Processing device

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

[Technical Field]

[0001] The present invention relates to the technical field of a computing device and a computing method for performing computations to visually grasp the flow of sound radiated in an acoustic space, for example, as well as a computer program and a recording medium. [Background technology]

[0002] As a means of determining the localized direction of sound, there is a known technique for visually grasping the flow of sound radiated in an acoustic space. For example, Patent Documents 1 and 2 disclose a technique for calculating the direction of radiated energy from sound pressure and particle velocity at multiple detection points. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-236636 [Patent Document 2] Patent No. 5181865 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the techniques described in the above-mentioned Patent Documents 1 and 2 require high sensitivity for devices such as microphones that detect sound, which means that detecting sound flow requires the use of, for example, a dedicated tool, which leads to technical problems such as increased costs.

[0005] The above is an example of the problem that the present invention aims to solve. An object of the present invention is to provide a calculation device and a calculation method, as well as a computer program and a recording medium, that are capable of suitably detecting the flow of sound radiated in an acoustic space. [Means for solving the problem]

[0006] A calculation device that solves the above problem includes a sound detection means that detects sound from a sound source at at least two locations, and a calculation means that performs calculations related to the propagation direction of the sound from the sound source based on the time at which the sound is detected at each of the at least two locations.

[0007] 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 a calculation step of performing a calculation related to the propagation direction of the sound from the sound source based on the time at which the sound was detected at each of the at least two locations.

[0008] A computer program for solving the above problem causes a computer to execute a sound detection step of detecting sound from a sound source at at least two locations, and a calculation step of performing a calculation related to the propagation direction of the sound from the sound source based on the time at which the sound was detected at each of the at least two locations.

[0009] A recording medium for solving the above problem has the above-mentioned computer program recorded thereon. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing the overall configuration of a computing device according to a first embodiment. [Figure 2] 1 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. [Figure 3] 1 is a graph (part 1) showing signals detected by a reference microphone and peripheral microphones according to the first embodiment. [Figure 4] FIG. 10 is a conceptual diagram (part 2) showing the positional relationship between a sound source, a reference microphone, and peripheral microphones according to the first embodiment. [Figure 5] 10 is a graph (part 2) showing signals detected by the reference microphone and the peripheral microphones according to the first embodiment. [Figure 6] FIG. 10 is a conceptual diagram showing the positional relationship between a sound source, a reference microphone, and peripheral microphones according to a second embodiment. [Figure 7]10 is a graph showing signals detected by a reference microphone and peripheral microphones according to a second embodiment. [Figure 8] FIG. 10 is a conceptual diagram showing time difference vectors calculated in correspondence with the respective peripheral microphones. [Figure 9] FIG. 10 is a conceptual diagram showing the synthesis of time difference vectors calculated in correspondence with the respective peripheral microphones. [Figure 10] FIG. 2 is a plan view showing a display example on a display unit. [Figure 11] FIG. 10 is a conceptual diagram illustrating a convolution operation according to a third embodiment. [Figure 12] FIG. 10 is a conceptual diagram showing a method for calculating an average value according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] <1> The calculation device according to this embodiment includes a sound detection means for detecting sound from a sound source at at least two locations, and a calculation means for performing calculations related to the propagation direction of the sound from the sound source based on the time at which the sound is detected at each of the at least two locations.

[0012] According to the computing device of this embodiment, during operation, sound emitted from a sound source such as a speaker is detected by a 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 respectively acquire signals indicating sound obtained from two or more sound detectors (e.g., microphones) arranged at different locations.

[0013] The sound detected by the sound detection means is used for calculations in the calculation means. The calculation means according to this embodiment performs calculations related to the propagation direction of sound from the sound source based on the times at which the sound is detected at at least two locations. Note that the "calculation related to the propagation direction" here does not only mean calculations of data that directly indicate the propagation direction of the sound, but also includes calculations of data including the propagation direction of the sound, and sound pressure and phase at the detection position. The calculation means calculates the direction in which the sound emitted from the sound source is propagating, for example, based on the difference between the time when the sound was detected at one location and the time when the sound was detected at another location.

[0014] According to the above-described configuration, the propagation direction can be calculated using the times when sound was detected at different points (in other words, the propagation direction can be calculated as long as the time when sound was detected at each point is accurately known), so the sound detector does not require high sensitivity compared to when detecting the propagation direction using, for example, sound pressure or particle velocity. Therefore, the propagation direction of sound can be known with high accuracy using simple processing without using an expensive sound detector.

[0015] As described above, the calculation device according to this embodiment can suitably detect the flow of sound radiated in an acoustic space.

[0016] <2> In one aspect of the calculation device according to this 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 calculation means performs a calculation related to the propagation direction at the reference position based on the time difference between when the sound is detected at the reference position and when it is detected at the peripheral position.

[0017] According to this aspect, the sound detection means detects sound at a reference position and at least one peripheral position. When sound is detected at the reference position and the peripheral positions, the calculation 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 positions. The calculation means then further performs a calculation related to the propagation direction of the sound at the reference position based on the calculated time difference.

[0018] According to the above-described configuration, the propagation direction of sound at the reference position can be detected based on the difference in detection time between the reference position and the peripheral positions. If two or more peripheral positions are set, the time difference between the time when sound was detected at the reference position and the peripheral positions is calculated for each peripheral position. In this case, for example, the time difference vectors for each peripheral position can be combined and used. By increasing the number of peripheral positions, the propagation direction can be detected more accurately.

[0019] <3> In the aspect of detecting sound at a reference position and peripheral positions as described above, the sound detection means may detect sound at the reference position, a first peripheral position and a second peripheral position that are peripheral positions on the same plane as the reference position, and a third peripheral position that is a peripheral position that is not on the same plane, and the calculation means may perform a calculation related to the three-dimensional propagation direction at the reference position based on the time difference between when the sound is detected at the reference position and the first peripheral position, the second peripheral position, and the third peripheral position.

[0020] In this case, the sound detection means detects sound at a reference position and first, second, and third peripheral positions. The first and second peripheral positions 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 on which the first and second peripheral positions are located. Note that peripheral positions may be set other than the first, second, and third peripheral positions, and the time at which sound is detected at other peripheral positions can also be used for the calculations described below.

[0021] When sound is detected at the reference position and the first, second, and third peripheral positions, the calculation 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 first, second, and third peripheral positions. The calculation means then performs a calculation related to the sound propagation direction at the reference position based on the calculated time difference. In this embodiment, as described above, the first and second peripheral positions are set as peripheral positions located on the same plane as the reference position, and the third peripheral position is set as a peripheral position not located on the same plane as the first and second peripheral positions. Therefore, the calculation means can calculate the time difference for at least three different directions, and as a result, can perform a calculation related to the sound propagation direction in three dimensions.

[0022] <4> In the aspect in which sound is detected at a reference position and peripheral positions as described above, the calculation means may perform a calculation related to the propagation direction at the reference position based on the time difference between a first peak or a maximum value of the signal indicating the sound detected at the reference position and the peripheral positions.

[0023] In this case, the sound detection time at the reference position and the surrounding positions is compared based on the first peak (i.e., the first peak detected after detection begins) or the maximum value. Therefore, even if there are multiple peaks in the signal indicating the detected sound, the difference in detection time can be calculated accurately.

[0024] <5> In the aspect of detecting sound at a reference position and peripheral positions as described above, the calculation means may convolute a sine wave corresponding to a desired frequency with the signal indicating the sound detected at each of the reference position and the peripheral positions, and perform a calculation related to the propagation direction of the sound having the desired frequency at the reference position.

[0025] In this case, by performing a convolution operation on a sine wave corresponding to a desired frequency in advance, it becomes easier to perform calculations related to the propagation direction of a sound having the desired frequency. Specifically, the convolution operation makes the peak of the signal corresponding to the sound having the desired frequency among the sounds detected by the sound detection means appear prominently. Therefore, it becomes easier to calculate the propagation direction using, for example, the difference in peak positions.

[0026] <6> In the aspect of performing a convolution operation of a sine wave corresponding to a desired frequency as described above, the calculation means may perform a calculation related to the propagation direction at the reference position based on an average value of the time difference between when the sound is detected at the reference position and the peripheral positions over a predetermined period.

[0027] In this case, the time difference at which the sound is detected is calculated multiple times over a predetermined period (i.e., using multiple peaks). Then, calculations related to the propagation direction are performed based on the average value of the multiple time differences. In this way, it is possible to calculate the steady 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 when one first peak or maximum value is used for the time difference.

[0028] <7> In another aspect of the calculation device according to this embodiment, the calculation means performs calculations related to the propagation direction based on 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.

[0029] According to this aspect, in addition to the time difference at which the sound is detected, the sound pressure (amplitude) of the detected sound is used in the calculation. Therefore, it is possible to know the sound volume as well as the sound propagation direction, and information regarding the propagation direction can be calculated as information including the propagation direction and the sound volume. Therefore, more appropriate display is possible, for example, when visualizing information regarding the propagation direction.

[0030] <8> In another aspect of the arithmetic device according to the present embodiment, the arithmetic device further comprises a display means for displaying the propagation direction in accordance with the calculation result by the arithmetic means.

[0031] According to this aspect, it is possible to visually grasp the propagation direction calculated by the calculation means.

[0032] <9> In the aspect further comprising a display means as described above, the display means may display the propagation direction as a vector.

[0033] In this case, the propagation direction is displayed as a vector, making it possible to grasp the flow of sound more intuitively.

[0034] <10> The calculation method according to this embodiment includes a sound detection step of detecting sound from a sound source at at least two locations, and a calculation step of performing a calculation related to the propagation direction of the sound from the sound source based on the time at which the sound was detected at each of the at least two locations.

[0035] According to the calculation method of this embodiment, like the calculation device described above, it is possible to suitably detect the flow of sound radiated into an acoustic space.

[0036] The calculation method according to this embodiment can also employ various aspects similar to those of the calculation device according to this embodiment described above.

[0037] <11> The computer program according to this embodiment causes a computer to execute a sound detection step of detecting sound from a sound source at at least two locations, and a calculation step of performing a calculation related to the propagation direction of the sound from the sound source based on the time at which the sound was detected at each of the at least two locations.

[0038] According to the computer program of this embodiment, it is possible to preferably detect the flow of sound radiated in an acoustic space, similar to the above-described calculation device and calculation method.

[0039] The computer program according to this embodiment can also employ various aspects similar to those of the arithmetic device according to this embodiment described above.

[0040] <12> The recording medium according to this embodiment stores the computer program according to the embodiment described above.

[0041] According to the recording medium of this embodiment, by executing the recorded computer program, it is possible to suitably detect the flow of sound radiated in an acoustic space. [Example]

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0043] <First Example> First, the configuration of a calculation device 100 according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the overall configuration of the calculation device according to the first embodiment.

[0044] In FIG. 1, a calculation device 100 according to the first embodiment is configured to include a sound detection unit 110 and a calculation unit 120 as main components.

[0045] The sound detection unit 110 is an example of the "sound detection means" of the present invention, and receives as input signals indicative of sounds detected by the connected reference microphone 210 and peripheral microphone 220. The reference microphone 210 and peripheral microphone 220 are configured as, for example, general microphones, and detect sounds emitted from a sound source 300. The sound detection unit 110 is configured to be able to output the input signals (i.e., signals indicative of sounds detected by the reference microphone 210 (hereinafter referred to as "reference microphone signals" as appropriate) and signals indicative of sounds detected by the peripheral microphone 220 (hereinafter referred to as "peripheral microphone signals" as appropriate)) directly or after performing various processes thereon to the calculation unit 120.

[0046] The calculation unit 120 is an example of the "calculation means" of the present invention, and includes a time difference calculation unit 121 and a propagation direction calculation unit 122. The time difference calculation unit 121 compares the reference microphone signal and the peripheral microphone signal input from the sound detection unit 110 to calculate the time difference between when sound is detected by the reference microphone 210 and the peripheral microphone 220, and outputs the time difference to the propagation direction calculation unit 122. The propagation direction calculation unit 122 calculates the propagation direction of the sound radiated 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 propagation direction of the sound to the display unit 400.

[0047] 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. The display unit 400 is capable of displaying the sound propagation direction calculated by the calculation unit 120 in a manner that allows the direction to be visually grasped.

[0048] Next, the operation of the arithmetic device 100 according to the first embodiment will be described with reference to Fig. 2 to Fig. 5. Fig. 2 and Fig. 4 are conceptual diagrams showing the positional relationship between the sound source, the reference microphone, and the peripheral microphones according to the first embodiment, respectively. Fig. 3 and Fig. 5 are graphs showing the signals detected by the reference microphone and the peripheral microphones according to the first embodiment, respectively.

[0049] 2, when viewed in the X direction with the origin as the reference, consider a case where reference microphone 210 is located closer to the origin than peripheral microphone 220, and sound from sound source 300 located behind the origin is radiated in the positive X direction. In this case, it is considered that the sound radiated from sound source 300 is first detected by reference microphone 210, and then detected by peripheral microphone 220.

[0050] 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 the microphone located far from the origin and the microphone located close to the origin. Specifically, the time difference calculation unit 121 calculates the time difference from the time T1 when the maximum value of the peripheral microphone signal located far from the origin is detected to the time T0 when the maximum value of the reference microphone signal located close to the origin is detected. Note that the time difference calculation unit 121 may calculate the time difference by comparing another peak, such as the first peak, instead of the maximum value.

[0051] 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. 2. In other words, the propagation direction of the sound is calculated as the positive direction when viewed in the X direction.

[0052] 4, consider a case where, when viewed in the X direction with the origin as the reference, reference microphone 210 is placed closer to the origin than peripheral microphone 220, and sound from sound source 300, which is placed farther from the origin than peripheral microphone 220, is radiated in the negative X direction. In this case, it is considered that the sound radiated from sound source 300 is first detected by peripheral microphone 220, and then detected by reference microphone 210.

[0053] Assume now that the sound detection unit 110 detects the reference microphone signal and the peripheral microphone signals as shown in FIG. 5. In this case, the time difference calculation unit 121 calculates the time difference between time T1 when the maximum value of the peripheral microphone signal located far from the origin is detected and time T0 when the maximum value of the reference microphone signal located close to the origin is detected. The calculated time difference is T1-T0<0. As a result, the propagation direction of the sound at the reference position where the reference microphone 210 is located is calculated by the propagation direction calculation unit 122 as the propagation direction vector D2 shown in FIG. 4. In other words, the propagation direction of the sound is calculated as the negative direction when viewed in the X direction.

[0054] As described above, the arithmetic device 100 according to the first embodiment can calculate the propagation direction of sound by utilizing the difference between the time when sound is detected by the reference microphone 210 and the time when sound is detected by the peripheral microphone 220. In particular, the arithmetic device according to the first embodiment only needs to accurately detect the timing when sound is detected, so it can preferably determine the propagation direction without using, for example, a highly sensitive microphone.

[0055] <Second Example> Next, a calculation 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. 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 time difference vectors calculated corresponding to each peripheral microphone. 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 a display unit.

[0056] The second embodiment differs from the first embodiment only in some configurations, and is otherwise generally the same. Therefore, the following will describe in detail the differences from the first embodiment, and will omit the description of other overlapping portions as appropriate.

[0057] 6, in the arithmetic device 100 according to the second embodiment, a plurality of peripheral microphones 220 are arranged with respect to 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, it is considered that sound emitted from the sound source 300 is first detected by the first peripheral microphone 221, then detected by the reference microphone 210, further detected by the second peripheral microphone 222 and the third peripheral microphone 223, and finally detected by the fourth peripheral microphone 224.

[0058] 7, it is assumed that the reference microphone signal and each peripheral microphone signal (specifically, a first peripheral microphone signal indicating sound detected by the first peripheral microphone 221, a second peripheral microphone signal indicating sound detected by the second peripheral microphone 222, a third peripheral microphone signal indicating sound detected by the third peripheral microphone 223, and a fourth peripheral microphone signal indicating sound detected by the fourth peripheral microphone 224) are detected as shown in the figure in sound detection unit 110. Note that the second peripheral microphone signal and the third peripheral microphone signal are detected as similar signals at approximately the same time, and are therefore shown together in the figure.

[0059] As shown in FIG. 8 , the time difference calculation unit 121 first calculates the time difference between the detection of corresponding peaks of the reference microphone signal and each peripheral microphone signal in each axial direction. Specifically, the time difference between the first peripheral microphone and the fourth peripheral microphone, which are arranged in the X direction relative to the reference microphone, is calculated. The time difference between the reference microphone signal and the first peripheral microphone signal is calculated by subtracting the first peripheral microphone signal, which is arranged close to the reference microphone signal, from the reference microphone signal, which is arranged farther away in the X direction. That is, T0-T1>0. As a result, the time difference vector x1 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, which is arranged farther away in the X direction, and the reference microphone signal, which is arranged close to the reference microphone signal, is calculated. That is, T0-T4<0. As a result, the time difference vector x2 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, which are arranged in the Y direction relative to the reference microphone, is calculated. The time difference between the reference microphone signal and the second peripheral microphone signal is calculated by subtracting the second peripheral microphone signal, which is positioned closer to the reference microphone signal positioned farther away in the Y direction, from the reference microphone signal positioned closer to the second peripheral microphone signal. That is, T0 - T2 < 0. As a result, the time difference vector y1 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 subtracting the third peripheral microphone signal, which is positioned farther away in the Y direction, from the reference microphone signal positioned closer to the third peripheral microphone signal. That is, T3 - T1 > 0. As a result, the time difference vector y2 between the reference microphone 210 and the third peripheral microphone 223 is calculated as a vector in the positive direction in the Y direction.

[0060] 9, the propagation direction calculation unit 122 calculates a sound propagation direction vector D3 at the reference position by combining the time difference vectors x1, x2, y1, and y2 calculated for each of the peripheral microphones 220. Specifically, the propagation direction vector D3 is calculated using the following equation (1).

[0061] 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 X direction, with the Y direction components being cancelled out.

[0062] As shown in FIG. 10, such calculation of the propagation direction vector is performed, for example, using multiple locations as reference positions, and calculation is performed at each reference position. The multiple propagation direction vectors calculated in this manner are displayed on the display unit 400 in accordance with the corresponding reference positions. In the example shown in the figure, the propagation direction of sound emitted from a sound source 300 located to the front right of the user 500 is displayed. The intensity of the sound pressure is also expressed by the shade of each vector. Specifically, the darker the color, the stronger the sound pressure, and it can be seen that the sound pressure decreases as the distance from the sound source 300 increases. In this way, other data such as sound pressure may be displayed in addition to the sound propagation direction.

[0063] As described above, according to the arithmetic device of 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, the peripheral microphones are arranged on the same plane, so the two-dimensional propagation direction is calculated. In contrast, for example, if other peripheral microphones are arranged in positions that are not on the same plane, it is also possible to calculate the three-dimensional propagation direction. Note that the three-dimensional propagation direction can also be calculated in the same manner as described above (i.e., by calculating the time difference vectors with respect to the respective peripheral microphone signals and combining them), and therefore a detailed description thereof will be omitted here.

[0064] <Third Example> Next, a calculation device according to a third embodiment will be described with reference to Fig. 11. Fig. 11 is a conceptual diagram showing a convolution calculation according to the third embodiment.

[0065] The third embodiment differs from the first embodiment described above only in the method of calculating the propagation direction, and is otherwise generally similar. Therefore, the following will describe in detail only the differences from the first embodiment already described, and will omit explanations of other overlapping parts as appropriate. In the third embodiment, the placement of the reference microphone 210 and the peripheral microphones 220 is assumed to be the same as that shown in FIG. 2.

[0066] As shown in FIG. 11 , in the calculation device 100 according to the third embodiment, the calculation 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 the 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 the peripheral microphone signal after the convolution operation, the propagation direction of the sound having the desired frequency can be determined. Specifically, a propagation direction vector is calculated using the time difference between time T0 when a peak is detected in the reference microphone signal after the convolution operation and time T1 when a peak is detected in the peripheral microphone signal.

[0067] <Fourth Example> Next, a calculation device according to a fourth embodiment will be described with reference to Fig. 12. Fig. 12 is a conceptual diagram showing a method for calculating an average value according to the fourth embodiment.

[0068] The fourth embodiment differs from the fourth embodiment described above only in the method of calculating the propagation direction, and is otherwise generally similar. Therefore, the following will describe in detail only the differences from the fourth embodiment already described, and will omit explanations of other overlapping parts as appropriate. In the fourth embodiment, the placement of the reference microphone 210 and the peripheral microphones 220 is also the same as that shown in FIG. 2.

[0069] 12, in the arithmetic device 100 according to the fourth embodiment, first, 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, as in the third embodiment. As a result, sound peaks corresponding to the desired frequency appear prominently in each of the reference microphone signal and the peripheral microphone signal.

[0070] Next, the average value of the time difference over a predetermined period is calculated using the reference microphone signal and the surrounding microphone signals after the convolution operation. Specifically, first, a plurality of time differences are calculated for each period Δt corresponding to each peak. That is, the time difference T1 between the first peaks is calculated by multiplying the detection time T of the first peak of the reference microphone signal by the time Δt. 01 and the detection time T of the first peak of the surrounding microphone 11 It is calculated using the following formula (2).

[0071] T1=T 11 -T 01 ···(2) Similarly, the time difference T2 between the second peaks is the detection time T 02 and the detection time T of the first peak of the surrounding microphone 12 It is calculated using the following formula (3).

[0072] T2=T 12 -T 02 ···(3) And the time difference between the n-th peaks, T n is the detection time T of the nth peak of the reference microphone signal 0n and the detection time T of the first peak of the surrounding microphone 1n is calculated using the following formula (4).

[0073] T n =T 1n -T 0n ···(4) These n time differences T1 to T n Once calculated, n time differences T1 to T n The average value of T a is calculated using the following formula (5):

[0074] T a =(T1+T2+ T n-1 +T n ) / n ···(5) The average time difference calculated in this way is T a By using this method, it is possible to calculate the steady sound propagation direction of sound radiated into space, compared to when only the time difference of one peak is used.

[0075] The present invention is not limited to the above-described embodiments, but can be modified as appropriate within the scope of the claims and the gist or idea of ​​the invention as can be read from the entire specification, and arithmetic devices and arithmetic methods, as well as computer programs and recording media, that involve such modifications are also included in the technical scope of the present invention. [Explanation of symbols]

[0076] 100 Computing equipment 110 Sound detection unit 120 Arithmetic section 121 Time difference calculation unit 122 Propagation direction calculation unit 210 Reference Microphone 220 Peripheral Microphone 300 sound sources 400 Display 500 users

Claims

[Claim 1] A sound detection means for detecting a sound from a sound source at at least two points; a calculation means for performing a calculation related to a propagation direction of the sound from the sound source based on a time when the sound was detected at each of the at least two locations; A computing device comprising:

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