Inspection equipment and image generation equipment

Abstract

To easily grasp inspection results.SOLUTION: An inspection device 30 includes: a phased array type ultrasonic probe 32 that is arranged on an end face 42 in an axial direction of a rod-shaped test object 10, emits ultrasonic waves into the interior of the test object 10, and receives ultrasonic echoes reflected from the test object: and an image generation unit 70 that generates a cross-sectional image 80 representing an outer edge of the test object 10 in a cross-section perpendicular to the axial direction of the test object 10 based on the ultrasonic echoes.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an inspection apparatus and an image generation apparatus. [Background technology]

[0002] For example, Patent Document 1 discloses an inspection method for inspecting bolts for thinning using a phased array ultrasonic probe. In this inspection method, a sector scan is performed in the diameter direction of the bolt, and a sectorial view of the vertical cross section of the bolt after the sector scan is displayed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-163773 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the technology of Patent Document 1, the user has to infer the actual location or degree of thinning within the bolt from a sectional view image of the bolt's vertical cross section, making it difficult to intuitively understand the inspection results.

[0005] An object of the present disclosure is to provide an inspection device and an image generation device that allow inspection results to be easily understood. [Means for solving the problem]

[0006] In order to solve the above problem, an inspection device according to one aspect of the present disclosure includes: a phased array ultrasonic probe that is placed on an end surface of a rod-shaped object to be inspected in an axial direction, that emits ultrasonic waves into the inside of the object to be inspected, and that receives ultrasonic echoes reflected from the object to be inspected; and an image generation unit that generates, based on the ultrasonic echoes, a cross-sectional image that depicts an outer edge of the object to be inspected in a cross section perpendicular to the axial direction of the object to be inspected. When the distance from the central axis in the radial direction perpendicular to the central axis of the ultrasonic probe is defined as a radius (R), the image generation unit converts the time information of the received ultrasonic echo into depth information indicating the depth (Z) of the object to be inspected in the central axis direction, detects a signal where the amplitude of the ultrasonic echo converted into depth information is equal to or greater than a predetermined threshold, sets the depth (Z) in the central axis direction, keeps a second angle (θ) around the central axis constant, identifies the radius (R) corresponding to the ultrasonic echo whose signal is detected among the multiple ultrasonic echoes in the radial direction, performs a minimum radius selection process to select the smallest minimum radius (Rmin) among the identified radii (R), changes the second angle (θ) and performs the minimum radius selection process for each second angle (θ), and connects the plots on the cross-sectional image of the minimum radius (Rmin) selected for each second angle (θ) to depict the outer edge of the object to be inspected in the cross-sectional image, and generates a cross-sectional image at the set depth (Z). .

[0007] The inspection device may further include an ultrasonic control unit that controls the radiation direction of ultrasonic waves emitted by the ultrasonic probe, and the ultrasonic control unit may keep a first angle (Φ) formed between the central axis of the ultrasonic probe and the radiation direction constant, change the radiation direction toward a second angle (θ) around the central axis, and perform a circumferential scan in which ultrasonic waves are emitted and ultrasonic echoes are received for each second angle (θ), and perform the circumferential scan for each first angle (Φ) by changing the first angle (Φ).

[0010] The image generation unit may extract a plurality of detected signals that are close to each other in at least one of the second angle (θ) around the central axis and the depth (Z) in the central axis direction, and perform a minimum radius selection process using the extracted plurality of signals as processing targets.

[0011] The image generating unit may change the setting of the depth (Z) in the central axis direction and generate a plurality of cross-sectional images for each set depth (Z).

[0012] The inspection device may further include an evaluation unit that evaluates the degree of wall thinning, which is the degree of reduction in the wall thickness of the inspection object in a direction perpendicular to the axial direction of the inspection object, based on the cross-sectional image.

[0013] The evaluation unit may evaluate the degree of thinning of the inspection object based on the cross-sectional area of ​​a region surrounded by the outer edge of the inspection object in the cross-sectional image.

[0014] In order to solve the above problem, an image generating device according to one aspect of the present disclosure is provided, which is arranged on an end face of a rod-shaped object to be inspected in the axial direction, and acquires ultrasonic echoes from a phased array ultrasonic probe that emits ultrasonic waves into the interior of the object to be inspected and receives ultrasonic echoes reflected from the object to be inspected, and generates a cross-sectional image that depicts the outer edge of the object to be inspected in a cross section perpendicular to the axial direction of the object to be inspected based on the ultrasonic echoes. , an image generating device, in which when the distance from the central axis in the radial direction perpendicular to the central axis of the ultrasonic probe is defined as a radius (R), converts time information of the received ultrasonic echo into depth information indicating the depth (Z) of the object to be inspected in the central axis direction, detects a signal where the amplitude of the ultrasonic echo converted into depth information is equal to or greater than a predetermined threshold, sets the depth (Z) in the central axis direction, keeps a second angle (θ) around the central axis constant, identifies the radius (R) corresponding to the ultrasonic echo whose signal is detected from among multiple ultrasonic echoes in the radial direction, performs a minimum radius selection process to select the smallest of the identified radii (R), changes the second angle (θ) and performs the minimum radius selection process for each second angle (θ), and connects the plots on the cross-sectional image of the minimum radii (Rmin) selected for each second angle (θ), thereby depicting the outer edge of the object to be inspected in the cross-sectional image, and generates a cross-sectional image at the set depth (Z). . [Effects of the Invention]

[0015] According to the present disclosure, it becomes possible to easily understand the test results. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram illustrating an inspection object 10 of an inspection device according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating the configuration of the inspection device according to this embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of an ultrasonic wave emission method according to this embodiment. [Figure 4] FIG. 4 is a diagram illustrating another example of the ultrasonic wave emission method according to this embodiment. [Figure 5] Fig. 5A is a diagram showing the relationship between the radiation direction of ultrasound and the central axis direction of the ultrasound probe according to this embodiment. Fig. 5B is a diagram showing the amplitude of ultrasound echoes versus time in the radiation direction of ultrasound according to this embodiment. Fig. 5C is a diagram showing the amplitude of ultrasound echoes versus depth Z in the central axis direction of the ultrasound probe according to this embodiment. Fig. 5D is a diagram showing the amplitude of ultrasound echoes versus radius R in the radial direction perpendicular to the central axis of the ultrasound probe according to this embodiment. [Figure 6] Fig. 6A is a diagram showing an example of a cross-sectional image of an inspection object at a depth Z1 in which no thinning has occurred according to the present embodiment. Fig. 6B is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the central axis direction when ultrasonic waves are emitted in a direction in which the first angle Φ is Φ1 and the second angle θ is θ1 according to the present embodiment. Fig. 6C is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the central axis direction when ultrasonic waves are emitted in a direction in which the first angle Φ is Φ1 and the second angle θ is θ2 according to the present embodiment. Fig. 6D is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the central axis direction when ultrasonic waves are emitted in a direction in which the first angle Φ is Φ1 and the second angle θ is θ3 according to the present embodiment. [Figure 7]Fig. 7A is a diagram showing an example of a cross-sectional image of an object to be inspected at a depth Z2 where thinning has occurred, according to the present embodiment. Fig. 7B is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the central axis direction when ultrasonic waves are emitted in a direction where the first angle Φ is Φ2 and the second angle θ is θ1, according to the present embodiment. Fig. 7C is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the central axis direction when ultrasonic waves are emitted in a direction where the first angle Φ is Φ2 and the second angle θ is θ2, according to the present embodiment. Fig. 7D is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the central axis direction when ultrasonic waves are emitted in a direction where the first angle Φ is Φ2 and the second angle θ is θ3, according to the present embodiment. [Figure 8] FIG. 8 is a diagram illustrating the process of drawing the outer edge of the inspection object in the cross-sectional image according to this embodiment. [Figure 9] FIG. 9 is a flowchart illustrating the flow of operations of the ultrasound control unit according to this embodiment. [Figure 10] FIG. 10 is a flowchart illustrating the flow of operations of the image generating device according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

[0018] FIG. 1 is a diagram illustrating an inspection object 10 of an inspection device according to this embodiment. The inspection object 10 is an object formed in a rod shape. The inspection object 10 is, for example, a bolt 10a that fastens a structure to the ground, but is not limited to this example and may be any rod-shaped object, such as a rebar with a relatively large outer diameter. Furthermore, the inspection object 10 is not limited to a round bar, but may also be a square bar.

[0019] The structure 12 includes a base plate 14 and support posts 16. The base plate 14 is formed, for example, in the shape of a rectangular flat plate. Through holes 20 are provided near the four corners of the base plate 14, penetrating the base plate 14 in the thickness direction. The support posts 16 are formed in the shape of rods, and stand vertically upward from the upper surface of the base plate 14. The sign 18 is provided on the top of the support posts 16.

[0020] A concrete block 24 is provided at a position on the ground 22 where the structure 12 will be installed. The axial lower portion of the bolt 10a, which is the inspection object 10, is embedded inside the concrete block 24. The axial upper portion of the bolt 10a is exposed from the concrete block 24 and protrudes vertically upward from the top surface of the concrete block 24. Four bolts 10a are provided to correspond to the through holes 20 in the base plate 14.

[0021] The base plate 14 is installed on the concrete block 24 so that each bolt 10a is inserted into its corresponding through-hole 20. When the base plate 14 is installed on the concrete block 24, the top of the bolt 10a protrudes vertically upward from the upper surface of the base plate 14. A thread is formed on the top of the bolt 10a. With the bolt 10a inserted into the through-hole 20, a nut 26 is attached to the top of the bolt 10a, and the base plate 14 is fixed to the concrete block 24 by tightening the nut 26. An upper end surface 28 of the bolt 10a is exposed. However, the side and lower end surfaces of the bolt 10a are covered by the concrete block 24, the base plate 14, and the nut 26.

[0022] Here, for example, due to environmental factors such as rainwater accumulating on the concrete block 24, water may seep into the gap between the concrete block 24 and the base plate 14. If this happens, the water that seeps into the gap may cause rust on the bolt 10a. If corrosion of the bolt 10a progresses due to rust or the like, the bolt 10a may thin out, potentially reducing its mechanical strength. Thinning refers to a decrease in the radial thickness of the inspection object 10, which is perpendicular to the axial direction.

[0023] For these reasons, it is desirable to inspect the degree of wall thinning of the inspection object 10, using the bolt 10a as the inspection object 10. It is also desirable to inspect the degree of wall thinning of the inspection object 10 without removing the base plate 14 from the concrete block 24.

[0024] Therefore, the inspection device of this embodiment uses an ultrasonic probe to non-destructively inspect the degree of wall thinning of an inspection object 10 such as a bolt 10a. The configuration of the inspection device will be described below.

[0025] 2 is a schematic diagram illustrating the configuration of an inspection device 30 according to this embodiment. The inspection object 10 of the inspection device 30 is not limited to a bolt 10a, and any rod-shaped object may be used as the inspection object 10. The inspection device 30 includes an ultrasonic probe 32, a flaw detection device 34, and an image generation device 36.

[0026] The ultrasonic probe 32 is a phased array type ultrasonic probe having a plurality of transducers. For example, the ultrasonic probe 32 is an annular array probe in which a plurality of transducers are arranged in a circular ring-shaped plane. In an annular array probe, the transducers are distributed in the circumferential direction of the ultrasonic probe 32, and the transducers are distributed in the radial direction of the ultrasonic probe 32. Note that the ultrasonic probe 32 is not limited to an annular array probe, and may be one in which the transducers are arranged in a square-shaped plane, for example.

[0027] The transducer of the ultrasonic probe 32 is formed of, for example, a piezoelectric element. When a voltage is applied to the transducer, the transducer vibrates. When the transducer vibrates, the ultrasonic probe 32 emits ultrasonic waves from the emission surface 40. The ultrasonic probe 32 emits ultrasonic waves from the emission surface 40, which are ultrasonic waves generated by each of the multiple transducers superimposed on each other. In this embodiment, the ultrasonic waves emitted from the ultrasonic probe 32 refer to the superimposed ultrasonic waves. The ultrasonic probe 32 is capable of changing the direction of ultrasonic wave emission by controlling the vibration timing of each of the multiple transducers individually.

[0028] The ultrasonic probe 32 is disposed on an end surface 42 in the axial direction of the rod-shaped inspection object 10. More specifically, the ultrasonic probe 32 is disposed so that an emission surface 40 that emits ultrasonic waves is in contact with the end surface 42 of the inspection object 10. For example, if the inspection object 10 is the bolt 10a of FIG. 1 , the ultrasonic probe 32 is disposed on the upper end surface 28 of the bolt 10a. Furthermore, the central axis 44 of the ultrasonic probe 32 extends perpendicular to the emission surface 40. The ultrasonic probe 32 is preferably disposed so that the central axis 44 of the ultrasonic probe 32 is parallel to the axial direction of the inspection object 10. Furthermore, the ultrasonic probe 32 is more preferably disposed so that the central axis 44 of the ultrasonic probe 32 and the central axis 46 of the inspection object 10 approximately overlap.

[0029] Since the radiation surface 40 of the ultrasonic probe 32 is in contact with the end face of the inspection object 10 , the ultrasonic probe 32 can radiate ultrasonic waves into the interior of the inspection object 10 .

[0030] Ultrasonic waves emitted into the object of inspection 10 propagate within the object of inspection 10 and are reflected, for example, by the side surfaces of the object of inspection 10. A portion of the reflected ultrasonic waves propagate within the object of inspection 10 and return to the emission surface 40 of the ultrasonic probe 32. Hereinafter, ultrasonic waves that reflect off the emitted ultrasonic waves and reach the ultrasonic probe 32 may be referred to as ultrasonic echoes. The ultrasonic probe 32 can receive ultrasonic echoes reflected from the object of inspection 10. For example, a vibrator vibrates when it receives an ultrasonic echo and converts the vibrations into a voltage. Therefore, the magnitude of the ultrasonic echo received by the ultrasonic probe 32 corresponds to the amplitude of the voltage converted by the vibrator.

[0031] The flaw detection device 34 includes an ultrasonic control unit 50 and a storage device 52. The ultrasonic control unit 50 controls the radiation direction of ultrasonic waves emitted by the ultrasonic probe 32. For example, the ultrasonic control unit 50 is electrically connected to the ultrasonic probe 32. The ultrasonic control unit 50 has a plurality of delay circuits corresponding to each of the plurality of transducers of the ultrasonic probe 32. The ultrasonic control unit 50 controls the delay amount in the delay circuit for each delay circuit. This controls the application timing of the voltage applied to the transducer for each transducer. In other words, the timing at which the transducer vibrates is controlled for each transducer. As a result, the ultrasonic control unit 50 can radiate ultrasonic waves in a radiation direction corresponding to the balance of the delay amounts of the plurality of delay circuits, in other words, the balance of the vibration timing of the plurality of transducers.

[0032] The storage device 52 is configured with a non-volatile storage element and stores data indicating the ultrasonic echoes detected by the ultrasonic probe 32, etc.

[0033] Fig. 3 is a diagram illustrating an example of an ultrasonic wave emission method according to this embodiment. The ultrasonic wave control unit 50 emits ultrasonic waves in one emission direction and acquires ultrasonic echoes from the ultrasonic waves, and repeats this operation by changing the emission direction of the ultrasonic waves. Hereinafter, the repeated emission of ultrasonic waves and acquisition of ultrasonic echoes by changing the emission direction may be referred to as scanning. The solid arrow A10 in Fig. 3 is an example of the emission direction of ultrasonic waves. The dashed arrow A12 is an example of the scanning direction.

[0034] Here, the angle formed between the central axis 44 of the ultrasonic probe 32 and the radiation direction of the ultrasonic waves, as illustrated by the solid arrow A10, is defined as a first angle Φ. The angle around the central axis 44 of the ultrasonic probe 32 is defined as a second angle θ. The distance from the central axis 44 of the ultrasonic probe 32 in a radial direction perpendicular to the central axis 44 is defined as a radius R. The distance from the radiation surface 40 of the ultrasonic probe 32 in the direction of the central axis 44 of the ultrasonic probe 32 is defined as a depth Z. The depth Z corresponds to the distance from the end face 42 of the object of inspection 10 in the axial direction of the object of inspection 10. It is also assumed that ultrasonic waves are radiated in the radiation direction from the intersection of the radiation surface 40 with the central axis 44, as illustrated by the solid arrow A10.

[0035] The ultrasound control unit 50 performs a circumferential scan by keeping the first angle Φ constant and changing the radiation direction (solid arrow A10) in the direction of a second angle θ, as illustrated by the dashed arrow A12, to emit ultrasound waves and receive ultrasound echoes for each second angle θ. The ultrasound control unit 50 performs a circumferential scan so that the second angle θ goes around once. The ultrasound control unit 50 then changes the first angle Φ and performs such a circumferential scan for each first angle Φ. This corresponds to changing the radius R at a certain depth Z and performing a circumferential scan for each radius R. For example, the ultrasound control unit 50 performs a circumferential scan while changing the first angle Φ so that the first angle Φ increases in stages.

[0036] By performing such a scan, the ultrasonic control unit 50 can efficiently acquire ultrasonic echoes from the end face of the rod-shaped inspection object 10.

[0037] The method of emitting ultrasonic waves is not limited to the method exemplified in Fig. 3. Fig. 4 is a diagram for explaining another example of the method of emitting ultrasonic waves according to this embodiment.

[0038] The ultrasound control unit 50 may perform a sector scan in which, while keeping the second angle θ constant, the radiation direction (solid arrow A10) is changed in the direction of the first angle Φ, as exemplified by the dashed arrow A22, to emit ultrasound waves at each first angle Φ and receive ultrasound echoes. For example, the ultrasound control unit 50 may change the first angle Φ so that the first angle Φ increases in steps from 0°. This corresponds to changing the radius R at a certain depth Z, emitting ultrasound waves at each radius R, and receiving ultrasound echoes. The ultrasound control unit 50 may then change the second angle θ and perform such a sector scan at each second angle θ. The ultrasound control unit 50 may repeatedly perform sector scans so that the second angle θ goes around once.

[0039] 2, the image generating device 36 includes a user interface 60 and a control device 62. The image generating device 36 is electrically connected to the flaw detection device 34. The user interface 60 includes an output device such as a display that presents various information to the user, and an input device such as a keyboard or mouse that accepts input operations from the user.

[0040] The control device 62 includes one or more processors 64 and one or more memories 66 connected to the processors 64. The memories 66 include a ROM in which programs and the like are stored, and a RAM as a work area. The processor 64 controls the entire image generation device 36 in cooperation with the programs stored in the memory 66. The image generation device 36 also functions as an image generation unit 70 and an evaluation unit 72 by executing the programs.

[0041] The image generating unit 70 can acquire ultrasonic echoes from the ultrasonic probe 32 via the flaw detection device 34. For example, the image generating unit 70 can acquire data indicating the ultrasonic echoes from the storage device 52 of the flaw detection device 34. Based on the acquired ultrasonic echoes, the image generating unit 70 generates a cross-sectional image 80 that depicts the outer edge of the inspection object 10 in a cross section perpendicular to the axial direction of the inspection object 10. FIG. 2 shows an example of the cross-sectional image 80. A line 82 corresponding to the outer edge of the inspection object 10 is shown within the cross-sectional image 80. The image generating unit 70 generates the cross-sectional image 80 at a certain depth Z. A method for generating the cross-sectional image 80 by the image generating unit 70 will be described later.

[0042] The evaluation unit 72 evaluates the degree of wall thinning, which is the degree of reduction in the wall thickness of the inspection object 10 in a direction perpendicular to the axial direction of the inspection object 10, based on the cross-sectional image 80 generated by the image generation unit 70. This allows the user to quantitatively grasp the inspection results regarding wall thinning of the inspection object 10.

[0043] For example, the evaluation unit 72 evaluates the degree of wall thinning of the inspection object 10 based on the cross-sectional area of ​​a region surrounded by the outer edge of the inspection object 10 in the cross-sectional image 80 (e.g., line 82 in the cross-sectional image 80 in FIG. 2 ). More specifically, the evaluation unit 72 derives the cross-sectional area of ​​the region surrounded by the outer edge of the inspection object 10 in the cross-sectional image 80. The evaluation unit 72 compares the derived cross-sectional area with a predetermined standard and derives the ratio of the cross-sectional area to the predetermined standard. Alternatively, the evaluation unit 72 may derive a difference value by subtracting the cross-sectional area from the predetermined standard and derive the ratio of the difference value to the predetermined standard. In this way, the evaluation unit 72 can easily derive the cross-sectional area of ​​the region surrounded by the outer edge of the inspection object 10 from the cross-sectional image 80, and can easily evaluate the degree of wall thinning based on the cross-sectional area. This allows the evaluation unit 72 to reduce the processing load related to the evaluation.

[0044] Furthermore, the evaluation unit 72 may compare the radius from the center of a figure showing the outer edge of the inspection object 10 drawn in the cross-sectional image 80 with a predetermined standard to evaluate the degree of thinning.

[0045] The predetermined standard may be, for example, the cross-sectional area or radius R when the inspection object 10 is sound, that is, when no thinning occurs in the inspection object 10. The predetermined standard may also be the cross-sectional area or radius R of the inspection object at a depth Z different from the depth Z corresponding to the cross section for which the degree of thinning is being evaluated.

[0046] The image generating unit 70 may display the generated cross-sectional image 80 on the display of the user interface 60. The evaluating unit 72 may also display the evaluation result of the degree of wall thinning on the display of the user interface 60.

[0047] Next, a method for generating the cross-sectional image 80 by the image generating unit 70 will be described with reference to the following FIGS.

[0048] The image generating unit 70 converts the time information of the received ultrasonic echo into depth information indicating the depth Z of the object 10 in the direction of the central axis 44 of the ultrasonic probe 32, and generates a cross-sectional image 80 based on the depth information.

[0049] Fig. 5A is a diagram showing the relationship between the radiation direction of ultrasound and the direction of the central axis 44 of the ultrasound probe 32 according to this embodiment. Fig. 5B is a diagram showing the amplitude of an ultrasound echo with respect to time in the radiation direction of ultrasound according to this embodiment. Fig. 5C is a diagram showing the amplitude of an ultrasound echo with respect to depth Z in the direction of the central axis 44 of the ultrasound probe 32 according to this embodiment. Fig. 5D is a diagram showing the amplitude of an ultrasound echo with respect to radius R in the radial direction perpendicular to the central axis 44 of the ultrasound probe 32 according to this embodiment.

[0050] 5A, the radiation direction of the ultrasonic waves is inclined at a first angle Φ with respect to the direction of the central axis 44 of the ultrasonic probe 32. Therefore, strictly speaking, the distance in the radiation direction and the distance in the direction of the central axis 44 are different.

[0051] Here, the distance in the radiation direction corresponding to a certain time t in the radiation direction is defined as distance T. Time t can be converted into distance T based on the sound speed of ultrasound. Depth Z corresponding to distance T is expressed as a function of the first angle Φ (for example, Z = TcosΦ). Furthermore, radius R corresponding to distance T is expressed as a function of the first angle Φ (for example, R = TsinΦ). Therefore, information on time t in the radiation direction can be converted into information on depth Z corresponding to that time t, and information on time t in the radiation direction can be converted into information on radius R corresponding to that time t.

[0052] Furthermore, for one radiation direction specified by the first angle Φ and the second angle θ, data indicating the amplitude of the ultrasonic echo with respect to time in the radiation direction is acquired, as exemplified in Fig. 5B. Data indicating the amplitude of the ultrasonic echo with respect to time in the radiation direction is acquired for each radiation direction, i.e., for each combination of the first angle Φ and the second angle θ.

[0053] As described above, since time t in the radial direction can be converted to depth Z in the direction of central axis 44, the image generation unit 70 converts each time in the radial direction on the horizontal axis shown in Fig. 5B into each depth Z in the direction of central axis 44 shown in Fig. 5C. As a result, for example, when an amplitude peak occurs at a certain time t in Fig. 5B, the amplitude peak will appear at the depth Z in Fig. 5C corresponding to that time t. The image generation unit 70 converts information about time in the radial direction into information about depth Z in the direction of central axis 44 for multiple ultrasonic echo data for each radial direction.

[0054] Furthermore, as described above, since time t in the radial direction can be converted into radius R in the radial direction, the image generation unit 70 converts each time in the radial direction on the horizontal axis shown in Fig. 5B into each radius R in the radial direction shown in Fig. 5D. As a result, for example, when an amplitude peak occurs at a certain time t in Fig. 5B, an amplitude peak will appear at the radius R in Fig. 5D corresponding to that time t. The image generation unit 70 converts information about time in the radial direction into information about radius R in the radial direction for multiple pieces of ultrasonic echo data for each radial direction.

[0055] In this way, the image generation unit 70 converts the time information of the direction of ultrasound radiation into information indicating the depth Z, and then converts the time information into information indicating the radius R, thereby making it easier to generate the cross-sectional image 80.

[0056] As shown in Figures 5B to 5D, a predetermined threshold is set in advance for the amplitude of the ultrasonic echo. The predetermined threshold is set, for example, to a value that allows the ultrasonic echo to be distinguished from noise. As shown in Figure 5C, the image generation unit 70 detects a signal in which the amplitude of the ultrasonic echo converted into depth information is equal to or greater than the predetermined threshold. This allows the image generation unit 70 to remove noise from the ultrasonic echo converted into depth information, thereby improving the accuracy of the cross-sectional image 80.

[0057] The image generating unit 70 further extracts, from among the signals whose amplitude is equal to or greater than a threshold, a plurality of signals whose second angles θ and / or depths Z are close to each other. The plurality of signals whose second angles θ are close to each other refers to signals whose deviation in the second angle θ from the second angle θ corresponding to one signal falls within a predetermined angle range and the single signal. The predetermined angle range may be set to any value sufficiently small relative to one rotation, such as a few degrees. The plurality of signals whose depths Z are close to each other refers to signals whose deviation in the depth Z from the depth Z corresponding to one signal falls within a predetermined depth range and the single signal. The predetermined depth range may be set to any value sufficiently small relative to the axial length of the object 10, such as a few millimeters.

[0058] Here, it is estimated that the outer edge of the inspection object 10 in one cross-sectional image 80 that is ultimately generated is formed by a chain of points whose second angle θ is close. Therefore, the image generation unit 70 extracts signals whose second angle θ is close to each other, thereby extracting signals involved in depicting the outer edge and removing noise unrelated to the outer edge. Furthermore, in multiple cross-sectional images 80 whose depths Z are close to each other, it is estimated that the outer edge of the inspection object 10 in each cross-sectional image 80 is connected in a chain in the depth Z direction. Therefore, the image generation unit 70 extracts signals whose depths Z are close to each other, thereby extracting signals involved in depicting the outer edge and removing noise unrelated to the outer edge.

[0059] The image generating unit 70 processes the extracted signals to identify the outer edge of the object 10 for drawing a cross-sectional image 80 .

[0060] Fig. 6A is a diagram showing an example of a cross-sectional image 80 at a depth Z1 of the inspection object 10 in which no thinning has occurred according to the present embodiment. Fig. 6B is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the direction of the central axis 44 when ultrasonic waves are emitted in a direction in which the first angle Φ is Φ1 and the second angle θ is θ1 according to the present embodiment. Fig. 6C is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the direction of the central axis 44 when ultrasonic waves are emitted in a direction in which the first angle Φ is Φ1 and the second angle θ is θ2 according to the present embodiment. Fig. 6D is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the direction of the central axis 44 when ultrasonic waves are emitted in a direction in which the first angle Φ is Φ1 and the second angle θ is θ3 according to the present embodiment.

[0061] In Figure 6A, arrow B1 indicates a radius R11 whose radial directions are Φ1 and θ1 and whose depth corresponds to Z1. Arrow B2 indicates a radius R11 whose radial directions are Φ1 and θ2 and whose depth corresponds to Z1. Arrow B3 indicates a radius R11 whose radial directions are Φ1 and θ3 and whose depth corresponds to Z1.

[0062] 6B to 6D, when no thinning has occurred in the inspection object 10, ultrasonic echo signals whose amplitude is equal to or greater than the threshold value at Z1 are detected in the ultrasonic echoes of the pair of Φ1 and θ1, the pair of Φ1 and θ2, and the pair of Φ1 and θ3. Furthermore, even when signals whose second angle θ and depth Z are close to each other are extracted, signals whose amplitude is equal to or greater than the threshold value at Z1 are extracted.

[0063] The detected and extracted signals are associated with values ​​of a first angle Φ, a second angle θ, a depth Z, and a radius R.

[0064] When generating a cross-sectional image 80 of Z1, a signal corresponding to Z1 is selected from the detected and extracted signals. The image generating unit 70 can form a line 82 by plotting points corresponding to the second angle θ and radius R associated with each signal corresponding to Z1 on the cross-sectional image 80. In the example of FIG. 6A, the radius R is common to all of θ1, θ2, and θ3, at R11, and therefore the line 82 is formed as a circle. As a result, it is estimated that the outer edge of the inspection object 10 is circular, and therefore it can be estimated that no thinning has occurred in the inspection object 10.

[0065] 7A is a diagram showing an example of a cross-sectional image of the inspection object 10 at a depth Z2 where thinning has occurred according to the present embodiment. FIG. 7B is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the direction of the central axis 44 when ultrasonic waves are emitted in a direction in which the first angle Φ is Φ2 and the second angle θ is θ1 according to the present embodiment. FIG. 7C is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the direction of the central axis 44 when ultrasonic waves are emitted in a direction in which the first angle Φ is Φ2 and the second angle θ is θ2 according to the present embodiment. FIG. 7D is a diagram showing the amplitude of an ultrasonic echo with respect to the depth Z in the direction of the central axis 44 when ultrasonic waves are emitted in a direction in which the first angle Φ is Φ2 and the second angle θ is θ3 according to the present embodiment.

[0066] 7A indicates a radius R22 whose radial directions are Φ2 and θ1 and whose depth corresponds to Z2. Arrow C2 indicates a radius R22 whose radial directions are Φ2 and θ2 and whose depth corresponds to Z2. Arrow C3 indicates a radius R22 whose radial directions are Φ2 and θ3 and whose depth corresponds to Z2. Radius R22 is smaller than the original radius R of the inspection object 10 (e.g., radius R11 in FIG. 6A).

[0067] For example, as shown in Fig. 7A, in the cross section at Z2, it is assumed that thinning occurs in the radial direction at θ2, but not in the radial directions at θ1 and θ3. In this example, for θ1 where no thinning occurs, no ultrasonic echo is detected at depth Z2, as shown in Fig. 7B. Similarly, for θ3 where no thinning occurs, no ultrasonic echo is detected at depth Z2, as shown in Fig. 7D. In other words, under these conditions, it can be inferred that the ultrasonic waves do not reach the outer edge of the inspection object 10, and no thinning occurs.

[0068] In contrast, for θ2 where thinning has occurred, an ultrasonic echo is detected at a depth of Z2, as shown in Figure 7C. In other words, under these conditions, it can be estimated that the ultrasonic waves have reached the outer edge of the inspection object 10. Because R22 is smaller than the original radius R of the inspection object 10, it can be estimated that thinning has occurred under these conditions.

[0069] 8 is a diagram illustrating the process of depicting the outer edge of the inspection object 10 in a cross-sectional image 80 according to this embodiment. FIG. 8 shows an example of a cross-sectional image 80 of the inspection object 10 at a depth Z2 where thinning has occurred. Arrow C2 in FIG. 8 indicates a radius R22 whose radial directions are Φ2 and θ2 and whose depth corresponds to Z2. Arrow C12 indicates a radius R21 whose radial directions are Φ1 and θ2 and whose depth corresponds to Z2.

[0070] As described above, the image generating unit 70 sets the depth Z at which the cross-sectional image 80 is to be generated, and selects, from the detected and extracted signals, a signal that corresponds to the depth Z. The image generating unit 70 can form a line 82 on the cross-sectional image 80 by plotting points that correspond to the second angle θ and the radius R that are associated with the selected signal.

[0071] However, for example, there is a risk that an ultrasonic echo signal similar to that of R22 may be detected between R22, where the radius R has decreased due to thinning, and R21, which corresponds to the original radius R. If this happens, there may be multiple plot candidates in the radial direction under the same θ2 conditions, and it may not be possible to accurately draw the line 82 indicating the outer edge of the inspection object 10.

[0072] Therefore, the image generating unit 70 keeps the second angle θ constant and identifies the radius R corresponding to the ultrasonic echo whose signal is detected among the multiple ultrasonic echoes in the radial direction. Then, the image generating unit 70 selects the smallest minimum radius Rmin from the identified radii R. Hereinafter, the process of selecting such a minimum radius Rmin may be referred to as a minimum radius selection process.

[0073] 8, the image generation unit 70 sets the second angle θ to a constant θ2 and identifies the radius R corresponding to the ultrasonic echoes whose signals are detected among the multiple ultrasonic echoes in the radial direction at θ2. For example, if there are multiple ultrasonic echoes whose signals are detected between R22 and R21, the image generation unit 70 identifies the radius R corresponding to each of the multiple ultrasonic echoes. Then, the image generation unit selects R22, which is the smallest of the multiple identified radii, as the minimum radius Rmin.

[0074] This allows the image generating unit 70 to accurately draw the line 82 indicating the outer edge of the object 10 even if there are a plurality of ultrasonic echoes whose signals are detected in the radial direction.

[0075] The image generating unit 70 performs the above-described minimum radius selection process for each second angle θ by changing the second angle θ. Then, the image generating unit 70 draws a line 82 corresponding to the outer edge of the inspection object 10 by connecting plots on the cross-sectional image 80 of the minimum radii Rmin selected for each second angle θ. In this way, the image generating unit 70 can generate the cross-sectional image 80 at the set depth Z. This allows the image generating unit 70 to accurately form the line 82 corresponding to the outer edge of the inspection object 10, regardless of whether the inspection object 10 is a healthy portion where no thinning has occurred or a thinned portion where thinning has occurred.

[0076] Furthermore, the image generating unit 70 may change the setting of the depth Z in the direction of the central axis 44 and generate multiple cross-sectional images 80 for each set depth Z. This allows the evaluating unit 72 to evaluate the degree of thinning of the inspection object 10 not only in two dimensions of the cross section but also in three dimensions including the depth Z direction. As a result, the user can grasp the degree of thinning of the inspection object 10 in more detail.

[0077] 9 is a flowchart illustrating the flow of operations of the ultrasound control unit 50 according to this embodiment. When the ultrasound control unit 50 receives an instruction to start a scan, it first sets a first angle Φ (S10). For example, the ultrasound control unit 50 sets the first angle Φ to the smallest angle within the control range of the first angle Φ.

[0078] Next, the ultrasonic control unit 50 sets a second angle θ (S11). For example, the ultrasonic control unit 50 sets the second angle θ to the smallest angle within the control range of the second angle. The ultrasonic control unit 50 causes the ultrasonic probe 32 to emit ultrasonic waves in an emission direction corresponding to the set first angle Φ and second angle θ (S12). The ultrasonic control unit 50 enters a standby state in which it can receive ultrasonic echoes for a predetermined time after emitting the ultrasonic waves, and acquires the ultrasonic echoes (S13). The ultrasonic control unit 50 stores the acquired ultrasonic echoes in the storage device 52 (S14).

[0079] Next, the ultrasonic control unit 50 determines whether the second angle θ has completed one cycle (S15). If the second angle θ has not completed one cycle (NO in S15), the ultrasonic control unit 50 resets the second angle θ (S11) and repeats the processing from step S11 onwards. For example, the ultrasonic control unit 50 changes the second angle θ to a value that is one step larger. At this time, the first angle Φ is not changed and is maintained constant.

[0080] In step S15, if the second angle θ has completed one revolution (YES in S15), the ultrasound control unit 50 determines whether the first angle Φ is equal to or greater than a predetermined angle (S16). The predetermined angle is set to a value that allows ultrasonic echoes to be acquired from a sufficiently wide area within the inspection object 10.

[0081] If the first angle Φ is less than the predetermined angle (NO in S16), the ultrasound control unit 50 resets the first angle Φ (S10) and repeats the processing from step S10 onwards. For example, the ultrasound control unit 50 changes the first angle Φ to a value one step larger. If the first angle Φ is equal to or greater than the predetermined angle (YES in S16), the ultrasound control unit 50 ends the processing related to the scan.

[0082] 10 is a flowchart illustrating the operation flow of the image generation device 36 according to this embodiment. When the scan-related processing by the ultrasound control unit 50 is completed, the image generation unit 70 starts the series of processing shown in FIG.

[0083] First, the image generation unit 70 acquires ultrasonic echo data from the flaw detection device 34, converts the time information of the ultrasonic echo into depth information, and generates an ultrasonic echo based on the depth Z (S20). The image generation unit 70 also converts the time information of the ultrasonic echo into radius information, and generates an ultrasonic echo based on the radius R (S21). The ultrasonic echo based on time, the ultrasonic echo based on the depth Z, and the ultrasonic echo based on the radius R are associated with each other.

[0084] Next, the image generator 70 detects a signal in which the amplitude of the ultrasonic echo converted into depth information is equal to or greater than a predetermined threshold (S22). The predetermined threshold is set to a value that allows the ultrasonic echo to be distinguished from noise.

[0085] Next, the image generating unit 70 extracts signals from the signals detected in step S22 that are close to each other in at least one of the second angle θ and the depth Z (S23). This extracts ultrasonic echoes related to the outer edge of the inspection object 10, and removes ultrasonic echoes unrelated to the outer edge of the inspection object 10. This improves the accuracy of depicting the outer edge of the inspection object 10 in the cross-sectional image 80.

[0086] Next, the image generating unit 70 sets the range of the depth Z for generating the cross-sectional image 80 (S24). For example, the image generating unit 70 may set the range of the depth Z based on the length of the object 10 in the axial direction.

[0087] Next, the image generating unit 70 sets a depth Z at which the cross-sectional image 80 is to be generated (S30). For example, the image generating unit 70 sets the minimum depth Z within the range of the depth Z. That is, the image generating unit 70 processes the signal corresponding to the set depth Z among the signals detected in step S22 and extracted in step S23 in the subsequent processing.

[0088] Next, the image generating unit 70 sets the second angle θ (S31). This keeps the second angle θ constant. For example, the image generating unit 70 sets the second angle θ to the smallest angle within the control range of the second angle θ. That is, the image generating unit 70 further processes signals corresponding to the set second angle θ from among the signals processed in step S30 in the subsequent processing. In steps S30 and S31, with the depth Z and the second angle θ fixed, signals in the radial direction perpendicular to the central axis 44 are processed.

[0089] Next, the image generating unit 70 identifies the radius R corresponding to the ultrasonic echoes whose signals were detected and extracted in steps S22 and S23, among the multiple ultrasonic echoes in the radial direction perpendicular to the central axis 44. Then, the image generating unit 70 performs a minimum radius selection process to select the smallest radius Rmin among the identified radii R (S32).

[0090] Next, the image generation unit 70 determines whether the second angle θ has completed one cycle (S33). If the second angle θ has not completed one cycle (NO in S33), the image generation unit 70 resets the second angle θ (S31) and repeats the processing from step S31 onwards. For example, the image generation unit 70 changes the second angle θ to a value that is one step larger, keeps the second angle θ constant at the changed value, and executes the minimum radius selection processing of step S32. In other words, the image generation unit 70 changes the second angle θ and executes the minimum radius selection processing of step S32 for each second angle θ.

[0091] If the second angle θ has completed one revolution (YES in S33), the image generating unit 70 generates a cross-sectional image 80 at the depth Z set in step S30 based on the selected minimum radius Rmin (S34). More specifically, the image generating unit 70 plots the second angle θ corresponding to the signal corresponding to the selected minimum radius Rmin and the position specified by the minimum radius Rmin on the cross-sectional image at the set depth Z. The image generating unit 70 performs this plotting for each minimum radius Rmin selected for each second angle θ. The image generating unit 70 draws a line 82 indicating the outer edge of the object 10 in the cross-sectional image 80 by connecting multiple plots on the cross-sectional image 80 obtained in this manner.

[0092] Next, the image generating unit 70 determines whether or not cross-sectional images 80 have been generated for the entire range within the range of depth Z set in step S24 (S36). If there is a depth Z for which a cross-sectional image 80 has not been generated (NO in S36), the image generating unit 70 sets the depth Z for which no cross-sectional image has been generated (S30) and repeats the processing from step S30 onwards. That is, the image generating unit 70 changes the setting of depth Z and generates multiple cross-sectional images 80 for each set depth Z.

[0093] When cross-sectional images 80 are generated for the entire range within the depth Z (YES in S36), the evaluation unit 72 executes an evaluation process to evaluate the degree of wall thinning for each of the generated cross-sectional images 80 (S37). For example, the evaluation unit 72 evaluates the degree of wall thinning based on the cross-sectional area of ​​a region surrounded by the outer edge of the inspection object 10 in the cross-sectional image 80.

[0094] Next, the image generating unit 70 displays the generated cross-sectional image 80 on the display, and the evaluating unit 72 displays the evaluation result on the display (S38), thereby completing the series of processes.

[0095] As described above, the inspection device 30 of this embodiment includes a phased array ultrasonic probe 32 and an image generation unit 70. The ultrasonic probe 32 is disposed on the end face 42 of the rod-shaped inspection object 10 in the axial direction, emits ultrasonic waves into the interior of the inspection object 10, and receives ultrasonic echoes reflected from the inspection object 10. The image generation unit 70 generates a cross-sectional image 80 that depicts the outer edge of the inspection object 10 in a cross section perpendicular to the axial direction of the inspection object 10, based on the ultrasonic echoes. The inspection device 30 of this embodiment generates a cross-sectional image 80 that depicts the outer edge of the inspection object 10, allowing the user to intuitively grasp the outer edge of the inspection object 10.

[0096] Therefore, according to the inspection device 30 of this embodiment, it is possible to easily grasp the inspection results.

[0097] Furthermore, the image generating device 36 of this embodiment is disposed on an end surface 42 in the axial direction of the rod-shaped inspection object 10, and acquires ultrasonic echoes from a phased array ultrasonic probe 32 that emits ultrasonic waves into the interior of the inspection object 10 and receives ultrasonic echoes reflected from the inspection object 10. Based on the ultrasonic echoes, the image generating device 36 generates a cross-sectional image 80 that depicts the outer edge of the inspection object 10 in a cross section perpendicular to the axial direction of the inspection object 10. The image generating device 36 of this embodiment also generates a cross-sectional image 80 that depicts the outer edge of the inspection object 10, allowing the user to intuitively grasp the outer edge of the inspection object 10. Therefore, the image generating device 36 of this embodiment makes it possible to easily grasp the inspection results.

[0098] Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0099] This disclosure can contribute, for example, to Goal 12 of the Sustainable Development Goals (SDGs), "Ensure sustainable consumption and production patterns." [Explanation of symbols]

[0100] 10. Subjects of Inspection 30 Inspection equipment 32 Ultrasonic probe 36 Image generation device 42 End face 50 Ultrasonic control unit 70 Image generation unit 72 Evaluation Department 80 cross-sectional images

Claims

1. a phased array ultrasonic probe that is disposed on an end surface of a rod-shaped object to be inspected in an axial direction, and that emits ultrasonic waves into the object to be inspected and receives ultrasonic echoes reflected from the object to be inspected; an image generating unit that generates a cross-sectional image depicting an outer edge of the inspection object in a cross section perpendicular to the axial direction of the inspection object based on the ultrasonic echo; Equipped with When the distance from the central axis in a radial direction perpendicular to the central axis of the ultrasonic probe is defined as a radius (R), The image generation unit converting time information of the received ultrasonic echo into depth information indicating a depth (Z) of the object to be inspected in the central axis direction; Detecting a signal in which the amplitude of the ultrasonic echo converted into the depth information is equal to or greater than a predetermined threshold; A depth (Z) in the direction of the central axis is set, A minimum radius selection process is performed to identify the radius (R) corresponding to the ultrasonic echo at which the signal is detected among the plurality of ultrasonic echoes in the radial direction while keeping the second angle (θ) around the central axis constant, and to select a minimum radius (Rmin) that is the smallest among the identified radii (R); The second angle (θ) is changed, and the minimum radius selection process is executed for each second angle (θ); By connecting the plots on the cross-sectional image of the minimum radius (Rmin) selected for each second angle (θ), an outer edge of the object to be inspected in the cross-sectional image is drawn, and the cross-sectional image at the set depth (Z) is generated. Inspection equipment.

2. an ultrasonic control unit that controls the radiation direction of the ultrasonic waves radiated by the ultrasonic probe; The ultrasonic control unit a circumferential scan is performed in which a first angle (Φ) formed between a central axis of the ultrasonic probe and the radiation direction is kept constant, the radiation direction is changed in a direction of a second angle (θ) around the central axis, and the ultrasonic waves are emitted and the ultrasonic echoes are received for each second angle (θ); The inspection device according to claim 1 , wherein the circumferential scan is performed for each of the first angles (Φ) by changing the first angle (Φ).

3. The image generation unit extracting a plurality of signals from the detected signals, the signals being close to each other in at least one of the second angle (θ) around the central axis and the depth (Z) in the central axis direction; The inspection device according to claim 1 , wherein the minimum radius selection process is performed on the extracted plurality of signals as processing targets.

4. The image generation unit The inspection device according to claim 1 , wherein a setting of the depth (Z) in the central axis direction is changed, and a plurality of the cross-sectional images are generated for each of the set depths (Z).

5. 5. The inspection device according to claim 1, further comprising an evaluation unit that evaluates a degree of wall thinning, which is a degree of reduction in the wall thickness of the object to be inspected in a direction perpendicular to the axial direction of the object to be inspected, based on the cross-sectional image.

6. The inspection device according to claim 5 , wherein the evaluation unit evaluates the degree of thinning of the inspection object based on a cross-sectional area of ​​a region surrounded by an outer edge of the inspection object in the cross-sectional image.

7. an image generating device that is arranged on an end face of a rod-shaped object to be inspected in an axial direction, that acquires ultrasonic echoes from a phased array ultrasonic probe that emits ultrasonic waves into the inside of the object to be inspected and receives ultrasonic echoes reflected from the object to be inspected, and that generates a cross-sectional image that depicts an outer edge of the object to be inspected in a cross section perpendicular to the axial direction of the object to be inspected based on the ultrasonic echoes; When the distance from the central axis in a radial direction perpendicular to the central axis of the ultrasonic probe is defined as a radius (R), converting time information of the received ultrasonic echo into depth information indicating a depth (Z) of the object to be inspected in the central axis direction; Detecting a signal in which the amplitude of the ultrasonic echo converted into the depth information is equal to or greater than a predetermined threshold; A depth (Z) in the direction of the central axis is set, A minimum radius selection process is performed to identify the radius (R) corresponding to the ultrasonic echo at which the signal is detected among the plurality of ultrasonic echoes in the radial direction while keeping the second angle (θ) around the central axis constant, and to select a minimum radius (Rmin) that is the smallest among the identified radii (R); The second angle (θ) is changed, and the minimum radius selection process is executed for each second angle (θ); By connecting the plots on the cross-sectional image of the minimum radius (Rmin) selected for each second angle (θ), an outer edge of the object to be inspected in the cross-sectional image is drawn, and the cross-sectional image at the set depth (Z) is generated. Image generating device.