JP2017163448A - Sound adjustment device and sound adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a sense of incompatibility in audibility from being given to a listener while securing followability of sound adjustment with respect to a change of an ambient sound environment.SOLUTION: A calculation section 720 periodically calculates a first average value μbeing an average value of absolute values of amplitude levels of ambient sounds collected by a sound collection section 810 and a standard deviation σ of the amplitude levels. The calculation section 720 calculates an upper limit value and a lower limit value of an ordinary level range on the basis of the first average value μand the standard deviation σ, thereby determining the ordinary level range. Next, the calculation section 720 calculates a second average value μbeing an average value of absolute values of amplitude levels of ambient sounds within the determined ordinary level range. On the basis of the second average value μcalculated by the calculation section 720, an adjustment section 740 then performs adjustment of an output sound including sound volume adjustment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sound adjustment device, a sound adjustment method, a sound adjustment program, and a recording medium on which the sound adjustment program is recorded.

  2. Description of the Related Art Conventionally, it has been widely performed to listen to content sound such as music sound through a headphone or an earphone using a portable audio device. In the case of listening to content audio via such headphones or earphones, the ambient sound becomes noise.

  Therefore, a technique for adjusting the output volume according to the volume of the ambient sound has been proposed (see Patent Document 1: hereinafter referred to as “conventional example”). In the conventional technique, the level of noise is detected by performing amplification, detection and filtering on the sound collection result of the ambient sound, and the output volume is adjusted according to the detection result.

JP-A-4-357707

  In the conventional technology described above, when a sudden ambient sound is generated, the output volume is adjusted from the sound collection result including the sudden ambient sound without considering the influence of the sudden ambient sound. Was. For this reason, even if the time averaging process of the waveform of the sound collection result is performed, the output sound volume is to be adjusted in a manner in which the influence of a sudden ambient sound is added.

  As a result, in the conventional technique, in an environment where sudden ambient sounds with a relatively large volume are frequently generated, the output volume changes frequently and the listener feels uncomfortable. Will give. In addition, with the conventional technology, the output volume frequently changes greatly even in an environment where the sudden decrease in the volume of ambient sounds frequently occurs, giving the listener a sense of discomfort in the sense of hearing. Become.

  In order to prevent the listener from feeling uncomfortable due to frequent large changes in the output volume, it is conceivable to perform a time averaging process over a long period of time. However, if time averaging processing is performed over a long period of time, the followability of the volume adjustment to changes in the ambient sound environment will deteriorate.

  For this reason, there is a demand for a technique that can suppress the listener from giving a sense of discomfort to the listener while ensuring the followability of the volume adjustment to the change in the ambient sound environment. Responding to such a request is cited as one of the problems to be solved by the present invention.

  The invention according to claim 1 periodically determines a normal level range based on a statistic of an absolute value of an amplitude level of a collected ambient sound, and the amplitude level of the ambient sound within the normal level range. A calculation unit that calculates one of an average value and a median value of absolute values; and an adjustment unit that adjusts an output sound including volume adjustment based on a calculation result by the calculation unit. It is an adjustment device.

  The invention according to claim 10 is a sound adjustment method used in a sound adjustment apparatus including a calculation unit and an adjustment unit, wherein the calculation unit periodically performs an amplitude level of ambient sound collected. A calculation step of determining a normal level range based on a statistic of an absolute value of and calculating one of an average value and a median value of an absolute value of an amplitude level of the ambient sound within the normal level range; An adjustment step of adjusting the output sound including the volume adjustment based on the calculation result of the calculation step.

  The invention described in claim 11 is a sound adjustment program that causes a computer included in the sound adjustment apparatus to execute the sound adjustment method according to claim 10.

  The invention described in claim 12 is a recording medium in which the sound adjustment program according to claim 11 is recorded so as to be readable by a computer included in the sound adjustment device.

1 is a block diagram illustrating a schematic configuration of a sound adjustment device according to an embodiment of the present invention. It is a block diagram which shows the schematic structure of the sound adjustment apparatus which concerns on one Example of this invention. It is a figure for demonstrating the content of the coefficient table of FIG. It is a flowchart of the control process of the sound adjustment by the process control unit of FIG. It is a figure which illustrates the sound wave collection form of the stationary ambient sound, and the sound wave collection form of the ambient sound including sudden sound. It is a figure which shows the absolute value waveform of the sound collection form of the stationary ambient sound of FIG. 5 (A), and the absolute value waveform of the sound collection form of the ambient sound containing the sudden sound of FIG. 5 (B). It is a figure which shows the 1st average value in the case of a stationary ambient sound, the 1st average value in the case of the ambient sound containing sudden sound, and the 2nd average value in the case of the ambient sound containing sudden sound. It is a figure which illustrates the sound-acquisition form of the ambient sound in which the ambient sound is steady and the sound collection form of the ambient sound including sudden volume reduction. FIG. 9A is a diagram showing an absolute value waveform of a sound collecting form of a stationary ambient sound in FIG. 8A and an absolute value waveform of a sound collecting form of an ambient sound including sudden volume reduction in FIG. is there. A first average value in the case of a steady ambient sound, a first average value in the case of an ambient sound including sudden volume reduction, and a second average value in the case of an ambient sound including sudden volume reduction FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description and drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

[Constitution]
FIG. 1 shows a schematic configuration of a sound adjustment device 700 according to an embodiment. As shown in FIG. 1, the sound adjustment device 700 is connected to a sound collection unit 810, a sound content source 820, and a sound output unit 830.

  Here, the sound collection unit 810 includes a sound collection device such as a microphone. The sound collection unit 810 collects ambient sounds using a sound collection device. Then, the sound collection unit 810 sends the sound collection result to the sound adjustment device 700 as sound collection data.

  In addition, the sound content source 820 sends the sound content data to the sound adjustment device 700. Examples of such a sound content source 820 include a CD player, a DVD player, a communication unit that acquires sound content data from a sound content server, and the like.

  The sound output unit 830 includes a sound output device such as a headphone or an earphone. The sound output unit 830 receives the output sound signal sent from the sound adjustment device 700. Then, the sound output unit 830 outputs a sound corresponding to the output sound signal.

  Note that the influence of the sound output from the sound output device of the sound output unit 830 on the sound collection result by the sound collection unit 810 can be ignored.

<Configuration of Sound Adjustment Device 700>
As shown in FIG. 1, the sound adjustment device 700 includes an acquisition unit 710 and a calculation unit 720. In addition, the sound adjustment device 700 includes a sound reproduction unit 730, an adjustment unit 740, and an amplification unit 750.

  Upon receiving the acquisition command sent from the calculation unit 720, the acquisition unit 710 acquires ambient sound related information. Such ambient sound related information includes regional attribute information at the current position, weather information at the current position, the current time zone, and the like. The acquisition result obtained by the acquisition unit 710 is sent to the calculation unit 720.

The calculation unit 720 receives sound collection data sent from the sound collection unit 810. Then, the calculation unit 720 calculates the second average value μ ₂ during the immediately preceding time T _P every time a predetermined time T _P elapses. The second average value μ ₂ calculated in this way is sent to the adjustment unit 740. In addition, the calculation unit 720 sends an acquisition command to the acquisition unit 710.

The calculation process of the second average value μ ₂ by the calculation unit 720 will be described later.

  The sound reproduction unit 730 receives the sound content data sent from the sound content source 820. Then, the sound reproducing unit 730 reproduces a sound signal corresponding to the sound content data. The reproduced sound signal is sent to the adjustment unit 740.

The adjustment unit 740 receives the sound signal sent from the sound reproduction unit 730 and the second average value μ ₂ sent from the calculation unit 720. Then, the adjustment unit 740 adjusts the sound signal based on the second average value μ ₂ and generates an adjusted sound signal. The adjusted sound signal generated in this way is sent to the amplifying unit 750.

  Note that the sound adjustment processing by the adjustment unit 740 will be described later.

  The amplifying unit 750 receives the adjusted sound signal sent from the adjusting unit 740. Then, the amplifying unit 750 performs power amplification of the adjusted sound signal to generate an output sound signal. The output sound signal generated in this way is sent to the sound output unit 830.

[Operation]
Next, the operation of the sound adjustment apparatus 700 configured as described above will be described mainly focusing on the calculation process of the second average value μ ₂ by the calculation unit 720 and the sound adjustment process by the adjustment unit 740.

  It is assumed that sound content data is sequentially sent from the sound content source 820. Further, it is assumed that sound collection data is sequentially transmitted from the sound collection unit 810.

  When the sound content data sent from the sound content source 820 is received, the sound reproducing unit 730 reproduces a sound signal corresponding to the sound content data. Then, the sound reproducing unit 730 sends the reproduced sound signal to the adjusting unit 740.

When receiving the sound signal sent from the sound reproduction unit 730, the adjustment unit 740 performs sound adjustment processing based on the second average value μ ₂ sent from the calculation unit 720 most recently, and generates an adjustment sound signal. Then, the adjustment unit 740 sends the generated adjustment sound signal to the amplification unit 750. In the present embodiment, the adjustment unit 740 performs frequency characteristic adjustment processing and volume adjustment processing as sound adjustment processing.

  Here, the adjustment unit 740 performs low-frequency emphasis processing as frequency characteristic adjustment processing. This is because the ambient noise, that is, the environmental noise sound for listening to the content sound, generally has such a characteristic that the level gradually decreases from the low range to the high range. For this reason, in the present embodiment, “the low band is boosted and the band that tends to be masked is increased”.

Further, as the volume adjustment process, the adjustment unit 740 controls the volume adjustment device such as an electronic volume to increase the volume of the output sound as the second average value μ ₂ reflecting the level of the ambient sound increases. Make adjustments. On the other hand, the adjustment unit 740 controls the volume adjustment device to adjust the volume of the output sound to decrease as the second average value μ ₂ decreases.

  Upon receiving the adjustment sound signal sent from the adjustment unit 740, the amplification unit 750 performs power amplification of the adjustment sound signal to generate an output sound signal. Then, the amplification unit 750 sends the generated output sound signal to the sound output unit 830. As a result, a sound corresponding to the output sound signal is output from the sound output unit 830.

The sound reproducing portion 730 described above, in parallel with the operation of the adjustment unit 740 and amplification unit 750, and calculator 720 cooperate with acquiring unit 710, performs a calculation process of the second average value mu _2. Hereinafter, the calculation process of the second average value μ ₂ will be described.

<Calculation process of second average value μ ₂ >
Calculator 720, each time a pre-determined time T _P is passed from the second average value mu ₂ calculated in the previous periodically perform a new second calculation of the average value mu _2.

Such In the second average value mu ₂ calculation processing, calculation unit 720, first, when the time T _P from the second average value mu ₂ calculating the last time elapses, the collection of the time period T _P immediately preceding data N ( Absolute value data | N (T) | of T) is calculated. Subsequently, the calculation unit 720 calculates the first average value μ ₁ that is the average value of the absolute value data | N (T) | and the standard deviation σ of the absolute value data | N (T) |.

Subsequently, the computing unit 720 determines the normal level range of the ambient sound in the time period T _P immediately before. In determining the normal level range, the calculation unit 720 first sends an acquisition command to the acquisition unit 710. Upon receiving this acquisition command, the acquisition unit 710 acquires ambient sound related information as described above. Then, the acquisition unit 710 sends the acquisition result to the calculation unit 720.

  When the ambient sound related information sent from the acquisition unit 710 is received, the calculation unit 720 determines the value of the first coefficient α and the value of the second coefficient β based on the ambient sound related information. The relationship between the content of the ambient sound related information and the value of the first coefficient α and the value of the second coefficient β is determined in advance based on experiments, simulations, experiences, and the like.

Subsequently, the calculation unit 720 uses the determined value of the first coefficient α and the value of the second coefficient β, and the first average value μ ₁ and the standard deviation σ calculated in advance, and the following (1) , (2) the formula, by calculating the upper limit LV _U and lower LV _L normal level range of the ambient sound in the time period T _P immediately before to determine the normal level range.
LV _U = μ ₁ + α · σ (1)
LV _L = μ ₁ −β · σ (2)

Next, the calculation unit 720 extracts absolute value data within the determined normal level range from the absolute value data | N (T) |. Subsequently, the calculation unit 720 calculates the average value of the extracted absolute value data as the second average value μ ₂ . Then, the calculation unit 720 sends the calculated second average value μ ₂ to the adjustment unit 740.

As described above, in the present embodiment, the calculation unit 720 periodically includes the first average value μ ₁ that is the average value of the absolute values of the amplitude levels of the ambient sounds collected by the sound collection unit 810 and the relevant value. The standard deviation σ of the absolute value is calculated. Subsequently, the calculation unit 720 determines the normal level range based on the first average value μ ₁ and the standard deviation σ. Next, the calculation unit 720 calculates a second average value μ ₂ that is an average value of the absolute values of the amplitude levels of the surrounding sounds within the determined normal level range. Then, the adjustment unit 740 adjusts the output sound including the volume adjustment based on the second average value μ ₂ calculated by the calculation unit 720.

  Therefore, according to the present embodiment, it is possible to prevent the listener from giving a sense of discomfort to the listener while ensuring followability of the sound adjustment including the volume adjustment to the change in the ambient sound environment.

In the present embodiment, the normal level range of the ambient sound is determined based on the first average value μ ₁ and the standard deviation σ, which are average values of the absolute values of the amplitude levels of the ambient sound. For this reason, the normal level range of ambient sounds can be reasonably determined.

  In the present embodiment, the normal level range of the ambient sound is determined using the above-described equations (1) and (2). For this reason, the normal level range of the ambient sound can be determined more reasonably.

  In the present embodiment, with reference to the ambient sound related information acquired by the acquisition unit 710, the value of the first coefficient α in (1) and the value of the second coefficient β in (2) are determined. . For this reason, the normal level range of the ambient sound can be determined more reasonably.

[Modification of Embodiment]
The present invention is not limited to the above embodiment, and various modifications can be made.

For example, in the above embodiment, in determining the normal level range, the absolute value data for a period of time T _P just before | using first average value mu ₁ is an average value | N (T). On the other hand, instead of the first average value μ ₁ , the median value M ₁ of the absolute value data | N (T) | may be adopted.

In the above embodiment, the absolute value data within the determined normal level range is extracted from the absolute value data | N (T) |, and the second average that is the average value of the extracted absolute value data is extracted. The value μ ₂ was calculated for sound adjustment. On the other hand, instead of the second average value μ ₂ , the median value M ₂ of the absolute value data within the determined normal level range may be adopted.

  In the above embodiment, the values of the first and second coefficients are determined with reference to the ambient sound related information. On the other hand, at least one of the values of the first and second coefficients may be determined in advance based on experiment, simulation, experience, etc. as a value not related to the ambient sound related information.

  In the above embodiment, the normal level range is determined by calculating both the upper limit and the lower limit of the normal level range. On the other hand, only the upper limit or the lower limit may be calculated to determine the normal level range.

  In the above embodiment, as the ambient sound environment information, the region attribute information at the current position, the weather information at the current position, and the current time zone are exemplified, but any number of these information may be adopted. Good. In addition to or in place of these three types of information, other information may be employed as the ambient sound environment information. When a plurality of types of information are employed as the ambient sound environment information, the value of the first coefficient α and the value of the second coefficient β are determined by experiment, simulation, experience, for each combination of the plurality of types of information employed. Etc., based on the above.

  Note that a part or all of the calculation unit 720, the sound reproduction unit 730, and the adjustment unit 740 of the sound adjustment device 700 of the above embodiment are replaced with a central processing unit (CPU), a DSP (Digital Signal Processor), and the like. The computer is configured as a computing unit provided, and a part of or all of the functions of the calculation unit 720, the sound reproduction unit 730, and the adjustment unit 740 are performed by executing a program prepared in advance on the computer. Good. This program is recorded on a computer-readable recording medium such as a hard disk, CD-ROM, or DVD, and is loaded from the recording medium and executed by the computer. The program may be acquired in a form recorded on a portable recording medium such as a CD-ROM or DVD, or may be acquired in a distribution form via a network such as the Internet. Also good.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In the following description and drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.
[Constitution]
FIG. 2 shows a schematic configuration of a sound adjustment apparatus 100 according to an embodiment. The sound adjustment device 100 is an aspect of the sound adjustment device 700 (see FIG. 1) of the above-described embodiment.

  As shown in FIG. 2, the sound adjustment device 100 is connected to a sound collection unit 210, a sound content source 220, and a sound output unit 230 arranged outside. Here, the sound collection unit 210 is configured in the same manner as the sound collection unit 810 described above. Then, the sound collection result by the sound collection unit 210 is sent to the sound adjustment device 100 as sound collection data.

  The sound content source 220 is configured in the same manner as the sound content source 820 described above. The sound content data is sent from the sound content source 220 to the sound adjustment device 100.

  The sound output unit 230 is configured in the same manner as the sound output unit 830 described above. The sound output unit 230 outputs a sound corresponding to the output sound signal sent from the sound adjustment device 100.

<Configuration of Sound Adjustment Device 100>
As shown in FIG. 2, the sound adjustment device 100 includes a processing control unit 110, a storage unit 120, a position detection unit 140, and a wireless communication unit 150. In addition, the sound adjustment device 100 includes a sound reproduction unit 160, an adjustment unit 170, and an amplification unit 180.

  The processing control unit 110 performs overall control of the entire sound adjustment apparatus 100 and performs various processes. The processing control unit 110 will be described later.

  The storage unit 120 includes a nonvolatile storage element, and stores various information data used in the sound adjustment device 100. Such information data includes a coefficient table TBL. The storage control unit 110 can access the storage unit 120.

  The contents of the coefficient table TBL stored in the storage unit 120 will be described later.

  The position detection unit 140 performs GPS positioning and detects the current position. The detection result by the position detection unit 140 is sequentially sent to the processing control unit 110. The position detection unit 140 performs a part of the function of the acquisition unit 710 described above.

  The wireless communication unit 150 is used for communication between the processing control unit 110 and an external server device. By using the wireless communication unit 150, the processing control unit 110 acquires the weather information at the current position detected by the position detection unit 140 from the weather information server, and displays the area attribute information to which the current position belongs as a map. Obtain from the information server. That is, the wireless communication unit 150 performs a part of the function of the acquisition unit 710 described above.

  The sound reproduction unit 160 receives the sound content data sent from the sound content source 220. Then, the sound reproduction unit 160 reproduces a sound signal corresponding to the sound content data. The sound signal reproduced in this way is sent to the adjustment unit 170. That is, the sound reproduction unit 160 functions as the sound reproduction unit 730 described above.

The adjustment unit 170 receives the sound signal sent from the sound reproduction unit 160. Then, the adjustment unit 170 adjusts the sound signal based on the second average value μ ₂ sent from the processing control unit 110, and generates an adjusted sound signal. The adjusted sound signal generated in this way is sent to the amplification unit 180. In other words, the adjustment unit 170 performs the function of the adjustment unit 740 described above.

  The amplification unit 180 receives the adjustment sound signal sent from the adjustment unit 170. Then, the amplification unit 180 performs power amplification of the adjusted sound signal to generate an output sound signal. The output sound signal generated in this way is sent to the sound output unit 230. That is, the amplification unit 180 functions as the above-described amplification unit 750.

  Next, the processing control unit 110 will be described. The processing control unit 110 includes a central processing unit (CPU) and peripheral circuits (including a clock mechanism). Various functions as the sound adjustment device 100 are realized by the processing control unit 110 executing various programs. These functions include a part of the function of the acquisition unit 710 and the function of the calculation unit 720 in the above-described embodiment.

  The sound adjustment control process executed by the process control unit 110 will be described later.

<Contents of coefficient table TBL>
Here, the contents of the coefficient table TBL stored in the storage unit 120 will be described.

In the coefficient table TBL, as shown in FIG. 3, the value α _ijk and the second coefficient of the first coefficient α corresponding to the combination of the regional attribute, time zone, and weather, which are ambient sound related information, are associated with the combination. The value β _ijk of β is registered. In the present embodiment, the relationship between the combination of the contents of the three types of ambient sound related information described above and the value α _ijk of the first coefficient α and the value β _ijk of the second coefficient β depends on experiment, simulation, experience, etc. Is determined in advance.

In the present embodiment, the downtown area, the residential area, and the quiet area are distinguished as regional attributes. Here, for example, the value α _ijk of the first coefficient α and the value β _ijk of the second coefficient β become smaller in the order of the downtown area, the residential area, and the quiet area.

In the present embodiment, daytime and nighttime are distinguished as time zones. Here, for example, the value α _ijk of the first coefficient α and the value β _ijk of the second coefficient β increase in the order of daytime and nighttime.

In the present embodiment, the weather is classified into fine or cloudy, rain and snow. Here, for example, the value α _ijk of the first coefficient α and the value β _ijk of the second coefficient β become smaller in the order of rain, clear or cloudy, and snow.

[Operation]
Next, the operation of the sound adjustment apparatus 100 configured as described above will be described mainly focusing on the sound adjustment control process executed by the process control unit 110.

  As a premise, it is assumed that sound content data is sequentially transmitted from the sound content source 220. In addition, it is assumed that sound collection data is sequentially transmitted from the sound collection unit 210.

  Note that the processing control unit 110 buffers the sound collection data sent from the sound collection unit 210 in the buffer area of the storage unit 120.

  When the sound content data sent from the sound content source 220 is received, the sound reproduction unit 160 reproduces a sound signal corresponding to the sound content data. Then, the sound reproduction unit 160 sends the reproduced sound signal to the adjustment unit 170.

Upon receiving the sound signal sent from the sound reproduction unit 160, the adjustment unit 170 performs sound adjustment processing based on the second average value μ ₂ sent from the processing control unit 110 most recently, and generates an adjustment sound signal. . Then, the adjustment unit 170 sends the generated adjustment sound signal to the amplification unit 180.

  In this example, as in the case of the above-described embodiment, the adjustment unit 170 performs frequency characteristic adjustment processing and volume adjustment processing as sound adjustment processing.

  When receiving the adjustment sound signal sent from the adjustment unit 170, the amplification unit 180 performs power amplification of the adjustment sound signal to generate an output sound signal. Then, the amplification unit 180 sends the generated output sound signal to the sound output unit 230. As a result, a sound corresponding to the output sound signal is output from the sound output unit 230.

  In parallel with the operations of the sound reproduction unit 160, the adjustment unit 170, and the amplification unit 180 described above, the processing control unit 110 executes a sound adjustment control process. The sound adjustment control process executed by the process control unit 110 will be described below.

In the sound adjustment control process, as shown in FIG. 4, first, in step S11, the process control unit 110 has passed a predetermined time T _P from the previous calculation of the second average value μ ₂ . It is determined whether or not. If the result of the determination in step S11 is negative (step S11: N), the process of step S11 is repeated.

When time _TP has elapsed and the result of the determination in step S11 is affirmative (step S11: Y), the process proceeds to step S12. In this step S12, the processing control unit 110 uses the first average value μ ₁ and the standard deviation σ that are the average values of the absolute value data | N (T) | of the collected data N (T) for the period of the previous time T _P. Is calculated.

Such first when the average value mu ₁ and calculating the standard deviation σ, the process control unit 110 is first read collected data N of the time period T _P immediately before the storage unit 120 (T). Subsequently, the processing control unit 110 calculates absolute value data | N (T) | of the read collected data N (T). Then, the processing control unit 110 calculates the first average value μ ₁ that is the average value of the absolute value data | N (T) | and the standard deviation σ of the absolute value data | N (T) |.

  Next, in step S13, the normal level range of the absolute value data | N (T) | is determined. When determining such a normal level range, the processing control unit 110 acquires ambient sound related information.

  That is, the processing control unit 110 uses the internal clock mechanism to specify the current time, and acquires time zone information indicating whether it is a daytime time zone or a night time zone. Further, the processing control unit 110 obtains, from the map information server, the region attribute to which the current position belongs, using the wireless communication unit 150, with the latest detected position sent from the position detection unit 140 as the current position. Further, the processing control unit 110 acquires the weather at the current position from the weather server using the wireless communication unit 150, with the latest detected position sent from the position detection unit 140 as the current position.

Subsequently, the processing control unit 110 refers to the coefficient table TBL in the storage unit 120 based on the acquired three types of information, and determines the value of the first coefficient α and the value of the second coefficient β. Then, the processing control unit 110 uses the determined value of the first coefficient α and the value of the second coefficient β, and the previously calculated first average value μ ₁ and standard deviation σ as described above (1 ), (2) the formula, by calculating the upper limit LV _U and lower LV _L normal level range of the ambient sound in the time period T _P immediately before to determine the normal level range.

Next, in step S14, the process control unit 110 extracts absolute value data within the determined normal level range from the absolute value data | N (T) |. Subsequently, the processing control unit 110 calculates the average value of the extracted absolute value data as the second average value μ ₂ . Then, the process control unit 110 sends the calculated second average value μ ₂ to the adjustment unit 170.

  When the process of step S14 ends, the process returns to step S11. Thereafter, the processes of steps S11 to S14 are repeated.

FIG. 5A shows an example of a steady ambient sound collection form N ₀ (T), and FIG. 5B shows an ambient sound collection form N ₁ (including sudden sound). An example of T) is shown. 6A shows the absolute value waveform | N ₀ (T) |, and FIG. 6B shows the absolute value waveform | N ₁ (T) |.

7 shows the first average value of the absolute value waveform | N ₀ (T) |, the first average value of the absolute value waveform | N ₁ (T) |, and the absolute value waveform | N ₁ (T). The transition of the second average value of | is shown. As can be seen from FIG. 7, the absolute value waveform | N ₁ (T) | second mean value of the absolute value waveform | N ₁ (T) | compared to the first average value of, in general, the absolute value The waveform | N ₀ (T) | changes at a value close to the first average value, and the influence of the presence of sudden sound is mitigated.

In addition, FIG. 8A, which is a reprint of FIG. 5A, shows an example of a steady ambient sound collection form N ₀ (T), and FIG. 8B shows a sudden volume reduction. An example of an ambient sound collection form N ₂ (T) including ambient sound is shown. FIG. 9A, which is a reprint of FIG. 6A, shows the absolute value waveform | N ₀ (T) |, and FIG. 9B shows the absolute value waveform | N ₂ (T) | It is shown.

FIG. 10 shows the first average value of the absolute value waveform | N ₀ (T) |, the first average value of the absolute value waveform | N ₂ (T) |, and the absolute value waveform | N ₂ (T). The second average value of | is shown. As can be seen from FIG. 10, the absolute value waveform | N ₂ (T) | second mean value of the absolute value waveform | N ₂ (T) | compared to the first average value of, in general, the absolute value The waveform | N ₀ (T) | changes at a value close to the first average value, and the influence of sudden volume reduction is mitigated.

As described above, in the present embodiment, the processing control unit 110 periodically includes the first average value μ ₁ that is the average value of the absolute values of the amplitude levels of the ambient sounds collected by the sound collection unit 210 and A standard deviation σ of the absolute value is calculated. Subsequently, the processing control unit 110 determines the normal level range based on the first average value μ ₁ and the standard deviation σ. Next, the processing control unit 110 calculates a second average value μ ₂ that is an average value of the absolute values of the amplitude levels of the surrounding sounds within the determined normal level range. Then, the adjustment unit 170 adjusts the output sound including the volume adjustment based on the second average value μ ₂ calculated by the processing control unit 110.

  Therefore, according to the present embodiment, it is possible to suppress the listener from giving a sense of discomfort to the listener while ensuring the followability of the sound adjustment including the volume adjustment to the change in the ambient sound environment.

In this embodiment, the normal level range of the ambient sound is determined based on the first average value μ ₁ that is the average value of the absolute values of the amplitude levels of the ambient sound and the standard deviation σ of the absolute value. For this reason, the normal level range of ambient sounds can be reasonably determined.

  In this embodiment, the normal level range of the ambient sound is determined using the above-described equations (1) and (2). For this reason, the normal level range of the ambient sound can be determined more reasonably.

  In the present embodiment, the value of the first coefficient α in (1) and the value of the second coefficient β in equation (2) are determined with reference to the acquired ambient sound related information. For this reason, the normal level range of the ambient sound can be determined more reasonably.

[Modification of Example]
The present invention is not limited to the above embodiments, and various modifications can be made. That is, the same modification as that of the above-described embodiment can be applied to the above-described example.

DESCRIPTION OF SYMBOLS 100 ... Sound adjustment apparatus 110 ... Processing control unit (a part of acquisition part, calculation part)
140 ... position detection unit (part of acquisition unit)
150 ... Wireless communication unit (part of acquisition unit)
170 ... Adjustment unit (adjustment unit)
700 ... Sound adjustment device 710 ... Acquisition unit 720 ... Calculation unit 740 ... Adjustment unit

Claims (12)

Periodically, a normal level range is determined based on a statistic of the absolute value of the amplitude level of the collected ambient sound, and an average value and a median value of the absolute values of the amplitude levels of the ambient sound within the normal level range are determined. A calculation unit for calculating one of the following;
An adjustment unit that adjusts an output sound including volume adjustment based on a calculation result by the calculation unit;
A sound adjusting device comprising:   The sound adjustment apparatus according to claim 1, wherein the statistic is an average value and a standard deviation. The calculation unit calculates the upper limit LV _U of the normal level range based on the average value μ, the standard deviation σ, and the first coefficient α according to the following equation (I):
LV _U = μ + α · σ (I)
The sound adjusting device according to claim 2, wherein An acquisition unit for acquiring ambient sound related information related to the volume of the ambient sound;
The calculation unit determines a value of the first coefficient α based on an acquisition result by the acquisition unit.
The sound adjusting device according to claim 3. The calculation unit calculates the lower limit LV _L of the normal level range based on the average value μ, the standard deviation σ, and the second coefficient β according to the following equation (II):
LV _L = μ−β · σ (II)
The sound adjusting device according to claim 2, wherein An acquisition unit for acquiring ambient sound related information related to the volume of the ambient sound;
The calculation unit determines a value of the second coefficient β based on an acquisition result by the acquisition unit.
The sound adjusting device according to claim 5, wherein The calculation unit includes:
The upper limit LV _U of the normal level range is calculated by the following equation (I) based on the average value μ, the standard deviation σ, and the first coefficient α:
LV _U = μ + α · σ (I)
The lower limit LV _L of the normal level range is calculated by the following equation (II) based on the average value μ, the standard deviation σ, and the second coefficient β.
LV _L = μ−β · σ (II)
The sound adjusting device according to claim 2, wherein An acquisition unit for acquiring ambient sound related information related to the volume of the ambient sound;
The calculation unit determines a value of the first coefficient α and a value of the second coefficient β based on an acquisition result by the acquisition unit.
The sound adjustment apparatus according to claim 7, wherein   The acoustic adjustment apparatus according to claim 1, wherein the statistics are a median value and a standard deviation. A sound adjustment method used in a sound adjustment device including a calculation unit and an adjustment unit,
The calculation unit periodically determines a normal level range based on a statistic of an absolute value of the amplitude level of the collected ambient sound, and calculates an absolute value of the amplitude level of the ambient sound within the normal level range. A calculation step of calculating one of an average value and a median value;
An adjustment step in which the adjustment unit adjusts an output sound including volume adjustment based on a calculation result of the calculation step;
A sound adjustment method comprising:   A sound adjustment program for causing a computer included in the sound adjustment apparatus to execute the sound adjustment method according to claim 10.   12. A recording medium on which the sound adjustment program according to claim 11 is recorded so as to be readable by a computer included in the sound adjustment device.

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