JP6779727B2 - Ultrasonic flaw detector, data processing device and ultrasonic flaw detector - Google Patents

Description

Embodiments of the present invention relate to ultrasonic flaw detection devices, data processing devices, and ultrasonic flaw detection methods.

Ultrasonic testing (UT) is a technology that can confirm the soundness of the surface and inside of structural materials in a non-destructive manner, and is an indispensable inspection technology in various fields. The phased array ultrasonic flaw detection test (PAUT: Phased Array UT) is capable of forming an arbitrary waveform by arranging small piezoelectric elements for transmitting and receiving ultrasonic waves and transmitting ultrasonic waves by shifting the timing (delay time) for each piezoelectric element. , Also widely used in industrial applications.

Compared to monocular probes that can emit ultrasonic waves only at a predetermined angle, phased array ultrasonic flaw detection technology has the potential to detect a wide range with a single flaw detection, detect flaws at multiple angles, and handle complex shapes. It is a big attraction that the work man-hours can be reduced. Phased array ultrasonic flaw detection technology has been undertaken in various ways to further speed up inspections. Originally, in the phased array ultrasonic flaw detection test, the flaw detection refraction angle and the focal depth are freely controlled by exciting a plurality of element groups with a time delay.

In this case, a set of delay times is given to one element group to obtain a flaw detection result of one waveform (hereinafter, this is referred to as one sequence), but when the number of sequences exceeds, for example, 1000, The measurement time becomes long. Therefore, attempts have been made to reduce the measurement time by reducing the number of times ultrasonic waves are transmitted and received as much as possible.

In the above-mentioned phased array ultrasonic flaw detection test, when there are n transmitting / receiving elements, if the raw waveforms of n receiving elements, that is, n × n raw waveforms can be recorded for each transmitting element, the waveform is followed by the delay time. All conditions can be reconfigured offline by shifting the time axis of and adding them together. Several attempts have been made to speed up phased array ultrasonic testing using this concept.

For example, a technique of transmitting and receiving ultrasonic waves only once and synthesizing the received signals obtained there under arbitrary flaw detection conditions, or a sequence of transmitting ultrasonic waves with one element and receiving ultrasonic waves with multiple elements is performed. There is known a technique that enables pseudo transmission / reception focus by synthesizing the obtained waveforms by repeatedly changing the element that transmits the sound wave.

In addition, improvement of the signal-to-noise ratio (SN ratio) is an issue in order to prevent noise from being mistakenly recognized as a defect in an inspection target such as a welded portion where anisotropy or crystal grains are coarsened. .. For example, in welding part inspection, in addition to the technology using a database and simulation, the technology of designing a dedicated probe is also known. Recently, a flaw detection method in which the size of an array element or the like is changed is also known.

Japanese Patent No. 3704065 Japanese Unexamined Patent Publication No. 2009-281805 Japanese Patent No. 5588918 Japanese Unexamined Patent Publication No. 2001-343370

However, the above-mentioned various measures to prevent false recognition of noise as a defect are aimed at improving the fundamental signal-to-noise ratio (SN ratio), and are defect echoes (reflected waves of ultrasonic waves reflected by defects). ) And noise are still difficult to distinguish effectively.

Based on the above, the embodiment of the present invention utilizes the fact that the behavior of the noise signal intensity change and the defect echo signal intensity change when the flaw detection conditions are changed is different, so that the ultrasonic flaw detection of the welded portion or the like can be performed. The purpose is to make it possible to effectively discriminate between defect echo and noise even in a noisy object without prior investigation or comparison with a database.

To achieve the above object, an ultrasonic flaw detection apparatus according to the present embodiment, a plurality of ultrasonic elements arranged in parallel to receive the ultrasonic waves reflected by said object to transmit ultrasonic waves to the inspection target A delay time for calculating a delay time for shifting the timing at which the ultrasonic element transmits and receives ultrasonic waves, and an ultrasonic array probe having the above, a potential difference applying unit capable of applying a potential difference that causes vibration to the ultrasonic element. Received by the calculation unit, a switching unit that switches between a state in which the potential difference applying unit applies a potential difference to the ultrasonic element and a state in which the potential difference applying unit does not apply a potential difference to the ultrasonic element, and the ultrasonic element. A feature amount calculation unit that calculates a feature amount related to a synthetic echo obtained by synthesizing a received wave according to the delay time, and a feature amount change calculation that calculates a change in the feature amount in response to a change in the ultrasonic flaw detection condition for the inspection target. and parts, and the feature quantity of the maximum value or the reference testing conditions as determined defect determining section whether a defect based on the change of the feature quantity using the determination parameter giving the minimum value, calculated the feature comprising a display unit for displaying the change in the amount, and as the determination parameter, is characterized by using two or more different flaw refraction angle condition.
Further, the ultrasonic flaw detector according to the present embodiment is an ultrasonic array probe having a plurality of ultrasonic elements arranged in parallel with each other to transmit ultrasonic waves to an inspection target and receive the ultrasonic waves reflected by the inspection target. A potential difference application unit capable of applying a potential difference that causes vibration to the ultrasonic element, a delay time calculation unit that calculates a delay time for shifting the timing at which the ultrasonic element transmits and receives ultrasonic waves, and the potential difference. A switching unit that switches between a state in which the application unit applies a potential difference to the ultrasonic element and a state in which the potential difference application unit does not apply a potential difference to the ultrasonic element, and a delay time of the received wave received by the ultrasonic element. The feature amount calculation unit that calculates the feature amount related to the synthetic echo synthesized according to the above, the feature amount change calculation unit that calculates the change of the feature amount in response to the change of the ultrasonic flaw detection condition to the inspection target, and the calculated above. A display unit for displaying changes in the feature amount is provided, and the feature amount is a change in the center position of an echo region in which the intensity of the synthetic echo exceeds or exceeds a predetermined threshold value. It is characterized by that.

Further, the data processing device according to the present embodiment is a data processing device that processes signal data transmitted and received to an inspection target by an ultrasonic array probe having a plurality of ultrasonic elements, and the ultrasonic element emits ultrasonic waves. A delay time calculation unit that calculates a delay time for shifting the transmission / reception timing, a state in which the potential difference applying unit applies a potential difference to the ultrasonic element, and a state in which the potential difference applying unit does not apply a potential difference to the ultrasonic element. A switching unit that switches between, a feature amount calculation unit that calculates a feature amount related to a synthetic echo obtained by synthesizing a received wave received by the ultrasonic element according to the delay time, and a change in the flaw detection condition of the ultrasonic wave to the inspection target. Whether or not the defect is based on the change in the feature amount using the feature amount change calculation unit that calculates the change in the feature amount with respect to the target, the reference flaw detection condition that gives the maximum value or the minimum value of the feature amount, and the determination parameter. a defect determining unit determines a display unit for displaying the change in the calculated said feature amount, characterized in that it comprises a.

Further, in the ultrasonic flaw detection method according to the present embodiment, an image of the inside of the inspection target is obtained by the imaging unit based on a composite waveform of the received ultrasonic waves transmitted from the ultrasonic element of the ultrasonic array probe to the inspection target. The feature amount calculation step of creating the image, the feature amount calculation unit calculates the feature amount based on the image, and the feature amount change calculation unit changes the feature amount in response to the change of the flaw detection condition. a feature quantity variation calculation step of calculating, whether defect determination unit is a defect on the basis of a change of the feature quantity using the determination parameter and the reference flaw detection condition giving the maximum or minimum value of the feature amount a determination step of determining, display unit, have a, and a display step of displaying a change in the characteristic quantity, as the determination parameter, is characterized by using two or more different flaw refraction angle condition ..
Further, in the ultrasonic flaw detection method according to the present embodiment, an image of the inside of the inspection target is based on a composite waveform of the received wave of the ultrasonic wave transmitted from the ultrasonic element of the ultrasonic array probe to the inspection target by the imaging unit. The feature amount calculation step of creating the image, the feature amount calculation unit calculates the feature amount based on the image, and the feature amount change calculation unit changes the feature amount in response to a change in the flaw detection condition. The feature amount change calculation step for calculating the feature amount change calculation step, the pattern selection step in which the defect determination unit selects a change pattern based on the calculation result in the feature amount change calculation step, and the defect determination unit determines the selected change. A parameter reading step of reading the corresponding determination parameter from the parameter storage unit based on the pattern, and a flaw detection condition determination step in which the defect determination unit determines a reference flaw detection condition based on the calculation result in the feature quantity change calculation step. The defect determination unit determines whether or not the echo is based on a defect based on the calculation result in the feature amount change calculation step, the determination parameter, and the reference flaw detection condition, and the display unit is the feature. A display step that displays the change in quantity, and
It is characterized by having.

According to the embodiment of the present invention, defect echo and noise can be effectively discriminated from each other.

It is a block diagram which shows the structure of the ultrasonic flaw detection apparatus which concerns on 1st Embodiment. It is a conceptual vertical sectional view which shows the transmission of the ultrasonic wave of the ultrasonic flaw detector which concerns on 1st Embodiment. It is a conceptual diagram which shows the progress state of the ultrasonic wave of the ultrasonic flaw detector which concerns on 1st Embodiment. It is a conceptual diagram for demonstrating the traveling direction of ultrasonic waves of the ultrasonic flaw detection apparatus which concerns on 1st Embodiment. It is a graph which shows the temporal change of the synthetic signal of the echo signal by the ultrasonic flaw detector which concerns on 1st Embodiment. It is a conceptual diagram which shows the case where there is a defect in the flaw detection space area. This is the result of visualization of the flaw detection space area when there is a defect in the flaw detection space region. It is a conceptual diagram which shows the case where there is a welded part in addition to a defect in a flaw detection space region. It is an image obtained as a result of visualization of the flaw detection space region when there is a welded portion in addition to the defect in the flaw detection space region. It is the 1st image explaining the extraction of the significant echo region from the visualization result of the flaw detection space region in the ultrasonic flaw detection method which concerns on 1st Embodiment, (a) is before extraction of a significant echo region, (b). Indicates after extraction of the significant echo region. It is the 2nd image explaining the extraction of the significant echo region from the visualization result of the flaw detection space region in the ultrasonic flaw detection method which concerns on 1st Embodiment, (a) is before extraction of a significant echo region, (b). Indicates after extraction of the significant echo region. It is an image of the echo intensity distribution by visualization of the flaw detection space region when the flaw detection refraction angle β in the ultrasonic flaw detection method according to the first embodiment is changed, and (a) is an image in which β is 20 ° and (b). Is the case where β is 30 °, and (c) is the case where β is 40 °. It is a graph which shows the example of the change of the echo intensity when the flaw detection refraction angle β in the ultrasonic flaw detection method which concerns on 1st Embodiment is changed. It is a flow chart which shows the procedure in the ultrasonic flaw detection method which concerns on 1st Embodiment. It is a graph explaining an example of the determination content of the presence or absence of a defect in the defect determination part in the ultrasonic flaw detection method which concerns on 1st Embodiment. It is a flow chart which shows the procedure of determination in the ultrasonic flaw detection method which concerns on 1st Embodiment. It is a graph which shows the example of the change of the echo intensity when the focal depth F is changed in the modification of the ultrasonic flaw detection method which concerns on 1st Embodiment. It is a block diagram which shows the structure of the ultrasonic flaw detection apparatus which concerns on 2nd Embodiment. It is an image which shows the example of the change of the central position of the echo region of the flaw detection space region when the flaw detection refraction angle β in the ultrasonic flaw detection method which concerns on 2nd Embodiment is changed, and (a) is the image which shows the example of change of β by 20 ° , (B) is the case where β is 30 °, and (c) is the case where β is 40 °. It is a graph which shows the example of the change of the center position of the echo region of the flaw detection space region when the flaw detection refraction angle β is changed in the ultrasonic flaw detection method which concerns on 2nd Embodiment. It is a block diagram which shows the structure of the ultrasonic flaw detection apparatus which concerns on 3rd Embodiment. An example of a change in the frequency distribution of the luminance value in each pixel in the flaw detection space region when the flaw detection refraction angle β in the ultrasonic flaw detection method according to the third embodiment is changed, and is a graph showing the case of noise. Is. A graph showing the case of a defect, which is an example of a change in the frequency distribution of the brightness value in each pixel in the flaw detection space region when the flaw detection refraction angle β in the ultrasonic flaw detection method according to the third embodiment is changed. Is. It is a block diagram which shows the structure of the ultrasonic flaw detection apparatus which concerns on 4th Embodiment. It is a graph which shows the example of the change of the echo intensity at the time of changing the flaw detection refraction angle β in the ultrasonic flaw detection method which concerns on 4th Embodiment. It is a conceptual explanatory view for explaining the integration in the ultrasonic flaw detection method which concerns on 4th Embodiment, and (a) is the flaw detection refraction angle when the flaw detection refraction angle as a flaw detection condition is in the range of βs to βe. When is βs, (b) shows the result of integration when the flaw detection refraction angle is βe. It is a figure for comparison explaining the effect of integration in the ultrasonic flaw detection method which concerns on 4th Embodiment, (a) shows the case of not integrating, (b) shows the case of integration. It is a block diagram which shows the structure of the ultrasonic flaw detection apparatus which concerns on 5th Embodiment. It is a flow chart which shows the procedure in the ultrasonic flaw detection method which concerns on 5th Embodiment. It is a block diagram which shows the state of each transmission of the ultrasonic wave in the ultrasonic flaw detection method which concerns on 5th Embodiment. It is a waveform diagram which shows a part of the echo waveform by transmission of the ultrasonic wave in the ultrasonic flaw detection method which concerns on 5th Embodiment. It is a waveform diagram explaining the delay time at the time of transmission and reception of ultrasonic waves in the ultrasonic flaw detection method which concerns on 5th Embodiment. It is a waveform diagram which shows the composite waveform of the echo by the ultrasonic flaw detection method which concerns on 5th Embodiment. It is a block diagram which shows the structure of the ultrasonic flaw detection apparatus which concerns on 6th Embodiment.

Hereinafter, the ultrasonic flaw detector, the data processing apparatus, and the ultrasonic flaw detector method according to the embodiment of the present invention will be described with reference to the drawings. Here, parts that are the same as or similar to each other are designated by a common reference numeral, and duplicate description will be omitted.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of an ultrasonic flaw detector according to the first embodiment. The ultrasonic flaw detection device 100 includes an ultrasonic array probe 10, a transmission / reception unit 20, a calculation unit 30, a storage unit 40, a control calculation unit 50, a display unit 60, and an input unit 70. The ultrasonic flaw detector 100 aims to detect a defect 2 inherent in the inspection target 1.

The ultrasonic array probe 10 has a plurality of ultrasonic elements 11. The ultrasonic elements 11 are arranged one-dimensionally (one direction) at regular intervals from each other. The ultrasonic element 11 is made of ceramics, a composite material, or other piezoelectric element capable of generating ultrasonic waves by a piezoelectric effect, a piezoelectric element made of a polymer film, or other mechanism capable of generating ultrasonic waves, or ultrasonic damping. It is composed of any of the damping material, the front plate attached to the ultrasonic oscillation surface, or a combination thereof, and is generally called an ultrasonic probe.

Although the example in which the ultrasonic array probe 10 has the ultrasonic element 11 which is arranged one-dimensionally has been described, the present invention is not limited to this. For example, a 1.5-dimensional array probe in which piezoelectric elements are divided into non-uniform sizes in the depth direction of a linear array probe, a matrix array probe in which piezoelectric elements are arranged two-dimensionally, and ring-shaped piezoelectric elements are concentric. Arranged ring array probes, split ring array probes in which the piezoelectric elements of the ring array probe are divided in the circumferential direction, non-uniform array probes in which the piezoelectric elements are non-uniformly arranged, and circles in which the elements are arranged in the circumferential direction of the arc. An arc-shaped array probe, a spherical array probe in which an element is arranged on the surface of a spherical surface, or the like may be used.

Further, so-called tandem flaw detection may be performed in which a plurality of these array probes are used in combination regardless of the type. In addition, the above array probes include those that can be used in air or in water by caulking or packing.

At the time of inspection of the inspection target 1, an acoustic propagation medium 5 also called a wedge is provided between the ultrasonic array probe 10 and the inspection target 1. The acoustic propagation medium 5 is for incidenting ultrasonic waves on the inspection target 1 at an angle having high directivity. As the acoustic propagation medium 5, an isotropic material capable of propagating ultrasonic waves and whose acoustic impedance can be grasped is used. When the surface of the inspection target 1 is flat, the acoustic propagation medium 5 does not have to be used.

Examples of the isotropic material used as the acoustic propagation medium 5 include acrylic, polyimide, gel, and other polymers. It is possible to use a material having an acoustic impedance close to or the same as that of the front plate (not shown) of the ultrasonic element 11, or a material having an acoustic impedance close to or the same as that of the inspection target 1. Further, it may be a composite material in which the acoustic impedance is changed stepwise or gradually.

Further, in order to prevent the multiple reflection waves in the acoustic propagation medium 5 from affecting the flaw detection result, a damping material is arranged inside and outside the acoustic propagation medium 5, a mountain-shaped wave-eliminating shape is provided, and a multiple reflection reduction mechanism is provided. May have. In the following description, the display of the acoustic propagation medium 5 may be omitted in the explanatory diagram when the ultrasonic waves are incident on the inspection target 1 from the ultrasonic array probe 10.

The contact portion of the path from the ultrasonic array probe 10 to the inspection target 1, that is, the contact portion between the ultrasonic array probe 10 and the acoustic propagation medium 5, the contact portion between the acoustic propagation medium 5 and the inspection target 1, or the acoustic. An acoustic contact medium (not shown) is used for propagating ultrasonic waves at the contact portion between the ultrasonic array probe 10 and the inspection target 1 when the propagation medium 5 is not used. The acoustic contact medium is a medium capable of propagating ultrasonic waves, such as water, glycerin, machine oil, castor oil, acrylic, polystyrene, and gel.

The transmitting / receiving unit 20 includes a potential difference applying unit 21, a switching unit 22, and an AD conversion unit 23. The potential difference application unit 21 applies a potential difference that causes vibration to the ultrasonic element 11 to the ultrasonic element 11 that is connected so as to be applicable. Based on the command from the control calculation unit 50, the switching unit 22 switches between the state of being connected to the potential difference applying unit 21 and the state of not being connected to the potential difference applying unit 21 for each of the ultrasonic elements 11. Do. The AD conversion unit 23 digitizes the signal (echo signal) received by each of the ultrasonic elements 11 and outputs the digital ultrasonic waveform to the storage unit 40.

The storage unit 40 has a signal processing information storage unit 41 and a parameter storage unit 42. The signal processing information storage unit 41 stores the ultrasonic echo signal (digital ultrasonic waveform data) received by the transmission / reception unit 20. In addition, the calculation processing result in the calculation unit 30 is stored as processing information. The parameter storage unit 42 stores determination parameters used for determination by the defect determination unit 37 of the calculation unit 30, which will be described later. The determination parameter is input from the input unit 70.

FIG. 2 is a conceptual vertical cross-sectional view showing the transmission of ultrasonic waves. The flaw detection when a general phased array is used is shown. Appropriate time delay for each ultrasonic element 11 constituting the drive element group defined in the ultrasonic array probe 10 in order to inject ultrasonic waves into the inside of the inspection target 1 at an arbitrary flaw detection refraction angle β and a focal position. Is given and oscillates. This makes it possible to control the incident angle α and the focal position (not shown or described) of the ultrasonic wave on the inspection target 1.

A linear scanning method that obtains a cross-sectional view of the ultrasonic elements 11 in the direction in which they are lined up by scanning the drive element group in the ultrasonic array probe 10. The position of the drive element group is fixed and only the flaw detection refraction angle β There is a sector scan method or the like in which a fan-shaped cross-sectional view is obtained by scanning. In the present embodiment, the linear scan method will be typically described as an example, but in addition to the sector scan method, a plurality of ultrasonic waves such as Dynamic Depth Focusing (DDF) that changes the focal depth according to the region to be measured. Another flaw detection method may be used in which the element 11 is controlled for a delay time.

The calculation unit 30 includes a delay time calculation unit 31, a signal synthesis unit 32, a visualization unit 33, an extraction unit 34, an intensity distribution calculation unit 35a as a feature amount calculation unit 35, and an intensity distribution change calculation as a feature amount change calculation unit 36. It has a unit 36a and a defect determination unit 37.

The delay time calculation unit 31 applies a voltage from the potential difference application unit 21 to a plurality of ultrasonic elements 11 as a drive element group in order to focus the ultrasonic waves to a predetermined flaw detection refraction angle β and focal depth. The timing for switching to, that is, the delay time for shifting the timing of ultrasonic wave transmission is calculated. Based on this delay time, the switching unit 22 switches, and each ultrasonic element 11 is put into a voltage application state. That is, by driving each ultrasonic element 11 based on the delay time calculated from the desired flaw detection conditions in the delay time calculation unit 31, the ultrasonic array probe 10 can perform flaw detection under the desired flaw detection conditions. .. The flaw detection condition is a flaw detection parameter for ultrasonic flaw detection, and includes at least one of the flaw detection refraction angle β and the focal depth in the present embodiment, but other necessary flaw detection conditions are required for flaw detection. It may be a flaw detection parameter.

The delay time is calculated from the relative positional relationship between the ultrasonic array probe 10 and the inspection target 1, the flaw detection refraction angle β, the focus depth, the surface shape of the inspection target 1, the acoustic propagation medium 5, and the sound velocity in the inspection target 1. ..

At this time, even if the surface shape of the inspection target 1 is not a general flat surface or an inclined flat surface but has a curvature or an uneven portion, the geometric calculation can be performed in consideration of the curvature or uneven portion. The surface shape of the inspection target 1 may be calculated using the flight time of ultrasonic waves emitted from the ultrasonic element 11, or shape data such as an existing drawing may be read. Further, an inspection target surface shape measuring means such as a camera or a laser range finder may be attached to the ultrasonic array probe 10 or separately provided near the ultrasonic array probe 10. In addition, the delay time itself, which has been calculated in advance, can be read and used.

When inspecting the inspection target 1, for example, the inspection target 1 may be inspected for each region, and instead of using all the ultrasonic elements 11 included in the ultrasonic array probe 10.
Some of the ultrasonic elements 11 may be used as the same group at the same time, and the groups may be moved sequentially. As described above, the ultrasonic element 11 used in the same group is referred to as a drive element group. The drive element group may be the case of all the ultrasonic elements 11 in the ultrasonic array probe 10.

Further, the delay time calculation unit 31 also calculates the delay time for shifting the timing on the receiving side in the same manner.

The signal synthesizer 32 uses the data of each digital ultrasonic waveform (echo waveform) received by the ultrasonic element 11 of the driving element group, and receives each according to the delay time on the receiving side of each ultrasonic element 11. The digital ultrasonic waveform data (echo waveform signal) of the above is moved on the time axis and added or averaged to obtain a composite signal (composite echo signal). The composition may be a method other than addition or addition averaging. The synthesis result in the signal synthesis unit 32 is stored in the signal processing information storage unit 41.

FIG. 3 is a conceptual diagram showing a progress state of ultrasonic waves of the ultrasonic flaw detector according to the first embodiment. Each line indicating the path of the ultrasonic wave is transmitted to each of the plurality of ultrasonic elements 11 belonging to the respective driving element groups by delaying the delay time calculated by the delay time calculation unit 31.

FIG. 4 is a conceptual diagram for explaining the traveling direction of ultrasonic waves. Now, a case where there are four ultrasonic elements 11 belonging to the driving element group will be described as an example. The transmission positions where ultrasonic waves are emitted from each of the ultrasonic elements 11 are P1, P2, P3 and P4, and the ultrasonic waves emitted from these transmission positions are C1, C2, C3 and C4.

If no delay time is provided, the ultrasonic waves propagate while traveling in front of the ultrasonic array probe 10, that is, parallel to the straight line L0 in which the ultrasonic elements 11 are arranged.

On the other hand, assuming that the transmission time from each transmission position is deviated by Δt, the distance traveled by each ultrasonic wave is gradually delayed. That is, the ultrasonic waves emitted from P1 travel to C1, but the latest ultrasonic waves emitted from P4 travel only to C4. As a result, the envelope LC is tilted from the straight line L0 in which the ultrasonic elements 11 are arranged. Assuming that the vector extending in the direction perpendicular to the envelope LC from the center of the ultrasonic element 11 belonging to the driving element group is the main beam L1, the main beam L1 is inclined from the direction perpendicular to the straight line L0. By providing the sequential delay time in this way, the direction of the synthesized ultrasonic waves can be angled.

The above is the linear scan method. As described above, there are a plurality of sector scan methods such as a sector scan method in which the position of the driving element group is fixed and only the flaw detection refraction angle β is scanned to obtain a fan-shaped cross-sectional view. Other flaw detection methods may be performed by controlling the delay time of the ultrasonic element of the above.

FIG. 5 is a graph showing a temporal change of a composite signal (composite echo signal) of an echo signal which is a reception signal of the ultrasonic element 11 of the ultrasonic flaw detector according to the present embodiment. The horizontal axis shows time, and the vertical axis shows the vibration intensity of the combined waveform (synthetic echo) of ultrasonic waves that are received waves (echo). The first half of the time change shows the propagation in the acoustic propagation medium 5, and the second half shows the propagation in the inspection target 1.

The visualization unit 33 calculates the sound line propagating from the center of the driving element group to the ultrasonic main beam L1 based on the relative positional relationship between the ultrasonic array probe 10 and the inspection target 1 and the shape of the inspection target 1. , The strength of the synthesized signal is plotted in the flaw detection space region of the inspection target 1 according to the sound line. By sequentially scanning the drive element group, a contour diagram or a flaw detection image of the signal strength in the flaw detection space region is generated. The calculation result in the visualization unit 33 and the information for generating the contour diagram are stored in the signal processing information storage unit 41.

FIG. 6 is a conceptual diagram showing a case where there is a defect in the flaw detection space area. This is the case where the defect 2 is present in the inspection target 1. At the time of this imaging, the amplitude of vibration or the square of the amplitude of vibration is replaced with brightness.

Imaging is a method generally called B-scan or S-scan. This image is reconstructed by the refraction angle and the flaw detection refraction angle according to the flaw detection condition such as the incident condition of the ultrasonic wave to the inspection target at the time of flaw detection. The following examples will be described using B-scan.

As shown in FIG. 6, when the acoustic propagation medium 5 is located between the ultrasonic array probe 10 and the inspection target 1, the propagation position thereof can also be visualized. The propagation speed in the acoustic propagation medium 5 is, for example, about 1500 m / sec in the case of water. When the material of the inspection target 1 is, for example, iron, the propagation speed in the inspection target 1 is about 5900 m / sec.

The dimensions, incident angle α, and flaw detection refraction angle β of the acoustic propagation medium 5 are known, and the propagation speed of ultrasonic waves in the acoustic propagation medium 5 and the inspection target 1 is also known. Therefore, each time related to the composite waveform has a one-to-one correspondence with the propagation position in the acoustic propagation medium 5 and the propagation position in the inspection target 1 in the flaw detection space region, and the temporal change of the composite waveform is each in the flaw detection space region. Can be replaced with a position.

FIG. 7 is a visualization result of the flaw detection space region when there is a defect in the flaw detection space region. In the case of B-scan, the visualization unit 33 determines the intensity of the ultrasonic signal in the process of ultrasonic wave propagation in the parallel plane of the ultrasonic element 11 in the ultrasonic array probe 10 in this way. It is shown by change. The portion indicated by Ed in FIG. 7 corresponds to the defect.

FIG. 8 is a conceptual diagram showing a case where there is a welded portion in addition to the defect in the flaw detection space region. Further, FIG. 9 is a visualization result of the flaw detection space area in this case. The portion indicated by Ed in FIG. 9 corresponds to the defect 2. On the other hand, the portion indicated by En corresponds to the welded portion 3. As described above, at first glance, it is very difficult to distinguish between the defect 2 and the welded portion 3.

In the extraction unit 34 shown in FIG. 1, the intensity of the synthesized echo synthesized by the echo which is the received wave is equal to or higher than a predetermined value (or exceeds a predetermined strength) in the flaw detection space region based on the synthesized signal or the visualization result. ) Region (echo region) is extracted as a significant echo region. The predetermined intensity threshold can be set based on experience, for example, the echo intensity distribution in a test using a test piece whose internal state is known.

FIG. 10 is a first image illustrating extraction of a significant echo region from the visualization result of the flaw detection space region in the ultrasonic flaw detection method according to the first embodiment, and FIG. 10A is a first image before extraction of the significant echo region. , (B) show after extraction of the significant echo region. In this way, a threshold value is set and all echoes below the threshold value are eliminated.

FIG. 11 is a second image for explaining the extraction of the significant echo region from the visualization result of the flaw detection space region in the ultrasonic flaw detection method according to the first embodiment, and FIG. 11A is a second image before extraction of the significant echo region. , (B) show after extraction of the significant echo region. This also sets a threshold value and eliminates all echoes below the threshold value.

The intensity distribution calculation unit 35a as the feature amount calculation unit 35 shown in FIG. 1 calculates the brightness of the image visualized by the visualization unit 33, that is, the intensity distribution at each position of the composite signal. The intensity distribution change calculation unit 36a as the feature amount change calculation unit 36 calculates the change in the intensity distribution corresponding to the change in the flaw detection condition.

Let EIj be the echo intensity in a certain echo region Ej. At this time, j is a natural number and represents the index of the echo region in a certain flaw detection space region. The intensity of the composite echo can be expressed, for example, by the brightness in the imaged state. The brightness of each point in the echo region of the index j is set in proportion to the amplitude of the ultrasonic vibration at that point, the square of the amplitude, or the like. The echo intensity EIj of the echo region Ej of the index j is defined by the addition, averaging, peak value, or other representative value of the luminance at each point in the echo region Ej. Since this echo intensity EIj changes depending on the flaw detection conditions such as the flaw detection refraction angle β and the position of the focal point, if these are used as variables and the flaw detection condition θ is set, it is expressed as the echo strength EIj (θ) under each flaw detection condition.

FIG. 12 is an image of the echo intensity distribution by imaging the flaw detection space region when the flaw detection refraction angle β in the ultrasonic flaw detection method according to the first embodiment is changed, and FIG. 12 (a) shows an image in which β is 20 °. , (B) is the case where β is 30 °, and (c) is the case where β is 40 °. That is, the case where the flaw detection condition is the flaw detection refraction angle. In FIG. 12, E1 and E2 are displayed as echo regions. Increasing the flaw detection refraction angle β from 20 ° to 40 ° reduces the echo intensity corresponding to the representative value of brightness.

FIG. 13 is a graph showing an example of a change in echo intensity when the flaw detection refraction angle β in the ultrasonic flaw detection method according to the first embodiment is changed. The horizontal axis is the flaw detection refraction angle β as the flaw detection condition θ, and the vertical axis is the echo intensity EI of the echo region as the feature quantity. The curves E1 and E2 correspond to the echo regions E1 and E2 in FIG. 12, respectively.

When the flaw detection refraction angle β is continuously changed from 20 ° to 40 ° in 1 ° increments, θ has a total of 21 patterns from 0 to 20, and echoes for changes in the flaw detection refraction angle β as the flaw detection condition θ. The change in intensity EIj (θ) is represented by a graph as shown in FIG. As described above, since the change tendency with respect to the change of the flaw detection condition θ is clearly different between E1 and E2, it can be recognized that the significant echo regions extracted in these two echo regions have different origins.

The display unit 60 displays the change in echo intensity with respect to the change in the flaw detection condition θ calculated by the intensity distribution change calculation unit 36a. The display unit 60 further detects flaws such as the composite signal of the ultrasonic echo, the visualization result, the coordinates of the ultrasonic array probe 10, the relative position with respect to the inspection target 1, the delay time, the focal depth, and the flaw detection refraction angle β. The condition θ and the like may be further displayed.

The control calculation unit 50 controls the transmission / reception unit 20, the calculation unit 30, the storage unit 40, and the display unit 60 to match the timing between them.

FIG. 14 is a flow chart showing a procedure in the ultrasonic flaw detection method according to the first embodiment. First, the ultrasonic array probe 10 is installed on the inspection target 1 (step S01). Next, the delay time calculation unit 31 calculates the delay time according to the flaw detection condition (step S02). Ultrasonic waves are sequentially transmitted from each ultrasonic element 11 according to the delay time on the transmitting side (step S03).

Next, the signal synthesis unit 32 synthesizes the waveform received by the ultrasonic element 11 according to the delay time on the receiving side, and derives the composite waveform (step S04). Next, based on each composite waveform data, the visualization unit 33 creates an image by visualization (step S05). Next, it is determined whether or not the necessary scan is completed (step S06). The determination is, for example, whether or not all the driving element groups have been completed. If it is not completed (step S06 NO), step S02 and subsequent steps are repeated.

If it is determined that the scanning is completed (YES in step S06), the extraction unit 34 then performs the extraction process (step S07). Next, the intensity distribution calculation unit 35a, which is the feature amount calculation unit 35, calculates the intensity distribution. Further, the intensity distribution change calculation unit 36a, which is the feature amount change calculation unit 36, calculates the change in the intensity distribution, which is the feature amount, with respect to the change in the flaw detection conditions (step S08). The display unit 60 displays the change in the intensity distribution, which is the change in the feature amount, with the flaw detection condition as a parameter. Alternatively, the change in strength with respect to the change in the flaw detection condition is displayed in the form of a graph in which the flaw detection condition is plotted on the horizontal axis and the strength is plotted on the vertical axis for each specific portion (step S09). Next, a defect is determined and evaluated based on the change in strength with respect to the change in flaw detection conditions (step S10).

As shown in FIG. 13, since the change tendency of the echo intensity EI as a feature amount with respect to the change of the flaw detection refraction angle β as the flaw detection condition θ is clearly different between E1 and E2, it is extracted in these two echo regions. It can be recognized that the significant echo regions obtained have different origins as described above.

For example, if the echo intensity EI measured under each flaw detection condition has no dependency on the flaw detection condition or has a small dependency on the flaw detection condition, it is noise with a large uncertain factor, and there is a dependency on the flaw detection condition. The assumed E2 is assumed to be a defect that is a stable scattering source. In this way, by extracting a region having a strong echo intensity, changing the flaw detection conditions, and investigating the change tendency, it is possible to determine that E1 is noise and E2 is a defect echo.

In FIG. 13, the signal of E2 shows an example in which as the flaw detection refraction angle β changes from 20 ° to 40 °, it increases monotonically, reaches a maximum value, and then decreases monotonically. It depends on the shape and inclination of the defect, and if it can be determined that the relationship between the flaw detection refraction angle and the echo intensity is significant, such as monotonically decreasing or increasing, it can be distinguished from the defect echo.

FIG. 15 is a graph illustrating an example of determination contents of presence / absence of a defect in the defect determination unit. The horizontal axis represents the flaw detection refraction angle β as a flaw detection condition, and the vertical axis represents the echo intensity EI as a feature quantity.

This example is a case where the echo intensity EI monotonously increases with respect to the increase in the flaw detection refraction angle β, reaches a maximum value, and then decreases monotonically. The flaw detection refraction angle that gives the maximum value Em of the echo intensity is defined as the reference angle βm as the reference flaw detection condition. The reference angle βm is the reference for the flaw detection conditions at the time of judgment.

Now, the flaw detection refraction angles that give the echo intensity Ed that the echo intensity decreases by the value of the determination feature amount change width ΔEd, for example, 3 dB or 6 dB from the maximum value Em are βd1 and βd2 (however, βd1 <βd2, respectively) from FIG. ). If the flaw detection refraction angles βd1 and βd2 are within a predetermined width, the echo is determined to be a defect echo.

Specifically, based on two determination flaw detection condition change widths Δβ1 and Δβ2 having predetermined values, β1, β2, β3, and β4 (β1 <β2 <β3 <β4) are expressed by the following equations (1) to It is set by the formula (4). However, 0 <Δβ1 <Δβ2.
β1 = βm−Δβ2… (1)
β2 = βm-Δβ1 ... (2)
β3 = βm + Δβ1 ... (3)
β4 = βm + Δβ2… (4)

Here, if the following equations (5) and (6) are satisfied, the echo is determined to be a defective echo.
β1 <βd1 <β2 ... (5)
β3 <βd2 <β3 ... (6)

For example, when the judgment feature amount change width ΔEd is 3 dB and the judgment flaw detection condition change widths Δβ1 and Δβ2 are 5 ° and 15 °, respectively, the refraction flaw detection angles β whose echo intensity decreases by 3 dB from the peak value are βd1 and βd2. Let (βd1 <βd2). At this time, if the following equations (7) and (8) are satisfied, the echo is determined to be a defective echo.
βm-15 ° <β1 <βm-5 °… (7)
βm + 5 ° <β2 <βm + 15 °… (8)

The above is the case where the echo intensity EI monotonously increases with respect to the increase in the flaw detection refraction angle β and then decreases monotonically after reaching the maximum value, but the echo intensity EI becomes monotonous with respect to the increase in the flaw detection refraction angle β. Even when the minimum value is taken after the decrease and then monotonously increases, the same determination can be made by setting the minimum value Emin of the echo intensity and the flaw detection refraction angle at this time as the reference angle βmin as the reference flaw detection condition.

Further, when the echo intensity EI decreases monotonically with the increase of the flaw detection refraction angle β, it can be determined by the same method. Specifically, when the angular region of the flaw detection refraction angle β is from βm to βn, the maximum value Em of the echo intensity is taken at the reference angle βm as the reference flaw detection condition. The change width ΔEd and the judgment flaw detection condition change width are Δβ1 and Δβ2 (where Δβ1 <Δβ2). Further, the flaw detection refraction angle β that gives the echo intensity Ed that decreases by the determination feature amount change width ΔEd from the maximum value Em of the echo intensity is defined as βd.

At this time, if the following equation (9) holds, the echo is determined to be a defective echo.
βm + Δβ1 <βd <βm + Δβ2… (9)

When the echo intensity EI increases monotonically with respect to the increase in the flaw detection refraction angle β, it can be determined by the same method. Further, the determination may be made based on the minimum value of the echo intensity. That is, when the angle region of the flaw detection refraction angle β is from βmin to βn, the flaw detection refraction angle that takes the minimum value Emin of the echo intensity is set as the reference angle βmin as the reference flaw detection condition. For example, the increase width of the echo intensity is defined as the determination feature amount change width ΔEd, and the judgment flaw detection condition change width is Δβ1 and Δβ2 (where Δβ1 <Δβ2). Further, the flaw detection refraction angle β that gives the echo intensity Ed that increases by the determination feature amount change width ΔEd from the minimum value Em of the echo intensity is defined as βd.

At this time, if the following equation (9) holds, the echo is determined to be a defective echo.
βmin + Δβ1 <βd <βmin + Δβ2… (10)

As described above, the defect determination unit 37 determines whether or not the echo is a defect echo by a determination formula according to the pattern of change in the echo intensity EI as a feature amount with respect to the flaw detection refraction angle β, which is the flaw detection condition. The determination parameters such as the determination feature amount change width ΔEd and the determination flaw detection condition change widths Δβ1 and Δβ2 used in the above examples are stored in the parameter storage unit 42 of the storage unit 40. The parameter storage unit 42 stores the determination parameter input from the input unit 70.

These determination parameters include, for example, whether the change in echo intensity EI as a feature amount with respect to the flaw detection refraction angle β, which is the flaw detection condition, has a maximum value or a minimum value, is monotonically increasing, or is monotonically decreasing. Different ones may be used depending on the pattern of. In addition, empirically more appropriate parameters can be used as determination parameters based on information on the inspection target portion such as the material of the inspection target or the history received by the inspection target.

In the above case, the case where the flaw detection condition is the flaw detection refraction angle is shown as an example, but in the case of the change in the feature amount with respect to other flaw detection conditions, whether or not it is a defect echo is determined by the same method. be able to.

FIG. 16 is a flow chart showing a determination procedure in the ultrasonic flaw detection method. As shown in FIG. 14, the intensity distribution change calculation unit 36a, which is the feature amount change calculation unit 36, calculates the change in the intensity distribution (step S08), and the display unit 60 sets the flaw detection conditions for each specific portion, for example, on the horizontal axis. , Displayed as a change in strength with respect to a change in flaw detection conditions in the form of a graph with strength on the vertical axis (step S09). After this, as the determination evaluation step S10, it is determined whether or not each specific portion is a defect echo. The detailed procedure of the judgment evaluation step S10 is shown below.

First, the defect determination unit 37 selects a change pattern (step S11). That is, for example, a pattern in which the feature amount monotonically increases with respect to an increase in flaw detection conditions and then reaches a maximum value and then monotonically decreases, or a pattern in which the feature quantity monotonically decreases with respect to an increase in flaw detection conditions. It is classified based on the graph creation data given to the display unit 60 by the feature amount change calculation unit 36.

Next, the defect determination unit 37 reads out the determination parameters corresponding to the classified patterns from the parameter storage unit 42 (step S12). At this time, if information about the inspection target part such as the material of the inspection target or the history received by the inspection target is acquired via the input unit 70, an appropriate determination parameter is selected according to the information. ..

Next, the defect determination unit 37 determines the reference flaw detection condition based on the graph creation data (step S13). For example, if the pattern is such that the maximum value is taken after the feature amount monotonically increases and then monotonously decreases with respect to the increase in the feature amount, the flaw detection condition that gives the maximum value of the feature amount is set as the reference flaw detection condition.

Next, the defect determination unit 37 determines whether or not the portion of interest is due to a defect echo from the graph creation data using the selected determination parameter, for example, by the method shown in FIG. (Step S14). The defect determination unit 37 outputs the result of this determination to the display unit 60, and the display unit 60 displays the determination result (step S15).

As described above, in the present embodiment, by displaying the change in echo intensity with respect to the change in the flaw detection refraction angle, the defect echo in the object having a large noise on the ultrasonic flaw detection such as the welded portion (super reflected by the defect in the inspection target). It is possible to distinguish between the reflected wave of ultrasonic waves) and noise.

FIG. 17 is a graph showing an example of a change in echo intensity when the focal depth F is changed in a modified example of the ultrasonic flaw detection method according to the first embodiment. In the present embodiment, the flaw detection angle is changed, but of course, what is changed is not limited to the flaw detection angle. For example, as shown in FIG. 17, the flaw detection conditions such as the position of the focal point are changed at that time. It may also display the change in echo intensity.

[Second Embodiment]
FIG. 18 is a block diagram showing a configuration of an ultrasonic flaw detector according to a second embodiment. The second embodiment is a modification of the first embodiment. In the present embodiment, the feature amount calculation unit 35 has a center position change calculation unit 35b, and the feature amount change calculation unit 36 has a center position change calculation unit 36b. That is, in the first embodiment, the feature amount is the echo intensity, but in the present embodiment, the feature amount is the center position of the echo region.

The center position (echo center position) of the echo region in a certain echo region Ej is represented by EPj. At this time, j is a natural number and represents the index of the echo in a certain flaw detection space region. The echo center position is represented by (Xj, Zj) for a two-dimensional flaw detection image and (Xj, Yj, Zj) for three-dimensional coordinates. As the echo center position, the center position of the echo region Ej is used. However, it does not necessarily have to be the center of the echo region Ej as long as the change corresponding to the change in the flaw detection condition can be confirmed as the feature quantity. For example, the coordinates at which the composite echo has the maximum intensity among the points in the echo region Ej may be used, the center of gravity of the pixel group exceeding a certain threshold value may be used, and the maximum values of X, Y, and Z, respectively. , The minimum value, the center value, and the like may be used. That is, it may be anything that is uniquely obtained by a specific logic.

The echo center position under each flaw detection condition is represented by EPj (θ), and the coordinates are represented by Xj (θ), Yj (θ), and Zj (θ).

For example, an example is shown when the flaw detection condition θ is the flaw detection refraction angle β. FIG. 19 is an image showing an example of a change in the center position of the echo region of the flaw detection space region when the flaw detection refraction angle β in the ultrasonic flaw detection method according to the second embodiment is changed. β is 20 °, (b) is β at 30 °, and (c) is β at 40 °. The broken line represents the echo center position.

FIG. 20 is a graph showing an example of a change in the center position of the echo region of the flaw detection space region when the flaw detection refraction angle β in the ultrasonic flaw detection method according to the second embodiment is changed. When β is continuously changed from 20 ° to 40 °, for example, in 1 ° increments, θ has a total of 21 patterns from 0 to 20, and the Xj (θ) change of the echo center position EPj (θ) is It is represented by a schematic diagram as shown in FIG.

As the flaw detection refraction angle β increases, that is, in FIG. 19, as the flaw detection condition θ increases, the position of the echo region E1 moves significantly, or there is a point where it becomes discontinuous in some places. On the other hand, the position of the echo region E2 has not moved significantly. Using this tendency, for example, E1 whose center position changes greatly depending on the flaw detection conditions is presumed to be noise peculiar to the material. On the other hand, E2 whose center position does not change much even if the flaw detection conditions are changed is presumed to be a defect that is a stable scattering source. In this way, it is possible to distinguish E1 as noise and E2 as defect echo.

[Third Embodiment]
FIG. 21 is a block diagram showing a configuration of an ultrasonic flaw detector according to a third embodiment. The third embodiment is a modification of the first embodiment. In the present embodiment, the feature amount calculation unit 35 has a brightness value frequency distribution calculation unit 35c, and the feature amount change calculation unit 36 has a brightness value frequency distribution change calculation unit 36c. That is, in the present embodiment, the luminance value in each pixel in the flaw detection space region is used as the feature amount.

FIG. 22 shows the frequency of the luminance value (that is, the intensity of the synthetic echo) at each pixel (each point) in the flaw detection space region when the flaw detection refraction angle β in the ultrasonic flaw detection method according to the third embodiment is changed. It is an example of the change of distribution, and is the graph which shows the case of noise. Here, the frequency distribution of the luminance values is the distribution of the appearance frequency of the luminance values for each of the pixels in the image region of the echo region of interest in the image region. FIG. 23 shows the frequency of the luminance value (that is, the intensity of the synthetic echo) at each pixel (each point) in the flaw detection space region when the flaw detection refraction angle β in the ultrasonic flaw detection method according to the third embodiment is changed. It is an example of the change of distribution, and is the graph which shows the case of a defect.

In this way, for example, noise whose position and intensity are easily affected by the beam direction has an irregular tendency of change as in E1. On the other hand, defect echo, which is a relatively stable scattering source, can be estimated such that the amount of change changes stably as seen in E2.

At this time, in comparison of the change tendency, correlation amount calculation, peak number, peak position, offset amount, etc. can be compared, graph smoothing by a filter, approximation using Gaussian function and exponential logarithmic function superposition, etc. May reduce the calculation load.

In addition, in the 1st to 3rd embodiments, the features are shown as the echo intensity, the center position of the echo region, and the brightness value of each pixel in the flaw detection space region, respectively. As for the amount, various information obtained from the received ultrasonic wave can be used, and information that can be a feature amount thereof can be appropriately combined and used.

[Fourth Embodiment]
FIG. 24 is a block diagram showing a configuration of an ultrasonic flaw detector according to a fourth embodiment. The fourth embodiment is a modification of the first embodiment, in which the calculation unit 30 further includes an integrated calculation unit 38. The integrated calculation unit 38 performs integrated processing using any plurality of flaw detection images obtained as a result of processing by the visualization unit 33, and obtains an integrated image having a higher SN ratio. The contents of the integration will be described below.

FIG. 25 is a graph showing the change in echo intensity when the flaw detection refraction angle β is changed. One flaw detection image generated by the visualization unit 33 is obtained for each flaw detection condition (for example, flaw detection refraction angle β). Here, when a plurality of flaw detection images are selected, they can be selected from arbitrary flaw detection conditions, but they may be selected with reference to the flaw detection conditions as shown in FIG. 25. Here, an example in which the flaw detection condition is set to the flaw detection refraction angle β will be described, but other flaw detection conditions such as the focal depth may be used. The integration range is, for example, the range from βs to βe as shown in FIG. In this case, all the values in this range may be used for integration, or only a plurality of points may be thinned out.

FIG. 26 is a conceptual explanatory diagram for explaining the integration. When the flaw detection refraction angle is in the range of βs to βe as the flaw detection condition, (a) is when the flaw detection refraction angle is βs, (b) is when the flaw detection refraction angle is βe, and (c) is the integrated result. Shown.

The integration is performed by superimposing the features in a plurality of flaw detection images at each position to be inspected. As a concrete method of integration, any method such as averaging and infinite product may be used. When the flaw detection refraction angle is sequentially increased from βs to βe, the range covered by the ultrasonic waves incident when the flaw detection refraction angle shown in (a) is βs and the flaw detection refraction angle shown in (b) are βe. The range where the range covered by the sometimes incident ultrasonic waves overlaps is the area surrounded by the thick line in (c), and this is displayed as the integrated image area. This integrated image region is a range covered by any ultrasonic wave having a flaw detection refraction angle of βs or more and βe or less.

For example, taking the case shown in FIG. 25 as an example, in the case of the noise shown by the broken line E1, the echo intensity EI as a feature amount changes greatly depending on the change in the flaw detection refraction angle β as the flaw detection condition. Therefore, for example, the averaging value in the case of averaging is smaller than the averaging value of the defect echo shown by the solid line E2, which does not fluctuate much due to the change in the flaw detection refraction angle β. In this way, the integration will increase the signal-to-noise ratio.

FIG. 27 is a comparative diagram for explaining the effect of integration, in which (a) shows the case of not integrating and (b) shows the case of integration. In the case of only one angle shown in (a), the SN ratio is extremely small, and the image is substantially indistinguishable from defects and noise. On the other hand, the integrated image shown in (b) is an integrated image of six, and an integrated image having a high SN ratio in which defects can be clearly discriminated is obtained.

In general, the sensitivity changes depending on the flaw detection refraction angle β. Therefore, if the dependence of the sensitivity on the flaw detection refraction angle β is confirmed in advance and the sensitivity data is acquired, the feature amount of the flaw detection image for each flaw detection refraction angle is sensitively calibrated and then integrated. Can be done. As the sensitivity calibration value, the sensitivity calibration value depending on the angle may be multiplied as a coefficient or added as an offset value for each flaw detection image. The sensitivity also changes depending on the frequency of the ultrasonic waves. Therefore, when a plurality of frequencies are used, the sensitivity of the flaw detection image for each frequency may be calibrated and then integrated.

Further, in the process of generating the flaw detection image, rattling may occur for each pixel due to pixel omission or the like. In order to suppress such a situation, a smoothing process such as applying a Gaussian filter may be provided.

As described above, by integrating according to the present embodiment, it is possible to more reliably discriminate between defect echo and noise.

[Fifth Embodiment]
FIG. 28 is a block diagram showing a configuration of an ultrasonic flaw detector according to a fifth embodiment. This embodiment is a modification of the first embodiment. Instead of the switching unit 22, the delay time calculation unit 31 and the signal synthesis unit 32 in the first embodiment, the fifth embodiment has a switching unit 22a, a delay time calculation unit 31a and a signal synthesis unit 32a. The contents of each will be described later.

FIG. 29 is a flow chart showing a procedure in the ultrasonic flaw detection method according to the fifth embodiment. This embodiment is a modification of the first embodiment. The steps with the same content as the first embodiment are numbered the same as the first embodiment. Hereinafter, steps different from those of the first embodiment will be described.

FIG. 30 is a block diagram showing each transmission state of ultrasonic waves in the ultrasonic flaw detection method according to the fifth embodiment. Among the ultrasonic elements 11 included in the ultrasonic array probe 10, it is assumed that N elements of the first element to the Nth element are used. The ultrasonic element 11 used may be all of the ultrasonic elements 11 included in the ultrasonic array probe 10.

After step S01, the switching unit 22a of the transmitting / receiving unit 20 transmits ultrasonic waves one by one to all the ultrasonic elements 11 used, that is, the first element to the Nth element (step S11). .. FIG. 30 (a) shows transmission from the first element, (b) shows transmission from the second element, and (c) shows transmission from the Nth element. The ultrasonic waves transmitted from each are received by all the ultrasonic elements 11 including the ultrasonic element 11 itself. Each time transmission from the first element to the Nth element, the signal processing information storage unit 41 of the storage unit 40 stores the waveforms received by all the ultrasonic elements 11.

Next, the transmitting / receiving unit 20 determines whether or not the transmission of all the ultrasonic elements 11 has been completed (step S12). If it is determined that the process is not completed (step S12 NO), step S11 is repeated. If it is determined that all of the items have been completed (YES in step S12), the process proceeds to the next step.

Next, the delay time calculation unit 31a serves as a reference for the time from transmission to reception for each combination of the transmitted ultrasonic element 11 and the received ultrasonic element 11 for each divided portion of the inspection target 1. The increase / decrease with respect to the time (reference time) is calculated as the delay time (step S13). Each waveform data thus obtained is synthesized (step S14).

FIG. 31 is a waveform diagram showing a part of an echo waveform (received waveform) due to transmission of ultrasonic waves in the ultrasonic flaw detection method according to the fifth embodiment. In order to simplify the description, the case where the number of elements is three is described as shown in FIG. Now, the case where the portion where the inspection target 1 is divided is the defect 2 is shown. That is, there are nine combinations, such as a case where the transmission is transmitted from the first element and reaches the defect 2 and is received by the first element, or a case where the transmission is transmitted from the third element and reaches the defect 2 and is received by the third element.

First, the waveform as it is is called the basic waveform without considering the delay time. The ultrasonic waves transmitted from the first element and received by the first to third elements are referred to as Uf1, 1, Uf1, 2, and Uf1, 3, respectively. The ultrasonic waves transmitted from the second element and received by the first to third elements are referred to as Uf2,1, Uf2,2, and Uf2,3, respectively. Similarly, the ultrasonic waves transmitted from the third element and received by the first to third elements are referred to as Uf3,1, Uf3,2, and Uf3,3, respectively.

FIG. 32 is a waveform diagram illustrating a delay time during transmission and reception of ultrasonic waves. FIG. 32 is based on the time required for a round trip when the first element receives the echo transmitted from the first element, reaches the defect 2, and is reflected by the defect 2.

As shown in FIG. 31, the distance from the second element to the defect 2 is shorter than the distance from the first element to the defect 2, and the distance from the third element to the defect 2 is even shorter. Therefore, in order for the ultrasonic waves from each element to reach the defect 2 at the same time, it is necessary to delay the time of transmission from the second element from the time of transmission from the first element. Further, the time point of transmission from the third element needs to be further delayed.

Similarly, on the return route, the distance from the defect 2 to the second element is shorter than the distance from the defect 2 to the first element, and the distance from the defect 2 to the third element is further shorter. As a result, in order to superimpose the respective waves, it is necessary to delay the time of reception of the second element. Further, the time of reception of the third element needs to be further delayed.

The transmission delay time and the reception delay time shown in FIG. 32 are the delay times derived as described above. Further, FIG. 33 is a waveform diagram showing a composite waveform of echoes. Since the arrival time points are matched by the delay time calculation unit 31a, the composite waveform can be calculated under a large SN ratio in the synthesis by the signal synthesis unit 32a.

In the present embodiment, the flaw detection conditions in which the flaw detection refraction angle β, the focus depth, and the like are changed by the subsequent signal processing in the calculation unit 30 by transmitting once for each ultrasonic element 11 are covered. Can be obtained. Specifically, if the delay time calculation unit 31a sets the delay time according to the purpose, the signal synthesis unit 32a can obtain the composite waveform.

That is, the online inspection of the inspection target 1 is actually carried out continuously because the transmission of each ultrasonic element 11 is performed only once and the calculation or the like is not required each time. be able to. Subsequent processing can be performed offline, and the time required for on-site inspection work can be significantly reduced.

[Sixth Embodiment]
FIG. 34 is a block diagram showing the configuration of the ultrasonic flaw detector according to the sixth embodiment. This embodiment is a modification of the first embodiment. The calculation unit 30 of the ultrasonic flaw detection device 100 in the sixth embodiment has a surface shape calculation unit 39 to be inspected.

The inspection target surface shape calculation unit 39 acquires the surface shape of the inspection target 1 when the surface of the inspection target 1 has a complicated curved surface or uneven surface instead of a flat surface. Specifically, the surface shape may be visualized by an aperture synthesis method using a basic waveform, and the surface shape of the inspection target 1 may be obtained from the result. Alternatively, the surface shape may be read from the design drawing. Alternatively, an inspection target surface shape measuring means such as a camera or a laser range finder may be attached to the ultrasonic array probe 10 or separately provided near the ultrasonic array probe 10. Once the surface shape is obtained, it can be used repeatedly for delay time calculation.

[Other Embodiments]
Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention.

Moreover, you may combine the features of each embodiment. For example, the features of the fourth embodiment may be combined with the features of other embodiments. Alternatively, the features of the sixth embodiment may be combined with the first to fourth embodiments. Alternatively, the fifth and sixth embodiments may be further combined.

Furthermore, these embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention as well as the invention described in the claims and the equivalent scope thereof.

1 ... Inspection target, 2 ... Defect, 3 ... Welded part, 5 ... Acoustic propagation medium, 10 ... Ultrasonic array probe, 11 ... Ultrasonic element, 20 ... Transmitting and transmitting part, 21 ... Potential difference applying part, 22, 22a ... Switching Unit, 23 ... AD conversion unit, 30 ... Calculation unit, 31, 31a ... Delay time calculation unit, 32, 32a ... Signal synthesis unit, 33 ... Visualization unit, 34 ... Extraction unit, 35 ... Feature amount calculation unit, 35a ... Intensity distribution calculation unit, 35b ... Center position calculation unit, 35c ... Brightness value frequency distribution calculation unit, 36 ... Feature amount change calculation unit, 36a ... Intensity distribution change calculation unit, 36b ... Center position change calculation unit, 36c ... Brightness value frequency Distribution change calculation unit, 37 ... defect determination unit, 38 ... integrated calculation unit, 39 ... inspection target surface shape calculation unit, 40 ... storage unit, 41 ... signal processing information storage unit, 42 ... parameter storage unit, 50 ... control calculation unit , 60 ... Display unit, 70 ... Input unit, 100 ... Ultrasonic flaw detector

Claims (12)

And ultrasonic array probe having a plurality of ultrasonic elements arranged in parallel to receive the ultrasonic waves reflected by said object to transmit ultrasonic waves into the test object,
A potential difference application unit capable of applying a potential difference that causes vibration to the ultrasonic element,
A delay time calculation unit that calculates a delay time for shifting the timing at which the ultrasonic element transmits and receives the ultrasonic waves, and
A switching unit that switches between a state in which the potential difference applying unit applies a potential difference to the ultrasonic element and a state in which the potential difference applying unit does not apply a potential difference to the ultrasonic element.
A feature amount calculation unit that calculates a feature amount related to a synthetic echo obtained by synthesizing a received wave received by the ultrasonic element according to the delay time, and a feature amount calculation unit.
A feature amount change calculation unit that calculates a change in the feature amount with respect to a change in the ultrasonic flaw detection condition for the inspection target, and a feature amount change calculation unit.
A defect determination unit that determines whether or not a defect is a defect based on a change in the feature amount using a reference flaw detection condition that gives the maximum or minimum value of the feature amount and a determination parameter.
A display unit for displaying the change in the calculated said feature amount,
With
An ultrasonic flaw detector , characterized in that two or more different flaw detection / refraction angle conditions are used as the determination parameters . Further provided with an integrated calculation unit that integrates the features of the synthetic echo obtained by a plurality of flaw detection conditions.
The ultrasonic flaw detector according to claim 1, wherein the display unit can further display an integrated image based on the image data integrated by the integrated calculation unit . The ultrasonic flaw detector according to claim 1 or 2, wherein the feature amount is the intensity of the synthetic echo . The feature amount, according to claim 1 or claim 2, wherein the intensity of the synthesized echo is a change in the center position of the echo region as a predetermined or said threshold value or more than the threshold value Ultrasonic flaw detector. The claim is characterized in that the feature amount is a distribution of the intensity of the synthetic echo at each point in an echo region where the intensity of the synthetic echo exceeds or exceeds a predetermined threshold value. 1 or the ultrasonic flaw detector according to claim 2 . An ultrasonic array probe having a plurality of ultrasonic elements arranged in parallel with each other, which transmits ultrasonic waves to an inspection target and receives the ultrasonic waves reflected by the inspection target.
A potential difference application unit capable of applying a potential difference that causes vibration to the ultrasonic element,
A delay time calculation unit that calculates a delay time for shifting the timing at which the ultrasonic element transmits and receives the ultrasonic waves, and
A switching unit that switches between a state in which the potential difference applying unit applies a potential difference to the ultrasonic element and a state in which the potential difference applying unit does not apply a potential difference to the ultrasonic element.
A feature amount calculation unit that calculates a feature amount related to a synthetic echo obtained by synthesizing a received wave received by the ultrasonic element according to the delay time, and a feature amount calculation unit.
A feature amount change calculation unit that calculates a change in the feature amount with respect to a change in the ultrasonic flaw detection condition for the inspection target, and a feature amount change calculation unit.
A display unit that displays the calculated change in the feature amount, and
With
An ultrasonic flaw detector, wherein the feature amount is a change in the center position of an echo region in which the intensity of the synthetic echo exceeds or exceeds a predetermined threshold value . In the switching unit, the ultrasonic element transmits ultrasonic waves to the inspection target based on the delay time, and the ultrasonic element receives the ultrasonic waves from the inspection target based on the delay time. The ultrasonic flaw detector according to any one of claims 1 to 4, wherein the application of a potential difference to each of the ultrasonic elements is switched. It also has a signal synthesizer
The switching unit switches so that each of the ultrasonic elements sequentially transmits ultrasonic waves without the delay time.
The signal synthesizing unit synthesizes the received waves received by the ultrasonic elements by transmitting ultrasonic waves from each of the ultrasonic elements by shifting the delay time corresponding to each received wave.
The ultrasonic flaw detector according to any one of claims 1 to 4, wherein the ultrasonic flaw detector is characterized by this. In a data processing device that processes signal data transmitted and received to an inspection target by an ultrasonic array probe having a plurality of ultrasonic elements.
A delay time calculation unit that calculates a delay time for shifting the timing at which the ultrasonic element transmits and receives ultrasonic waves, and
A switching unit that switches between a state in which the potential difference applying unit applies a potential difference to the ultrasonic element and a state in which the potential difference applying unit does not apply a potential difference to the ultrasonic element.
A feature amount calculation unit that calculates a feature amount related to a synthetic echo obtained by synthesizing a received wave received by the ultrasonic element according to the delay time, and a feature amount calculation unit.
A feature amount change calculation unit that calculates a change in the feature amount with respect to a change in the ultrasonic flaw detection condition for the inspection target, and a feature amount change calculation unit.
A defect determination unit that determines whether or not a defect is a defect based on a change in the feature amount using a reference flaw detection condition that gives the maximum or minimum value of the feature amount and a determination parameter.
A display unit that displays the calculated change in the feature amount, and
Equipped with a,
A data processing apparatus characterized in that two or more different flaw detection / refraction angle conditions are used as the determination parameters . A video creation step in which the visualization unit creates an image of the inside of the inspection target based on the composite waveform of the received ultrasonic wave transmitted from the ultrasonic element of the ultrasonic array probe to the inspection target.
The feature amount calculation step in which the feature amount calculation unit calculates the feature amount based on the video, and
The feature amount change calculation unit calculates the change in the feature amount in response to the change in the flaw detection condition, and the feature amount change calculation step .
Defect determination unit, and the maximum value or determining whether or not a defect based on the change of the characteristic amount with a reference flaw detection condition and determining parameter giving the minimum value of the feature amount,
A display step in which the display unit displays the change in the feature amount, and
Have a,
An ultrasonic flaw detection method characterized in that two or more different flaw detection refraction angle conditions are used as the determination parameters . The defect determination unit, and a pattern selecting step based on the calculation result in the feature quantity variation calculation step, selecting the change pattern,
A parameter reading step in which the defect determination unit reads out the corresponding determination parameter from the parameter storage unit based on the selected change pattern.
A flaw detection condition determination step in which the defect determination unit determines the reference flaw detection condition based on the calculation result in the feature amount change calculation step, and
The ultrasonic flaw detection method according to claim 10, wherein the method is characterized by having. A video creation step in which the imaging unit creates an image of the inside of the inspection target based on the composite waveform of the received ultrasonic wave transmitted from the ultrasonic element of the ultrasonic array probe to the inspection target.
A feature amount calculation step in which the feature amount calculation unit calculates a feature amount based on the video,
The feature amount change calculation unit calculates the change in the feature amount in response to the change in the flaw detection condition, and the feature amount change calculation step.
A pattern selection step in which the defect determination unit selects a change pattern based on the calculation result in the feature amount change calculation step,
A parameter reading step in which the defect determination unit reads out the corresponding determination parameter from the parameter storage unit based on the selected change pattern.
A flaw detection condition determination step in which the defect determination unit determines a reference flaw detection condition based on the calculation result in the feature amount change calculation step, and
A determination step in which the defect determination unit determines whether or not the echo is based on a defect based on the calculation result in the feature amount change calculation step, the determination parameter, and the reference flaw detection condition.
A display step in which the display unit displays the change in the feature amount, and
An ultrasonic flaw detection method characterized by having.

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