Ultrasonic measuring method, ultrasonic inspection method, and ultrasonic measuring apparatus

Abstract

To provide an ultrasonic measurement method, an ultrasonic inspection method, and an ultrasonic measurement device that achieve both measurement of a surface shape of an inspection object by a high-frequency ultrasonic signal and high S / N measurement of a bottom surface shape by high-sensitivity transmission / reception of a low-frequency ultrasonic signal.SOLUTION: At each of the scanning positions of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6, at least one of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 is rotated about a straight line passing through the center of the transmitting surface of the high-frequency transmitting sensor 5 or about a straight line passing through the center of the receiving surface of the high-frequency receiving sensor 6, and the first signal is recorded at a rotation angle at which the ultrasonic propagation path falls within the corresponding directivity angle range.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic measurement method, an ultrasonic inspection method, and an ultrasonic measurement device for an object to be inspected, and in particular to an ultrasonic measurement method, an ultrasonic inspection method, and an ultrasonic measurement device for measuring the surface shape and bottom shape of an object to be inspected that is immersed in a liquid such as water. [Background technology]

[0002] Patent Document 1 describes an ultrasonic flaw detection method and an ultrasonic flaw detection device that include the steps of controlling the transmission and reception of ultrasonic waves from low-frequency elements and high-frequency elements of an ultrasonic array probe, determining the boundary between the wedge and the object to be inspected based on the waveforms of ultrasonic waves received by the high-frequency elements with higher vibration frequencies among two or more types of low-frequency elements and high-frequency elements of the arranged ultrasonic array probe, and imaging the inside of the object to be inspected based on the waveforms of ultrasonic waves received by the low-frequency elements with lower vibration frequencies among the arranged ultrasonic array probe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-3020 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, aperture synthesis techniques such as Full Matrix Capture (hereinafter referred to as FMC) processing have been attracting attention. This technique calculates the ultrasonic path inside an object from the positional information of the transmitting and receiving ultrasonic sensors, the ultrasonic sound speed inside the object, and information on the ultrasonic waveform, and visualizes the inside of the object.

[0005] However, if the surface shape of the object to be inspected is not flat and the ultrasonic sensor cannot be placed in close contact, the space between the ultrasonic sensor and the object to be inspected is filled with an intermediate catalytic medium to allow the ultrasonic waves to propagate.

[0006] When the ultrasonic sound velocity inside the object being inspected differs from that of the intermediate catalytic medium, the ultrasonic waves are refracted at the interface between the object being inspected and the intermediate catalytic medium. Therefore, imaging methods that do not take into account the refraction of ultrasonic waves will generate large errors, and measures must be taken to address this.

[0007] Therefore, a method has been proposed in which information on the surface shape of the object being inspected is extracted from information on the ultrasonic waveform that propagates through an intermediate catalytic medium and is reflected on the surface of the object being inspected, and the position at which the ultrasonic wave is refracted is identified to calculate the ultrasonic propagation path inside the object being inspected.

[0008] In addition, a method has been proposed that uses an array sensor in which high-frequency elements and low-frequency elements with different frequencies are arranged alternately, determining the surface shape of the object to be inspected with the high-frequency array and imaging the inside of the object with the low-frequency array, thereby achieving both highly accurate extraction of the surface shape and highly sensitive measurement of the deep part of the object to be inspected. For example, a technology described in Patent Document 1 is an example of shape measurement using multi-frequency ultrasound.

[0009] In ultrasonic measurements of an object immersed in a liquid such as water, the liquid is considered to be an intermediate catalytic medium, and the surface shape of the object is measured with a high-frequency ultrasonic sensor, while the bottom shape is measured with a low-frequency ultrasonic sensor. However, it has become clear that there is room for improvement as follows.

[0010] If there is a large amount of scattering or attenuation of ultrasonic waves inside the object under inspection, the sensitivity of the low-frequency ultrasonic signal will decrease. However, if the ultrasonic sensor is brought closer to the surface of the object under inspection, the sensitivity of the low-frequency signal will increase, allowing the shape of the bottom surface to be imaged with a high S / N ratio.

[0011] However, as a result of intensive research by the present inventors, it was found that with the configuration of Patent Document 1, there are cases where the path of the high-frequency ultrasonic waves deviates from the directivity angle of the high-frequency ultrasonic sensor, and that there is room for further improvement in the transmission and reception of high-frequency ultrasonic waves reflected on the surface of the object to be inspected.

[0012] An object of the present invention is to provide an ultrasonic measurement method, an ultrasonic inspection method, and an ultrasonic measurement device that can measure the surface shape of an object to be inspected using high-frequency ultrasonic signals and measure the bottom surface shape with a high S / N ratio using highly sensitive transmission and reception of low-frequency ultrasonic signals. [Means for solving the problem]

[0013] The present invention includes a plurality of means for solving the above-mentioned problems, and examples thereof include a first recording step in which ultrasonic waves of a first frequency are transmitted from a first transmitting sensor to an object under test in a liquid, and a first signal is received by a first receiving sensor, and a transmission and reception process is performed while changing the positions of the first transmitting sensor and the first receiving sensor, thereby recording a plurality of the first signals; a second recording step in which ultrasonic waves of a second frequency lower than the first frequency are transmitted from a second transmitting sensor to the object under test, and a transmission and reception process in which second signals are received by a second receiving sensor, while changing the positions of the second transmitting sensor and the second receiving sensor, thereby recording a plurality of the second signals; and an F recording step in which the plurality of first signals obtained in the first recording step are added with a time difference based on a difference in the propagation path of the ultrasonic waves of the first frequency. The method includes a surface shape calculation step of calculating the surface shape of the object under test by MC processing, and a bottom shape calculation step of calculating the bottom shape of the object under test by FMC processing of adding the second signals recorded in the second recording step with a time difference based on a propagation path assumed to be taken by ultrasonic waves of the second frequency that have traveled straight through the liquid and are refracted at the surface of the object under test, and in the first recording step, at the scanning positions of the first transmitting sensor and the first receiving sensor, at least one of the first transmitting sensor and the first receiving sensor is rotated around a rotation axis that is a straight line passing through the center of its transmitting surface in the first transmitting sensor, and around a rotation axis that is a straight line passing through the center of its receiving surface in the first receiving sensor, to record the first signal at a rotation angle where the ultrasonic propagation path is within the respective directivity angle ranges. [Effects of the Invention]

[0014] According to the present invention, it is possible to measure the surface shape of an object to be inspected using high-frequency ultrasonic signals and to measure the bottom shape with a high S / N ratio using high-sensitivity transmission and reception of low-frequency ultrasonic signals. Objects, configurations, and effects other than those described above will become clear from the following description of the embodiments. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is an explanatory diagram showing the overall configuration including an ultrasonic measuring device according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing the configuration of a scanning device in the ultrasonic measurement device according to the first embodiment. [Figure 3] FIG. 2 is a diagram illustrating the configuration of a scanning device in the ultrasonic measurement device according to the first embodiment. [Figure 4] 10 is an explanatory diagram illustrating how the ultrasonic path is placed within the directivity angle range of the sensor by rotating the ultrasonic sensor in the present invention. FIG. [Figure 5] 10 is an explanatory diagram illustrating how the ultrasonic path is placed within the directivity angle range of the sensor by rotating the ultrasonic sensor in the present invention. FIG. [Figure 6] 10 is an explanatory diagram illustrating how the ultrasonic path is placed within the directivity angle range of the sensor by rotating the ultrasonic sensor in the present invention. FIG. [Figure 7] 1 is an explanatory diagram showing the correspondence between the ultrasonic propagation path and the directivity angle of the sensor when the high-frequency ultrasonic sensor and the object to be inspected are separated from each other in the present invention. FIG. [Figure 8] 1 is an explanatory diagram showing the correspondence between the ultrasonic propagation path and the directivity angle of the sensor when the high-frequency ultrasonic sensor and the object to be inspected are close to each other in the present invention. FIG. [Figure 9] 10 is an explanatory diagram showing a method of rotating the ultrasonic sensor to fit within the ultrasonic propagation path and the directivity angle range of the sensor when the high-frequency ultrasonic sensor and the object to be inspected are approaching each other in the present invention. FIG. [Figure 10] 1 is an explanatory diagram showing the correspondence between the ultrasonic propagation path and the directivity angle of the sensor when the low-frequency ultrasonic sensor and the object to be inspected are close to each other in the present invention. FIG. [Figure 11] FIG. 10 is an explanatory diagram for explaining FMC processing. [Figure 12]1 is a flowchart showing the procedure of the ultrasonic measurement method of the first embodiment. [Figure 13] 10 is an explanatory diagram illustrating a method for appropriately manipulating the rotation angle of the sensor when the transmitting sensor and the receiving sensor scan from the same scanning position to different scanning positions. FIG. [Figure 14] 10 is an explanatory diagram illustrating a method for appropriately manipulating the rotation angle of the sensor when the transmitting sensor and the receiving sensor scan from different scan positions to further different scan positions. FIG. [Figure 15] FIG. 10 is an explanatory diagram showing the configuration of an ultrasonic measurement device in a second embodiment. [Figure 16] FIG. 10 is an explanatory diagram showing the configuration of an ultrasonic measurement device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the ultrasonic measurement method, ultrasonic inspection method, and ultrasonic measurement device of the present invention will be described with reference to the drawings. In the drawings used in this specification, identical or similar reference numerals are used to designate identical or corresponding components, and repeated explanations of these components may be omitted.

[0017] Example 1 A first embodiment of an ultrasonic measurement method, an ultrasonic inspection method, and an ultrasonic measurement device according to the present invention will be described with reference to FIGS. 1 to 14. FIG.

[0018] In Example 1, the liquid is water, and a scanning device that scans with an ultrasonic sensor is placed above an object to be inspected that is at the bottom of the water, to measure the surface shape and bottom shape of the object to be inspected. Although this example illustrates a case where the liquid is water, the liquid is not limited to water.

[0019] First, the overall configuration of the measurement system including the ultrasonic measuring device and the object to be inspected and the details of each part will be described with reference to Fig. 1 to Fig. 11. Fig. 1 is an explanatory diagram showing the overall configuration including the ultrasonic measuring device in Example 1. Fig. 2 is an explanatory diagram showing the configuration of the scanning device in the ultrasonic measuring device in Example 1, and Fig. 3 is a diagram showing the configuration of the scanning device in the ultrasonic measuring device in Example 1.

[0020] The ultrasonic measuring device shown in Figure 1 is a device for measuring the surface shape and bottom shape of an object to be inspected 1 located on the bottom 2 of water 3, and is composed of a scanning device 10, a scanning device control unit 30, a switch 24, an ultrasonic flaw detector 20, and a signal processing unit 40, etc.

[0021] The scanning device 10 is equipped with a high-frequency transmitting sensor 5 that transmits ultrasonic waves of a first frequency to the object under test 1 in the water, a high-frequency receiving sensor 6 that receives a first signal derived from the ultrasonic waves of the first frequency, a low-frequency transmitting sensor 7 that transmits ultrasonic waves of a second frequency lower than the first frequency to the object under test 1, and a low-frequency receiving sensor 8 that receives a second signal derived from the ultrasonic waves of the second frequency, and is structured to be placed above the object under test 1 and stopped by an anchor 9.

[0022] In the present invention, the preferred frequency range of the first frequency transmitted from the high-frequency transmitting sensor 5 is 500 [kHz]-5 [MHz], and the preferred frequency range of the second frequency, which is lower than the first frequency transmitted from the low-frequency transmitting sensor 7, is 50 [kHz]-500 [kHz], but is not necessarily limited to these ranges.

[0023] This scanning device 10 has a structure as shown in Figure 3 in order to scan the high-frequency transmitting sensor 5, high-frequency receiving sensor 6, low-frequency transmitting sensor 7, and low-frequency receiving sensor 8 at the scanning positions shown in Figure 2 on the object under test 1.

[0024] The high-frequency transmitting sensor 5 is scanned in one axial direction along a beam 11 attached to the frame 17 of the scanning device 10, and the rotation angle can be changed at each scanning position by a rotation mechanism 13 that rotates the high-frequency transmitting sensor 5 around a straight line passing through the center of the ultrasonic wave transmission surface as the rotation axis.

[0025] The high-frequency receiving sensor 6 is scanned in one axial direction along a beam 12 attached to the frame 17 of the scanning device 10, and the rotation angle can be changed at each scanning position by a rotation mechanism 14 that rotates the high-frequency receiving sensor 6 around a straight line passing through the center of the ultrasonic wave receiving surface as the rotation axis.

[0026] The rotation mechanisms 13 and 14 are capable of rotating the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 in opposite directions. Although this embodiment shows a configuration in which both the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 are rotatable, it is also possible to rotate only one of them.

[0027] The low-frequency transmitting sensor 7 is scanned in one axis direction along the beam 16 , and the low-frequency receiving sensor 8 is scanned in one axis direction along the beam 15 .

[0028] The operation of a configuration for achieving both measurement of the surface shape of an object under test 1 and high S / N measurement of the bottom shape will be described with reference to Figures 4 to 11. Figures 4 to 6 are explanatory diagrams illustrating the rotation of an ultrasonic sensor to fit the ultrasonic path within the sensor's beam angle range in the present invention, Figure 7 is an explanatory diagram showing the correspondence between the ultrasonic propagation path and the beam angle of the sensor when the high-frequency ultrasonic sensor and the object under test are separated in the present invention, Figure 8 is an explanatory diagram showing the correspondence between the ultrasonic propagation path and the beam angle of the sensor when the high-frequency ultrasonic sensor and the object under test are approaching in the present invention, Figure 9 is an explanatory diagram showing a method for rotating the ultrasonic sensor to fit the ultrasonic propagation path within the beam angle range of the sensor when the high-frequency ultrasonic sensor and the object under test are approaching in the present invention, Figure 10 is an explanatory diagram showing the correspondence between the ultrasonic propagation path and the beam angle of the sensor when the low-frequency ultrasonic sensor and the object under test are approaching in the present invention, and Figure 11 is an explanatory diagram for explaining FMC processing.

[0029] As shown in Figure 4, a high-frequency ultrasonic wave is transmitted by a high-frequency transmitting ultrasonic sensor (high-frequency transmitting sensor 5), and the ultrasonic waves reflected by the surface of the object under test 1 are received by a high-frequency ultrasonic receiving sensor (high-frequency receiving sensor 6). When the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 are positioned close to each other, the ultrasonic path falls within the range of the beam angle θ, so that ultrasonic waves can be transmitted and received, and the ultrasonic signal can be recorded.

[0030] As shown in FIG. 5, when the high frequency receiving sensor 6 is positioned farther away from the high frequency transmitting sensor 5, the ultrasonic path deviates from the beam angle θ, and the ultrasonic signal cannot be recorded.

[0031] As shown in Figure 6, if the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 are rotated in opposite directions so that the ultrasonic propagation path is within the range of the beam angle θ, ultrasonic waves can be transmitted and received even if the distance remains long, and ultrasonic signals can be recorded. In this case, if the ultrasonic sensor is rotated around the transmitting and receiving surface as the axis of rotation, changes in propagation time due to rotation can be suppressed, preventing a decrease in S / N when adding signals in FMC processing.

[0032] As shown in Figure 7, when the object under test 1 is located on the bottom 2 of the water 3, the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 receive the reflected waves from the surface of the object under test 1. The high-frequency transmitting sensor 5 is set to sensor scanning position "1", and the high-frequency receiving sensor 6 scans sensor scanning positions "1", "2", "3", "4", and "5" in order.

[0033] When the scanning surfaces of the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 are separated from the object under test 1, the ultrasonic path falls within the beam angle range at all scanning positions, and ultrasonic signals can be recorded.

[0034] As shown in Figure 8, when the scanning surfaces of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 approach the object under test 1, ultrasonic signals can be recorded if the high-frequency receiving sensor 6 is at sensor scanning positions "1" and "2", but if the sensor scanning positions are "3", "4", and "5", the ultrasonic propagation path deviates from the directivity angle and ultrasonic signals cannot be recorded.

[0035] However, as shown in Figure 9, if the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 are rotated so that the propagation path of the ultrasonic waves is within the range of the directivity angle θ when the high-frequency receiving sensor 6 scans at each scanning position, it becomes possible to transmit and receive ultrasonic waves at all scanning positions and record ultrasonic signals.

[0036] As shown in Figure 10, using a low-frequency transmitting ultrasonic sensor (low-frequency transmitting sensor 7) and a low-frequency receiving ultrasonic sensor (low-frequency receiving sensor 8), ultrasonic waves are transmitted from the low-frequency transmitting sensor 7, propagate through the water, refract at the surface of the object under test 1, propagate inside the object under test 1, reflect at the bottom, propagate inside the object under test 1, refract at the surface, propagate through the water, and propagate along the path to the low-frequency receiving sensor 8.Even if the distance between the low-frequency transmitting sensor 7 and the low-frequency receiving sensor 8 is large, the propagation path of the ultrasonic waves is within the range of the directivity angle of the ultrasonic sensor, so ultrasonic signals can be recorded without rotating the low-frequency ultrasonic sensor.

[0037] Therefore, the high-frequency transmitting sensor 5 and high-frequency receiving sensor 6 for measuring the surface shape of the object 1 to be inspected are rotated so that the ultrasonic path falls within the beam angle range according to the scanning position, but the low-frequency transmitting sensor 7 and low-frequency receiving sensor 8 for measuring the bottom shape of the object 1 to be inspected do not need to be rotated.

[0038] Returning to FIG. 1, the scanning device control unit 30 is made up of a sensor scanning instruction unit 31, a sensor position calculation unit 32, and a sensor rotation instruction unit 33.

[0039] The sensor scan instruction unit 31 outputs scan command signals for the high-frequency transmitting sensor 5, high-frequency receiving sensor 6, low-frequency transmitting sensor 7, and low-frequency receiving sensor 8. The sensor position calculation unit 32 measures the positions of the high-frequency transmitting sensor 5, high-frequency receiving sensor 6, low-frequency transmitting sensor 7, and low-frequency receiving sensor 8 after scanning. The sensor rotation instruction unit 33 changes the rotation angles of the high-frequency transmitting sensor 5 and high-frequency receiving sensor 6 and measures the rotation angles.

[0040] Although an example is given in which the sensor position calculation unit 32 measures the positions of the high-frequency transmitting sensor 5, high-frequency receiving sensor 6, low-frequency transmitting sensor 7, and low-frequency receiving sensor 8 after scanning, instead of or in addition to measuring the scanning positions of these sensors, a configuration in which the positions of the high-frequency transmitting sensor 5, high-frequency receiving sensor 6, low-frequency transmitting sensor 7, and low-frequency receiving sensor 8 after scanning can be obtained from the scanning position instruction signal from the sensor scanning instruction unit 31.

[0041] The switch 24 connects either the signal lines of the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 or the signal lines of the low frequency transmitting sensor 7 and the low frequency receiving sensor 8 to the ultrasonic flaw detector 20 .

[0042] The ultrasonic flaw detector 20 is composed of an oscillator 21, a receiver 22, and a waveform display unit 23.

[0043] The oscillator 21 applies a voltage signal to the high-frequency transmitting sensor 5 or the low-frequency transmitting sensor 7 to transmit ultrasonic waves. The receiver 22 amplifies the ultrasonic signal received by the high-frequency receiving sensor 6 or the low-frequency receiving sensor 8. The waveform display unit 23 displays the ultrasonic signal being transmitted and the ultrasonic signal waveform (first signal) being received.

[0044] The signal processing unit 40 is made up of a sensor position / ultrasonic signal recording unit 41, an FMC calculation unit 42, an FMC result storage unit 43, and a display unit 44.

[0045] The sensor position / ultrasonic signal recording unit 41 stores the sensor position information calculated by the sensor position calculation unit 32 and the ultrasonic signal received by the receiving unit 22 .

[0046] The FMC calculation unit 42 is a part that performs FMC processing on the first signal to calculate the surface shape of the object under test 1, and calculates the bottom shape of the object under test 1 from the second signal and the surface shape, and executes signal processing.

[0047] Specifically, the FMC calculation unit 42 performs the following FMC calculation on the data recorded in the sensor position / ultrasonic signal recording unit 41. Consider the sensor position in Figure 11, where transmission is performed at the mth measurement point and reception is performed at the nth measurement point.

[0048] Ultrasonic signal W mn (τ) at time τ pmn The reflection source of the echo that appears in the figure is located at any position that satisfies the following equation (1):

[0049]

number

[0050] Here, c in equation (1) is the speed of sound, r pm , r pn are the distances from elements m and n to the ultrasonic reflection source p, respectively, and are given by the following equation (2) for the reflection source coordinates p(r,θ) expressed in polar coordinates.

[0051]

number

[0052] Here, x in equation (2) m ,x n are the coordinates of the centers of the ultrasonic sensors m and n, respectively.

[0053] The same can be said for the waveforms obtained with other combinations of transmitting and receiving points, so by adding all the waveforms together, the signal value Sp(r,θ) at the ultrasonic reflection source p(r,θ) is given by the following equation (3), where k is the measurement point.

[0054]

number

[0055] The signal value Sp(r, θ) is calculated for all pixels in the ultrasound measurement range to be imaged, and the image can be created by displaying the brightness according to the signal value strength.

[0056] The FMC result storage unit 43 stores the signals imaged by the FMC calculation unit 42. The display unit 44 displays the signal processing results such as the signals imaged by the FMC calculation unit 42.

[0057] Next, the flow of the ultrasonic measurement method and ultrasonic inspection method of this embodiment, which is preferably executed by the above-mentioned ultrasonic measurement device, will be described with reference to Figures 12 to 14. First, the overall flow will be described with reference to Figure 12. Figure 12 is a diagram showing an example of the procedure of the measurement work.

[0058] 12, F1 to F10 are steps for measuring the surface shape of the test object 1 using a high-frequency sensor, and F11 to F19 are steps for measuring the bottom shape of the test object 1 using a low-frequency sensor. Of F11 to F19, F11 to F17 do not need to be performed after all of the steps F1 to F10 have been completed, and they may be performed in parallel.

[0059] Since the sound velocity of the ultrasonic waves is required in the FMC calculation, first, as shown in FIG. 12, the sound velocity of the water 3 is measured, or the temperature of the water 3 is measured and the sound velocity is calculated (F1).

[0060] Next, the number N of scanning positions for the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 is determined, and the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 are placed in their initial positions (F2). For example, in FIG. 2, scanning position "0" and scanning position "1" for the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 are the same position, and the initial position of the high frequency transmitting sensor 5 is set as scanning position "i"=0, and the initial position of the high frequency receiving sensor 6 is set as scanning position "j"=0.

[0061] Next, the scanning position of the high frequency transmitting sensor 5 is advanced to the next position, and the scanning position of the high frequency receiving sensor 6 is advanced to the next position (F3, F4).

[0062] Thereafter, the rotation angles of the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 are adjusted (F5), and the high frequency ultrasonic signal is recorded (F6).

[0063] Here, a method for adjusting the rotation angle of the high frequency signal at F5 will be described.

[0064] FIG. 13 illustrates a case where the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 are both at the sensor scanning position "1" and then the high frequency receiving sensor 6 is scanned to the sensor scanning position "2."

[0065] When the two sensors are at the same scanning position, there is no need to set a rotation angle, so point both sensors downward (0°) and check that the ultrasonic signal is being received on the waveform display unit 23 in Figure 1.

[0066] Next, the high frequency receiving sensor 6 is scanned to scanning position "2", and then the rotation angle of the high frequency transmitting sensor 5 is adjusted while watching the waveform display unit 23, and the difference Δφ1 in the rotation angle at which the amplitude of the ultrasonic signal is maximized is determined.

[0067] Therefore, when the high-frequency transmitting sensor 5 is at scanning position "1" and the high-frequency receiving sensor 6 is at scanning position "2", the rotation angle φ(1,2) of the high-frequency transmitting sensor 5 is 1 / 2×Δφ1, and the rotation angle Ψ(1,2) of the high-frequency receiving sensor 6 is adjusted to be 1 / 2×Δφ1, and the ultrasonic signal is recorded.

[0068] FIG. 14 is a diagram illustrating a case where the high frequency transmitting sensor 5 is at scanning position "1" and the high frequency receiving sensor 6 is at scanning position "i", and then the high frequency receiving sensor 6 is scanned to scanning position "i+1".

[0069] In this case, first, it is confirmed that the ultrasonic signal is received on the waveform display unit 23 when the rotation angle of the high-frequency transmitting sensor 5 is φ(1,i) and the rotation angle of the high-frequency receiving sensor 6 is Ψ(1,i).

[0070] Then, the high-frequency receiving sensor 6 is scanned to scanning position "i+1", and the rotation angle of the high-frequency transmitting sensor 5 is adjusted while watching the waveform display unit 23 to determine the difference Δφ(i+1) in the rotation angle at which the amplitude of the ultrasonic signal is maximized.

[0071] Therefore, when the high-frequency transmitting sensor 5 is at scanning position "1" and the high-frequency receiving sensor 6 is at scanning position "i+1", the rotation angle φ(1,i+1) of the high-frequency transmitting sensor 5 is adjusted to be φ(i)+1 / 2×Δφ(i+1), and the rotation angle Ψ(1,i+1) of the high-frequency receiving sensor 6 is adjusted to be Ψ(1,i)+1 / 2×Δφ(i+1), and ultrasonic signals are recorded.

[0072] That is, the high-frequency transmitting sensor 5 is rotated toward the high-frequency receiving sensor 6 by an angle 1 / 2×Δφ(i+1), which is half the difference in rotation angle Δφ(i+1), and the high-frequency receiving sensor 6 is rotated toward the high-frequency transmitting sensor 5 by an angle 1 / 2×Δφ(i+1), which is half the difference in rotation angle Δφ(i+1).

[0073] In this way, in the first recording step, at the scanning positions of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6, at least one of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 is rotated, preferably in opposite directions, with the high-frequency transmitting sensor 5 using a straight line passing through the center of its transmitting surface as the rotation axis, and the high-frequency receiving sensor 6 using a straight line passing through the center of its receiving surface as the rotation axis, to record the first signal at a rotation angle that brings the ultrasonic propagation path within each of the directivity angle ranges.

[0074] Therefore, in F5 of the first recording step, when the rotation angle of the high-frequency transmitting sensor 5 is φT, the rotation angle of the high-frequency receiving sensor 6 is φR, and the first signal can be transmitted and received, and at least one of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 is scanned to change the distance between them, the high-frequency transmitting sensor 5 is rotated to determine the rotation angle change amount Δφ at which the amplitude of the first signal is maximized, and the first signal can be recorded by scanning so that the rotation angle of the high-frequency transmitting sensor 5 is φT+1 / 2×Δφ and the rotation angle of the high-frequency receiving sensor 6 is φR-1 / 2×Δφ.

[0075] Although an example has been given in which the rotation angle change amount Δφ is obtained by rotating the high-frequency transmitting sensor 5, it is sufficient that the final rotation angle of the high-frequency transmitting sensor 5 is φT+1 / 2×Δφ and the rotation angle of the high-frequency receiving sensor 6 is φR-1 / 2×Δφ, and the rotation angle change amount Δφ may be obtained by rotating only the high-frequency receiving sensor 6, or by rotating both the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6.

[0076] In the above-mentioned steps F3 to F8, the two high-frequency transmitting sensors 5 and the high-frequency receiving sensor 6 are scanned from the sensor scanning position "1" to N (F7, F8), and the rotation angle is manipulated before recording the high-frequency ultrasonic signal. 2 The sensor position information and ultrasonic signals are recorded. 2 As long as a set of ultrasonic signals can be recorded, the order in which the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 are scanned can be different from that shown in FIG.

[0077] These processes F2 to F8 correspond to the first recording step in which ultrasonic waves of a first frequency are transmitted from the high-frequency transmitting sensor 5 to the test object 1 in the water, and the high-frequency receiving sensor 6 receives the first signal, and this transmission and reception process is performed while changing the positions of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6, thereby recording multiple first signals.

[0078] The data acquired in steps F2 to F8 is subjected to FMC processing (F9), and the surface shape of the object 1 to be inspected is calculated (F10).

[0079] These steps F9 and F10 correspond to a surface shape calculation step in which the surface shape of the object to be inspected 1 is calculated by FMC processing, which adds together multiple first signals obtained by the first recording step with a time difference based on the difference in the propagation path of ultrasonic waves of the first frequency.

[0080] Since low-frequency ultrasound propagates through the water 3 and the inside of the test object 1, the speed of sound in water is measured at F1. Therefore, in parallel with, before, or after the above F1 to F10, a portion of the test object 1 is sampled and the speed of sound within the test object 1 is measured (F11).

[0081] Next, the number M of scanning positions for the low-frequency transmitting sensor 7 and the low-frequency receiving sensor 8 is determined, and the low-frequency transmitting sensor 7 and the low-frequency receiving sensor 8 are placed at their initial positions (F12). For example, in FIG. 2, scanning position "0" and scanning position "1" for the low-frequency transmitting sensor 7 and the low-frequency receiving sensor 8 are the same position, and the initial position of the low-frequency transmitting sensor 7 is set as scanning position "k" = 0, and the initial position of the low-frequency receiving sensor 8 is set as scanning position "l" = 0.

[0082] Next, the scanning position of the low-frequency transmitting sensor 7 is advanced to the next position, and the scanning position of the low-frequency receiving sensor 8 is advanced to the next position (F13, F14).

[0083] After that, the low frequency ultrasonic signal is recorded (F15).

[0084] By scanning the two low-frequency transmitting sensors 7 and the low-frequency receiving sensor 8 from the sensor scanning position "1" to M (F16, F17) in the procedure of F13 to F15 described above, the low-frequency ultrasonic signals are recorded. 2 The pair of sensor position information and ultrasonic signals are recorded.

[0085] In addition, M 2 As long as a set of ultrasonic signals can be recorded, the order in which the low-frequency transmitting sensor 7 and the low-frequency receiving sensor 8 are scanned can be different from that shown in FIG.

[0086] These processes F12 to F17 correspond to a second recording step in which ultrasonic waves of a second frequency lower than the first frequency are transmitted from the low-frequency transmitting sensor 7 to the test object 1, and a transmission / reception process in which the low-frequency receiving sensor 8 receives the second signal is performed while changing the positions of the low-frequency transmitting sensor 7 and the low-frequency receiving sensor 8, thereby recording multiple second signals.

[0087] Using the data acquired in F12 to F17 and the surface shape data of the object to be inspected 1 obtained in F10 above, FMC processing is performed (F18) assuming that the ultrasonic waves are refracted at the surface of the object to be inspected 1, and the bottom shape of the object to be inspected 1 is calculated (F19).

[0088] These steps F18 and F19 correspond to the bottom shape calculation step in which the bottom shape of the test object 1 is calculated by FMC processing, which adds the second signal recorded in the second recording step with a time difference based on the propagation path assumed to be taken when the second frequency ultrasound that has traveled straight through the water is refracted at the surface of the test object 1.

[0089] Using the above-mentioned device and following the above-mentioned procedure, it is possible to measure the surface and bottom shapes of one cross section below the sensor scanning line of the test object 1. Therefore, by measuring the surface and bottom shapes of multiple cross sections while changing the sensor scanning line and interpolating the surface and bottom shape data, it is possible to calculate the surface and bottom shapes of the entire test object 1. Therefore, the volume of the test object 1 can be found by taking the difference between the surface and bottom shapes of the entire test object 1. In addition, the weight of the test object 1 can be found by measuring the specific gravity of a portion of the test object 1 sampled at F11 in Figure 12.

[0090] Next, the effects of this embodiment will be described.

[0091] The ultrasonic measurement method of the first embodiment of the present invention described above includes a first recording step in which ultrasonic waves of a first frequency are transmitted from the high-frequency transmitting sensor 5 to the object underwater 1 under test, and a transmission / reception process of receiving a first signal by the high-frequency receiving sensor 6 is performed while changing the positions of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6, thereby recording a plurality of first signals; a second recording step in which ultrasonic waves of a second frequency lower than the first frequency are transmitted from the low-frequency transmitting sensor 7 to the object under test 1, and a transmission / reception process of receiving a second signal by the low-frequency receiving sensor 8 is performed while changing the positions of the low-frequency transmitting sensor 7 and the low-frequency receiving sensor 8, thereby recording a plurality of second signals; and an FMC (Frequency Measurement) step in which the plurality of first signals obtained in the first recording step are added with a time difference based on the difference in the propagation path of the ultrasonic waves of the first frequency. and a bottom shape calculation step of calculating the bottom shape of the object to be inspected 1 by FMC processing, which adds up the second signals recorded in the second recording step with a time difference based on the propagation path assumed to be taken by ultrasonic waves of a second frequency that have traveled straight through water and are refracted at the surface of the object to be inspected 1. In the first recording step, at each scanning position of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6, at least one of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 is rotated around a straight line passing through the center of its transmitting surface as the rotation axis for the high-frequency transmitting sensor 5, and around a straight line passing through the center of its receiving surface as the rotation axis for the high-frequency receiving sensor 6, and the first signal is recorded at a rotation angle at which the ultrasonic propagation path is within the respective directivity angle ranges.

[0092] The ultrasonic measuring device of this embodiment also includes a high-frequency transmitting sensor 5 that transmits ultrasonic waves of a first frequency to the object under test 1 in water, a high-frequency receiving sensor 6 that receives a first signal derived from the ultrasonic waves of the first frequency, a low-frequency transmitting sensor 7 that transmits ultrasonic waves of a second frequency that is lower than the first frequency to the object under test 1, a low-frequency receiving sensor 8 that receives a second signal derived from the ultrasonic waves of the second frequency, a scanning device 10 that scans the high-frequency transmitting sensor 5, the high-frequency receiving sensor 6, the low-frequency transmitting sensor 7, and the low-frequency receiving sensor 8, and a scanning device 11 that scans the high-frequency transmitting sensor 5, the high-frequency receiving sensor 6, the low-frequency transmitting sensor 7, and the low-frequency receiving sensor 8. and an FMC calculation unit 42 that performs FMC processing on the first signal to calculate the surface shape of the object 1 to be inspected and calculates the bottom shape of the object 1 to be inspected from the second signal and the surface shape. Either the high-frequency transmitting sensor 5 or the high-frequency receiving sensor 6 has a rotation mechanism 13, 14 that rotates at least one of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 at the scanning position of each of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6, with a straight line passing through the center of its transmitting surface as the rotation axis in the case of the high-frequency transmitting sensor 5, or with a straight line passing through the center of its receiving surface as the rotation axis in the case of the high-frequency receiving sensor 6.

[0093] This allows the high-frequency transmitting sensor and receiving sensor to rotate while transmitting and receiving, maximizing the receiving sensitivity and performing measurements. This allows the surface shape of the object under test 1 to be measured with high accuracy, making it possible to measure both the surface shape of the object under test using high-frequency ultrasonic signals and the bottom surface shape with high S / N ratios by highly sensitive transmission and reception of low-frequency ultrasonic signals.

[0094] Furthermore, in the first recording step, when the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 are rotated in opposite directions, particularly when the rotation angle of the high frequency transmitting sensor 5 is φT and the rotation angle of the high frequency receiving sensor 6 is φR and the first signal can be transmitted and received, and at least one of the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 is scanned to change the distance between them, at least one of the high frequency transmitting sensor 5 and the high frequency receiving sensor 6 is rotated to determine the rotation angle change amount Δφ at which the amplitude of the first signal is maximized, and the first signal is recorded by scanning so that the rotation angle of the high frequency transmitting sensor 5 is φT+1 / 2×Δφ and the rotation angle of the high frequency receiving sensor 6 is φR-1 / 2×Δφ, so the rotation angle can be adjusted quickly to the position where sensitivity is maximized and measurement can be performed, thereby shortening the measurement time.

[0095] Furthermore, by using an ultrasonic inspection method that includes each step of the ultrasonic measurement method and a volume calculation step that calculates the volume of the object to be inspected 1 from the surface shape calculated in the surface shape calculation step and the bottom shape calculated in the bottom shape calculation step, more information about the object to be inspected 1 can be obtained.

[0096] Furthermore, by further providing a sensor rotation instruction unit 33 that measures the rotation angle of the high-frequency transmitting sensor 5, a sensor rotation instruction unit 33 that measures the rotation angle of the high-frequency receiving sensor 6, and a waveform display unit 23 that displays the ultrasonic signal being transmitted and the first signal being received, it is possible to grasp the situation during measurement using high-frequency ultrasonic waves, and the rotation angles of the high-frequency transmitting sensor 5 and the high-frequency receiving sensor 6 can be set more quickly.

[0097] Furthermore, by further providing a display unit 44 that displays the signal processing results, it is possible to very easily grasp the shape of the object under test 1.

[0098] <Example 2> Second Embodiment An ultrasonic measurement method, an ultrasonic inspection method, and an ultrasonic measurement device according to a second embodiment of the present invention will be described with reference to Fig. 15. Fig. 15 is a diagram showing the device configuration of the ultrasonic measurement device according to the second embodiment.

[0099] In Example 2, a Remotely Operated Vehicle (hereinafter referred to as ROV) equipped with a transmitting sensor and an ROV equipped with a receiving sensor are caused to swim above an object to be inspected that is located on the bottom of the water, and the surface and bottom shapes of the object to be scanned are measured.

[0100] The ultrasonic measuring device of this embodiment shown in FIG. 15 is suitable for a case where water 53 is standing on a floor 52 of a building and an object to be inspected 51 is located in the water.

[0101] As shown in Figure 15, the transmitting ROV 61 is equipped with a transmitting unit consisting of a high-frequency transmitting sensor 55 and a low-frequency transmitting sensor 57, whose rotation angle is adjusted by a sensor rotation control unit 82 and a rotation mechanism 63, and the transmitting ROV control device 81 can scan positions on the water surface.

[0102] In addition, the receiving ROV 62 is equipped with a receiving unit consisting of a high-frequency receiving sensor 56 and a low-frequency receiving sensor 58, the rotation angle of which is adjusted by a sensor rotation control unit 84 and a rotation mechanism 64, and can scan positions on the water surface using the receiving ROV control device 83.

[0103] The positions of the transmitting ROV 61, including the high-frequency transmitting sensor 55 and the low-frequency transmitting sensor 57, and the receiving ROV 62, including the high-frequency receiving sensor 56 and the low-frequency receiving sensor 58, are measured by a point cloud sensor 85 attached to the ceiling 54 of the building, and the positions of each are calculated by a sensor position calculation unit 86.

[0104] In this embodiment, ultrasonic waves are transmitted when a high-frequency voltage signal is applied from the oscillator 76 of the high-frequency flaw detector 75 to the high-frequency transmitting sensor 55. The ultrasonic waves propagate through the water and are reflected by the surface of the object under test. They are received by the high-frequency receiving sensor 56, amplified by the receiving unit 77, and the ultrasonic signal is displayed on the waveform display unit 78.

[0105] Similarly, when a low-frequency voltage signal is applied from the oscillator 71 of the low-frequency flaw detector 70 to the low-frequency transmitting sensor 57, an ultrasonic wave is transmitted. The ultrasonic wave propagates through the water, is refracted on the surface of the object under test, and is reflected on the bottom surface. The ultrasonic wave is received by the low-frequency receiving sensor 58, amplified by the receiving unit 72, and the ultrasonic signal is displayed on the waveform display unit 73.

[0106] The sensor position information calculated by the sensor position calculation unit 86, the high-frequency ultrasonic signal (first signal) received by the receiving unit 77, and the low-frequency ultrasonic signal (second signal) received by the receiving unit 72 are stored in a sensor position / ultrasonic signal recording unit 91 in a signal processing unit 90, and are subjected to signal processing in an FMC calculation unit 92. The visualized FMC calculation results are stored in an FMC result storage unit 93 and are also displayed on a display unit 94.

[0107] By using these devices and performing the same procedures as in Example 1, measurement results of the surface shape and bottom shape of the object 1 to be inspected can be obtained.

[0108] The other configurations and operations are substantially the same as those of the ultrasonic measurement method, ultrasonic inspection method, and ultrasonic measurement device of the first embodiment, and details thereof will be omitted.

[0109] The ultrasonic measurement method, ultrasonic inspection method, and ultrasonic measurement device according to the second embodiment of the present invention also provide substantially the same effects as those of the ultrasonic measurement method, ultrasonic inspection method, and ultrasonic measurement device according to the first embodiment described above.

[0110] Furthermore, by further providing a transmitting ROV 61 that can be equipped with a transmitting unit and swims on the water surface or underwater, and a receiving ROV 62 that can be equipped with a receiving unit and swims on the water surface or underwater independently from the transmitting ROV 61, it becomes possible to obtain information on the subject 51 that is submerged at a location away from the water's edge.

[0111] Example 3 An ultrasonic measurement method, an ultrasonic inspection method, and an ultrasonic measurement device according to a third embodiment of the present invention will be described with reference to Fig. 16. Fig. 16 is a diagram showing the device configuration of the ultrasonic measurement device according to the third embodiment.

[0112] In the ultrasonic measurement device of this embodiment shown in FIG. 16, instead of the ROV in the ultrasonic measurement device of the second embodiment, an ultrasonic sensor scans using a traveling device that travels underwater.

[0113] Specifically, a transmitting unit traveling device 97 equipped with a transmitting unit consisting of a high-frequency transmitting sensor 55 and a low-frequency transmitting sensor 57 and traveling on crawlers on the surface of the bottom of the water 2, and a transmitting unit traveling device 97 equipped with a receiving unit consisting of a high-frequency receiving sensor 56 and a low-frequency receiving sensor 58 and similarly traveling on crawlers on the surface of the bottom of the water 2 can be used. It is desirable that the receiving unit traveling device 98 be able to travel independently of the transmitting unit traveling device 97.

[0114] In this case, the sensor scanning surface may not be flat, but by measuring the sensor position using an underwater point cloud sensor (not shown), it is possible to obtain measurement results of the surface shape and bottom shape of the object to be inspected in the same manner as described above.

[0115] The other configurations and operations are substantially the same as those of the ultrasonic measurement method, ultrasonic inspection method, and ultrasonic measurement device of the second embodiment, and the details are omitted here.

[0116] The ultrasonic measurement method, ultrasonic inspection method, and ultrasonic measurement device according to the third embodiment of the present invention also provide substantially the same effects as those of the ultrasonic measurement method, ultrasonic inspection method, and ultrasonic measurement device according to the second embodiment described above.

[0117] Furthermore, by mounting the transmitting unit on a transmitting unit traveling device 97 that travels on the surface of the test object 51 and mounting the receiving unit on a receiving unit traveling device 98 that travels on the surface of the test object 51, it becomes possible to perform measurements at a position closer to the test object 1, thereby further improving the measurement accuracy.

[0118] <Other> It should be noted that the present invention is not limited to the above-described embodiment, and includes various modifications. The above-described embodiment has been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to an embodiment having all of the described configurations.

[0119] It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment, or to add, delete, or replace part of the configuration of each embodiment with the configuration of another embodiment. [Explanation of symbols]

[0120] 1,51...Test object 2...Underwater 3,53…Water 5, 55...High frequency transmitting sensor (first transmitting sensor) 6, 56...High frequency receiving sensor (first receiving sensor) 7, 57...Low frequency transmitting sensor (second transmitting sensor) 8, 58...Low frequency receiving sensor (second receiving sensor) 9...Anchor 10...Scanning device (scanning mechanism) 11,12,15,16…Beam 13, 14, 63, 64...Rotation mechanism 17...frame 20…Ultrasonic flaw detector 21...Oscillator 22...Receiver 23…Waveform display section 24...Switch 30...Scanning device control section 31...Sensor scanning instruction unit 32...Sensor position calculation unit (position determination mechanism) 33...Sensor rotation instruction unit (transmission angle measurement mechanism, reception angle measurement mechanism) 40, 90...Signal processing section 41, 91...Sensor position / ultrasonic signal recording section 42, 92...FMC calculation unit (processing unit) 43,93…FMC result storage unit 44,94...Display section 52...Floor 54...Ceiling 61...Transmitting ROV (scanning mechanism, first swimming movement device) 62... Receiving ROV (scanning mechanism, second swimming mobile device) 70...Low frequency flaw detector 71, 76...Oscillator 72, 77...Receiver 73,78...Waveform display section 75...High frequency flaw detector 81...Transmitting ROV control device (positioning mechanism) 82...Sensor rotation control unit (transmission angle measurement mechanism) 83... Receiving ROV control device (positioning mechanism) 84...Sensor rotation control unit (receiving angle measurement mechanism) 85...Point cloud sensor (positioning mechanism) 86...Sensor position calculation unit (position determination mechanism) 97...Transmitting unit traveling device (scanning mechanism, first traveling moving device) 98... Receiving unit traveling device (scanning mechanism, second traveling moving device)

Claims

1. a first recording step of transmitting ultrasonic waves of a first frequency from a first transmitting sensor to an object under test in a liquid and receiving first signals by a first receiving sensor while changing the positions of the first transmitting sensor and the first receiving sensor, thereby recording a plurality of the first signals; a second recording step of transmitting ultrasonic waves of a second frequency lower than the first frequency from a second transmitting sensor to the test object and receiving second signals by a second receiving sensor while changing the positions of the second transmitting sensor and the second receiving sensor, thereby recording a plurality of the second signals; a surface shape calculation step of calculating a surface shape of the object to be inspected by FMC processing of adding the plurality of first signals obtained in the first recording step with a time difference based on a difference in propagation paths of the ultrasonic waves of the first frequency; a bottom surface shape calculation step of calculating a bottom surface shape of the object under test by FMC processing in which the second signals recorded in the second recording step are added with a time difference based on a propagation path assumed to be taken by the ultrasonic waves of the second frequency that have traveled straight through the liquid and are refracted at the surface of the object under test, In the first recording step, at the scanning positions of the first transmitting sensor and the first receiving sensor, at least one of the first transmitting sensor and the first receiving sensor is rotated around a rotation axis that is a straight line passing through the center of its transmitting surface in the first transmitting sensor, and around a rotation axis that is a straight line passing through the center of its receiving surface in the first receiving sensor, to record the first signal at a rotation angle at which the ultrasonic propagation path falls within each directivity angle range. Ultrasonic measurement method.

2. The ultrasonic measurement method according to claim 1, the first transmitting sensor and the second transmitting sensor are a set of transmitting units, the first receiving sensor and the second receiving sensor are a pair of receiving units, Independently scanning the transmitting unit and the receiving unit Ultrasonic measurement method.

3. 3. The ultrasonic measurement method according to claim 2, The transmitting unit is mounted on a first swimming / moving device that swims on the surface of the liquid or in the liquid; The receiving unit is mounted on a second swimming / moving device that swims on the liquid surface or in the liquid. Ultrasonic measurement method.

4. 3. The ultrasonic measurement method according to claim 2, The transmitting unit is mounted on a first traveling and moving device that travels on the surface of the object under test; The receiving unit is mounted on a second moving device that moves on the surface of the object to be inspected. Ultrasonic measurement method.

5. The ultrasonic measurement method according to claim 1, In the first recording step, at least one of the first transmitting sensor and the first receiving sensor is rotated in opposite directions, with a straight line passing through the center of its transmitting surface as a rotation axis in the first transmitting sensor, and with a straight line passing through the center of its receiving surface as a rotation axis in the first receiving sensor. Ultrasonic measurement method.

6. The ultrasonic measurement method according to claim 5, In the first recording step, when the rotation angle of the first transmitting sensor is φT, the rotation angle of the first receiving sensor is φR, and the first signal can be transmitted and received, and at least one of the first transmitting sensor and the first receiving sensor is scanned to change the distance between the first transmitting sensor and the first receiving sensor, Rotating at least one of the first transmitting sensor and the first receiving sensor to determine a rotation angle change amount Δφ at which the amplitude of the first signal is maximized; The first signal is recorded by scanning the first transmitting sensor so that the rotation angle is φT+1 / 2×Δφ and the first receiving sensor so that the rotation angle is φR-1 / 2×Δφ. Ultrasonic measurement method.

7. Each step of the ultrasonic measurement method according to any one of claims 1 to 6; a volume calculation step of calculating a volume of the object to be inspected from the surface shape calculated in the surface shape calculation step and the bottom shape calculated in the bottom shape calculation step. Ultrasound testing methods.

8. a first transmitting sensor that transmits ultrasonic waves of a first frequency to an object under test that is immersed in a liquid; a first receiving sensor that receives a first signal derived from the ultrasonic wave of the first frequency; a second transmitting sensor that transmits ultrasonic waves of a second frequency that is lower than the first frequency to the object under test; a second receiving sensor that receives a second signal derived from the ultrasonic wave of the second frequency; a scanning mechanism that scans the first transmitting sensor, the first receiving sensor, the second transmitting sensor, and the second receiving sensor; a position determination mechanism that determines scanning positions of the first transmitting sensor, the first receiving sensor, the second transmitting sensor, and the second receiving sensor; a processing unit that performs FMC processing on the first signal to calculate a surface shape of the object under test, and calculates a bottom shape of the object under test from the second signal and the surface shape, One of the first transmitting sensor and the first receiving sensor has a rotation mechanism that rotates at least one of the first transmitting sensor and the first receiving sensor at the scanning positions of the first transmitting sensor and the first receiving sensor, with a straight line passing through the center of its transmitting surface as a rotation axis in the first transmitting sensor, and with a straight line passing through the center of its receiving surface as a rotation axis in the first receiving sensor. Ultrasonic measuring device.

9. The ultrasonic measuring device according to claim 8, a transmitting unit that simultaneously scans the first transmitting sensor and the second transmitting sensor; a receiving unit that is independent of the transmitting unit and that simultaneously scans the first receiving sensor and the second receiving sensor. Ultrasonic measuring device.

10. The ultrasonic measuring device according to claim 9, a first swimming / moving device capable of mounting the transmitting unit and swimming on the surface of the liquid or in the liquid; a second swimming / moving device capable of mounting the receiving unit and swimming independently of the first swimming / moving device on the liquid surface or in the liquid. Ultrasonic measuring device.

11. The ultrasonic measuring device according to claim 9, a first traveling / moving device capable of mounting the transmission unit and configured to travel on the surface of the object under test; a second traveling and moving device capable of mounting the receiving unit and running on the surface of the object under test independently from the first traveling and moving device. Ultrasonic measuring device.

12. The ultrasonic measuring device according to any one of claims 8 to 11, a transmission angle measurement mechanism that measures a rotation angle of the first transmission sensor; a receiving angle measurement mechanism that measures a rotation angle of the first receiving sensor; and a waveform display unit that displays the transmitted ultrasonic signal and the received first signal. Ultrasonic measuring device.

13. The ultrasonic measuring device according to claim 8, Further provided with a display unit for displaying the signal processing results Ultrasonic measuring device.

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