JP2023170531A - Sound pressure detector, sound pressure detection system, sound pressure detection method, sound source estimation method, and program - Google Patents

Abstract

To provide a sound pressure detector that detects sound pressure without using a microphone.SOLUTION: The sound pressure detector comprises: a polarization camera that captures the image of a transparent tabular member; a displacement distribution calculation unit that calculates the distribution of displacement occurring to the tabular member due to a sound on the basis of the image captured by the polarization camera when the sound has reached the tabular member; and a pressure distribution calculation unit that calculates the distribution of sound pressure added to the tabular member on the basis of the distribution of displacement calculated by the displacement distribution calculation unit and the function that estimates the distribution of pressure added to the tabular member from the distribution of displacement occurring to the tabular member.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a sound pressure detection device, a sound pressure detection system, a sound pressure detection method, a sound source estimation method, and a program.

Patent Document 1 discloses a method of detecting the position of a noise source generated from an object placed in a wind tunnel using a microphone. When searching for sound sources in a wind tunnel, it is necessary to take measures against the influence of the wind and the location of the microphone. Regarding the influence of wind, when wind hits the microphone, pressure fluctuations due to the wind flow are measured, generating noise in a wide frequency range. Therefore, it is necessary to install the microphone in a position where it is not exposed to wind. The installation location needs to be somewhere that can accommodate multiple microphones and is not easily affected by wind. These measures may require equipment modifications. If sound source detection can be performed while avoiding the effects of wind and issues related to installation location, costs and labor can be reduced.

Non-Patent Document 1 discloses a technique in which a plurality of microphone arrays are installed facing a sound source and a sound source distribution is estimated from differences in measurement results at each measurement point. For example, a technique has been disclosed that estimates the direction of a sound source position from the difference in arrival time of sounds received by two or more microphones.

Japanese Patent Application Publication No. 2002-333367

Koichi Sasaki, Yasushi Takano, "Sound source detection technology using microphone array", Noise Control, Vol. 28, No. 2 (2004), p. 80-84

To avoid problems related to wind effects and location, methods for detecting sound pressure using means other than microphones are needed.

The present disclosure provides a sound pressure detection device, a sound pressure detection system, a sound pressure detection method, a sound source estimation method, and a program that can solve the above problems.

The sound pressure detection device of the present disclosure includes a polarizing camera that photographs a transparent plate-like member, and an image that is taken by the polarizing camera when the sound reaches the plate-like member. a displacement distribution calculation unit that calculates a distribution of displacement occurring in the plate-shaped member, a distribution of the displacement calculated by the displacement distribution calculation unit, and a sound applied to the plate-shaped member from the distribution of displacement occurring in the plate-shaped member; and a pressure distribution calculation unit that calculates a distribution of sound pressure applied to the plate-shaped member based on a conversion function that estimates a pressure distribution.

The sound pressure detection system of the present disclosure includes a structure including one or more windows configured by the plate-shaped member, and the sound pressure detection device.

The sound pressure detection method of the present disclosure includes the steps of photographing a transparent plate-like member with a polarizing camera, and detecting the sound pressure based on the image taken by the polarizing camera when the sound reaches the plate-like member. The step of calculating the distribution of displacement occurring in the plate-shaped member, the distribution of displacement calculated in the step of calculating the distribution of displacement, and the distribution of displacement occurring in the plate-shaped member, the plate-shaped member a conversion function for estimating a distribution of sound pressure applied to the plate-shaped member; and a step of calculating a distribution of sound pressure applied to the plate-shaped member.

The sound source estimation method of the present disclosure includes a step of calculating a sound pressure distribution, and a sound pressure distribution calculated in the step of calculating the sound pressure distribution, using the sound pressure detection method described above. The method includes a step of estimating a sound source by regarding the sound pressure as sound pressure detected by a plurality of microphones installed in a range of the member.

The program of the present disclosure includes the steps of: acquiring an image of a transparent plate-like member taken by a polarizing camera; , calculating the distribution of displacement caused in the plate-shaped member by the sound, the distribution of displacement calculated in the step of calculating the distribution of displacement, and the distribution of displacement caused in the plate-shaped member, a conversion function for estimating the distribution of sound pressure applied to the plate-shaped member; and a step of calculating a distribution of sound pressure applied to the plate-shaped member based on the conversion function.

According to the above-described sound pressure detection device, sound pressure detection system, sound pressure detection method, sound source estimation method, and program, sound pressure can be detected without using a microphone.

FIG. 1 is a diagram illustrating an example of a sound source estimation system according to an embodiment. It is a figure explaining the pressure distribution estimation method concerning an embodiment. FIG. 2 is a first diagram illustrating a method for calculating a conversion function according to an embodiment. FIG. 3 is a second diagram illustrating a method for calculating a conversion function according to the embodiment. It is a figure showing an example of the sound source estimation method concerning an embodiment. It is a flow chart which shows an example of sound source estimation processing concerning an embodiment. It is a figure showing an example of the monitoring window concerning an embodiment. FIG. 1 is a diagram illustrating an example of a hardware configuration of a sound source estimation device according to an embodiment.

<Embodiment>
The sound pressure detection method and sound source estimation method of the present disclosure will be described below with reference to FIGS. 1 to 7.
(composition)
FIG. 1 is a diagram illustrating an example of a sound source estimation system according to an embodiment. The sound source estimation system 100 was installed so as to photograph the entire surface of the test equipment 1, the monitoring window 2 provided in the test equipment 1, the equipment to be inspected 3 placed in the test equipment 1, and the monitoring window 2. It includes a polarization camera 4 and a sound source estimation device 10. For example, the test facility 1 is a wind tunnel test facility, and the device to be inspected 3 is an aircraft wing. By placing an aircraft wing in a wind tunnel test facility and blowing air through it, a test is conducted to simulate the state of an aircraft in flight, and to determine where on the wing the sound comes from. The test equipment 1 is provided with a monitoring window 2 made of a transparent plate-like member such as resin or glass, so that the inside of the test equipment 1 can be checked from the outside. As described above, in the method of searching for a sound source by installing a microphone in the test equipment 1, the sound emitted by the device under test 3 cannot be properly captured due to the influence of wind, making it difficult to estimate the sound source. In this embodiment, a monitoring window 2 is used instead of a microphone. The displacement of the monitoring window 2 due to sound is photographed by a polarizing camera 4, and from the photographed image of the monitoring window 2, the displacement of the vibration component vibrating at the frequency of the sound emitted by the equipment to be inspected 3 is calculated. Then, by converting the displacement at each position of the monitoring window 2 into sound pressure, a measurement result similar to that obtained when a plurality of microphones are provided in the test equipment 1 to measure sound is obtained, and the sound source is estimated.

The sound source estimation device 10 includes an image acquisition section 11, a displacement distribution calculation section 12, a pressure distribution calculation section 13, a sound source estimation section 14, a conversion function calculation section 15, a storage section 16, and an output section 17. .
The image acquisition unit 11 acquires images (moving images or continuously photographed still images) taken by the polarizing camera 4. The image acquisition unit 11 stores the acquired image in the storage unit 16.

The displacement distribution calculation unit 12 calculates the distribution of displacement of the monitoring window 2 due to the wind in the wind tunnel test or the sound emitted by the equipment 3 to be inspected. When the polarizing camera 4 photographs a transparent plate such as the monitoring window 2, an image showing the transparent plate is photographed. However, when light passes through a transparent object, polarization occurs when the refractive index changes due to deformation. Therefore, when the monitoring window 2 is displaced due to sound pressure, an image colored by polarized light is photographed. The displacement distribution calculation unit 12 calculates the displacement or color change of each part of the monitoring window 2 based on the color of the image. Furthermore, the displacement distribution calculation unit 12 calculates the frequency of displacement of the monitoring window 2 from periodic color changes in images continuously captured by the polarization camera 4. The displacement distribution calculation unit 12 selects a frequency at which the sound source is desired to be estimated (sound emitted by the device to be inspected 3, hereinafter referred to as a target frequency) from among various frequencies detected from the time-series images taken by the polarization camera 4. ), and calculate the amount of displacement based on the change in color of the extracted vibration component. The displacement distribution calculation unit 12 performs such processing on a plurality of positions in the monitoring window 2, and calculates the spatial distribution of displacement occurring in the monitoring window 2 during the wind tunnel test. Note that the number of target frequencies may be plural instead of one.

The pressure distribution calculation unit 13 calculates the distribution of pressure (load) applied to the monitoring window 2 based on the displacement distribution of the monitoring window 2 calculated by the displacement distribution calculation unit 12. The pressure distribution calculation unit 13 converts the displacement distribution of the monitoring window 2 calculated by the displacement distribution calculation unit 12 using a conversion function TF ⁻¹ (an inverse function of the transfer function TF described later) obtained through a vibration characteristic acquisition test in advance. Then, the pressure (sound pressure) applied to the monitoring window 2 is converted into a spatial distribution.

The sound source estimating unit 14 estimates the sound source distribution S of the sound emitted from the device 3 to be inspected, based on the pressure distribution of the monitoring window 2 calculated by the pressure distribution calculating unit 13.

The conversion function calculation unit 15 calculates a conversion function TF ^-1 that converts the displacement distribution of the monitoring window 2 into a pressure distribution based on the displacement distribution and pressure distribution (load distribution) of the monitoring window 2 detected in a preliminary vibration characteristic acquisition test. Calculate. In the vibration characteristic acquisition test, blows are applied to various parts of the monitoring window 2, and images of the monitoring window 2 are photographed using the polarizing camera 4. The conversion function calculation unit 15 performs the process similar to the process described in the displacement distribution calculation unit 12 based on the photographed images (moving images or continuously photographed still images) to determine the amount of damage that occurs in the monitoring window 2 due to the impact. Calculate the displacement distribution of the target frequency. The conversion function calculation unit 15 collects data on the displacement distribution of the monitoring window 2 that occurs when a blow is applied to various parts of the monitoring window 2, and transmits data representing the relationship between the load and the position of the blow caused by the blow and the displacement distribution caused by the blow. Calculate the function TF. The conversion function calculation unit 15 calculates an inverse function TF ⁻¹ of the transfer function TF, and stores this function in the storage unit 16 as the conversion function TF ⁻¹ .

The storage unit 16 stores images taken by the polarization camera 4, conversion functions, calculation processes in sound source estimation, data of calculation results, and the like.
The output unit 17 outputs the sound source position, sound source direction, sound source distribution, etc. estimated by the sound source estimation.

Next, an image taken by the polarizing camera 4 will be explained. An image taken with no pressure applied to the monitoring window 2 shows the monitoring window 2 displayed transparently. The stronger the pressure is applied to the monitoring window 2, the more the transparent plate forming the monitoring window 2 is displaced. Then, in the image taken by the polarizing camera 4, each position of the monitoring window 2 is displayed in a color corresponding to the amount of displacement at that position. For example, areas with a small amount of displacement are displayed in blue, areas with a large amount of displacement are displayed in red, and areas with displacement of between that size are displayed in a color that continuously changes depending on the amount of displacement, such as yellow or green. be done. When wind or sound occurs within the test facility 1, the monitoring window 2 vibrates due to the pressure of the wind or sound. Therefore, each position in the image captured by the monitoring window 2 is displayed in a color depending on the magnitude of vibration (displacement), and the color changes at various frequencies. By paying attention to the change in color at each position in the image, the amount of displacement and the frequency of displacement at the corresponding position in the monitoring window 2 can be analyzed.

FIG. 2 shows an outline of the pressure distribution estimation method according to the embodiment. In this embodiment, instead of detecting the sound pressure using a microphone, the sound pressure is detected by calculating the displacement distribution of the monitoring window 2, converting the displacement distribution into a pressure distribution, and estimating the pressure distribution. The procedure is, prior to estimating the source of the sound emitted from the equipment under test 3, (1) conduct a vibration characteristic acquisition test, analyze the relationship between the displacement distribution and pressure distribution of the monitoring window 2, and calculate the above-mentioned conversion function TF. Get ^-1 . Next, (2) a wind tunnel test is performed to calculate the displacement distribution of the monitoring window 2. (3) The calculation result of the displacement distribution of the monitoring window 2 is input to the conversion function TF ^-1 to obtain the pressure distribution of the monitoring window 2. The pressure distribution of the monitoring window 2, which indicates what kind of pressure is applied to which position on the monitoring window 2, is the same as arranging multiple microphones in the range of the monitoring window 2 and detecting sound pressure using these microphones. From this, the sound source estimation device 10 estimates the sound source of the device under test 3 by applying a conventional sound source detection method that performs sound source detection based on the sound pressure detected by a plurality of microphones to the pressure distribution of the monitoring window 2. I do.

(1) Vibration characteristic acquisition test As shown at 30A in FIG. 2, in the vibration characteristic acquisition test, a hammer or the like is used to strike multiple locations on the monitoring window 2. Here, as shown in FIG. 3A, the monitoring window 2 is divided into m×n areas, and a blow is applied to each of the m×n areas. Then, the monitoring window 2 is photographed by a polarizing camera 4 from before to after the impact. The image acquisition section 11 records the photographed image in the storage section 16 together with the photographing time. The conversion function calculation unit 15 calculates a transfer function TF indicating the relationship between load and displacement based on the response amount for each frequency (graph 30A1 in FIG. 2) based on images taken at each time (described later). Here, the response amount is the displacement amount of the monitoring window 2/the applied load.

For example, as described above, the monitoring window 2 is divided into m×n areas, and a blow is applied to each of the m×n areas. The conversion function calculation unit 15 analyzes the response amount for each frequency for each of the m×n regions of the monitoring window 2. Each cell divided into m×n cells is expressed as (m, n). As shown in FIG. 3A, the impact load applied to (1,1) is F _1,1,k , the impact load applied to (1,2) is F _1,2,k ,..., (m , n) are assumed to be F _{m, n, k} . Also, the displacement of (1,1) of the target frequency measured when a load of F _1,1,k is applied to (1,1), and the load of F _1,2,k is applied to (1,1). Displacement of (1, 1) of the target frequency measured when applying the load, ..., displacement of (1, 1) of the target frequency measured when adding the load of F _{m, n, k} to (1, 1). The displacement obtained by adding up all of the displacements in 1) is expressed as x _{1, 1, k} . The conversion function calculation unit 15 calculates the total displacement of the target frequency measured when each cell is hit in the vibration characteristic acquisition test for all cells, x _1,1,k , x _1,2,k , ..., calculate x _{m, n, k} . Here, k is the target frequency.

Then, it can be expressed as equation (1) in FIG. 3B. TF is such that when each cell is hit with a load F _1,1,k ~F _m,n,k , a displacement x _1,1,k ~x _m,n,k of target frequency k occurs in each cell. In this case, it is a transfer function that shows the relationship between the two. The conversion function calculation unit 15 calculates a transfer function TF that satisfies equation (1). Once the transfer function TF has been calculated, the conversion function calculation unit 15 calculates an inverse function TF ⁻¹ of the transfer function TF, and stores this function in the storage unit 16 as the conversion function TF ⁻¹ . When the conversion function TF ^-1 is used, the load generated in each cell, in other words, is determined by the displacement x _1,1,k ~x _m,n,k generated in each cell of the monitoring window 2 and equation (2) of FIG. 3B. The pressures F _1,1,k to F _m,n,k generated in each cell can be calculated. If the pressure generated in each cell can be calculated, it can be regarded as the same as if a microphone was installed in each cell and each microphone detected the sound pressure of F _{1, 1, k} to F _{m, n, k,} respectively. , the sound source estimation can be performed by applying the conventional sound source estimation method. The conversion function calculation unit 15 calculates the conversion function TF ⁻¹ for each target frequency and records it in the storage unit 16.

(2) Wind tunnel test Once the conversion function TF ⁻¹ can be calculated through a preliminary vibration characteristic acquisition test, a wind tunnel test is performed to estimate the sound source of the device 3 to be inspected. The equipment 3 to be inspected is placed in the test facility 1 and a wind tunnel test is performed. During this time, the monitoring window 2 is photographed by the polarizing camera 4. The image acquisition section 11 records the photographed image in the storage section 16. The displacement distribution calculation unit 12 calculates a time-series displacement distribution of the monitoring window 2 based on the time-series images taken by the polarizing camera 4. For example, the displacement distribution calculation unit 12 calculates momentary displacement for each frequency for each m×n cell illustrated in FIG. 3A (graph 30B1 in FIG. 2).

(3) Estimating the pressure distribution of the monitoring window Once the momentary displacement of each cell of the monitoring window 2 for each frequency can be calculated by the wind tunnel test, the pressure distribution calculation unit 13 calculates the time-series pressure distribution of the monitoring window 2. . At this time, it is assumed that the pressure applied to each cell is uniform. The pressure distribution calculation unit 13 extracts the time series displacement distribution for the target frequency, reads out the conversion function TF ⁻¹ stored in the storage unit 16, and calculates the time series applied to each cell using equation (2) of FIG. 3B. Calculate the pressure. The pressure distribution calculation unit 13 calculates a time-series pressure distribution (pressure of each cell) occurring in the monitoring window 2.

(4) Sound source estimation The sound source estimator 14 calculates the momentary pressure distribution occurring in the monitoring window 2, and estimates the sound source based on the time difference when the pressure propagates to each cell. For example, the time difference when sound arrives at each cell is calculated from the phase of the transfer function between each cell. The moment-to-moment changes in the pressure distribution calculated in (3) are considered to be changes in the pressure distribution caused by the phase delay in the arrival of the sound, and the time at which the sound arrives at each cell is estimated from the calculated transfer function. Note that the above-mentioned transfer function is calculated from the pressure waveform between each cell. Alternatively, when the pressure in a certain cell exceeds a threshold value, it may be assumed that the sound has reached that cell at that time. If the arrival time of sound to each cell can be estimated using these methods, the sound source estimation unit 14 can perform sound source estimation by using a conventional sound source estimation method. FIG. 4 shows an example of a sound source estimation method. FIG. 4 is a diagram of a part of the monitoring window 2 viewed from above. As described with reference to FIG. 3B, cells formed by dividing m×n are lined up. One cell is considered one microphone. The cells 201 to 204 receive the sound emitted by the device under test 3 and the wind from the wind tunnel test, and the pressure causes displacement. As shown in the figure, cells 202 and 203 receive the sound E emitted from the device 3 to be tested. At this time, the sound E enters the cells 202 and 203 at a predetermined arrival angle θ. Here, the arrival angle θ is the incident angle of the sound E with respect to the vertical direction of the monitoring window 2. The distance between the center of cell 202 and the center of cell 203 is d ₀ , the path difference between the sound E received by cell 202 and the sound E received by cell 203 is d _1, the speed of sound E is c, and the distance to cell 202 is The time difference between the time when the sound wave E arrived and the time when the sound wave E arrived at the cell 203 is assumed to be Δt. Then, the following equation (3) holds true.
Δt・c=d ₁ =d ₀・sin(θ)...(3)
By solving equation (3) for θ, the direction θ from the cell 203 of the monitoring window 2 to the sound source can be calculated. Once the direction θ can be calculated, the sound source distribution can be estimated using known techniques, as disclosed in Non-Patent Document 1 and the like. For example, the range surrounded by a straight line extending in the direction θ from the center of the cell 202, a straight line extending in the direction θ from the center of the cell 203, and the device 3 to be tested may be estimated as the sound source distribution S. Moreover, here, as an example of sound source estimation, a method of estimating the arrival direction θ of a sound wave based on the arrival time difference Δt of the sound wave has been described. However, the sound source estimation method is not limited to this, and other methods may be used.

(motion)
Next, the flow of the sound source estimation process will be explained with reference to FIG.
FIG. 5 is a flowchart illustrating an example of the sound source estimation process according to the embodiment.
In advance, a vibration characteristic acquisition test is performed, and the conversion function calculation unit 15 calculates the conversion function TF ^-1 (step S1). The conversion function calculation unit 15 learns the relationship between the position and magnitude of the load applied to the monitoring window 2 and the resulting displacement distribution of the entire monitoring window 2, and once the displacement distribution is known, if the displacement distribution occurs, , a conversion function TF ⁻¹ is calculated that can inversely estimate what size is added to which part of the monitoring window 2. The conversion function calculation unit 15 records the conversion function TF ⁻¹ in the storage unit 16.

Next, a wind tunnel test is performed and the monitoring window 2 is photographed using the polarizing camera 4 (step S2). Since it is necessary to detect temporal changes in the displacement distribution of the monitoring window 2, the polarization camera 4 continuously photographs the monitoring window 2. The image acquisition unit 11 records the image taken by the polarization camera 4 in the storage unit 16.

Next, the displacement distribution calculation unit 12 calculates the displacement distribution of the monitoring window 2 (step S3). The displacement distribution calculation unit 12 reads out the photographed image from the storage unit 16, analyzes the image, and focuses on the frequency component whose color changes periodically at the target frequency for each cell divided into m×n. Calculate the change over time in the amount of displacement of the frequency component for each cell. The displacement distribution calculation unit 12 calculates the displacements x _1,1,k to x _m,n,k in equation (2) from time to time, and records the values in the storage unit 16.

Next, the pressure distribution calculation unit 13 calculates the pressure distribution of the monitoring window (step S4). The pressure distribution calculation unit 13 reads out the momentary displacements x _1,1,k to x _m,n,k calculated by the displacement distribution calculation unit 12 from the storage unit 16, and converts them into the conversion function TF calculated in step S1. ⁻¹ to calculate the instantaneous pressures F _1,1,k to F _m,n,k for each cell, and record the values in the storage unit 16.

Next, the sound source estimation unit 14 performs sound source estimation (step S5). The sound source estimating unit 14 considers momentary pressure changes for each cell as changes in sound pressure, and applies a conventional sound source estimation method using a microphone to estimate the distribution of sound sources at the target frequency. The output unit 17 outputs the estimated sound source distribution to a display device or the like.

As explained above, according to the present embodiment, instead of installing multiple microphones to measure the sound pressure level, one polarizing camera 4 (or even multiple cameras) is used by utilizing the originally existing monitoring window 2. ), the sound source is estimated by measuring the distribution of the displacement of the transparent plate of the monitoring window 2 deformed by the sound pressure. Since the position, direction, distribution, etc. of the sound source can be estimated without using a microphone, the sound source can be estimated without being affected by the wind even during a wind tunnel test. Furthermore, there is no need to newly install a microphone, and the sound source can be estimated using the existing monitoring window 2 without any installation work or equipment modification.

Further, the test facility 1 is not limited to a wind tunnel test facility. When the device 3 to be inspected is offered to the market as a product, various tests such as a durability test and a performance test are conducted before that. In that case, place the equipment under test 3 in a laboratory or test facility with windows, operate the equipment 3 under test, and check whether the operating sound is coming from the designed position or not. You may want to check to see if something like this occurs. These laboratories and test facilities are often equipped with windows so that the inside can be observed. In such a case, the laboratory or test equipment can be used as the test equipment 1 in Figure 1, and the window can be used as the monitoring window 2, and the window can be photographed using the polarizing camera 4 to estimate the sound source and locate the designed position of the sound. You can check to see if it is coming from. Further, when an abnormal noise or the like is measured, it is possible to estimate from which part of the device 3 to be inspected the abnormal noise or the like is emitted.

Furthermore, by applying the sound source estimation described above, it is possible to perform sound source estimation using a plurality of monitoring windows. FIG. 6 shows an example of a structure provided with a plurality of monitoring windows. Containers that store substances with high specific gravity, such as water, may not be able to have large windows from the viewpoint of durability. Such containers may be provided with multiple small windows. In such a case, each window can be regarded as one cell in FIG. 3B, the displacement distribution can be measured, and the sound source can be estimated. In the example of FIG. 6, monitoring windows 2a to 2t are provided. The monitoring windows 2a to 2t are photographed with the polarizing camera 4, and each window is regarded as one cell, and the time-series displacement and pressure are calculated for each window using the method described using FIGS. 1 to 5. . Then, each window is regarded as one microphone to perform sound source estimation. Thereby, it is possible to perform sound source estimation even for a structure provided with a small window that is difficult to divide into m×n regions. Note that if each window is sufficiently large, each window may be divided into a plurality of cells and the sound pressure may be calculated for each cell. Thereby, sound source estimation can be performed in the same manner as when sound source estimation is performed using microphones for the number of cells in one window multiplied by the total number of windows.

Further, in the above description, the source of sound generated inside a structure such as a wind tunnel test facility, a laboratory, or a test facility is estimated, but the sound source estimation method of the present embodiment is not limited thereto. For example, the window of the passenger seat of an airplane in flight is treated like a plurality of windows illustrated in FIG. The sound source estimation method of this embodiment can also be applied to situations where the sound source of a sound emitted from a computer (.) is estimated. The same applies to trains and vehicles. For example, the source of the sound emitted from outside the moving object may be estimated by photographing windows provided in these moving objects with the polarizing camera 4 while the train or vehicle is running or stopped. In addition, by photographing the windows of a building such as an office with the polarizing camera 4 and applying the sound source estimation method of this embodiment, it is possible to estimate the noise source when there is a noise coming from outside, for example. It can also be used. In addition, in the above embodiment, (1) the transfer function TF indicating the relationship between the displacement distribution and pressure distribution of the monitoring window 2 is calculated in the vibration characteristic acquisition test, and (2) the displacement of the monitoring window 2 is calculated in the wind tunnel test. The pressure distribution of the monitoring window 2 was determined using the inverse function TF ^-1 of the transfer function TF in (3) Estimation of the pressure distribution of the monitoring window, but it may be configured as follows. . That is, (1) in the vibration characteristic acquisition test, the conversion function calculation unit 15 calculates the distribution of color changes of the monitoring window 2 in the image taken by the polarization camera 4 (for example, the cell (1, 1) is red; (1, 2) calculates the transfer function TF' that indicates the relationship between the color of each cell (orange, etc.) and the pressure distribution, and (2) in the wind tunnel test, the displacement distribution calculation unit 12 calculates the In (3) pressure distribution estimation of the monitoring window, the pressure distribution calculation unit 13 calculates the distribution of color changes (color for each cell) of the image captured in (2), and calculates the inverse function TF' of the transfer function TF ^{' - 1} may be used to determine the pressure distribution of the monitoring window 2 from the distribution of color changes in images taken of the monitoring window 2. Even with this configuration, the sound source can be estimated by (4) sound source estimation.

FIG. 7 is a diagram illustrating an example of the hardware configuration of the sound source estimation device according to the embodiment. The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input/output interface 904, and a communication interface 905.
The above-described sound source estimation device 10 is implemented in a computer 900. Each of the above-mentioned functions is stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, expands it to the main storage device 902, and executes the above processing according to the program. Further, the CPU 901 reserves a storage area in the main storage device 902 according to the program. Further, the CPU 901 secures a storage area in the auxiliary storage device 903 to store the data being processed according to the program.

A program for realizing all or part of the functions of the sound source estimation device 10 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed, thereby achieving each function. Processing may also be performed by the department. The "computer system" here includes hardware such as an OS and peripheral devices. Furthermore, the term "computer system" includes the homepage providing environment (or display environment) if a WWW system is used. Furthermore, the term "computer-readable recording medium" refers to portable media such as CDs, DVDs, and USBs, and storage devices such as hard disks built into computer systems. Further, when this program is distributed to the computer 900 via a communication line, the computer 900 that received the distribution may develop the program in the main storage device 902 and execute the above processing. Further, the above program may be one for realizing a part of the above-mentioned functions, and further may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system. .

As described above, several embodiments according to the present disclosure have been described, but all these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention as well as within the scope of the invention described in the claims and its equivalents.

<Additional notes>
The sound pressure detection device, sound pressure detection system, sound pressure detection method, sound source estimation method, and program described in each embodiment can be understood, for example, as follows.

(1) The sound pressure detection device (sound source estimation device 10) according to the first aspect includes a polarizing camera that photographs a transparent plate-shaped member, and a polarizing camera that detects when sound reaches the plate-shaped member. a displacement distribution calculation unit that calculates a distribution of displacement caused in the plate-shaped member by the sound based on a captured image; a distribution of the displacement calculated by the displacement distribution calculation unit; and a distribution of the displacement caused in the plate-shaped member. and a pressure distribution calculation unit that calculates a distribution of sound pressure applied to the plate-shaped member based on a conversion function that estimates a distribution of pressure applied to the plate-shaped member from a distribution of displacement.
Thereby, the distribution of sound pressure can be detected without installing a microphone. Furthermore, by applying a sound source estimation method to the detected sound pressure distribution, the sound source can be estimated without installing a microphone.

(2) The sound pressure detection device (sound source estimation device 10) according to the second aspect is the sound pressure detection device of (1), in which the displacement distribution calculation unit is based on the images taken in time series. Then, the amount of displacement of the vibration component whose color changes with the frequency of the sound is calculated for each region created by dividing the plate-shaped member.
Thereby, the displacement distribution occurring in the monitoring window can be calculated based on the image taken by the polarizing camera.

(3) The sound pressure detection device (sound source estimation device 10) according to the third aspect is the sound pressure detection device of (1) to (2), in which the conversion function divides the plate-shaped member. This is a function derived based on the relationship between the record of the displacement amount for each area with respect to the impact measured when the impact is applied to each area (cell) formed by the area, and the impact load for each area.
Thereby, the displacement distribution of the monitoring window can be converted into a sound pressure distribution.

(4) The sound pressure detection device (sound source estimation device 10) according to the fourth aspect is the sound pressure detection device of (1) to (3), and is configured to detect the sound pressure distribution calculated by the pressure distribution calculation section. , further comprising a sound source estimating unit that performs sound source estimation based on sound pressure detected by a plurality of microphones installed within the range of the plate-shaped member.
Thereby, sound source estimation can be performed without using a microphone.

(5) The sound pressure detection device (sound source estimation device 10) according to the fifth aspect includes a polarized camera that photographs a transparent plate-shaped member, and a polarized camera that detects when sound reaches the plate-shaped member. a color distribution calculation unit (displacement distribution calculation unit 12) that calculates a distribution of color changes caused in the image by the sound based on a photographed image; and a distribution of the color changes calculated by the color distribution calculation unit. , a conversion function that estimates the distribution of sound pressure applied to the plate-shaped member from the distribution of color changes occurring in the image; and pressure distribution calculation that calculates the distribution of sound pressure applied to the plate-shaped member based on . It is equipped with a section and a section.
Thereby, the distribution of sound pressure can be detected without installing a microphone. Furthermore, by applying a sound source estimation method to the detected sound pressure distribution, the sound source can be estimated without installing a microphone.

(6) The sound pressure detection system (sound source estimation system 100) according to the sixth aspect includes a structure including one or more windows configured by the plate-like member, and (1) to (5). The sound pressure detection device according to any one of the above is provided.
Thereby, sound pressure can be detected without using a microphone.

(7) The sound pressure detection system (sound source estimation system 100) according to the seventh aspect is the sound pressure detection system of (6), in which the structure is a wind tunnel test facility, a laboratory, a building, or a moving object. That's it.
If the structure is equipped with a window, sound pressure can be detected using the sound pressure detection device described in any one of (1) to (5).

(8) The sound pressure detection method according to the eighth aspect includes the steps of: photographing a transparent plate-shaped member with a polarizing camera; from the step of calculating the distribution of displacement occurring in the plate-shaped member, the distribution of displacement calculated in the step of calculating the distribution of displacement, and the distribution of displacement occurring in the plate-shaped member. and a step of calculating a distribution of sound pressure applied to the plate-shaped member based on a conversion function for estimating a distribution of pressure applied to the member.
Thereby, the distribution of sound pressure can be detected without installing a microphone.

(9) The sound source estimation method according to the ninth aspect includes the steps of photographing a transparent plate-shaped member with a polarizing camera, and based on the image photographed by the polarizing camera when sound reaches the plate-shaped member. from the step of calculating the distribution of displacement caused in the plate-shaped member by the sound, the distribution of displacement calculated in the step of calculating the distribution of displacement, and the distribution of the displacement caused in the plate-shaped member. a conversion function for estimating a distribution of pressure applied to the plate-shaped member; and a step of calculating a distribution of sound pressure applied to the plate-shaped member. estimating a sound source by regarding the distribution of the sound pressure as the sound pressure detected by a plurality of microphones installed in a region where the plate-shaped member is present.
Thereby, the sound source can be estimated without installing a microphone.

(10) The program according to the tenth aspect includes the steps of: acquiring an image of a transparent plate-shaped member taken by a polarizing camera; a step of calculating a distribution of displacement caused in the plate-shaped member by the sound based on an image taken by the person; a step of calculating the distribution of the displacement calculated in the step of calculating the distribution of the displacement; a conversion function that estimates a distribution of pressure applied to the plate-shaped member from a distribution of displacement occurring in the plate-shaped member; and a step of calculating a distribution of sound pressure applied to the plate-shaped member based on the conversion function.

1...Test equipment 2...Monitoring window 3...Device to be inspected 4...Polarizing camera S...Sound source distribution 10...Sound source estimation device 11...Image acquisition unit 12...Displacement Distribution calculation unit 13...Pressure distribution calculation unit 14...Sound source estimation unit 15...Conversion function calculation unit 16...Storage unit 17...Output unit 900...Computer 901...CPU
902... Main storage device 903... Auxiliary storage device 904... Input/output interface 905... Communication interface

Claims (10)

A polarizing camera that photographs a transparent plate-like member,
a displacement distribution calculation unit that calculates a distribution of displacement caused in the plate-shaped member by the sound, based on an image taken by the polarizing camera when the sound reaches the plate-shaped member;
Based on the displacement distribution calculated by the displacement distribution calculation unit and a conversion function that estimates the distribution of sound pressure applied to the plate-shaped member from the distribution of displacement occurring in the plate-shaped member, the plate-shaped a pressure distribution calculation unit that calculates the distribution of sound pressure applied to the member;
A sound pressure detection device comprising: The displacement distribution calculation unit calculates, based on the images taken in time series, the amount of displacement of a vibration component whose color changes with the frequency of the sound for each region formed by dividing the plate-shaped member. ,
The sound pressure detection device according to claim 1, comprising: The conversion function is a relationship between a record of the displacement amount for each region in response to the impact measured when the plate-shaped member is divided and a impact is applied to each region, and the impact load for each region. derived based on,
The sound pressure detection device according to claim 1 or 2. a sound source estimating unit that performs sound source estimation by regarding the sound pressure distribution calculated by the pressure distribution calculating unit as the sound pressure detected by a plurality of microphones installed in a range of the plate-shaped member;
The sound pressure detection device according to claim 1 or 2, further comprising: A polarizing camera that photographs a transparent plate-like member,
a color distribution calculation unit that calculates a distribution of color changes caused in the image by the sound, based on an image taken by the polarizing camera when the sound reaches the plate-shaped member;
The color distribution calculation unit calculates the color change distribution, and a conversion function that estimates the distribution of sound pressure applied to the plate-like member from the color change distribution that occurs in the image. a pressure distribution calculation unit that calculates the distribution of sound pressure applied to the shaped member;
A sound pressure detection device comprising: a structure comprising one or more windows configured by the plate-like member;
The sound pressure detection device according to claim 1 or claim 2,
Sound pressure detection system. The structure is any one of a wind tunnel test facility, a laboratory, a building, or a moving object;
The sound pressure detection system according to claim 6. a step of photographing a transparent plate-like member with a polarized camera;
calculating a distribution of displacement caused in the plate-shaped member by the sound, based on an image taken by the polarizing camera when the sound reaches the plate-shaped member;
Based on the displacement distribution calculated in the step of calculating the displacement distribution and a conversion function that estimates the distribution of sound pressure applied to the plate-shaped member from the distribution of displacement occurring in the plate-shaped member. , calculating the distribution of sound pressure applied to the plate-shaped member;
A sound pressure detection method having. Calculating the distribution of sound pressure by the sound pressure detection method according to claim 8;
The sound pressure distribution calculated in the step of calculating the sound pressure distribution is regarded as the sound pressure detected by a plurality of microphones installed in the area where the plate-shaped member is present, and the sound source is estimated. step and
A sound source estimation method having to the computer,
acquiring an image of the transparent plate-like member taken with a polarizing camera;
calculating a distribution of displacement caused in the plate-shaped member by the sound, based on an image taken by the polarizing camera when the sound reaches the plate-shaped member;
Based on the displacement distribution calculated in the step of calculating the displacement distribution and a conversion function that estimates the distribution of sound pressure applied to the plate-shaped member from the distribution of displacement occurring in the plate-shaped member. , calculating the distribution of sound pressure applied to the plate-shaped member;
A program to run.

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