Sound source position measuring method, sound source position measuring device, and gas leak detection method

Abstract

To provide a sound source position measuring method and a sound source position measuring device capable of detecting only a position of a real sound source with high accuracy by removing a virtual image sound source.SOLUTION: A sound source position measuring method according to the present invention includes: a sound wave receiving step of receiving sound waves within a measurement range; a moving body sound wave receiving step of receiving sound waves generated by a moving body for moving within the measurement range; a distance measuring step of measuring a distance to a structure within the measurement range; a moving body sound wave cancellation step of delaying and subtracting the sound waves received in the moving body sound wave receiving step by a time obtained by doubling the distance measured in the distance measuring step and dividing by the speed of sound from the sound waves received in the sound wave receiving step, and treating sound waves obtained by the subtraction as sound waves generated from the structure; and a sound source position calculation step of determining a position at which the sound waves are generated using the sound waves generated from the structure obtained in the moving body sound wave cancellation step.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a sound source position measuring method, a sound source position measuring device, and a gas leak detection method. [Background technology]

[0002] In plants and the like, it is necessary to quickly detect malfunctions such as corrosion holes in piping, deterioration or damage to electrical equipment, and the like, and perform repairs, etc. In order to detect such malfunctions, sound waves emitted when gas leaks from corrosion holes in piping, or sound waves emitted when corona discharge occurs in electrical equipment, are measured. Here, as a technology for measuring sound waves and detecting the direction of a sound source, Patent Document 1 describes a technology for receiving sound waves emitted from a sound source using a microphone array, and performing beamforming processing on the received sound waves to identify the direction of the sound source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-137323 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when there is a possibility that harmful gas is leaking around the measurement position of the sound wave, it is desirable to measure the sound wave from a remote position using a moving object such as a drone (unmanned aerial vehicle). However, when measuring the sound wave using a moving object, in the technology described in Patent Document 1, the microphone array also receives the noise sound generated by the moving object. As a result, in the technology described in Patent Document 1, the noise sound generated by the moving object is detected as a virtual sound source, and it may be difficult to accurately detect the position of the real sound source.

[0005] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a sound source position measuring method and a sound source position measuring device capable of accurately detecting only the position of a real sound source by removing a virtual sound source. Another object of the present invention is to provide a gas leak detection method capable of accurately detecting the position where a gas leak is occurring. [Means for solving the problem]

[0006] [1] The sound source position measuring method of the present invention includes a sound wave receiving step of receiving sound waves within a measurement range, a moving body sound wave receiving step of receiving sound waves generated by a moving body moving within the measurement range, a distance measurement step of measuring the distance to a structure within the measurement range, a moving body sound wave cancellation step of delaying and subtracting the sound waves received in the moving body sound wave receiving step from the sound waves received in the sound wave receiving step by a time obtained by doubling the distance measured in the distance measurement step and dividing it by the speed of sound, and treating the sound waves obtained by the subtraction as sound waves generated from the structure, and a sound source position calculation step of determining the generation position of the sound wave using the sound waves generated from the structure obtained by the moving body sound wave cancellation step.

[0007] [2] The sound source position measuring device of the present invention comprises an acoustic wave receiving unit that receives acoustic waves within a measurement range, a moving body acoustic wave receiving unit that receives acoustic waves generated by a moving body moving within the measurement range, a distance measuring unit that measures the distance to a structure within the measurement range, a moving body acoustic wave cancellation unit that delays and subtracts the acoustic waves received by the moving body acoustic wave receiving unit from the acoustic waves received by the acoustic wave receiving unit by a time obtained by doubling the distance measured by the distance measuring unit and dividing it by the speed of sound, and treats the sound waves obtained by the subtraction as sound waves generated from the structure, and a sound source position calculation unit that uses the sound waves generated from the structure and obtained by the moving body acoustic wave cancellation unit to determine the position at which the sound waves are generated.

[0008] [3] A gas leak detection method according to the present invention includes a step of detecting a location of a gas leak in the structure using a sound source location measurement method according to the present invention. Effect of the Invention

[0009] According to the sound source position measuring method and the sound source position measuring device of the present invention, it is possible to accurately detect only the position of the real sound source by removing the virtual sound source. Also, according to the gas leak detection method of the present invention, it is possible to accurately detect the position where the gas leak is occurring. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing the configuration of a sound source localization device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a state in which the sound source localization device shown in FIG. 1 is mounted on a moving object. [Diagram 3] FIG. 3 is a flowchart showing the flow of a sound source position measurement process according to an embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart showing the flow of the moving body sound wave cancellation process according to an embodiment of the present invention. [Diagram 5] FIG. 5 is a diagram for explaining the moving body sound wave cancellation process shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the configuration and operation of a sound source localization device according to an embodiment of the present invention will be described with reference to the drawings.

[0012] 〔composition〕 First, the configuration of a sound source position measuring device according to one embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a block diagram showing the configuration of a sound source position measuring device according to one embodiment of the present invention. Figure 2 is a diagram showing a state in which the sound source position measuring device shown in Figure 1 is mounted on a moving object.

[0013] As shown in FIG. 1, a sound source position measuring device 1 according to an embodiment of the present invention is configured by an information processing device and is connected to a terminal device 2 via an electric communication line. The terminal device 2 is configured by an information processing device such as a smartphone or a tablet terminal. The terminal device 2 includes an operation unit 21 that accepts user operation input (measurement on / off, various settings, etc.), a display unit 22 that displays various information, and a communication unit 23 that transmits and receives various information via an electric communication line. Also, as shown in FIG. 2, the sound source position measuring device 1 is mounted on a mobile object 3 such as a drone for moving within a measurement range, and is configured to be able to measure sound waves NA generated from a structure A from a remote position.

[0014] Returning to Fig. 1, the sound source position measuring device 1 includes a sound wave receiving unit 11, a moving body sound wave receiving unit 12, a distance measuring unit 13, a communication unit 14, a storage unit 15, and a control unit 16.

[0015] The sonic wave receiving unit 11 is composed of a microphone (acoustic sensor) array. The sonic wave receiving unit 11 receives sound waves within the measurement range (sound waves NA and N2 in the example shown in FIG. 2) and outputs information about the received sound waves to the control unit 16. The microphone array arrangement is preferably an arrangement that is less likely to generate grating lobes. The microphones may have one measurement frequency or a combination of multiple frequencies. A sound insulation hood 4 (see FIG. 2) may be attached around the sonic wave receiving unit 11 to prevent noise from the surroundings of the measurement range from entering the measurement range of the sonic wave receiving unit 11.

[0016] The moving body sonic wave receiving unit 12 has the same configuration as the sonic wave receiving unit 11. The moving body sonic wave receiving unit 12 may have the same microphone array or the same measurement frequency specifications as the sonic wave receiving unit 11. When the moving body 3 is a drone, the moving body sonic wave receiving unit 12 may be installed in a central position between the propellers (see FIG. 2), or may be installed directly below each of the propellers. The moving body sonic wave receiving unit 12 receives the sonic waves generated by the moving body 3 (sound wave N1 in the example shown in FIG. 2) and outputs information regarding the received sonic waves generated by the moving body 3 to the control unit 16.

[0017] Note that the virtual sound source described above is a sound source that indicates a detection position other than the original detection position of the sound wave NA that directly arrives at the sound wave receiving unit 11 from the sound source existing in the structure A in FIG. 2. The detection position of the sound wave NA that directly arrives from the sound source of the structure A is the position of the actual sound source. On the other hand, the sound wave N1 emitted from the moving body 3 is reflected by the structure A and detected by the sound wave receiving unit 11 as the sound wave N2. At this time, the detection position of the sound wave N2 is apparently detected as being in the structure A. Therefore, the detection position of the sound wave N2 generated by the reflection of the sound wave N1 generated from the moving body 3 by the structure A with respect to the structure A is considered as the position of the virtual sound source.

[0018] The distance measurement unit 13 is composed of a distance measurement laser, LiDAR, 3D scanner, stereo camera, etc. The distance measurement unit 13 measures the distance to the structure A within the measurement range of the sound wave receiving unit 11 and outputs information regarding the measured distance to the control unit 16.

[0019] The communication unit 14 is composed of a communication circuit that conforms to the standard of the telecommunication line, and transmits and receives various information via the telecommunication line.

[0020] The storage unit 15 is composed of a non-volatile storage device and stores various information. In the present embodiment, the storage unit 15 stores N sound pressure maps M1 to MN indicating time series data of the generation positions of the sound wave NA generated by the sound source position measurement process described later.

[0021] The control unit 16 is composed of an arithmetic processing device such as a CPU. The control unit 16 functions as a sound source position calculation unit 16a, a moving body sound wave cancellation unit 16b, and an output processing unit 16c when the arithmetic processing device executes a computer program. The functions of these units will be described later.

[0022] The sound source position measuring device 1 having such a configuration executes the sound source position measuring process described below to accurately detect the generation position of the sound wave NA from the structure A. Hereinafter, the operation of the sound source position measuring device 1 when executing the sound source position measuring process will be described with reference to the flowchart shown in FIG.

[0023] [Sound source position measurement processing] Fig. 3 is a flowchart showing the flow of a sound source position measurement process according to an embodiment of the present invention. The flowchart shown in Fig. 3 starts when an execution command for the sound source position measurement process is input to the sound source position measurement device 1 via the terminal device 2, and the sound source position measurement process proceeds to step S1. Note that, for convenience of explanation, steps S1 to S3 will be explained in order below, but it is assumed that steps S1 to S3 are executed simultaneously.

[0024] In the process of step S1, the sound wave receiving unit 11 receives a sound wave NA generated from a structure A within the measurement range and a sound wave N2 generated by the sound wave N1 generated from the moving object 3 being reflected by the structure A. Then, the sound wave receiving unit 11 outputs information about the received sound waves NA and N2 to the control unit 16. This completes the process of step S1, and the sound source position measurement process proceeds to the process of step S2.

[0025] In the process of step S2, the moving body sound wave receiving unit 12 receives the sound wave N1 generated by the moving body 3, and outputs information about the received sound wave N1 to the control unit 16. This completes the process of step S2, and the sound source position measurement process proceeds to the process of step S3.

[0026] In the process of step S3, the distance measurement unit 13 measures the distance to the structure A within the measurement range of the sound wave receiving unit 11, and outputs information about the measured distance to the control unit 16. This completes the process of step S3, and the sound source position measurement process proceeds to the process of step S4.

[0027] In the process of step S4, the moving body sound wave cancellation unit 16b uses information on the sound wave N1 received by the moving body sound wave receiving unit 12 and information on the distance measured by the distance measuring unit 13 to remove the sound wave N2 from the sound waves NA and N2 measured by the sound wave receiving unit 11 (moving body sound wave cancellation process). This moving body sound wave cancellation process makes it possible to extract only the sound wave NA generated from the structure A. Details of this moving body sound wave cancellation process will be described later with reference to Figures 4 and 5. This completes the process of step S4, and the sound source position measurement process proceeds to the process of step S5.

[0028] In the process of step S5, the sound source position calculation unit 16a executes an aperture synthesis process using the sound wave NA extracted by the moving body sound wave cancellation unit 16b to calculate the generation position of the sound wave NA in a predetermined time range. Then, the sound source position calculation unit 16a stores data of the generation position of the sound wave NA in the predetermined time range in chronological order as N sound pressure maps M1 to MN in the storage unit 15. This completes the process of step S5, and the sound source position measurement process proceeds to the process of step S6.

[0029] In the process of step S6, the output processing unit 16c calculates the time average value of the generation position of the sound wave NA using the sound pressure maps M1 to MN stored in the storage unit 15 in the process of step S5. By calculating the time average value of the generation position of the sound wave NA, it is possible to remove noise sounds that randomly occur in the sound wave NA. This completes the process of step S6, and the sound source position measurement process proceeds to the process of step S7.

[0030] In the process of step S7, the output processing unit 16c transmits information on the time average value of the generation position of the sound source NA calculated in the process of step S6 to the terminal device 2 via the communication unit 14, and the terminal device 2 outputs the received information to the display unit 22. This completes the process of step S7, and the series of sound source position measurement processes ends.

[0031] [Mobile body sound wave cancellation processing] Next, the moving body sound wave cancellation process in step S4 above will be described in detail with reference to FIG. 4 and FIG.

[0032] Fig. 4 is a flowchart showing the flow of the moving body sound wave cancellation process according to one embodiment of the present invention. The flowchart shown in Fig. 4 starts when the processes of steps S1 to S3 shown in Fig. 3 are completed, and the moving body sound wave cancellation process proceeds to the process of step S11. Note that, for convenience of explanation, the processes of steps S11 to S13 will be explained in order below, but it is assumed that the processes of steps S11 to S13 are executed simultaneously.

[0033] In the process of step S11, the moving body sound wave cancellation unit 16b generates a sound wave signal SW1 (see FIG. 5(a)) indicating the time change in intensity of the sound waves NA and N2 received by the sound wave receiving unit 11. As a result, the process of step S11 or the moving body sound wave cancellation process proceeds to the process of step S15.

[0034] In the process of step S12, the moving body sound wave cancellation unit 16b generates a sound wave signal SW2 (see FIG. 5(b)) indicating a time change in intensity of the sound wave N1 received by the moving body sound wave receiving unit 12. This completes the process of step S12, and the moving body sound wave cancellation process proceeds to the process of step S14.

[0035] In the process of step S13, the moving body sound wave cancellation unit 16b calculates the delay time t [s] as a value (2L / 340) obtained by dividing the double value 2L of the distance L [m] to the structure A within the measurement range of the sound wave receiving unit 11 measured by the distance measurement unit 13 by the speed of sound (340 [m / s]). With this, the process of step S13 is completed, and the moving body sound wave cancellation process proceeds to the process of step S14.

[0036] In the process of step S14, the moving body sound wave cancellation unit 16b generates a sound wave signal SW3 (see FIG. 5(c)) by delaying the sound wave signal SW2 generated in the process of step S12 by the delay time t calculated in the process of step S13. This completes the process of step S14, and the moving body sound wave cancellation process proceeds to the process of step S15.

[0037] In the process of step S15, the sound signal SW4 is generated by subtracting the sound signal SW3 generated in the process of step S14 from the sound signal SW1 generated in the process of step S11, as a sound signal indicating the time change of the sound wave NA generated from the structure A. This completes the process of step S15, and the series of moving body sound wave cancellation processes ends.

[0038] As is clear from the above description, the sound source position measuring device 1 according to one embodiment of the present invention includes a sound wave receiving unit 11 that receives sound waves within a measurement range, a moving body sound wave receiving unit 12 that receives sound waves generated by a moving body 3 that moves within the measurement range, a distance measuring unit 13 that measures the distance to a structure A within the measurement range, a moving body sound wave canceling unit 16b that delays and subtracts the sound waves received by the moving body sound wave receiving unit 12 from the sound waves received by the sound wave receiving unit 11 by a time obtained by multiplying the distance measured by the distance measuring unit 13 by two and dividing it by the speed of sound, and uses the sound waves obtained by the subtraction as the sound waves generated from the structure A, and a sound source position calculating unit 16a that uses the sound waves generated from the structure A obtained by the moving body sound wave canceling unit 16b to find the generation position of the sound waves. This makes it possible to accurately detect the generation position of the sound waves from the structure A. In addition, by detecting the generation position of a gas leak in a structure using this sound source position measuring method, it is possible to accurately detect the position where the gas leak is generated.

[0039] Although the embodiments of the present invention have been described above, the present invention is not limited by the descriptions and drawings that form part of the disclosure of the present invention according to the present embodiments. In other words, other embodiments, examples, and operation techniques, etc., made by those skilled in the art based on the present embodiments are all included in the scope of the present invention. [Explanation of symbols]

[0040] 1. Sound source location measurement device 2 Terminal Equipment 3. Mobile 4. Soundproof hood 11. Sonic receiver 12 Mobile sonic receiver 13 Distance measurement section 14 Communications Department 15 Storage section 16 Control section 16a Sound source position calculation section 16b Mobile sound wave canceller 16c Output Processing Section 21 Control section 22 Display section 23 Communications Department

Claims

1. A sonic wave receiving step of receiving sonic waves within a measurement range; a moving body sonic wave receiving step of receiving sonic waves generated by a moving body moving within the measurement range; a distance measurement step of measuring a distance to a structure within the measurement range; a moving body sound wave canceling step of delaying and subtracting the sound wave received in the moving body sound wave receiving step from the sound wave received in the sound wave receiving step by a time obtained by doubling the distance measured in the distance measuring step and dividing it by the speed of sound, and treating the sound wave obtained by the subtraction as the sound wave generated from the structure; a sound source position calculation step of determining a generation position of the sound wave using the sound wave generated from the structure obtained by the moving body sound wave cancellation step; A sound source location measurement method comprising:

2. an ultrasonic wave receiving unit that receives ultrasonic waves within a measurement range; a moving body sonic wave receiving unit for receiving sonic waves generated by a moving body for moving within the measurement range; a distance measurement unit that measures a distance to a structure within the measurement range; a moving body sound wave canceling unit that delays and subtracts the sound waves received by the moving body sound wave receiving unit from the sound waves received by the sound wave receiving unit by a time obtained by doubling the distance measured by the distance measuring unit and dividing it by the speed of sound, and sets the sound waves obtained by the subtraction as sound waves generated from the structure; a sound source position calculation unit that uses the sound waves generated from the structure and obtained by the moving body sound wave cancellation unit to determine the generation position of the sound waves; A sound source position measuring device comprising:

3. A gas leak detection method comprising the step of detecting a location of a gas leak in the structure by using the sound source location measurement method according to claim 1.

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