Sound environment control system and sound environment control method

Abstract

The sound environment control system (100) involved in the present disclosure is a system for controlling the sound environment in a room (200), and comprises an information processing device (10), an output device (12), and a sensor (14). The information processing device (10) generates a sound having a plurality of frequency components. The output device (12) outputs the sound generated by the information processing device (10) to the room (200). The sensor (14) detects biological information of a person (M) present in the room (200). The sound includes meaningless sound that has no meaning to the person. The information processing device (10) uses the biological information detected by the sensor (14) to determine the state of the person (M). The information processing device (10) adjusts at least one of the frequency and magnitude of at least one frequency component that forms the meaningless sound according to the determined state of the person (M).

Description

Technical Field

[0001] The present disclosure relates to a sound environment control system and a sound environment control method. Background Art

[0002] Japanese Patent Application Laid-Open No. 7-59858 (Patent Document 1) discloses a relaxing sound device. The relaxing sound device is configured to output three types of sine wave audible frequency signals with a frequency difference of several Hz while outputting sound information such as music. By allowing the listener to listen to the three types of sine wave audible frequency signals in three dimensions, the sense of presence and relaxation can be enhanced compared to the case where the listener simply listens to sound information such as music.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 7-59858 Summary of the invention

[0006] There are individual differences in preferences for sound environments. Therefore, there may be cases where the effect of improving the sense of presence and relaxation is achieved for a certain listener, but not for other listeners. Therefore, in order to achieve a certain effect for all listeners, it is necessary to investigate individual preferences in advance and reflect the results of the investigation in the control of the sound environment.

[0007] The present disclosure is made to solve the above-mentioned problems, and an object of the present disclosure is to provide a sound environment control system and a sound environment control method that can provide a sound environment that can improve a person's work efficiency or comfort regardless of personal preference.

[0008] According to the sound environment control system disclosed in the present invention, the sound environment of a room where a person exists is controlled. The sound environment control system includes an information processing device, an output device, and a sensor. The information processing device generates a sound having multiple frequency components. The output device outputs the sound generated by the information processing device into the room. The sensor detects biological information of a person. The sound includes meaningless sound that has no meaning to a person. The information processing device uses the biological information detected by the sensor to determine the state of a person. The information processing device adjusts at least one of the frequency and magnitude of at least one frequency component that forms the meaningless sound according to the determined state of the person.

[0009] According to the sound environment control method disclosed in the present invention, the sound environment in a room where a person exists is controlled, wherein the method comprises: a step of generating a sound having multiple frequency components using a computer; a step of outputting the sound generated by the computer into the room; and a step of detecting biological information of a person using a sensor. The sound includes meaningless sound that has no meaning to a person. The step of generating the sound includes: a step of determining a person's state using biological information detected by the sensor; and a step of adjusting at least one of the frequency and magnitude of at least one frequency component that forms the meaningless sound according to the determined state of the person.

[0010] According to the present disclosure, it is possible to provide a sound environment that can improve a person's work efficiency or comfort regardless of personal preference. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 is an overall configuration diagram of a sound environment control system according to an embodiment of the present disclosure.

[0012] Figure 2 It is a diagram showing the hardware configuration of the information processing device.

[0013] Figure 3 It is a diagram showing an example of a functional configuration of an information processing device.

[0014] Figure 4 This is a flowchart showing the flow of processing of the sound environment control method according to the present embodiment.

[0015] Figure 5 This is a graph showing the relationship between the sound output from the sound environment control system into the room and the work efficiency of the test subjects present in the room.

[0016] Figure 6 This is a graph showing the relationship between the sound output from the sound environment control system into the room and the state of the brain waves of the subjects present in the room.

[0017] Figure 7 This is a flowchart showing the flow of processing of the sound environment control method according to the first modification example of the present embodiment.

[0018] Figure 8 It is an overall configuration diagram of a sound environment control system according to a second modified example of the present embodiment.

[0019] Fig. 9 This is a flowchart showing the flow of processing of the sound environment control method according to the second modification example of the present embodiment.

[0020] (Explanation of symbols)

[0021] 10: information processing device; 12: output device; 14: sensor; 20: CPU; 22: ROM; 21: RAM; 23: I / F device; 24: storage device; 30: meaningful sound source unit; 32: meaningless sound source unit; 34: sound synthesis unit; 36: sound quality adjustment unit; 38: state determination unit; 40: control unit; 100: sound environment control system; 200: indoor; 202: terminal device; M: person; S1~Sn: sound source. DETAILED DESCRIPTION

[0022] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals are attached to the same or corresponding parts in the drawings, and their description will not be repeated.

[0023] Implementation method 1.

[0024] <Structure of Sound Environment Control System>

[0025] Figure 1 1 is an overall configuration diagram of a sound environment control system according to an embodiment of the present disclosure.

[0026] like Figure 1 As shown, the sound environment control system 100 is a system for controlling the sound environment of a room 200. There is a person M in the room 200. Figure 1 In the example of FIG. 2 , person M performs input operations on terminal device 202 (eg, a notebook computer).

[0027] The sound environment control system 100 includes an information processing device 10, an output device 12, and a sensor 14. The information processing device 10 is communicatively connected to the output device 12 and the sensor 14 in a wired or wireless manner. The information processing device 10 can be installed indoors 200 or outdoors. The information processing device 10 can also be communicatively connected to the output device 12 and the sensor 14 via a communication network (representatively the Internet) not shown in the figure.

[0028] The information processing device 10 generates a sound having a plurality of frequency components. The plurality of frequency components include frequency components of at least one audible frequency band. The audible frequency band refers to the range of frequencies audible to humans, and is generally considered to be a frequency band of 20 Hz to 20 kHz. The plurality of frequency components may further include frequency components of an ultrasonic frequency band (a frequency band higher than 20 kHz) that is inaudible to humans.

[0029] The information processing device 10 is configured to generate meaningful sounds and meaningless sounds. In this specification, "meaningful sounds" refer to sounds that are meaningful to people. Meaningful sounds include, for example, music, people's voices, reading aloud, etc. In addition, in this specification, "meaningless sounds" refer to sounds that are meaningless to people. Meaningless sounds include, for example, natural sounds such as the sound of waves, the sound of wind, the sound of leaves rubbing against each other in trees, and the sound of gurgling water in rivers, the sound of vehicles such as cars, trains or airplanes, the sound of streets, the sound of people's footsteps, and the sound of air conditioners running.

[0030] As described later, the information processing device 10 is configured to generate a sound including at least one of a meaningless sound and a meaningful sound based on the output of the sensor 14. Thus, the sound environment control system 100 has a mode of providing only a meaningful sound to the room 200, a mode of providing a synthesized sound synthesized by a meaningful sound and a meaningless sound to the room 200, and a mode of providing only a meaningless sound to the room 200, and these modes can be switched selectively.

[0031] The output device 12 is installed in the room 200, and outputs the sound generated by the information processing device 10 to the room 200. Typically, the output device 12 is a speaker or a headset. The output device 12 converts the electrical signal received from the information processing device 10 into a sound signal, and outputs it as sound to the room 200. Figure 1 In the example, a configuration in which one output device 12 is used is illustrated, but a configuration in which a plurality of output devices are used to output sound to the room 200 may be used.

[0032] The sensor 14 detects biological information of a person M present in the room 200. The biological information includes information indicating the state of the organism, and information indicating the activities and movements of the body. For example, the biological information includes the movement of the eyes (eye movement, number of blinks, pupil diameter, etc.), the movement of the arms (especially the hands), the pulse rate, heart rate, brain waves, sweating, or the temperature of the extremities of the body. These biological information can be detected using well-known contact or non-contact sensors. Typically, the sensor 14 is a wearable device or a camera worn by a person.

[0033] exist Figure 1 In FIG. 1 , a camera installed in a room 200 is shown as one form of the sensor 14. The camera is configured to include the eyes or arms (particularly hands) of the person M in the photographing range. The camera outputs the photographed moving image to the information processing device 10. In addition, the camera may also be installed in the terminal device 202.

[0034] By analyzing the moving images captured by the above-mentioned camera, it is possible to detect the movement of the eyes or arms of the person M. Specifically, Figure 1 As shown, when a person M performs input operations to the terminal device 202, by analyzing the photographed motion images, the movements of the eyes of the person M facing the display of the terminal device 202 (such as eye movements) or the movements of the hands of the person M when operating the keyboard of the terminal device 202 (such as operation speed) can be measured.

[0035] For example, a person's pulse rate can be measured by photo plethysmography using a light emitting diode and an optical sensor (phototransistor, etc.).

[0036] For example, human brain waves can be detected by near-infrared spectroscopy or electroencephalograph. Near-infrared spectroscopy is a technique that uses a light source and a light-receiving sensor to observe changes in the amount of blood in the brain. An electroencephalograph is a sensor that picks up tiny currents generated by brain activity from electrodes attached to the skull and amplifies and measures them as brain waves. Brain wave information includes data representing basic rhythms including frequency bands such as alpha waves and beta waves.

[0037] Examples of human extremities include wrists, fingers, ears, noses, etc. The temperature of the extremities can be measured using a sensor worn on a part of the human body.

[0038] The information processing device 10 obtains the biological information of the person M detected by the sensor 14. The information processing device 10 uses the obtained biological information of the person M to determine the state of the person M. The state of the person M includes the work efficiency of the person M and the comfort of the person M. "Work efficiency" refers to the ratio of the work that can be performed within a certain period of time. For example, Figure 1 As shown, when inputting work to the terminal device 202, the work efficiency is equivalent to the ratio of the actual work volume (such as the amount of text input, etc.) within a certain period of time to the standard work volume that can be achieved within the time. "Comfort" refers to the property of having no unpleasantness in the body and mind and being in a good mood. In this specification, comfort refers to the feeling of comfort from the sound environment.

[0039] In this embodiment, the information processing device 10 is configured to use the biological information of the person M to determine the work efficiency of the person M. As an example, the information processing device 10 can determine the work efficiency of the person M based on the eye and / or hand movements of the person M within a certain period of time. In this case, data indicating the relationship between the eye and / or hand movements of the person M and the work efficiency of the person M is acquired in advance and stored in the storage device (refer to Figure 2The information processing device 10 refers to the data stored in the storage device and determines the work efficiency of the person M based on the eye and / or hand movements of the person M within a certain period of time detected by the sensor 14.

[0040] Alternatively, the information processing device 10 can judge the work efficiency of the person M based on the brain waves of the person M within a certain period of time. Generally speaking, the alpha wave in the brain wave is a brain wave that often appears with the back of the head as the center when the person is in a relaxed state with eyes closed and quiet. The beta wave is a brain wave that often appears when the person is awake. In addition, it is known that the state of the brain wave can be used to infer the degree of wakefulness of a person. As the degree of wakefulness decreases, the work efficiency also decreases, so the degree of wakefulness can be used as an indicator of work efficiency. In this case, data representing the relationship between the brain waves of the person M and the degree of wakefulness of the person M within a certain period of time is obtained in advance and stored in the storage device (refer to Figure 2 The information processing device 10 refers to the data stored in the storage device and determines the degree of wakefulness of the person M based on the brain waves of the person M detected by the sensor 14 within a certain period of time.

[0041] Furthermore, the information processing device 10 is configured to determine the comfort of the person M using the biological information of the person M. For example, the information processing device 10 can determine the comfort of the person M based on the temperature of the extremities (wrists, fingers, ears, nose, etc.) of the person M. Generally speaking, the fluctuation of the temperature of the extremities indicates the state of thermoregulation at an appropriate temperature for each individual, and thus becomes an index suitable for estimating the comfort of an individual. There is a tendency that the lower the temperature of the extremities, the lower the comfort.

[0042] The information processing device 10 controls at least one of the components, frequencies, and magnitudes (sound pressure levels) of the sound output from the output device 12 according to the state of the person M identified. Specifically, the information processing device 10 adjusts at least one of the frequency and magnitude (sound pressure level) of at least one frequency component that forms meaningless sound according to the state of the person M. In addition, the information processing device 10 adjusts at least one of the frequency and magnitude (sound pressure level) of the frequency component that forms meaningful sound according to the state of the person M. Thus, the output device 12 outputs only meaningful sound, only meaningless sound, or synthesized sound that synthesizes meaningful sound and meaningless sound to the room 200. Furthermore, the output device 12 can reproduce various meaningless sounds.

[0043] <Hardware Configuration of Information Processing Device>

[0044] Figure 2 It is shown Figure 1 FIG. 2 is a diagram showing a hardware configuration of an information processing device 10 .

[0045] like Figure 2As shown, the information processing device 10 is configured to include a CPU (Central Processing Unit) 20, a RAM (Random Access Memory) 21, a ROM (Read Only Memory) 22, an I / F (Interface) device 23, and a storage device 24. The CPU 20, the RAM 21, the ROM 22, the I / F device 23, and the storage device 24 exchange various data via a communication bus 25.

[0046] The CPU 20 develops and executes the program stored in the ROM 22 in the RAM 21. The program stored in the ROM 22 describes the processing to be executed by the information processing device 10.

[0047] The I / F device 23 is an input / output device for exchanging signals and data with the output device 12 and the sensor 14. The I / F device 23 receives biological information of the person M detected by the sensor 14 from the sensor 14. In addition, the I / F device 23 outputs the sound (electrical signal) generated by the information processing device 10 to the output device 12.

[0048] The storage device 24 is a storage device that stores various information, and stores biological information of the person M, information indicating the state of the person M, and data indicating the relationship between the biological information of the person M and the state of the person M. The storage device 24 is, for example, a hard disk drive (HDD) or a solid state drive (SSD).

[0049] <Functional Structure of Information Processing Device>

[0050] Figure 3 1 is a diagram showing a functional configuration example of the information processing device 10 . Figure 3 The functional configuration shown is realized by the CPU 20 reading out a program stored in the ROM 22 , developing it in the RAM 21 , and executing it.

[0051] like Figure 3 As shown, the information processing device 10 includes a meaningful sound source unit 30 , a meaningless sound source unit 32 , a speech synthesis unit 34 , a sound quality adjustment unit 36 ​​, a state determination unit 38 , and a control unit 40 .

[0052] The meaningful sound source unit 30 is a sound source unit for generating meaningful sounds. As described above, meaningful sounds refer to sounds that are meaningful to humans, typically music. The meaningful sound source unit 30 plays music, for example, according to a playlist that determines the order in which the music is played. Alternatively, the meaningful sound source unit 30 repeatedly plays pre-specified music. The meaningful sound source unit 30 outputs the meaningful sound to the sound synthesis unit 34.

[0053] The meaningless sound source unit 32 is a sound source unit for generating meaningless sounds. The meaningless sound source unit 32 includes a plurality of sound sources S1 to Sn (n is an integer greater than or equal to 2). Each of the plurality of sound sources S1 to Sn is configured to generate a sine wave (sound wave) in an audible frequency band. The plurality of sine waves generated by the plurality of sound sources S1 to Sn have frequency components different from each other. The frequency of each of the plurality of sine waves changes over time.

[0054] Specifically, the sound source Si (i is an integer greater than or equal to 1 and less than or equal to N) is configured to include an oscillator. i (t), a sine wave X is generated i (t) = sin(2πf i (t)·t). i (t) indicates the frequency changes with time. The meaningless sound source unit 32 generates a plurality of sinusoidal waves X1(t) to X n (t) The multiple sine waves are added to generate a composite wave. The meaningless sound source unit 32 outputs the generated composite wave to the speech synthesis unit 34.

[0055] The sound synthesizing unit 34 is controlled by the control unit 40 to synthesize the meaningful sound generated by the meaningful sound source unit 30 and the synthetic wave generated by the meaningless sound source unit 32. Here, the sound (synthesized sound) Y(t) generated by the sound synthesizing unit 34 can be simply expressed as shown in the following equation (1).

[0056] Y(t)=K0(t)·X0+Σ(K i (t)·X i (t))…(1)

[0057] Here, X0 is a meaningful sound generated by the meaningful sound source unit 30. i (t) is a sine wave generated by the sound source Si of the meaningless sound source unit 32. i (t) is the coefficient of the value change over time. Here, i is set to 1≦i≦n.

[0058] The second term on the right side of equation (1) represents the meaningless sound generated by the meaningless sound source unit 32. n (t) are multiplied by the coefficients K1(t)~K nThe coefficients K1(t) to K1(t) are added to generate meaningless sound. n The value of (t) changes with time. By making the coefficients K1(t) to K n The values ​​of each in (t) change, and the sine wave X1(t) to X n (t) The amplitude of each changes.

[0059] Thus, at least one of the frequency and magnitude of at least one frequency component forming the meaningless sound can be changed. i (t) frequency f i (t) changes with time. In addition, the sine wave X i The amplitude of (t) is determined by the coefficient K i By making the sine wave X1(t) to X n At least one of the frequency and amplitude of each of (t) changes with time, so that at least one of the frequency and magnitude of at least one frequency component forming the meaningless sound changes. As a result, multiple types of meaningless sounds including street sounds, river running sounds, etc. can be reproduced.

[0060] As shown in equation (1), the synthesized sound is a sound in which a meaningless sound is superimposed on a meaningful sound. n The value of each of K0(t) can change the components of the synthesized sound. If the value of the coefficient K0(t) multiplied by the meaningful sound X0 is set to 0, the synthesized sound is only a meaningless sound. If the coefficient K0(t) is set to a positive value, and the coefficients of the sine waves X1(t) to X2(t) are set to n (t) are multiplied by the coefficients K1(t)~K n If all values ​​of (t) are set to 0, the synthesized speech is only meaningful speech. The speech synthesizing unit 34 outputs the generated synthesized speech to the sound quality adjusting unit 36 ​​.

[0061] The sound quality adjustment unit 36 ​​is controlled by the control unit 40 to adjust at least one of the frequency and size (sound pressure level) of the synthesized sound output from the output device 12. Furthermore, the sound quality adjustment unit 36 ​​is configured to be able to add a frequency component of an ultrasonic frequency band (a frequency band higher than 20kHz) to the synthesized sound. In addition, it is known that there are individual differences in the audible frequency band of people. Generally speaking, the frequency component of the ultrasonic frequency band, which is a frequency band higher than 20kHz, becomes uncomfortable to hear as age increases. However, it has been found that the frequency component of the ultrasonic frequency band is transmitted to the brain via the skin near the ear and the ear bone, and the alpha wave in the brain wave increases.

[0062] The state determination unit 38 acquires biological information of the person M detected by the sensor 14. The state determination unit 38 determines the state of the person M using the acquired biological information of the person M. In the present embodiment, the state determination unit 38 determines the work efficiency of the person M using the biological information of the person M.

[0063] Specifically, the state determination unit 38 measures the movement of the eyes of the person M within a certain period of time from the moving image captured by the sensor 14 (for example, a camera). Figure 2 ) indicating the relationship between the eye movement of the person M and the work efficiency of the person M, and calculating an index indicating the work efficiency of the person M based on the measured value of the eye movement. The state determination unit 38 outputs the calculated index to the control unit 40.

[0064] The control unit 40 controls the sound synthesizing unit 34, the sound quality adjusting unit 36, and the meaningless sound source unit 32 according to the work efficiency of the person M determined by the state determining unit 38. Thus, the control unit 40 can change the sound output from the output device 12 to the room 200 according to the work efficiency of the person M.

[0065] Specifically, the control unit 40 compares the index indicating the work efficiency of the person M provided from the state determination unit 38 with a predetermined threshold value. If the work efficiency of the person M is lower than the threshold value, the control unit 40 changes the component of the synthesized speech generated by the speech synthesis unit 34.

[0066] As shown in equation (1), the synthesized sound includes a meaningful sound X0 and a plurality of sine waves X1(t) to X2(t) having different frequency components. n The control unit 40 controls the sound synthesizing unit 34 to adjust the value of the coefficient K0(t) by which the meaningful sound X0 is multiplied, and the value of the coefficient K0(t) for the sine waves X1(t) to X2(t). n (t) are multiplied by the coefficients K1(t)~K n Specifically, the control unit 40 changes the value of the coefficient K0(t) to change the ratio of the meaningful sound included in the synthesized sound. At this time, if the value of the coefficient K0(t) is set to 0, the meaningful sound can be removed from the synthesized sound.

[0067] In addition, the control unit 40 makes the sine waves X1(t) to X n (t) frequency f1(t)~f n (t) changes, and / or, makes the coefficient K1(t)~K nBy changing the value of (t), at least one of the frequency and magnitude (amplitude) of at least one frequency component of the meaningless sound included in the synthesized sound is changed. In this way, the type of meaningless sound can be changed. For example, the control unit 40 can be set to: n (t) and coefficients K1(t)~K n (t), a plurality of patterns corresponding to a plurality of types of meaningless sounds are prepared in advance, and a configuration is provided in which a plurality of patterns are selectively selected. Alternatively, the control unit 40 may also be configured to adjust the coefficients K1(t) to K n The values ​​of (t) are all set to 0 to remove meaningless sounds from the synthesized sound.

[0068] Furthermore, the control unit 40 changes at least one of the frequency and the magnitude (sound pressure level) of the synthesized sound adjusted by the sound synthesizer 34 by controlling the sound quality adjuster 36. The height of the synthesized sound changes by changing the frequency of the synthesized sound. Specifically, as the frequency of the synthesized sound is increased, the sound becomes higher, and as the frequency is decreased, the sound becomes lower.

[0069] The sound quality adjustment unit 36 ​​can adjust the volume of the sound into three stages, for example, small, medium, and large. In addition, the sound quality adjustment unit 36 ​​can change the frequency and / or volume of both the meaningful sound and the meaningless sound, or change the frequency and / or volume of either the meaningful sound or the meaningless sound. Furthermore, the sound quality adjustment unit 36 ​​can add a frequency component of the ultrasonic frequency band to the synthesized sound.

[0070] The control unit 40 monitors the work efficiency of the person M provided from the state determination unit 38, and controls the sound synthesis unit 34 and the sound quality adjustment unit 36 ​​as described above, thereby adjusting at least one of the component, frequency, and magnitude of the synthesized sound output from the output device 12 to the room 200. At this time, the control unit 40 is configured to adjust at least one of the component, frequency, and magnitude of the synthesized sound so that the work efficiency of the person M becomes greater than a threshold value. In this way, the sound environment of the room 200 is changed according to the work efficiency of the person M, so that the work efficiency of the person M can be restored.

[0071] <Sound environment control method>

[0072] Next, the sound environment control method according to the present embodiment will be described. Figure 4 1 is a flowchart showing the flow of processing of the sound environment control method according to the present embodiment. For example, a series of processing shown in the flowchart is executed by the information processing device 10 every time a predetermined condition is satisfied or every predetermined period.

[0073] like Figure 4As shown, the information processing device 10 generates a meaningful sound (step S01). In step S01, the information processing device 10 plays music according to a play list that determines the order in which the music is played. Alternatively, the information processing device 10 repeatedly plays a pre-specified music.

[0074] Next, the information processing device 10 generates meaningless sound (step S02). In step S02, the information processing device 10 generates a plurality of sine waves X1(t) to X2(t) having different frequency components using a plurality of sound sources S1 to Sn. n (t). Multiple sine waves X1(t)~X n (t) frequency f1(t)~f n (t) respectively change with time. Then, the information processing device 10 generates a plurality of sinusoidal waves X1(t) to X n (t) are added to generate a composite wave of multiple sine waves.

[0075] Next, the information processing device 10 synthesizes the meaningful sound generated in S01 and the meaningless sound (synthetic wave) generated in S02 (step S03). In S03, the synthesized sound is generated using the above formula (1). In addition, regarding the synthesized sound, the synthesized sound of the music and the pre-specified meaningless sound (such as the sound of hustle and bustle) can also be set by default. In this case, in formula (1), the coefficient K0(t) multiplied by the meaningful sound X0 is set to a positive value, and the coefficient K0(t) multiplied by the sine waves X1(t) to X2(t) is set to a positive value. n (t) are multiplied by the coefficients K1(t)~K n The value of (t) is set to a mode when reproducing a meaningless sound (for example, a bustling sound) specified in advance.

[0076] Furthermore, the information processing device 10 sends an electrical signal representing the synthesized sound generated in S03 to the output device 12. The output device 12 converts the electrical signal received from the information processing device 10 into a sound signal and outputs it as sound to the room 200 (step S04). The sensor 14 detects biological information of the person M present in the room 200. As an example, the sensor 14 is a camera installed in the room 200.

[0077] Next, the information processing device 10 acquires biological information of the person M detected by the sensor 14 (step S05). In S05, the information processing device 10 measures eye movements of the person M within a certain period of time based on a moving image captured by a camera as the sensor 14, as an example.

[0078] Then, the information processing device 10 uses the acquired biological information of the person M to determine the state of the person M (step S06). In step S06, the information processing device 10 refers to the biological information stored in advance in the storage device 24 (refer to Figure 2 ) representing the relationship between the eye movement of person M and the work efficiency of person M, and calculating an index representing the work efficiency of person M based on the measured value of the eye movement.

[0079] Next, the information processing device 10 changes at least one of the component, frequency, and volume of the sound output from the output device 12 to the room 200 according to the determined work efficiency of the person M.

[0080] Specifically, first, the information processing device 10 compares the index representing the work efficiency of the person M with a predetermined threshold value (step S07). When the work efficiency is above the threshold value (when the "yes" determination of S07), the information processing device 10 skips the processing of the subsequent steps S08 to S10 to keep the sound output from the output device 12, thereby maintaining the sound environment of the room 200.

[0081] On the other hand, when the work efficiency is less than the threshold value in step S07 (when S07 is determined to be "No"), the information processing device 10 adjusts the frequency and magnitude (amplitude) of at least one frequency component of the meaningless sound included in the sound output from the output device 12 (step S08). In S08, the information processing device 10 adjusts the frequency f1(t) to f1(t) in equation (1) to obtain the value of the frequency component f1(t) to f1(t) in equation (1). n (t) and / or coefficients K1(t)~K n By changing the value of (t), the type of meaningless sound can be changed. For example, the information processing device 10 can change the frequencies f1(t) to f1(t) corresponding to the busy sound. n (t) and coefficients K1(t)~K n The pattern of (t) is changed to frequencies f1(t) to f2(t) corresponding to other meaningless sounds (e.g., natural sounds of a valley). n (t) and coefficients K1(t)~K n Alternatively, the information processing device 10 can be configured by dividing the coefficients K1(t) to K n By setting all the values ​​of (t) to 0, meaningless sounds can be removed from the sounds output from the output device 12.

[0082] Next, the information processing device 10 adjusts the ratio of the meaningful sound included in the synthesized sound (step S09). In S09, the information processing device 10 changes the ratio of the meaningful sound included in the synthesized sound by changing the value of the coefficient K0(t) in equation (1). At this time, the information processing device 10 can remove the meaningful sound from the sound output from the output device 12 by setting the value of the coefficient K0(t) to 0.

[0083] Furthermore, the information processing device 10 adjusts at least one of the frequency and the magnitude of the synthesized sound synthesized by synthesizing the meaningless sound adjusted in S08 and the meaningful sound adjusted in S09 (step S10). In S10, the information processing device 10 may change the frequency of both the meaningful sound and the meaningless sound, or may change the frequency of either the meaningful sound or the meaningless sound. At this time, the information processing device 10 may also add a frequency component of the ultrasonic frequency band to the synthesized sound.

[0084] After at least one of the component, frequency, and size of the sound output from the output device 12 is changed through the processing of S08 to S10, the information processing device 10 returns to S06 and determines the work efficiency of the person M again. In addition, the information processing device 10 determines whether the work efficiency of the determined person M is above the threshold value (step S07). If the work efficiency is improved to be above the threshold value (when the "yes" judgment of S07), the information processing device 10 maintains the sound output from the output device 12 to maintain the sound environment of the room 200. On the other hand, if the work efficiency is less than the threshold value (when the "no" judgment of S07), the information processing device 10 changes the sound output to the room 200 by executing the processing of S08 to S10 again. The processing of S08 to S10 is repeatedly executed until the work efficiency of the person M becomes above the threshold value.

[0085] As described above, the sound environment control system 100 involved in this embodiment is configured to output a synthesized sound of meaningful sounds that are meaningful to people and meaningless sounds that are meaningless to people into a room. Moreover, in the above structure, the information processing device 10 adjusts the components of the synthesized sound based on the work efficiency determined based on the biological information of the people present in the room. Specifically, the information processing device 10 can change the type of meaningless sound by adjusting at least one of the frequency and size of at least one frequency component that forms the meaningless sound. In addition, the information processing device 10 can also remove one of the meaningful sound and the meaningless sound from the synthesized sound. Furthermore, the information processing device 10 can change at least one of the frequency and size of the synthesized sound output into the room according to the work efficiency of the people. As a result, the sound environment in the room can be changed according to the work efficiency of the people present in the room, so that the work efficiency of the people can be improved without relying on personal preferences.

[0086] <Experimental example>

[0087] Next, an experimental example of sound environment control executed using the sound environment control system 100 according to the present embodiment will be described.

[0088] (Experimental Example 1)

[0089] Figure 5 Graph showing the relationship between the sound output from the sound environment control system 100 into the room and the work efficiency of the test subject in the room. The horizontal axis of the graph represents time, and the vertical axis represents the work efficiency of the test subject. The test subject is a healthy adult male.

[0090] In this experiment, a subject in a room performs input operation on a terminal device (notebook computer), and the subject's eye movement during the input operation is photographed by a sensor 14 (e.g., a camera). In addition, in order to determine the subject's work efficiency, the information processing device 10 obtains data indicating the relationship between the subject's eye movement and work efficiency in advance and stores the data in the storage device 24 in the information processing device 10.

[0091] Figure 5 The graph shows how the working efficiency of the test subjects changes when the sound output from the output device 12 of the sound environment control system 100 to the room changes with time. Figure 5 As shown, in the experiment, the sound output from the output device 12 to the room 200 is changed at a predetermined time interval from a state without sound in the order of meaningful sound 1 (e.g., a song that the subject likes), meaningful sound 2 (e.g., a song that the subject hates), meaningless sound 1 (e.g., natural sound of a valley), meaningless sound 2 (e.g., driving sound of a car), meaningful sound 3 (e.g., reading aloud), and meaningless sound 3 (e.g., bustling sound). All the sounds have the same magnitude (sound pressure level).

[0092] The meaningful sounds 1 to 3 are obtained by setting the coefficient K0(t) to be a positive value and multiplying the meaningful sounds by a plurality of sinusoidal waves X1(t) to X n (t) is multiplied by multiple coefficients K1(t)~K n The meaningless sounds 1 to 3 are generated by setting the value of coefficient K0(t) to 0 in the information processing device 10 and making the plurality of sinusoidal waves X1(t) to X n (t) and / or the frequency of each of the plurality of sine waves X1(t) to X n (t) is multiplied by multiple coefficients K1(t)~K n The sound reproduced by changing the values ​​of each in (t).

[0093] The information processing device 10 measures the eye movements of the subject within a certain period of time by analyzing the moving images captured by the sensor 14. The information processing device 10 also refers to the data stored in the storage device 24 to calculate an index representing the subject's work efficiency based on the measured values.

[0094] from Figure 5 As can be seen from the graph, the test subject's work efficiency changes depending on the indoor sound environment. In particular, it can be seen that the test subject's work efficiency changes not only due to meaningful sounds such as music and reading, but also due to meaningless sounds such as natural sounds, driving sounds of cars, and bustling sounds. Figure 5 It was confirmed in the experimental example that the working efficiency showed a higher value when the meaningless sounds 1 and 3 were output into the room than when the meaningful sounds were output into the room.

[0095] according to Figure 5 The experimental results show that the working efficiency of the subject can be controlled by changing the sound output from the output device 12 to the room. Therefore, by setting the sound environment control system 100 to a structure that changes the sound output to the room while monitoring the working efficiency of the subject, it is possible to suppress the decrease in the working efficiency of the subject.

[0096] (Experimental Example 2)

[0097] Figure 6 Graph showing the relationship between the sound output from the sound environment control system 100 into the room and the state of the brain wave of the subject present in the room. The horizontal axis of the graph represents time, and the vertical axis represents the state of the brain wave of the subject. The subject is a healthy adult male.

[0098] In this experiment, a subject in a room performs input operation on a terminal device (laptop computer), and the subject's brain wave is measured by a sensor 14 (e.g., an electroencephalometer) worn by the subject. The subject's state (level of wakefulness) is determined by the information processing device 10 based on the brain wave information obtained from the measurement value of the sensor 14.

[0099] Figure 6 The graph shows how the state of the subject's brain wave changes when the sound output from the output device 12 of the sound environment control system 100 to the room changes over time. Figure 6As shown, in the experiment, the sound output from the output device 12 to the room is changed at a predetermined time interval from a state without sound in the order of meaningful sound 1 (e.g., fast-paced music), meaningful sound 2 (e.g., classical music), meaningless sound 1 (e.g., natural sound of a valley), and meaningless sound 2 (e.g., bustling sound). In this experimental example, the size (sound pressure level) of each of the above four sounds is changed in three stages in the order of small, medium, and large.

[0100] In the information processing device 10, the meaningless sounds 1 and 2 are generated by setting the value of the coefficient K0(t) to 0 and making the plurality of sinusoidal waves X1(t) to X n (t) and / or the frequency of each of the plurality of sine waves X1(t) to X n (t) is multiplied by multiple coefficients K1(t)~K n The sound reproduced by changing the values ​​of each in (t).

[0101] The information processing device 10 detects the intensity of the α wave and the β wave included in the brain wave of the subject based on the brain wave information of the subject measured by the sensor 14 (electroencephalometer). In addition, the intensity of the α wave and the β wave is represented by a voltage value (μV). Furthermore, the information processing device 10 infers the degree of wakefulness of the subject by calculating the ratio (β / α) of the intensity of the β wave to the intensity of the α wave.

[0102] from Figure 6 It can be seen that the intensity of each wave of the α wave and the β wave included in the subject's brain wave changes according to the sound environment in the room. Under meaningful sound 1 and meaningful sound 2, the intensity of the α wave and the intensity of the β wave are at the same level. In addition, regardless of which meaningful sound is used, the intensity of the α wave and the β wave hardly changes due to the size of the sound.

[0103] Furthermore, although the tunes are different between the meaningful sound 1 and the meaningful sound 2, no significant difference is found in the intensity of the α wave or the intensity of the β wave. As a result, the ratio (β / α) also hardly changes.

[0104] On the other hand, when the sound in the room changes from meaningful sound 2 to meaningless sound 1, both α waves and β waves increase. In particular, a significant increase is found in β waves. Due to the increase in β waves, the ratio (β / α) also increases in meaningless sound 1 compared to meaningful sound 1 and meaningful sound 2. In addition, in meaningless sound 1, the change in the intensity of β waves relative to the change in the size of the sound also becomes larger.

[0105] Furthermore, as the sound in the room changes from meaningless sound 1 to meaningless sound 2, the α wave and the β wave increase further. In particular, a significant increase is found in the β wave. Due to the increase in the β wave, the ratio (β / α) increases further in the meaningless sound 2 compared to the meaningless sound 1. In addition, the change in the intensity of the β wave relative to the size of the sound also increases as in the meaningless sound 1.

[0106] Here, it is known that α waves increase in a relaxed state and β waves increase in a wakeful state. And, it is considered that the higher the value of the ratio (β / α), the higher the wakefulness. Figure 6 In the experimental example, it was confirmed that: compared with meaningful sound 1 and meaningful sound 2, under meaningless sound 1 and meaningless sound 2, α waves and β waves (especially β waves) increased and the ratio (β / α) became higher. This means that for the subjects, the environment of meaningless sounds is more suitable for improving wakefulness than the environment of meaningful sounds. In addition, it was confirmed that: in the environment of meaningless sounds, the intensity of β waves can be controlled by the volume of the sound. Therefore, when it is determined that the subject's wakefulness is reduced based on the subject's brain wave information, the sound environment control system 100 changes the indoor sound environment in a way that the subject hears meaningless sounds, in the hope of improving the subject's wakefulness and suppressing the reduction in work efficiency.

[0107] <Other structural examples>

[0108] (1) In the above-mentioned embodiment, a structure is described in which the indoor sound environment is changed according to the work efficiency of the person present in the room determined based on the biological information of the person, but the sound environment control system and the sound environment control method involved in the present disclosure can also change the indoor sound environment according to the comfort of the person.

[0109] Figure 7 This is a flowchart showing the flow of processing of the sound environment control method according to the first modification of the present embodiment. For example, the information processing device 10 executes a series of processing shown in the flowchart every time a predetermined condition is satisfied or every predetermined period.

[0110] Figure 7 The flowchart shown is Figure 4 The flowchart shown in FIG. 1 is replaced by S06A and S07A. Figure 7 As shown, by executing Figure 4In the same S01 to S05, the information processing device 10 generates a synthesized sound of meaningful sound and meaningless sound and outputs it to the room 200 via the output device 12, and obtains the biological information of the person M detected by the sensor 14. In S05, as an example, the information processing device 10 measures the temperature of the extremities of the person M using the sensor 14 worn by the person M.

[0111] Then, the information processing device 10 uses the acquired biological information of the person M to determine the state of the person M (step S06A). In step S06A, the information processing device 10 refers to the biological information stored in advance in the storage device 24 (reference Figure 2 ) which represents the relationship between the temperature of the extremities of a person M and the comfort of the person M, and calculates an index representing the comfort of the person M based on the measured value of the temperature of the extremities.

[0112] Next, the information processing device 10 changes at least one of the component, frequency, and volume of the sound output from the output device 12 to the room 200 according to the determined comfort level of the person M.

[0113] Specifically, first, the information processing device 10 compares the index indicating the comfort of the person M with a predetermined threshold value (step S07A). When the comfort is above the threshold value (when the "yes" determination of S07A), the information processing device 10 skips the processing of the subsequent steps S08 to S10 to maintain the sound output from the output device 12, thereby maintaining the sound environment of the room 200.

[0114] On the other hand, if the comfort level is less than the threshold value in step S07A (“No” determination in step S07A), the information processing device 10 executes the same Figure 4 The same processing of S08 to S10 adjusts the sound output to the room 200. At this time, the information processing device 10 repeatedly executes the processing of S08 to S10 until the comfort level of the person M reaches or exceeds the threshold.

[0115] As described above, in the sound environment control system 100 according to the first modification of the present embodiment, the indoor sound environment can also be changed according to the comfort level determined based on the biological information of the person present in the room, so that the comfort level of the person can be improved regardless of personal preference.

[0116] (2) In the above embodiment, the control of the sound environment is described when there is only one person in the room. However, the sound environment control system and the sound environment control method according to the present disclosure can also be applied to a case where there are multiple people in the room.

[0117] For example, Figure 8As shown in FIG. 1 , it is assumed that a plurality of (for example, three) persons M1 to M3 exist in the room 200 . It is assumed that the persons M1 to M3 perform input operations on the terminal device 202 , respectively.

[0118] The sensor 14 detects biological information of the persons M1 to M3 in the room 200. The sensor 14 is, for example, a camera installed in the room 200, and is configured so as to include the eyes or arms (particularly hands) of each of the persons M1 to M3 in the photographic range. The camera outputs the photographed moving images to the information processing device 10. In addition, the camera may also be installed in the terminal device 202.

[0119] The information processing device 10 obtains the biological information of the persons M1 to M3 detected by the sensor 14, and determines the status (for example, work efficiency) of the persons M1 to M3 using the obtained biological information of the persons M1 to M3. The information processing device 10 controls at least one of the component, frequency, and magnitude (sound pressure level) of the sound output from the output device 12 according to the determined status (work efficiency) of the persons M1 to M3.

[0120] Fig. 9 This is a flowchart showing the flow of processing of the sound environment control method according to the second modification of the present embodiment. For example, the information processing device 10 executes a series of processing shown in the flowchart every time a predetermined condition is satisfied or every predetermined period.

[0121] Fig. 9 The flowchart shown is Figure 4 The flowchart shown in FIG. 1 is replaced with S05 to S07 by S05B, S06B, S06C, and S07B. Fig. 9 As shown, by executing Figure 4 Similarly, in S01 to S04, the information processing device 10 generates a synthesized sound of meaningful sound and meaningless sound and outputs it to the room 200 via the output device 12. The sensor 14 detects biological information of the persons M1 to M3 in the room 200. As an example, the sensor 14 is a camera installed in the room 200.

[0122] Next, the information processing device 10 obtains biological information of the persons M1 to M3 detected by the sensor 14 (step S05B). In S05B, as an example, the information processing device 10 measures the eye movement of each of the persons M1 to M3 within a certain period of time from a moving image captured by a camera as the sensor 14.

[0123] Then, the information processing device 10 uses the acquired biometric information of the persons M1 to M3 to determine the states of the persons M1 to M3 respectively (step S06B). In step S06B, the information processing device 10 refers to the biometric information stored in advance in the storage device 24 (reference Figure 2 ) representing the relationship between the eye movement and work efficiency of each of the persons M1 to M3, and calculating an index representing the work efficiency of each of the persons M1 to M3 based on the measured values ​​of the eye movement.

[0124] Next, the information processing device 10 calculates the average value of the work efficiency of the persons M1 to M3 identified in S06B (step S06C). The information processing device 10 changes at least one of the component, frequency, and volume of the sound output from the output device 12 to the room 200 according to the calculated average value of the work efficiency.

[0125] Specifically, first, the information processing device 10 compares the average value of the work efficiency with a predetermined threshold value (step S07B). When the average value of the work efficiency is greater than the threshold value (when the "yes" determination in S07B) is made, the information processing device 10 skips the subsequent processing of steps S08 to S10 to maintain the sound output from the output device 12, thereby maintaining the sound environment in the room 200.

[0126] On the other hand, if the average value of the work efficiency is less than the threshold value in step S07B (“No” determination in S07B), the information processing device 10 executes the Figure 4 The same process of S08 to S10 adjusts the sound output to the room 200. At this time, the information processing device 10 repeatedly executes the process of S08 to S10 until the average value of the work efficiency becomes equal to or greater than the threshold value.

[0127] As described above, in the sound environment control system 100 involved in the second modified example of this embodiment, the indoor sound environment can also be changed according to the work efficiency determined based on the biological information of multiple people present in the room, so that the work efficiency of each person can be improved regardless of personal preference.

[0128] In addition, Fig. 9 In the flowchart, an example of a structure in which the sound environment of the room 200 is changed when the average value of the work efficiency of persons M1 to M3 is less than a threshold value (when the "No" judgment is made in S07B), but a structure in which the sound environment of the room 200 is changed can also be set to be changed when at least one of the work efficiencies of persons M1 to M3 is less than a threshold value.

[0129] The embodiments disclosed herein are illustrative in all points and should not be construed as restrictive. The technical scope of the present disclosure is indicated by the claims rather than the description of the embodiments above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A sound environment control system, which controls the sound environment in a room where people are present, wherein: have: An information processing device that generates a sound having a plurality of frequency components; an output device for outputting the sound generated by the information processing device into the room; and A sensor detects biological information of the person, The plurality of frequency components include frequency components in at least one audible frequency band, The sound includes meaningless sound which is an audible sound having no meaning to the person, The information processing device determines the state of the person using the biological information detected by the sensor, and adjusts at least one of the frequency and the magnitude of at least one frequency component forming the meaningless sound according to the determined state of the person.

2. The sound environment control system according to claim 1, wherein: The state of the person includes the work efficiency of the person, The information processing device uses the biological information to determine the work efficiency, and when the determined work efficiency is lower than a predetermined threshold, changes at least one of the frequency and magnitude of at least one frequency component forming the meaningless sound in a manner that makes the work efficiency above the threshold.

3. The sound environment control system according to claim 1, wherein: The state of the person includes the comfort of the person, The information processing device uses the biological information to determine the comfort level, and when the determined comfort level is lower than a predetermined threshold, changes at least one of the frequency and magnitude of at least one frequency component forming the meaningless sound so that the comfort level becomes greater than the threshold.

4. The sound environment control system according to any one of claims 1 to 3, wherein: The information processing device is configured to generate the meaningless sound by synthesizing a plurality of sine waves having frequency components in mutually different audible frequency bands, The information processing device adjusts at least one of the frequency and the magnitude of at least one frequency component forming the meaningless sound by changing at least one of the frequency and the amplitude of the plurality of sine waves.

5. The sound environment control system according to any one of claims 1 to 3, wherein: The information processing device adds a frequency component in an ultrasonic frequency band to the plurality of frequency components according to the determined state of the person.

6. The sound environment control system according to any one of claims 1 to 3, wherein: The sounds also include meaningful sounds that are meaningful to the person, The information processing device further adjusts the ratio of the meaningful sound included in the sound according to the determined state of the person.

7. The sound environment control system according to any one of claims 1 to 3, wherein: The information processing device adjusts at least one of the frequency and the volume of the sound output into the room according to the determined state of the person.

8. The sound environment control system according to any one of claims 1 to 3, wherein: The sensor detects movement of the person's eyes, movement of the person's arms, and at least one of the person's pulse, brain waves, sweating, and temperature of a peripheral part.

9. The sound environment control system according to claim 2 or 3, wherein: When there are multiple persons in the room, The sensor detects the biological information of each of the plurality of persons, The information processing device uses the biological information detected by the sensor to determine the state of each of the multiple persons, and adjusts at least one of the frequency and magnitude of at least one frequency component that forms the meaningless sound based on the average value of the determined states of the multiple persons.

10. A sound environment control method for controlling the sound environment in a room, wherein: have: The steps of generating a sound having multiple frequency components using a computer; The step of outputting the sound generated by the computer into the room; and The step of detecting biological information of a person present in the room using a sensor, The plurality of frequency components include frequency components in at least one audible frequency band, The sound includes meaningless sound which is an audible sound having no meaning to a human, The steps of generating the sound include: A step of determining the state of the person using the biological information detected by the sensor; and The step of adjusting at least one of the frequency and the magnitude of at least one frequency component forming the meaningless sound according to the determined state of the person.

11. The sound environment control method according to claim 10, wherein: The state of the person includes the work efficiency of the person, The step of determining includes the step of determining the work efficiency using the biological information, The adjusting step includes, when the work efficiency is determined to be lower than a predetermined threshold, changing at least one of the frequency and magnitude of at least one frequency component forming the meaningless sound so that the work efficiency becomes equal to or greater than the threshold.

12. The sound environment control method according to claim 10, wherein: The state of the person includes the comfort of the person, The step of determining includes the step of determining the comfort using the biological information, The adjusting step includes, when the determined comfort level is lower than a predetermined threshold, changing at least one of the frequency and magnitude of at least one frequency component forming the meaningless sound so that the comfort level becomes equal to or greater than the threshold.

13. The sound environment control method according to any one of claims 10 to 12, wherein: The step of generating the sound further includes the step of forming the meaningless sound by synthesizing a plurality of sine waves having frequency components of mutually different audible frequency bands, The step of adjusting includes the step of adjusting at least one of the frequency and the magnitude of at least one frequency component forming the meaningless sound by changing at least one of the frequency and the amplitude of the plurality of sine waves.

14. The sound environment control method according to any one of claims 10 to 12, wherein: The step of generating the sound further includes the step of adding a frequency component in an ultrasonic frequency band to the plurality of frequency components according to the determined state of the person.

15. The sound environment control method according to any one of claims 10 to 12, wherein: The sounds also include meaningful sounds that are meaningful to the person, The step of generating the sound further includes the step of adjusting the ratio of the meaningful sound included in the sound according to the determined state of the person.

16. The sound environment control method according to any one of claims 10 to 12, wherein: The step of generating the sound includes the step of adjusting at least one of the frequency and the volume of the sound output into the room according to the determined state of the person.

17. A sound environment control system for controlling the sound environment in a room where a person is present, wherein: have: An information processing device that generates a sound having a plurality of frequency components; an output device for outputting the sound generated by the information processing device into the room; and A sensor detects biological information of the person, The plurality of frequency components include frequency components in at least one audible frequency band, The sound includes meaningless sound which is an audible sound having no meaning to the person, The information processing device uses the biological information detected by the sensor to determine the state of the person, and adjusts at least one of the frequency and the magnitude of at least one frequency component forming the meaningless sound according to the determined state of the person. When there are multiple persons in the room, The sensor detects the biological information of each of the plurality of persons, The information processing device uses the biological information detected by the sensor to determine the state of each of the multiple persons, and adjusts at least one of the frequency and magnitude of at least one frequency component that forms the meaningless sound based on the average value of the determined states of the multiple persons.

18. A method for controlling a sound environment in a room, wherein: have: The steps of generating a sound having multiple frequency components using a computer; The step of outputting the sound generated by the computer into the room; and The step of detecting biological information of a person present in the room using a sensor, The plurality of frequency components include frequency components in at least one audible frequency band, The sound includes meaningless sound which is an audible sound having no meaning to a human, The steps of generating the sound include: A step of determining the state of the person using the biological information detected by the sensor; and The step of adjusting at least one of the frequency and the magnitude of at least one frequency component forming the meaningless sound according to the determined state of the person, The detecting step includes: when a plurality of persons are present in the room, using the sensor to detect the biological information of each of the plurality of persons; The step of determining includes: for each of the plurality of persons, using the biological information detected by the sensor to determine the state of the person; The step of adjusting includes the step of adjusting at least one of the frequency and the magnitude of at least one frequency component forming the meaningless sound based on the determined average value of the states of the plurality of persons.

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