step S24 will be described.

[0172] Fig.13 This is a flowchart showing an example of a method for determining actions by the determination unit.

[0173] The determination unit 180 analyzes the video signal generated by the imaging of the camera 14 and detects the movement of the line of sight (eyes) of a person included in the video represented by the video signal ( S31 ).

[0174] Next, the determination unit 180 determines whether the person has closed his eyelids for a certain period of time ( S32 ).

[0175] When it is determined that the person has closed his eyelids for a certain period of time ( S32 : Yes), the determination unit 180 determines that the person's action is resting ( S33 ).

[0176] When determining that the person has not closed his eyelids for a certain period of time (S32: No), the determination unit 180 determines whether the line of sight has stopped for a certain period of time (S34). When the amount of movement of the line of sight is less than a predetermined amount, the determination unit 180 determines that the line of sight has stopped.

[0177] When determining that the line of sight has stopped for a certain period of time ( S34 : Yes), the determination unit 180 determines that the person's behavior is to work alone ( S35 ).

[0178] When determining that the line of sight has not stopped for a certain period of time (S34: No), the determination unit 180 analyzes the sound signal obtained from the microphone 15 (S36) and determines whether a conversation sound for a certain period of time is included (S37). The determination unit 180 may also determine that a conversation sound is included when the sound signal obtained from the microphone 15 includes the voices of multiple people.

[0179] When determining that the conversation voice is included for a certain period of time ( S37 : Yes), the determination unit 180 determines that the human action is a meeting ( S38 ).

[0180] When determining that there is no conversation sound including the predetermined period of time ( S37 : No), the determination unit 180 determines that the human action is resting ( S39 ).

[0181] [2-3. Effects, etc.]

[0182] The masked sound generating device 100A according to the present embodiment further includes a determination unit 180. The determination unit 180 determines an action performed by one or more persons in the first space 201. The first generating unit 140A generates a first masked sound signal so that, when the determination unit 180 determines that the action of the person is resting, the equivalent noise level is greater than when the determination unit 180 determines that the action of the person is intellectual activity. The second generating unit 150A generates a second masked sound signal so that, when the determination unit 180 determines that the action of the person is resting, the equivalent noise level is greater than when the determination unit 180 determines that the action of the person is intellectual activity.

[0183] It is known that when a person is resting, he or she can rest more efficiently when the sound pressure of the masking sound is greater than when the person is engaged in intellectual activity. Therefore, by making the equivalent noise level of the masking sound signal generated during rest greater than the equivalent noise level of the masking sound signal generated during intellectual activity, a person can rest more effectively.

[0184] In the masking sound generating device 100A according to the present embodiment, the first generating unit 140A generates the first masking sound signal so that when the determining unit 180 determines that the human action is an intellectual activity performed by two or more persons, the equivalent noise level is greater than when the human action is an intellectual activity performed by one person. The second generating unit 150A generates the second masking sound signal so that when the determining unit 180 determines that the human action is an intellectual activity performed by two or more persons, the equivalent noise level is greater than when the human action is an intellectual activity performed by one person.

[0185] It is known that when multiple people perform intellectual activities, people can perform intellectual activities more efficiently when the sound pressure of the masking sound is greater than when the intellectual activities are performed by one person. Therefore, by making the equivalent noise level of the masking sound signal generated in the intellectual activities of multiple people larger than that of the masking sound signal generated in the intellectual activities of one person, people can perform intellectual activities more efficiently.

[0186] (Other embodiments)

[0187] The masking sound generating device 100 according to Embodiment 1 may be connected to the microphone 11 and the speaker device 12 by wire or wirelessly. In the case of wireless connection, the masking sound generating device 100 may be connected to the microphone 11 and the speaker device 12 via a network such as the Internet so as to be communicable. In this case, the masking sound generating device 100 may also be a server.

[0188] Similarly, the masking sound generating device 100A according to Embodiment 2 may be connected to the microphones 11, 15, the speaker device 12, and the camera 14 by wired connection or wireless connection. In the case of wireless connection, the masking sound generating device 100A may be connected to the microphones 11, 15, the speaker device 12, and the camera 14 via a network such as the Internet so as to be communicable. In this case, the masking sound generating device 100 may also be a server.

[0189] In the masking sound generating devices 100 and 100A according to Embodiments 1 and 2, the sound source data is stored in the storage unit 130, but the present invention is not limited thereto. The masking sound generating devices 100 and 100A may download and acquire the sound source data from a server.

[0190] The masking sound generating apparatuses 100 and 100A according to Embodiments 1 and 2 may obtain either a digital sound pickup signal or an analog sound pickup signal from the microphone 11. Similarly, the masking sound generating apparatus 100A may obtain either a digital video signal or an analog video signal from the camera 14.

[0191] The masking sound generating device 100 according to the first embodiment is not limited to a structure that is separate from the microphone 11 and the speaker device 12, but may include (mount) the microphone 11 and the speaker device 12. Similarly, the masking sound generating device 100A according to the second embodiment is not limited to a structure that is separate from the microphones 11 and 15, the speaker device 12, and the camera 14, but may include (mount) the microphones 11 and 15, the speaker device 12, and the camera 14.

[0192] In addition, in the above-mentioned embodiments, each component may be formed by dedicated hardware, or implemented by executing a software program suitable for each component. Each component may also be implemented by a program execution unit such as a CPU or a processor reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory.

[0193] In addition, each component may be a circuit (or integrated circuit). These circuits may constitute one circuit as a whole, or they may be separate circuits. In addition, these circuits may be general circuits or dedicated circuits.

[0194] In addition, the entirety or specific aspects of the present disclosure may also be implemented by a system, device, method, integrated circuit, computer program, or a non-volatile recording medium such as a computer-readable CD-ROM. In addition, the present disclosure may also be implemented by any combination of a system, device, method, integrated circuit, computer program, and a computer-readable non-volatile recording medium.

[0195] For example, the present disclosure may be implemented as a masking sound generating method executed by a masking sound generating device (computer or DSP), or may be implemented as a program for causing a computer or DSP to execute the masking sound generating method.

[0196] In the above embodiment, the processing performed by a specific processing unit may be performed by another processing unit. In the operation of the masking sound generating system described in the above embodiment, the order of the multiple processing may be changed, and the multiple processing may be performed in parallel.

[0197] In addition, various modifications that can be conceived by those skilled in the art to the embodiments, or arbitrarily combining the components and functions in the embodiments without departing from the gist of the present disclosure, are also included in the present disclosure.

[0198] Industrial Applicability

[0199] The present disclosure is useful as a masking sound generating device or the like that can generate a sound signal for providing a comfortable sound environment for people using a space.

[0200] Description of reference numerals:

[0201] 1. 1A shielding sound generation system

[0202] 11 Microphones

[0203] 12 speaker system

[0204] 13 Partition

[0205] 14 Camera

[0206] 21 Amplifier

[0207] 22 speakers

[0208] 100, 100A shielding sound generating device

[0209] 101 Processor

[0210] 102 Main Memory

[0211] 103 Storage device

[0212] 104 Communication IF

[0213] 105 Input IF

[0214] 106 Display

[0215] 110, 110A Acquisition Department

[0216] 120 Inspection Department

[0217] 130 Storage

[0218] 140, 140A 1st generation unit

[0219] 150, 150A Second generation unit

[0220] 160 Synthesis Department

[0221] 170 Output

[0222] 180 Judgment Department

[0223] 201 No.1 Space

[0224] 202 The Second Space

Claims

1. A masking sound generating device, comprising: An acquisition unit that acquires a sound pickup signal generated by picking up sound with a microphone; a detection unit that detects a noise level of a sound collection space where the microphone is arranged based on the sound collection signal; A first generating unit, generating a first masking sound signal according to the noise level; a second generating unit that generates, based on the noise level, a second masking sound signal having a sound pressure greater than that of the first masking sound signal in a frequency band higher than the first frequency; a synthesizing unit that synthesizes the first masking sound signal and the second masking sound signal to generate a synthesized masking sound signal; and The output unit outputs the synthesized masking sound signal to a speaker that emits sound into a sound emission space.

2. The masking sound generating device according to claim 1, The first generating unit generates the first masking sound signal so that the maximum frequency thereof becomes lower as the noise level becomes higher.

3. The masking sound generating device according to claim 1, The second generation unit generates the second masking sound signal so that the lowest frequency becomes higher as the noise level becomes higher.

4. The masking sound generating device according to claim 2, The second generating unit generates the second masking sound signal so that the lowest frequency becomes larger as the noise level becomes larger.

5. The masking sound generating device according to claim 4, When the noise level is greater than or equal to the first threshold, The first generating unit generates the first masking sound signal so that all frequency bands thereof are cut off. The second generation unit generates the second masking sound signal so that the signal has an equivalent noise level corresponding to the noise level and a frequency band lower than the first frequency is cut off.

6. The masking sound generating device according to claim 4 or 5, When the noise level is equal to or higher than a second threshold value that is smaller than the first threshold value and is smaller than the first threshold value, The first generating unit generates the first masking sound signal so as to have an equivalent noise level corresponding to the noise level. The second generating unit generates the second masking sound signal so as to have an equivalent noise level corresponding to the noise level.

7. The masking sound generating device according to claim 6, When the noise level is equal to or higher than a third threshold value that is greater than the second threshold value and less than the first threshold value, and is less than the first threshold value, The first generating unit generates the first masking sound signal so that a frequency band higher than a second frequency is cut off. The second generating unit generates the second masking sound signal so that a frequency band lower than the first frequency is cut off.

8. The masking sound generating device according to claim 6, When the noise level is less than the second threshold, The first generating unit generates the first masking sound signal so as to have an equivalent noise level corresponding to the second threshold value, The second generating unit generates the second masking sound signal so as to have an equivalent noise level corresponding to the second threshold value.

9. The masking sound generating device according to any one of claims 1 to 5, further comprising: a determination unit for determining an action performed by one or more persons in the sound emission space; The first generation unit generates the first masking sound signal so that, when the determination unit determines that the action is resting, the equivalent noise level is greater than that when the determination unit determines that the action is mental activity. The second generation unit generates the second masking sound signal so that, when the determination unit determines that the action is resting, the equivalent noise level is greater than that when the determination unit determines that the action is mental activity.

10. The masking sound generating device according to claim 9, The first generating unit generates the first masking sound signal so that, when the determining unit determines that the action is an intellectual activity performed by two or more persons, the equivalent noise level is greater than that when the determining unit determines that the action is an intellectual activity performed by one person. The second generation unit generates the second masking sound signal so that, when the determination unit detects that the action is an intellectual activity performed by two or more persons, the equivalent noise level is greater than that when the determination unit determines that the action is an intellectual activity performed by one person.

11. The masking sound generating device according to any one of claims 1 to 5, further comprising: the microphone; and the speaker, The microphone is arranged on the side of the speaker opposite to the direction in which the speaker emits sound.

12. The masking sound generating device according to any one of claims 1 to 5, The first masking sound signal is a sound signal for masking noise. The second masking sound signal is a sound signal for modifying the first masking sound based on the first masking sound signal.

13. A method for generating a masking sound, executed by a computer, Acquire a sound pickup signal generated by picking up sound with a microphone, detecting a noise level of a sound collection space where the microphone is arranged based on the sound collection signal, generating a first masking sound signal according to the noise level, generating a second masking sound signal having a sound pressure greater than that of the first masking sound signal in a frequency band higher than the first frequency according to the noise level; synthesizing the first masking sound signal and the second masking sound signal, The synthesized synthesized masking sound signal is output to a speaker that emits sound into the sound emission space.

14. A program for causing a computer to execute the masking sound generating method according to claim 13.

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