Calculation device

Abstract

The system effectively detects the flow of sound radiated within an acoustic space. [Solution] The computing device (1) includes a sound detection means (110) that detects sound from a sound source (300) at at least two locations (210, 220), and a computing means (120) that performs calculations related to the propagation direction of sound from the sound source based on the times (T0, T1) at which sound is detected at each of the at least two locations. With such a computing device, it becomes possible to intuitively and simply know the flow of sound radiated into the acoustic space.

Description

[Technical Field]

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

[0002] As a means of determining the direction of sound localization, a technique is known that visually grasps the flow of sound radiated within 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 Publication No. 2005-236636 [Patent Document 2] Patent No. 5181865 [Overview of the Initiative] [Problems that the invention aims to solve]

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

[0005] The problems that this invention aims to solve include, as mentioned above, some examples. The object of this invention is to provide a computing device and a computing method capable of suitably detecting the flow of sound radiated in an acoustic space, as well as a computer program and a recording medium. [Means for solving the problem]

[0006] A computing device that solves the above problems comprises sound detection means for detecting sound from a sound source at at least two locations, and computing means for performing calculations 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.

[0007] A calculation method for solving the above problem comprises a sound detection step of detecting sound from a sound source at at least two locations, and a calculation step of performing calculations 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 that solves the above problem causes the computer to perform a sound detection step of detecting sound from a sound source at at least two locations, and a calculation step of performing calculations 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] The recording medium that solves the above problem contains the aforementioned computer program. [Brief explanation of the drawing]

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

Modes for Carrying Out the Invention

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

[0012] According to the arithmetic device of the present embodiment, during its operation, for example, sound radiated from a sound source such as a speaker is detected by the sound detection means. The sound detection means according to the present embodiment is configured to be able to detect sound at at least two locations. Specifically, for example, signals indicating sound obtained from two or more sound detectors (for example, microphones) arranged at different positions can be respectively acquired.

[0013] The sound detected by the sound detection means is used in calculations performed by the calculation means. In this embodiment, the calculation means performs calculations related to the propagation direction of the sound from the sound source based on the times when sound is detected at at least two locations. Here, "calculations related to the propagation direction" means not only calculations of data that directly indicate the propagation direction of sound, but also calculations of data including the propagation direction of sound, as well as sound pressure and phase at the detection location. For example, the calculation means calculates in what direction the sound emitted from the sound source is propagating based on the difference between the time when sound is detected at one location and the time when sound is detected at another location.

[0014] According to the above configuration, the propagation direction can be calculated using the time at which sound is detected at different locations (in other words, the propagation direction can be calculated if the time at which sound is detected at each location is known precisely). Therefore, compared to cases where the propagation direction is detected using sound pressure or particle velocity, for example, high sensitivity is not required for the sound detector. Thus, the propagation direction of sound can be determined accurately with simple processing without using expensive sound detectors.

[0015] As described above, the computing device according to this embodiment makes it possible to suitably detect the flow of sound radiated into the acoustic space.

[0016] <2> In one embodiment of the computing 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 computing means performs calculations related to the propagation direction at the reference position based on the time difference between the detection of the sound at the reference position and the peripheral position.

[0017] In this embodiment, the sound detection means detects sound at a reference position and at least one surrounding position. When sound is detected at the reference position and the surrounding position, the calculation means calculates the time difference between the time the sound was detected at the reference position and the time the sound was detected at the surrounding position. The calculation means then further performs calculations related to the direction of sound propagation at the reference position based on the calculated time difference.

[0018] According to the configuration described above, the direction of sound propagation at the reference position can be detected based on the difference in detection time between the reference position and the surrounding positions. If two or more surrounding positions are set, the time difference between the time sound is detected at the reference position and the time difference at each surrounding position will be calculated separately. In this case, for example, the time difference vectors for each surrounding position can be combined and used. Increasing the number of surrounding positions makes it possible to detect the propagation direction more accurately.

[0019] <3> In the embodiment described above, in which sound is detected at a reference position and surrounding positions, the sound detection means detects sound at the reference position, a first and second surrounding position which are coplanar surrounding positions with respect to the reference position, and a third surrounding position which is not coplanar surrounding position. The calculation means may then perform calculations related to the three-dimensional propagation direction at the reference position based on the time difference between the detection of sound at the reference position and the first, second, and third surrounding positions.

[0020] In this case, the sound detection means detects sound at the reference position and at the 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 first and second peripheral positions. Note that peripheral positions other than the first, second, and third peripheral positions may be set, and the time at which sound is detected at other peripheral positions can be used in the calculations described later.

[0021] When sound is detected at the reference position, the first, second, and third peripheral positions, the calculation means calculates the time difference between the time the sound was detected at the reference position and the time the sound was detected at the first, second, and third peripheral positions. The calculation means then further performs calculations related to the direction of sound propagation 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 plane in which the first and second peripheral positions are located. Therefore, the calculation means can calculate time differences in at least three different directions, and as a result can perform calculations related to the direction of sound propagation in three dimensions.

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

[0023] In this case, the sound detection time at the reference position and the surrounding position is compared using 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 embodiment described above, in which sound is detected at a reference position and a peripheral position, the calculation means may perform a convolution operation on the signal indicating the sound detected at each of the reference position and the peripheral position by a sine wave corresponding to a desired frequency, 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 the desired frequency in advance, calculations related to the propagation direction of sound with the desired frequency become easier. Specifically, the convolution operation makes the peak of the signal corresponding to the sound with the desired frequency among the sounds detected by the sound detection means appear prominently. Therefore, it becomes easy to calculate the propagation direction, for example, by using the difference in peak positions.

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

[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, while it is possible to calculate the transient propagation direction of sound radiated into space when using a single first peak or maximum value for the time difference, it is possible to calculate the steady propagation direction of sound radiated into space.

[0028] <7> In another embodiment of the computing device according to this embodiment, the computing means performs calculations related to the propagation direction based on the time at which the sound was detected at each of the at least two locations, as well as the sound pressure of the sound detected at each of the at least two locations.

[0029] In this embodiment, in addition to the time difference in which sound is detected, the sound pressure (amplitude) of the detected sound is used in the calculation. Therefore, it becomes possible to know the loudness of the sound in addition to the direction of propagation, and information regarding the direction of propagation can be calculated as information including the direction of propagation and the loudness of the sound. For this reason, a more appropriate display becomes possible, for example, when visualizing information regarding the direction of propagation.

[0030] <8> In another embodiment of the computing device according to this embodiment, a display means for displaying the propagation direction according to the calculation result by the computing means is further provided.

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

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

[0033] In this case, the propagation direction is displayed as a vector, making it possible to understand 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 calculations 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, it is possible to suitably detect the flow of sound radiated into the acoustic space, similar to the calculation device described above.

[0036] Furthermore, the calculation method according to this embodiment can also adopt various embodiments similar to those of the calculation device according to this embodiment described above.

[0037] <11> The computer program according to this embodiment causes the computer to perform a sound detection step of detecting sound from a sound source at at least two locations, and a calculation step of performing calculations 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 suitably detect the flow of sound radiated into the acoustic space, similar to the arithmetic device and arithmetic method described above.

[0039] Furthermore, the computer program according to this embodiment can also adopt various configurations similar to those described above for the arithmetic unit according to this embodiment.

[0040] <12> The recording medium according to this embodiment has the computer program according to this embodiment described above recorded on it.

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

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

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

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

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

[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 surrounding microphone signal input from the sound detection unit 110, calculates the time difference in which sound is detected in the reference microphone 210 and the surrounding microphone 220, and outputs it to the propagation direction calculation unit 122. 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 output data indicating the calculated sound propagation direction 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 direction of sound propagation calculated by the calculation unit 120 in a manner that allows for visual understanding.

[0048] Next, the operation of the arithmetic unit 100 according to the first embodiment will be described with reference to Figures 2 to 5. Figures 2 and 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. Figures 3 and 5 are graphs showing the signals detected by the reference microphone and peripheral microphones according to the first embodiment, respectively.

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

[0050] Here, as shown in Figure 3, let's assume that the sound detection unit 110 detects the reference microphone signal and the surrounding microphone signal as shown in the figure. In this case, the time difference calculation unit 121 calculates the time difference from the microphone located far from the origin to the microphone located nearby. Specifically, it calculates the time difference from the time T1 when the maximum value of the surrounding microphone signal located far from the origin is detected to the time T0 when the maximum value of the reference microphone signal located nearby the origin is detected. Note that the time difference calculation unit 121 may also calculate the time difference by comparing other peaks, such as a first peak, instead of the maximum value.

[0051] The time difference calculated from the signal in Figure 3 is T1-T0>0. As a result, the sound propagation direction 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 D1 shown in Figure 2. That is, the sound propagation direction is calculated as the positive direction when viewed in the X direction.

[0052] On the other hand, as shown in Figure 4, consider the case where, when viewed in the X direction with respect to the origin, the reference microphone 210 is positioned closer to the origin than the peripheral microphones 220, and sound from the sound source 300, which is positioned further from the origin than the peripheral microphones 220, is radiated in the negative direction of the X. In this case, it is thought that the sound radiated from the sound source 300 is first detected by the peripheral microphones 220, and then detected by the reference microphone 210.

[0053] Here, as shown in Figure 5, let's assume that the sound detection unit 110 detects the reference microphone signal and the surrounding microphone signal as shown in the figure. In this case, the time difference calculation unit 121 calculates the time difference from the time T1 when the maximum value of the surrounding microphone signal, which is located far from the origin, is detected, to the time T0 when the maximum value of the reference microphone signal, which is located near the origin, is detected. Then the calculated time difference is T1-T0<0. As a result, the direction of sound propagation 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 Figure 4. That is, the direction of sound propagation 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 direction of sound propagation 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 is possible to determine the direction of propagation without using, for example, a highly sensitive microphone.

[0055] <Second Example> Next, the calculation device according to the second embodiment will be described with reference to Figures 6 to 10. Here, Figure 6 is a conceptual diagram showing the positional relationship between the sound source, the reference microphone, and the peripheral microphones according to the second embodiment. Figure 7 is a graph showing the signals detected by the reference microphone and peripheral microphones according to the second embodiment, and Figure 8 is a conceptual diagram showing the time difference vector calculated for each peripheral microphone. Furthermore, Figure 9 is a conceptual diagram showing the synthesis of the time difference vectors calculated for each peripheral microphone, and Figure 10 is a plan view showing an example of the display unit.

[0056] The second embodiment differs from the first embodiment described above only in some configurations; otherwise, it is generally the same. Therefore, the following will explain in detail the parts that differ from the first embodiment already described, and will omit explanations of other overlapping parts as appropriate.

[0057] As shown in Figure 6, in the computing device 100 according to the second embodiment, multiple peripheral microphones 220 are arranged around one reference microphone 210. Specifically, the first peripheral microphone 221, the second peripheral microphone 222, the third peripheral microphone 223, and the fourth peripheral microphone 224 are arranged to surround the reference microphone 210. In this case, it is thought that the sound emitted from the sound source 300 is first detected by the first peripheral microphone 221, then by the reference microphone 210, then by the second peripheral microphone 222 and the third peripheral microphone 223, and finally by the fourth peripheral microphone 224.

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

[0059] As shown in Figure 8, the time difference calculation unit 121 first calculates the time difference in which the corresponding peaks of the reference microphone signal and each peripheral microphone signal are detected in each axial direction. Specifically, it calculates the time difference between the first peripheral microphone and the fourth peripheral microphone, which are positioned in the X direction relative to the reference microphone. The time difference between the reference microphone signal and the first peripheral microphone signal is calculated by taking the difference from the reference microphone signal, which is positioned farther away in the X direction, to the first peripheral microphone signal, which is positioned nearby. 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 positive vector in the X direction. In the case of the reference microphone signal and the fourth peripheral microphone signal, the difference from the fourth peripheral microphone signal, which is positioned farther away in the X direction, to the reference microphone signal, which is positioned nearby 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 positive vector in the X direction. Next, the time difference between the second peripheral microphone and the third peripheral microphone, which are positioned 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 determining the difference between the reference microphone signal, which is located farther away in the Y direction, and the second peripheral microphone signal, which is located nearby. 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 negative vector in the Y direction. The time difference between the reference microphone signal and the third peripheral microphone signal is calculated by determining the difference between the third peripheral microphone signal, which is located farther away in the Y direction, and the reference microphone signal, which is located nearby. 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 positive vector in the Y direction.

[0060] As shown in Figure 9, the propagation direction calculation unit 122 synthesizes the time difference vectors x1, x2, y1, and y2 calculated for each of the surrounding microphones 220 to calculate the sound propagation direction vector D3 at the reference position. Specifically, the propagation direction vector D3 is calculated using the following formula (1).

[0061] D3 = (x1 + x2) + j(y1 + y2) ... (1) As a result of the synthesis, the propagation direction vector D3 is calculated as a positive vector in the X direction, with the Y-direction component canceling out.

[0062] As shown in Figure 10, the calculation of such propagation direction vectors is performed, for example, using multiple reference positions, and calculations are performed at each reference position. The multiple propagation direction vectors calculated in this way are displayed on the display unit 400 according to their corresponding reference positions. In the example shown in the figure, the propagation direction of sound emitted from the sound source 300 located to the right and in front of the user 500 is displayed. The intensity of the sound pressure is also represented by the intensity of each vector. Specifically, the darker the color, the stronger the sound pressure, and it can be seen that the sound pressure decreases as you move further away from the sound source 300. In this way, other data such as sound pressure may also be displayed in addition to the sound propagation direction.

[0063] As explained above, the computing device according to the second embodiment makes it possible to determine the propagation direction on a two-dimensional plane by arranging multiple peripheral microphones 220. Incidentally, in the second embodiment, the peripheral microphones were arranged on the same plane, so the propagation direction in two dimensions was calculated. In contrast, if other peripheral microphones were placed at positions that were not on the same plane, for example, it would be possible to calculate the propagation direction in three dimensions as well. Note that the propagation direction in three dimensions can also be calculated in the same way as described above (i.e., by calculating the time difference vectors with each peripheral microphone signal and combining them), so a detailed explanation is omitted here.

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

[0065] The third embodiment differs from the first embodiment described above only in the method for calculating the propagation direction; otherwise, it is generally the same. Therefore, the following will explain in detail the parts that differ from the first embodiment already described, and will omit explanations of other overlapping parts as appropriate. In the third embodiment, the arrangement of the reference microphone 210 and the peripheral microphones 220 is the same as shown in Figure 2.

[0066] As shown in Figure 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 surrounding microphone signal. By performing such a convolution operation, a sound peak corresponding to the desired frequency becomes clearly visible in each of the reference microphone signal and the surrounding microphone signal. Therefore, by calculating the propagation direction using the reference microphone signal and the surrounding microphone signal after the convolution operation, the propagation direction of sound having the desired frequency can be determined. Specifically, the propagation direction vector is calculated using the time difference between the time T0 when the peak of the reference microphone signal after the convolution operation is detected and the time T1 when the peak of the surrounding microphone signal is detected.

[0067] <Fourth Example> Next, the calculation device according to the fourth embodiment will be described with reference to Figure 12. Here, Figure 12 is a conceptual diagram showing the method for calculating the 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; otherwise, it is generally the same. Therefore, the following will explain in detail the parts that differ from the fourth embodiment already described, and will omit explanations of other overlapping parts as appropriate. In the fourth embodiment as well, the arrangement of the reference microphone 210 and the peripheral microphones 220 is the same as shown in Figure 2.

[0069] As shown in FIG. 12, in the arithmetic unit 100 according to the fourth embodiment, first, as in the third embodiment, convolution operations of sine waves corresponding to a desired frequency are performed on each of the reference microphone signal and the peripheral microphone signal. As a result, in each of the reference microphone signal and the peripheral microphone signal, the peak of the sound corresponding to the desired frequency will appear prominently.

[0070] Subsequently, using the reference microphone signal and the peripheral microphone signal after the convolution operation, the average value of the time difference in a predetermined period is calculated. 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 the following formula (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 peripheral microphone.

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

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

[0073] T n = T 1n - T 0n ···(4) When these n time differences T1 to T n are calculated, the average value T n of the n time differences T1 to T a is calculated using the following formula (5).

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

[0075] The present invention is not limited to the embodiments described above, and can be modified as appropriate without contradicting the gist or idea of ​​the invention as can be read from the claims and specification as a whole. Calculation devices and calculation methods, as well as computer programs and recording media, that involve such modifications are also included within 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 microphones 300 sound sources 400 Display 500 users

Claims

[Claim 1] A sound detection means that detects sound from a sound source at at least two locations, 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 was detected at each of the at least two locations, and A computing device equipped with the following features.

Images