JP2023126485A - Processing device - Google Patents

Abstract

To provide a processing device capable of preferably detecting a sound flow radiated into an acoustic space.SOLUTION: A processing device (1) comprises: sound detection means (110) for detecting sounds from a sound source (300) at least at 2 points (210, 220); and calculation means (120) configured to perform a calculation concerning propagation direction in which the sounds propagate from the sound source on the basis of the time (T0, T1) when the sounds are detected at least at the 2 points. With the processing device the sound flow radiated into an acoustic space can be easily and intuitively comprehended.SELECTED DRAWING: Figure 6

Description

The present invention relates, for example, to the technical field of a computing device and a computing method that perform computing for visually grasping the flow of sound radiated into an acoustic space, as well as a computer program and a recording medium.

As a means of determining the localization direction of sound, a technique is known in which the flow of sound radiated into an acoustic space is visually grasped. For example, Patent Documents 1 and 2 disclose a technique of calculating the direction of radiated energy from sound pressure and particle velocity at a plurality of detection points.

JP2005-236636A Patent No. 5181865

However, the techniques described in Patent Documents 1 and 2 described above require high sensitivity for devices such as microphones that detect sound. Therefore, in order to detect the flow of sound, it is necessary to use, for example, a special tool, which causes technical problems such as an increase in cost.

Examples of the problems to be solved by the present invention include those mentioned above. An object of the present invention is to provide a computing device and a computing method, as well as a computer program and a recording medium, which can suitably detect the flow of sound radiated into an acoustic space.

A computing device that solves the above problem includes a sound detection means that detects a sound from a sound source at at least two locations, and a method for detecting a sound that propagates from the sound source based on a time when the sound is detected at each of the at least two locations. and calculation means for performing calculations related to the propagation direction.

A calculation method for solving the above problem includes a sound detection step of detecting sound from a sound source at at least two locations, and detecting the sound propagating from the sound source based on the time at which the sound is detected at each of the at least two locations. and a calculation step for performing calculations related to the propagation direction.

A computer program for solving the above problem includes a sound detection step of detecting a sound from a sound source at at least two locations, and detecting the sound from the sound source based on the time at which the sound is detected at each of the at least two locations. The computer is caused to perform an operation step of executing an operation related to the propagation direction.

A recording medium for solving the above problem has the above-mentioned computer program recorded thereon.

FIG. 1 is a schematic diagram showing the overall configuration of an arithmetic device according to a first embodiment. FIG. 2 is a conceptual diagram (part 1) showing the positional relationship between a sound source, a reference microphone, and peripheral microphones according to the first embodiment. 3 is a graph (part 1) showing signals detected by the reference microphone and peripheral microphones according to the first example. FIG. 3 is a conceptual diagram (Part 2) showing the positional relationship between the sound source, the reference microphone, and the surrounding microphones according to the first embodiment. 12 is a graph (part 2) showing signals detected by the reference microphone and peripheral microphones according to the first example. FIG. 7 is a conceptual diagram showing the positional relationship between a sound source, a reference microphone, and peripheral microphones according to a second embodiment. 7 is a graph showing signals detected by a reference microphone and peripheral microphones according to a second example. FIG. 3 is a conceptual diagram showing time difference vectors calculated corresponding to each peripheral microphone. FIG. 3 is a conceptual diagram showing the synthesis of time difference vectors calculated corresponding to each peripheral microphone. FIG. 3 is a plan view showing an example of display on the display unit. FIG. 7 is a conceptual diagram showing a convolution operation according to a third example. FIG. 7 is a conceptual diagram showing a method of calculating an average value according to a fourth example.

<1>
The arithmetic device according to the present embodiment includes a sound detecting means that detects the sound from the sound source at at least two locations, and a method for determining whether the sound propagates from the sound source based on the time at which the sound is detected at each of the at least two locations. and calculation means for performing calculations related to the propagation direction.

According to the arithmetic device of this embodiment, during its operation, the sound emitted from a sound source such as a speaker is detected by the sound detection means. The sound detection means according to this embodiment is configured to be able to detect sound at at least two locations. Specifically, it is configured to be able to acquire signals representing sounds obtained from two or more sound detectors (for example, microphones, etc.) arranged at different positions, for example.

The sound detected by the sound detection means is used for calculation by the calculation means. The calculation means according to the present embodiment performs calculations related to the propagation direction in which the sound propagates from the sound source, based on the times at which the sound is detected at at least two locations. Note that "calculation related to the direction of propagation" here refers not only to calculation of data that directly indicates the direction of sound propagation, but also to calculation of data including the direction of sound propagation, sound pressure and phase at the detection position. The purpose is to include operations such as. The calculation means calculates in what direction the sound emitted from the sound source is propagating, based on the difference between the time when the sound is detected at one location and the time when the sound is detected at another location, for example. Calculate whether .

According to the above configuration, the propagation direction can be calculated using the times when the sound was detected at different locations (in other words, if the time when the sound was detected at each location is accurately known, the propagation direction can be calculated). Therefore, a sound detector is not required to have high sensitivity compared to, for example, the case where the direction of propagation is detected using sound pressure or particle velocity. Therefore, the direction of sound propagation can be determined with high accuracy through simple processing without using an expensive sound detector.

As explained above, according to the arithmetic device according to the present embodiment, it is possible to suitably detect the flow of sound radiated into the acoustic space.

<2>
In one aspect of the arithmetic device according to the present embodiment, the sound detection means detects the sound at a reference position and at least one peripheral position located around the reference position, and the arithmetic means includes: An operation related to the propagation direction at the reference position is performed based on a time difference between when the sound was detected at the reference position and at the peripheral position.

According to this aspect, the sound detection means detects the sound at the reference position and at least one peripheral position. When the sound is detected at the reference position and the peripheral position, the calculating means calculates the time difference between the time when the sound was detected at the reference position and the time when the sound was detected at the peripheral position. The calculation means further performs calculations related to the sound propagation direction at the reference position based on the calculated time difference.

According to the above-described configuration, it is possible to detect the sound propagation direction at the reference position based on the difference in detection time between the reference position and the surrounding positions. Note that if two or more peripheral positions are set, the time difference from the time when the sound was detected at the reference position is calculated for each peripheral position. In this case, for example, time difference vectors for each peripheral position may be combined and used. By increasing the number of peripheral positions, it becomes possible to detect the propagation direction more accurately.

<3>
In the embodiment in which sound is detected at a reference position and a peripheral position as described above, the sound detecting means detects the reference position, a first peripheral position and a second peripheral position which are peripheral positions on the same plane as the reference position, A sound is detected at each of the third peripheral positions that are not on the same plane, and the calculation means detects a sound at each of the reference position, the first peripheral position, the second peripheral position, and the third peripheral position. A calculation related to the three-dimensional propagation direction at the reference position may be performed based on the time difference between when the sound was detected.

In this case, the sound detection means detects the sound at the reference position and the first, second, and third peripheral positions. The first peripheral position and the second peripheral position are peripheral positions located on the same plane as the reference position. On the other hand, the third peripheral position is a peripheral position that is not located on the same plane as the plane in which the first and second peripheral positions are located. Note that the peripheral positions may be set other than the first, second, and third peripheral positions, and the time during which sound was detected at other peripheral positions can also be used for calculations described later.

When the sound is detected at the reference position, the first, second and third peripheral positions, the calculation means calculates the time when the sound was detected at the reference position and the time when the sound was detected at the first, second and third peripheral positions. The time difference between the specified time and the specified time is calculated. The calculation means further performs calculations related to the sound propagation direction at the reference position based on the calculated time difference. In particular, in this aspect, as described above, the first and second peripheral positions are peripheral positions located on the same plane as the reference position, and the third peripheral position is a peripheral position where the first and second peripheral positions are located. It is set as a peripheral position that is not located on the same plane as the plane. Therefore, the calculation means can calculate time differences in at least three different directions, and as a result, it is possible to perform calculations in three-dimensional sound propagation directions.

<4>
In the embodiment in which the sound is detected at the reference position and the peripheral position as described above, the calculation means is based on the time difference between the first peak or maximum value of the signal indicating the sound detected at each of the reference position and the peripheral position. Then, an operation related to the propagation direction at the reference position may be performed.

In this case, the detection times of the sound at the reference position and the surrounding positions are compared based on the first peak (that is, the first peak detected after starting detection) or the maximum value. Therefore, even if there are multiple peaks in the signal representing the detected sound, the difference in detection time can be calculated accurately.

<5>
In the embodiment in which sound is detected at a reference position and a peripheral position as described above, the calculation means adds a sine wave corresponding to a desired frequency to a signal indicating the sound detected at each of the reference position and the peripheral position. A convolution operation may be performed to perform an operation related to the propagation direction of the sound having the desired frequency at the reference position.

In this case, by convolving the sine wave corresponding to the desired frequency in advance, calculations related to the propagation direction of the sound having the desired frequency can be easily performed. Specifically, by convolution calculation, a peak of a signal corresponding to a sound having a desired frequency among the sounds detected by the sound detection means appears prominently. Therefore, for example, it becomes easy to calculate the propagation direction using the difference in peak positions.

<6>
In the embodiment in which the convolution calculation of a sine wave corresponding to a desired frequency is performed as described above, the calculation means calculates the An operation related to the propagation direction at the reference position may be performed.

In this case, the time difference between when the sound was detected is calculated multiple times in a predetermined period (that is, using multiple peaks). Then, calculations related to the propagation direction are performed based on the average value of the plurality of time differences. In this way, when one first peak or maximum value is used for the time difference, it is possible to calculate the transient propagation direction of the sound radiated into the space, whereas it is possible to calculate the transient propagation direction of the sound radiated into the space. It is possible to calculate the direction of sound propagation.

<7>
In another aspect of the arithmetic device according to the present embodiment, the arithmetic means calculates the sound pressure of the sound detected at each of the at least two locations in addition to the time at which the sound was detected at each of the at least two locations. Based on the propagation direction, an operation related to the propagation direction is performed.

According to this aspect, in addition to the time difference when the sound is detected, the sound pressure (amplitude) of the detected sound is used for calculation. Therefore, it is possible to know the loudness of the sound in addition to the direction of sound propagation, and information regarding the propagation direction can be calculated as information including the propagation direction and the loudness of the sound. Therefore, more appropriate display is possible, for example, when visualizing information regarding the propagation direction.

<8>
In another aspect of the arithmetic device according to the present embodiment, the arithmetic device further includes display means for displaying the propagation direction according to a calculation result by the arithmetic means.

According to this aspect, it becomes possible to visually grasp the propagation direction calculated by the calculation means.

<9>
In an embodiment further including a display means as described above, the display means may display the propagation direction as a vector.

In this case, since the propagation direction is displayed as a vector, it becomes possible to understand the flow of sound more intuitively.

<10>
The calculation method according to the present embodiment includes a sound detection step of detecting a sound from a sound source at at least two locations, and a method for determining whether the sound propagates from the sound source based on the time at which the sound is detected at each of the at least two locations. and a calculation step for performing calculations related to the propagation direction.

According to the calculation method according to the present embodiment, similarly to the above-described calculation device, it is possible to suitably detect the flow of sound radiated into the acoustic space.

Note that the calculation method according to this embodiment can also adopt various aspects similar to the various aspects of the calculation device according to the above-described embodiment.

<11>
The computer program according to the present embodiment includes a sound detection step of detecting a sound from a sound source at at least two locations, and detecting the sound propagating from the sound source based on the time at which the sound is detected at each of the at least two locations. The computer is caused to perform an operation step of executing an operation related to the propagation direction.

According to the computer program according to the present embodiment, it is possible to suitably detect the flow of sound radiated into the acoustic space, similarly to the above-described arithmetic device and arithmetic method.

Note that the computer program according to the present embodiment can also adopt various aspects similar to the various aspects of the arithmetic device according to the present embodiment described above.

<12>
The computer program according to the above-described embodiment is recorded on the recording medium according to the present embodiment.

According to the recording medium according to this embodiment, by executing the recorded computer program, it is possible to suitably detect the flow of sound radiated into the acoustic space.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First example>
First, the configuration of an arithmetic device 100 according to a first embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram showing the overall configuration of an arithmetic device according to a first embodiment.

In FIG. 1, a calculation device 100 according to the first embodiment includes a sound detection section 110 and a calculation section 120 as main components.

The sound detection section 110 is an example of the "sound detection means" of the present invention, and receives as input a signal indicating the sound detected by the connected reference microphone 210 and peripheral microphone 220. Note that the reference microphone 210 and the peripheral microphone 220 are configured as, for example, general microphones, and detect the sound emitted from the sound source 300. The sound detection unit 110 generates an input signal (i.e., a signal indicating the sound detected by the reference microphone 210 (hereinafter referred to as a "reference microphone signal") and a signal indicating the sound detected by the peripheral microphone 220 (hereinafter referred to as "reference microphone signal")). , appropriately referred to as a "surrounding microphone signal")) can be output to the arithmetic unit 120 directly or after being subjected to various processes.

The calculation section 120 is an example of the "calculation means" of the present invention, and includes a time difference calculation section 121 and a propagation direction calculation section 122. The time difference calculation unit 121 compares the reference microphone signal and the surrounding microphone signal input from the sound detection unit 110, calculates the time difference between when the sound is detected at the reference microphone 210 and the surrounding microphone 220, and sends the sound to the propagation direction calculation unit 122. Output. The propagation direction calculation unit 122 calculates the propagation direction of the sound emitted from the sound source 300 based on the time difference calculated by the time difference calculation unit 121. The calculation unit 120 is configured to be able to output data indicating the calculated sound propagation direction to the display unit 400.

The display unit 400 is an example of the "display means" of the present invention, and is configured as a display such as a liquid crystal monitor, for example. The display unit 400 is capable of displaying the sound propagation direction calculated by the calculation unit 120 in a visually understandable manner.

Next, the operation of the arithmetic device 100 according to the first embodiment will be explained with reference to FIGS. 2 to 5. 2 and 4 are conceptual diagrams showing the positional relationship between the sound source, the reference microphone, and the peripheral microphones, respectively, according to the first embodiment. Further, FIGS. 3 and 5 are graphs showing signals detected by the reference microphone and peripheral microphones, respectively, according to the first embodiment.

As shown in FIG. 2, when viewed in the X direction with the origin as a reference, the reference microphone 210 is placed closer to the origin than the peripheral microphones 220, and the sound from the sound source 300 placed behind the origin is detected. Consider the case where is radiated in the positive direction of the X direction. In this case, it is considered that the sound emitted from the sound source 300 is first detected by the reference microphone 210 and then detected by the peripheral microphone 220.

Here, as shown in FIG. 3, it is assumed that the sound detection unit 110 detects the reference microphone signal and the peripheral microphone signal as shown in the figure. In this case, the time difference calculation unit 121 calculates the time difference between a microphone placed far away from the origin and a microphone placed nearby. Specifically, from time T1 when the maximum value of the peripheral microphone signal placed far away from the origin is detected to time T0 when the maximum value of the reference microphone signal placed near the origin is detected. Calculate the time difference. Note that the time difference calculation unit 121 may calculate the time difference by comparing other peaks such as the first peak instead of the maximum value.

The time difference calculated from the signals in FIG. 3 is T1-T0>0. As a result, the propagation direction of the sound at the reference position where the reference microphone 210 is placed is calculated by the propagation direction calculation unit 122 as the propagation direction vector D1 shown in FIG. That is, the sound propagation direction is calculated as the positive direction when viewed in the X direction.

On the other hand, as shown in FIG. 4, when viewed in the X direction with the origin as a reference, the reference microphone 210 is located closer to the origin than the peripheral microphones 220, and is located further from the origin than the peripheral microphones 220. Consider a case where sound from the sound source 300 is radiated in the negative direction of the X direction. In this case, it is considered that the sound emitted from the sound source 300 is first detected by the peripheral microphone 220 and then detected by the reference microphone 210.

As shown in FIG. 5, it is assumed that the sound detection unit 110 detects the reference microphone signal and the peripheral microphone signal as shown in the figure. In this case, the time difference calculation unit 121 detects the maximum value of the reference microphone signal placed near the origin from time T1 when the maximum value of the peripheral microphone signal placed far from the origin is detected. The time difference between the time T0 and the time T0 is calculated. Then, the calculated time difference becomes T1-T0<0. As a result, the propagation direction of the sound at the reference position where the reference microphone 210 is placed is calculated by the propagation direction calculation unit 122 as the propagation direction vector D2 shown in FIG. That is, the sound propagation direction is calculated as the negative direction when viewed in the X direction.

As explained above, according to the arithmetic device 100 according to the first embodiment, the difference between the time when the sound is detected by the reference microphone 210 and the time when the sound is detected by the peripheral microphone 220 is used to The direction of propagation can be calculated. In particular, in the arithmetic device according to the first embodiment, since it is only necessary to accurately detect the timing at which the sound is detected, the propagation direction can be suitably determined without using, for example, a highly sensitive microphone.

<Second example>
Next, an arithmetic device according to a second embodiment will be described with reference to FIGS. 6 to 10. FIG. 6 is a conceptual diagram showing the positional relationship between a sound source, a reference microphone, and peripheral microphones according to the second embodiment. Further, FIG. 7 is a graph showing signals detected by the reference microphone and peripheral microphones according to the second embodiment, and FIG. 8 is a conceptual diagram showing a time difference vector calculated corresponding to each peripheral microphone. Furthermore, FIG. 9 is a conceptual diagram showing the synthesis of time difference vectors calculated corresponding to each peripheral microphone, and FIG. 10 is a plan view showing an example of display on the display unit.

Note that the second embodiment differs from the first embodiment described above only in a part of the configuration, and is generally the same in other respects. Therefore, in the following, parts that are different from the first embodiment described above will be explained in detail, and explanations of other overlapping parts will be omitted as appropriate.

As shown in FIG. 6, in the arithmetic device 100 according to the second embodiment, a plurality of peripheral microphones 220 are arranged for one reference microphone 210. Specifically, a first peripheral microphone 221 , a second peripheral microphone 222 , a third peripheral microphone 223 , and a fourth peripheral microphone 224 are arranged so as to surround the reference microphone 210 . In this case, the sound emitted from the sound source 300 is first detected by the first peripheral microphone 221, then by the reference microphone 210, further thereafter by the second peripheral microphone 222 and third peripheral microphone 223, and finally by the second peripheral microphone 222 and the third peripheral microphone 223. It is considered that the fourth peripheral microphone 224 will detect the signal.

Here, as shown in FIG. 7, in the sound detection unit 110, a reference microphone signal and each peripheral microphone signal (specifically, a first peripheral microphone signal indicating the sound detected by the first peripheral microphone 221, a second peripheral microphone signal indicating the sound detected by the first peripheral microphone 221, a second peripheral microphone signal indicative of the sound detected by the microphone 222; a third peripheral microphone signal indicative of the sound detected by the third peripheral microphone 223; and a fourth peripheral microphone signal indicative of the sound detected by the fourth peripheral microphone 224. Suppose that a signal) is detected as shown in the figure. Note that the second peripheral microphone signal and the third peripheral microphone signal are shown together because they are detected as similar signals at approximately the same time.

As shown in FIG. 8, the time difference calculation unit 121 first calculates the time difference between when the corresponding peaks of the reference microphone signal and each peripheral microphone signal are detected in each axis direction. Specifically, the time difference between the first peripheral microphone and the fourth peripheral microphone arranged in the X direction with respect to the reference microphone is calculated. The time difference between the reference microphone signal and the first peripheral microphone signal is calculated by calculating the difference between the reference microphone signal located far away in the X direction and the first peripheral microphone signal located nearby. That is, T0-T1>0. As a result, the time difference vector x1 in the relationship between the reference microphone 210 and the first peripheral microphone 221 is calculated as a vector in the positive direction in the X direction. In the case of the reference microphone signal and the fourth peripheral microphone signal, the difference between the fourth peripheral microphone signal located far away in the X direction and the reference microphone signal located nearby is calculated. That is, T0-T4<0. As a result, the time difference vector x2 in the relationship between the reference microphone 210 and the fourth peripheral microphone 224 is calculated as a vector in the positive direction in the X direction. Next, the time difference between the second peripheral microphone and the third peripheral microphone arranged in the Y direction with respect to the reference microphone is calculated. The time difference between the reference microphone signal and the second peripheral microphone signal is calculated by calculating the difference between the reference microphone signal located far away in the Y direction and the second peripheral microphone signal located nearby. That is, T0-T2<0. As a result, the time difference vector y1 in the relationship between the reference microphone 210 and the second peripheral microphone 222 is calculated as a vector in the negative direction in the Y direction. The time difference between the reference microphone signal and the third peripheral microphone signal is calculated by calculating the difference between the third peripheral microphone signal located far away in the Y direction and the reference microphone signal located nearby. That is, T3-T1>0. As a result, the time difference vector y2 in the relationship between the reference microphone 210 and the third peripheral microphone 223 is calculated as a vector in the positive direction in the Y direction.

As shown in FIG. 9, the propagation direction calculation unit 122 synthesizes the time difference vectors x1, x2, y1, and y2 calculated for each of the peripheral microphones 220, respectively, and calculates the sound propagation direction vector D3 at the reference position. do. Specifically, the propagation direction vector D3 is calculated using the following formula (1).

D3=(x1+x2)+j(y1+y2)...(1)
As a result of the synthesis, the propagation direction vector D3 is calculated as a vector in the positive direction of the X direction, with the components in the Y direction cancelled.

As shown in FIG. 10, such calculation of the propagation direction vector is performed using, for example, a plurality of locations as reference positions, and is calculated at each reference position. The plurality of propagation direction vectors calculated in this way are displayed on the display unit 400 in alignment with the corresponding reference positions. In the example shown in the figure, the propagation direction of the sound emitted from the sound source 300 located in front and right of the user 500 is displayed. The intensity of the sound pressure is also expressed by the shading of each vector. Specifically, it can be seen that the darker the color, the stronger the sound pressure, and the farther from the sound source 300, the weaker the sound pressure is. In this way, in addition to the sound propagation direction, other data such as sound pressure may also be displayed.

As described above, according to the arithmetic device according to the second embodiment, by arranging a plurality of peripheral microphones 220, it is possible to know the propagation direction on a two-dimensional plane. Incidentally, in the second embodiment, since the peripheral microphones are arranged on the same plane, the two-dimensional propagation direction is calculated. On the other hand, for example, if other peripheral microphones are placed at positions that are not on the same plane, it is possible to calculate the propagation direction in three dimensions. Note that the three-dimensional propagation direction can be calculated in the same way as the method described above (that is, it can be calculated by calculating the time difference vector with each surrounding microphone signal and combining them), so here Detailed explanation will be omitted.

<Third Example>
Next, an arithmetic device according to a third embodiment will be described with reference to FIG. 11. FIG. 11 is a conceptual diagram showing the convolution operation according to the third embodiment.

Note that the third embodiment differs from the first embodiment described above only in the method of calculating the propagation direction, and is generally the same in other respects. Therefore, in the following, parts that are different from the first embodiment described above will be explained in detail, and explanations of other overlapping parts will be omitted as appropriate. In the third example, the arrangement of the reference microphone 210 and the peripheral microphone 220 is assumed to be the same as that shown in FIG. 2.

As shown in FIG. 11, in the arithmetic device 100 according to the third embodiment, the arithmetic unit 120 performs a convolution operation of a sine wave corresponding to a desired frequency on each of the reference microphone signal and the peripheral microphone signal. By performing such a convolution operation, a sound peak corresponding to a desired frequency appears prominently in each of the reference microphone signal and the peripheral microphone signal. Therefore, by calculating the propagation direction using the reference microphone signal and surrounding microphone signals after the convolution calculation, it is possible to know the propagation direction of sound having a desired frequency. Specifically, the propagation direction vector is calculated using the time difference between time T0 at which the peak of the reference microphone signal after the convolution calculation is detected and time T1 at which the peak of the peripheral microphone signal is detected.

<Fourth Example>
Next, an arithmetic device according to a fourth embodiment will be described with reference to FIG. 12. FIG. 12 is a conceptual diagram showing a method of calculating an average value according to the fourth embodiment.

Note that the fourth embodiment differs from the fourth embodiment described above only in the method of calculating the propagation direction, and is generally the same in other respects. Therefore, in the following, parts that are different from the fourth embodiment already described will be explained in detail, and explanations of other overlapping parts will be omitted as appropriate. In the fourth embodiment as well, the arrangement of the reference microphone 210 and the peripheral microphones 220 is assumed to be the same as that shown in FIG. 2.

As shown in FIG. 12, in the arithmetic device 100 according to the fourth embodiment, first, as in the third embodiment, a convolution operation of a sine wave corresponding to a desired frequency is performed on each of the reference microphone signal and the peripheral microphone signal. will be held. As a result, a sound peak corresponding to a desired frequency appears prominently in each of the reference microphone signal and the peripheral microphone signal.

Subsequently, the average value of the time difference in a predetermined period is calculated using the reference microphone signal and the peripheral microphone signal after the convolution calculation. Specifically, first, a plurality of time differences are calculated for each period Δt corresponding to each peak. That is, the time difference T ₁ between the first peaks is calculated using the following equation (2) using the detection time T ₀₁ of the first peak of the reference microphone signal and the detection time T ₁₁ of the first peak of the surrounding microphones.

T ₁ = T ₁₁ - T ₀₁ ...(2)
Similarly, the time difference _T2 between the second peaks is calculated using the following formula (3) using the detection time _T02 of the second peak of the reference microphone signal and the detection time _T12 of the first peak of the surrounding microphones. .

T ₂ = T ₁₂ - T ₀₂ ...(3)
Then, the time difference T _n between the n-th peaks is calculated using the following equation (4) using the detection time T _0n of the n-th peak of the reference microphone signal and the detection time T _1n of the first peak of the surrounding microphones.

T _n = T _1n - T _0n (4)
When these n time differences T ₁ to T _n are calculated, the average value T _a of the n time differences T ₁ to T _n is calculated using the following equation (5).

T _a =(T ₁ +T ₂ +...T _n-1 +T _n )/n...(5)
By using the average value T _a of the time differences calculated in this way, it is possible to calculate the steady sound propagation direction of the sound radiated into space, compared to the case where only the time difference of one peak is used. .

The present invention is not limited to the embodiments described above, and can be modified as appropriate within the scope or idea of the invention that can be read from the claims and the entire specification. Computing methods, computer programs, and recording media are also included within the technical scope of the present invention.

Reference Signs List 100 Arithmetic device 110 Sound detection section 120 Arithmetic section 121 Time difference calculation section 122 Propagation direction calculation section 210 Reference microphone 220 Surrounding microphone 300 Sound source 400 Display section 500 User

Claims (1)

sound detection means for detecting the sound from the sound source at at least two locations;
and a calculation means for performing calculations related to a propagation direction in which the sound propagates from the sound source based on times when the sound was detected at each of the at least two locations.