WO2019030815A1

WO2019030815A1 - Ultrasound examination method and ultrasound examination device

Info

Publication number: WO2019030815A1
Application number: PCT/JP2017/028718
Authority: WO
Inventors: 裕久溝田; 永島　良昭; 和之中畑
Original assignee: 株式会社日立製作所; 国立大学法人愛媛大学
Priority date: 2017-08-08
Filing date: 2017-08-08
Publication date: 2019-02-14
Also published as: JPWO2019030815A1; JP6782934B2

Abstract

The purpose of the present invention is to provide an ultrasound examination method and an ultrasound examination device capable of simultaneously displaying a plurality of flaws located at different sites in a single still image, while leveraging the advantages and overcoming the weaknesses of conventional back propagation analysis. The ultrasound examination method of the present invention uses ultrasonic waves to locate flaws inside a test specimen, and is characterized by comprising: a step for preparing a model of the test specimen; a step for setting and inputting a measurement condition for the ultrasonic waves; a step for controlling an ultrasonic probe in accordance with the measurement condition to emit incident ultrasonic waves into the test specimen and receive reflected waves of the incident waves; a step for performing a back propagation analysis on the model using waveform signals of the reflected waves, and creating a group of back propagation still images arranged in reverse-chronological order; a step for performing a forward propagation analysis on the model using waveform signals of the incident waves, and creating a group of forward propagation still images arranged in chronological order; and a step for calculating to combine the group of forward propagation still images and the group of back propagation still images to create a single still image showing the locations of the flaws.

Description

Ultrasonic inspection method and ultrasonic inspection apparatus

The present invention relates to a nondestructive inspection technique, and more particularly to an ultrasonic inspection method for positioning flaws in an object to be inspected using ultrasonic waves, and an ultrasonic inspection apparatus for carrying out the method. .

For the purpose of soundness management of large structures (for example, bridges, power plants), the importance of nondestructive inspection systems capable of detecting the internal damage of the members of the structures in a wide range and accurately is increasing. Ultrasonic inspection (UT) is one of the flaw inspection methods in such nondestructive inspection systems.

In ultrasonic inspection, a probe (also referred to as an ultrasonic probe) incorporating a transducer is applied to the subject to be irradiated with an ultrasonic wave (for example, 1 to 5 MHz), and the reflected wave (echo) is detected by the probe. It is an inspection method received by the child. At this time, if there is no flaw in the inside of the inspected object, an echo is generated on the surface of the inspected object (often the bottom / back side) opposite to the incident surface when there is no flaw in the inspected object. Since an echo occurs first in a flaw, it is possible to check the presence or absence and position of the flaw by analyzing and imaging the reception of the echo.

For example, Patent Document 1 (Japanese Patent Laid-Open No. 2014-062758) is a nondestructive inspection method for detecting a defect of an object to be inspected having a bent portion using a guide wave, and the inspection range of the object to be inspected is plural. First step of dividing into an inspection area, second step of calculating a transmission waveform compensating for distortion capable of reaching the inspection area divided in the first step, and calculated in the second step A third step of transmitting the transmission waveform and receiving a reflection waveform, and a fourth step of setting an analysis region in the inspection region and calculating a spatial waveform of a propagation time corresponding to the analysis region; The fifth step of combining the spatial waveform of the analysis area in the inspection area calculated in the fourth step and combining the inspection image, and combining the inspection image of the inspection area obtained in the fifth step Step 6 to obtain an examination image Non-destructive inspection method comprising is disclosed.

According to Patent Document 1, even in the case of inspecting a pipe having a bent portion, by providing a step for compensating for the distortion of the guide wave, all the ranges of the straight pipe portion, the inside of the bend, and the bend and thereafter are collectively. It is said that a defect distribution image can be obtained, and a sensitivity error in the circumferential direction of the pipe hardly occurs in the image. The technique of Patent Document 1 is considered to be able to accurately position flaws in a one-dimensional direction (longitudinal direction).

However, if localization of flaws in the two-dimensional or three-dimensional directions is to be performed by the technique of Patent Document 1, extremely complicated calculations are required, and a large calculation time is required or a problem can not be calculated. Is considered.

On the other hand, in recent years, a flaw detection method using an ultrasonic phased array has attracted attention from the viewpoint of improving the efficiency and accuracy of ultrasonic inspection in a two-dimensional direction and a three-dimensional direction. For example, in Patent Document 2 (Japanese Patent Laid-Open No. 2010-266414), in an ultrasonic flaw detection method using a phased array, an A-scope waveform signal obtained by each receiving element of the phased array is represented by a predetermined equation. A phased array aperture synthesizing method is characterized in that the amplitude of each signal is corrected by multiplying the inverse of the influence function and the B scope image is constructed by performing aperture synthesis processing on the corrected A scope waveform signal. , Has been disclosed.

According to Patent Document 2, it is possible to correct the received A-scope waveform signal to a constant echo intensity without diffusion attenuation by multiplying the A-scope waveform signal obtained by each receiving element by the inverse of a predetermined influence function. Then, by performing the aperture synthesis process using the A scope waveform signal after this correction, even if the distance from the probe is expanded, the decrease in detection sensitivity due to the attenuation of the ultrasonic wave is suppressed, and clear instructions can be obtained. , And is. That is, it is said that even flaws and defects located in the deep position of thick-walled specimens can be detected with the same sensitivity as those in shallow positions.

Here, in the aperture synthesis (AS) method, a waveform of an echo is received using a plurality of transducers, a trajectory that can be a reflection source of the received waveform is determined for each waveform, and the waveform of the waveform is obtained on each trajectory. It is a method of imaging the reflection source by superimposing high values. When the property of the examination area is uniform in the area other than the flaw (in other words, when the flaw is present in the acoustically homogeneous tissue form), the location of the flaw and the actual flaw determined by the aperture synthesis method It is known to show good agreement with the position of.

However, in the case where the region to be inspected includes an area of acoustically inhomogeneous tissue morphology (for example, in the case where the tissue morphology includes a region distinct from others as in a weld), the acoustically inhomogeneous The area has a large influence on the propagation characteristics and the reflection characteristics of ultrasonic waves, and therefore, in the conventional aperture synthesis method, there is a weak point that the position of a flaw obtained by analysis and the position of a real flaw are easily shifted.

In addition, when analysis is performed in consideration of the propagation characteristics and reflection characteristics of ultrasonic waves in the acoustically inhomogeneous region, the conventional aperture synthesis method requires extremely complicated calculation and requires a long calculation time, or There is a problem that calculation is too complicated and it is difficult to calculate a solution. For example, in the case of imaging a region to be inspected with a 1000 × 1000 mesh using an ultrasonic phased array probe including N transducers, the calculation for obtaining the propagation path and the propagation time is N × 10 ⁶ respectively. It will need to be done several times. Furthermore, when the ultrasonic phased array probe is scanned on the object to be inspected for flaw detection, the calculation is required for each measurement position.

For example, the technology of Patent Document 3 (WO 2014/167698 A1) has been reported as a countermeasure for the problem in the case of including the above-described acoustically inhomogeneous region. In Patent Document 3, in an ultrasonic inspection method for inspecting an object to be inspected using ultrasonic waves, a step of creating a first flaw detection image from a recorded ultrasonic waveform, and a waveform obtained by time-reversing the recorded ultrasonic waveform Creating a first propagation analysis model for analyzing the propagation of the ultrasonic wave to the inspection object with the input as a second flaw image from the result of performing the propagation analysis on the first propagation analysis model An ultrasonic inspection method is disclosed, characterized in that it comprises the steps of: In addition, the step of displaying a significant reflected signal from the first flaw detection image, and the step of performing a second propagation analysis for determining the propagation time of each ultrasonic wave from the significant reflected signal to each ultrasonic wave transmission position And a step of obtaining delay time information at each ultrasonic wave transmission position from the propagation time.

JP, 2014-062758, A JP, 2010-266414, A WO 2014/167698 International Publication No. 2015/092841

According to Patent Document 3, even when the inspection object / inspection area includes an acoustically inhomogeneous region, it is possible to carry out the defect position with high accuracy and shortening the inspection time. ing. The technique of Patent Document 3 creates a first propagation analysis model for analyzing the propagation of ultrasonic waves to a test object, using a waveform obtained by inverting the time of the recorded ultrasonic waveform in the process of analyzing the position of flaws. (It is time-reversal of the ultrasonic measurement waveform and numerical analysis on the object model, it is called back propagation analysis) is an important point, and it is an excellent technology to solve the problems of the prior art. It is considered one.

In the technique of Patent Document 3, as an analysis result, a plurality of still images (still image group) in which the states of propagation of ultrasonic waves are arranged in time series can be obtained. Then, the still image group is reproduced as an animation (moving image), and the position and size of the flaw can be determined by observing how the echo caused by the flaw propagates.

However, the method of determining the position and size of a still image group without reproducing and observing it as a moving image has a weakness that it always takes time for moving image observation in locating the position of a flaw. In other words, there is a weakness that it is difficult to directly display the analysis result of the flaw localization with one still image. For example, in the case where there are a plurality of flaws having different distances from the probe (ie, there are a plurality of flaws having different propagation times), each flaw is displayed on a still image of a different page. It becomes difficult to display together in the image.

In addition, the method of judging that a moving image has not been reproduced or observed has a weak point of uncertainty that the observer's subjectivity is likely to affect the position determination of a flaw.

When all still images obtained as analysis results are superimposed and one still image is synthesized, the propagation locus of ultrasonic waves (the locus of incident waves and the locus of echoes) is drawn in a band shape. As a result, there arises a problem that the position of the flaw is likely to be unclear. In particular, when there are a plurality of flaws, there is another problem that the flaws on the side closer to the probe are easily buried in the propagation path to the flaws on the side far from the probe and difficult to distinguish. It occurs.

From the above-mentioned circumstances, the object of the present invention is to overcome the conventional weakness while taking advantage of the conventional back propagation analysis in ultrasonic inspection for performing localization of flaws in the inside of a subject to be examined. An ultrasonic inspection method capable of simultaneously displaying a plurality of flaws different in position in one still image, and an ultrasonic inspection apparatus for performing the method.

(I) One aspect of the present invention is an ultrasonic inspection method which uses ultrasonic waves to position flaws inside a subject to be inspected,
A test object model preparation step of preparing a model of the test object;
A measurement condition input step of setting and inputting the measurement condition of the ultrasonic wave;
An ultrasonic measurement step of controlling a probe in accordance with the measurement conditions, transmitting an incident wave of the ultrasonic wave to the inside of the subject, and receiving a reflected wave of the incident wave by the probe;
Back propagation analysis step of performing back propagation analysis on the model using the waveform signal of the reflected wave to create a back propagation still image group arranged in a reverse time series;
A forward propagation analysis step of performing forward propagation analysis on the model using the waveform signal of the incident wave to create a forward propagation still image group arranged in time series;
Performing forward propagation / back propagation combined operation processing step of performing arithmetic processing combining the forward propagation still image group and the back propagation still image group to create a single still image displaying the position of the flaw; The present invention provides an ultrasonic inspection method characterized by

The present invention can add the following improvements and changes in the above-mentioned ultrasonic inspection method (I).
(I) The forward-propagation / back-propagation combining operation processing step obtains a Hadamard product by aligning time origins of each still image of the forward-propagating still image group and each still image of the back-propagating still image group The operation processing still image group creation substep which creates operation processing still image group by this, and the uniting processing substep which creates the single still image by summing the operation processing still image group.
(Ii) The back propagation analysis step includes a time inverted waveform signal creation substep of time inverting the waveform signal of the reflected wave to create a time inverted waveform signal, and the back propagation analysis based on the time inverted waveform signal To do
The forward propagation analysis step includes an incident waveform signal creation sub-step of creating a waveform signal of the incident wave of the ultrasonic wave, and the forward propagation analysis is performed based on the created incident waveform signal.

(II) Another aspect of the present invention is an ultrasonic inspection apparatus that uses ultrasonic waves to position flaws in an object to be inspected,
An input / output unit that inputs measurement conditions and analysis conditions of the ultrasonic wave and outputs an analysis result;
A measurement control unit configured to control a probe in accordance with the measurement condition, transmit an incident wave of the ultrasonic wave to the inside of the inspection object, and receive a reflected wave of the incident wave;
A data storage unit storing a model of the inspection object, the measurement condition, the analysis condition, a waveform signal of the reflected wave, a waveform signal of the incident wave, and an image based on the analysis;
And a waveform signal analysis processing unit that analyzes and processes the waveform signal of the incident wave and the waveform signal of the reflected wave according to the analysis condition on the model of the inspection object,
The waveform signal analysis processing unit
Back propagation analysis of creating a backward propagation still image group aligned in reverse time series using the waveform signal of the reflected wave, and order of creating a forward propagation still image group aligned in time series using the waveform signal of the incident wave Propagation analysis mechanism for propagation analysis,
Having an operation processing mechanism for performing forward propagation / back propagation combination arithmetic processing of combining the forward propagation still image group and the back propagation still image group to create a single still image displaying the position of the flaw; An ultrasonic inspection apparatus characterized by the present invention is provided.

The present invention can make the following improvements and modifications in the above-mentioned ultrasonic inspection apparatus (II).
(Iii) The forward-propagation / back-propagation combining operation processing is performed by taking a Hadamard product by aligning time origins of each still image of the forward-propagating still image group and each still image of the back-propagating still image group An algorithm for creating a still image group of operation processing and an algorithm for creating the single still image by summing up the group of operation processing still images are included.
(Iv) The data storage unit time-reverses the waveform signal of the reflected wave and the waveform signal of the reflected wave, and the measurement analysis condition storage mechanism that stores the model of the inspection object, the measurement condition, and the analysis condition. And a waveform signal storage mechanism for storing the time inverted waveform signal and the waveform signal of the incident wave, and an image based on the analysis, the back-propagated still image group, the forward-propagated still image group, the operation-processed still image group And an image data storage mechanism for storing the single still image.
(V) The waveform signal analysis processing unit further includes a test object model creating mechanism that creates a model of the test subject.
(Vi) The measurement control unit controls a probe control mechanism for controlling transmission and reception of the ultrasonic wave of the probe, a waveform signal generation mechanism for converting the received reflected wave into a waveform signal, and the probe And a probe drive mechanism responsible for position detection and scanning operations.

According to the present invention, in ultrasonic inspection for localization of flaws in an object to be inspected, the conventional weak point is overcome while taking advantage of the conventional back propagation analysis, and a single still image is obtained. It is possible to provide an ultrasonic inspection method capable of simultaneously displaying a plurality of flaws of different positions, and an ultrasonic inspection apparatus for carrying out the method.

It is a schematic diagram which shows schematic structure of the ultrasonic inspection apparatus which concerns on this invention. It is a flowchart which shows an example of the process in the ultrasonic inspection of this invention. It is a schematic diagram which shows an example of a to-be-tested object model. It is a schematic diagram which shows an example of a reflected wave measurement step. It is a schematic diagram which shows the relationship between the measured reflected waveform signal and its time inversion waveform signal. It is a schematic diagram which shows an example of the back propagation still image group obtained as a result of back propagation analysis. It is a schematic diagram which shows an example of the produced incident waveform signal. It is a schematic diagram which shows an example of the forward propagation still image group obtained as a result of forward propagation analysis. FIG. 7 is a schematic view in which each still image of a forward propagation still image group and each still image of a back propagation still image group are arranged with their time starting points aligned. It is a schematic diagram which shows an example of the arithmetic processing still image group obtained as a result of arithmetic processing still image group creation substep. It is a schematic diagram which shows an example of the single still image obtained as a result of a union process substep. The figure which shows an example of the result of having performed the waveform signal analysis process of the ultrasonic inspection which concerns on this invention with respect to the to-be-tested object model which has two flaws which mutually differ in position (tested object model figure, analysis result output figure) It is.

(Basic thought of the present invention)
The present inventors diligently studied the measurement and analysis process in ultrasonic examination in order to achieve the above-mentioned purpose. Among them, in addition to the back propagation analysis proposed in Patent Document 3 (WO 2014/167698 A1), forward propagation analysis is performed on the same object model as the back propagation analysis, and it is obtained by back propagation analysis. By combining and processing a still image group and a still image group obtained by forward propagation analysis, the propagation locus (path of incident wave) of an ultrasonic wave in a region other than a flaw position (echo generation source) inside the inspection object It has been found that the trajectory and the trajectory of the echo can be canceled. The present invention has been completed based on the findings.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described herein, and can be appropriately combined with the known technology or improved based on the known technology without departing from the technical concept of the invention. .

(Ultrasonic inspection device)
FIG. 1 is a schematic view showing a schematic configuration of an ultrasonic inspection apparatus according to the present invention. As shown in FIG. 1, the ultrasonic inspection apparatus 100 according to the present invention is an apparatus for locating a flaw in an object to be inspected using ultrasonic waves, and is roughly divided into ultrasonic measurement conditions and An input / output unit 40 which inputs an analysis condition and outputs an analysis result, and controls the probe 1 in accordance with the input measurement condition to transmit an incident wave of ultrasonic waves to the inside of the object to be inspected. A measurement control unit 10 for receiving a reflected wave, a waveform signal of an incident wave, a waveform signal of a reflected wave, a model of an inspection object, a data storage unit 20 for storing an analysis algorithm and a result of analysis processing, an incident waveform signal and a reflection And a waveform signal analysis processing unit 30 for analyzing and processing the waveform signal according to a predetermined analysis algorithm on the test object model. The internal configuration of each part will be described in detail in the following description of the flaw detection method.

(Ultrasound examination method)
As described above, in the ultrasonic inspection method of the present invention, in addition to the conventional back propagation analysis, forward propagation analysis of the incident wave is performed on the same object model as the back propagation analysis, and The greatest feature lies in performing arithmetic processing combining the still image group and the still image group obtained by back propagation analysis. Hereinafter, a process of measuring and analyzing ultrasonic waves using the ultrasonic inspection apparatus 100 of the present invention will be described.

FIG. 2 is a flow chart showing an example of the process in the ultrasonic inspection of the present invention. In FIG. 2, the test object model preparation step (S101) to the reflected wave measurement step (S103) is an ultrasonic measurement process, and the analysis condition input step (S201) to an analysis result output step (S205) is a waveform signal analysis process. is there.

(1) Ultrasonic Measurement Process A test object model preparation step S101 of preparing a model of a test object is performed. The test object model used in the present invention is a model that defines regions and conditions necessary for numerical analysis of the propagation phenomenon of ultrasonic waves. For example, the shape of the test region (analysis region), acoustic characteristics, It is a model that defines boundary conditions based on them, divided meshes used for analysis processing, and the like.

In this step S101, for example, the model creation is performed by the inspection object model creation mechanism 31 of the waveform signal analysis processing unit 30 based on the data regarding the inspection region input by the measurement analysis condition input mechanism 41 of the input / output unit 40 It is. The created test object model is stored in the measurement analysis condition storage mechanism 21 of the data storage unit 20 (for example, the test object model storage area of the measurement analysis condition storage mechanism 21).

The method of creating an object model and the mechanism for creating an object model are not particularly limited as long as an object model suitable for conventional back propagation analysis and forward propagation analysis of incident waves can be obtained, for example, Patent Document 4 The model creation method and apparatus configuration described in (WO 2015/092841 A1) can be suitably used.

In the present invention, there is no necessity to create the test object model in the ultrasonic inspection apparatus 100 (in other words, the test object model creation mechanism 31 of the waveform signal analysis processing unit 30 is not an essential configuration), A method and apparatus configuration for storing data of a test object model created by a test object model creation device separate from the ultrasonic inspection device 100 in the measurement analysis condition storage mechanism 21 via the measurement analysis condition input mechanism 41 Good.

Moreover, in order to facilitate understanding of the technology, the following description will be given by performing the test object model preparation step S101 before the measurement condition input step S102, but the present invention is not limited to that order. . In other words, the test object model preparation step S101 may be performed at any timing before the waveform signal analysis process.

Next, referring to the prepared test object model or the data on the inspection area, the ultrasonic measurement conditions (for example, ultrasonic transmission / reception position, ultrasonic incident direction, total measurement time, sampling interval, probe A scanning condition input step S102 is performed in which the scanning condition is set and the measurement condition is input by the measurement analysis condition input mechanism 41. The input measurement conditions are stored in the measurement analysis condition storage mechanism 21 (for example, the measurement condition storage area of the measurement analysis condition storage mechanism 21).

For example, when the transmitting / receiving position and the incident direction of the ultrasonic wave are set to the test object model prepared in step S101, the propagation required for the incident wave to reach the farthest part of the region to be inspected (inspection region) The time (incident wave propagation time) can be determined. Since ultrasonic inspection is an inspection method which measures and analyzes a waveform signal of echo, it is preferable to set twice or more times of incident wave propagation time as a total measurement time. Further, it is preferable to match the sampling interval Δt with the size of the divided mesh (for example, match the time for propagating to the adjacent mesh on the divided mesh with the sampling interval) from the viewpoint of analysis processing.

When the measurement condition input step S102 is performed by skipping the test object model preparation step S101 (for example, when it is necessary to perform an ultrasonic measurement urgently), the measurement condition input step S102 relates to the test region With reference to data (for example, shape data), provisionally, the length of time in which the ultrasonic wave seems to be able to sufficiently reciprocate the inspection area is set as the total measurement time, and the shortest sampling interval Δt is set as much as possible. It may be a method of setting.

Next, in accordance with the set measurement conditions, the probe control mechanism 11 of the measurement control unit 10 controls the probe 1 to transmit the incident wave of the ultrasonic wave to the inside of the object to be inspected, and the echo of the incident wave The reflected wave measurement step S103 of receiving the light by the probe 1 is performed. The echo received by the probe 1 is amplified and frequency-filtered and A / D converted by the waveform signal conversion mechanism 12 of the measurement control unit 10 to be a waveform signal. The waveform signalized echo (reflected waveform signal) is stored in the waveform signal storage mechanism 22 of the data storage unit 20 (for example, a reflected waveform signal storage area of the waveform signal storage mechanism 22).

The probe 1 used in the present invention is not particularly limited, and may be a probe having a single transducer, or a phased array probe (a linear array probe having a plurality of transducers). , Matrix array probe). From the viewpoint of inspection efficiency, it is desirable to use a phased array probe. The phased array probe may or may not be of a type that can select a transducer to transmit and a transducer to receive.

Further, the probe drive mechanism 13 of the measurement control unit 10 is responsible for position detection of the probe 1 and a scan operation. When scanning the probe 1 on a to-be-inspected object, after moving the probe 1, reflected wave measurement step S103 is repeated.

The ultrasonic measurement process will be described more specifically. FIG. 3 is a schematic view showing an example of a test object model, and FIG. 4 is a schematic view showing an example of a reflected wave measurement step. In FIGS. 3 to 4, from the viewpoint of simplifying the drawings and facilitating the technical understanding, there is only one point in the two-dimensional plane of the inspected object, and one incident wave of one pulse is transmitted and its reflected wave An example of receiving

Prepare a test object model (see FIG. 3) and set the measurement conditions of ultrasonic waves. In this case, a quadrangle is selected as the mesh shape, and the test object is obtained by dividing the length direction (x direction in FIG. 3) of the area to be inspected (x direction in FIG. 3) into 16 and the width direction (y direction in FIG. I prepared a model.

The transmission / reception position (the installation position of the probe) of the ultrasonic wave is set to three nodes (0, 1) to (0, 3) at the left end of the test object model (for example, a linear array probe including three transducers) When the incident direction of the ultrasonic wave is the x direction (without the delay time of oscillation between the transducers) and the size of the mesh and the sampling interval Δt are combined, “16 × Δt” can be obtained as the incident wave propagation time. Therefore, the total measurement time T is set to be “T ≧ 2 × 16 × Δt”. In this example, the total measurement time T is set as "T = 40 × Δt".

Next, ultrasonic measurement is performed according to the set measurement conditions. In this example, as shown in FIG. 4, it is assumed that there is a flaw extending over three nodes (5, 1) to (5, 3). When an ultrasonic wave is made incident from the probe 1 to the inside of the object under inspection according to the control of the probe control mechanism 11, the incident wave is reflected by the flaw and received by the probe 1 as an echo.

The received echo is waveform-signaled by the waveform signal conversion mechanism 12 and stored in the waveform signal storage mechanism 22 as a reflected waveform signal as shown in FIG. In this example, since there are flaws ranging from (5, 1) to (5, 3), the echo from the flaw is measured at a time of “10 × Δt”, and the measurement end time is “40 × Δt ”.

Preferably, the reflected waveform signal data to be stored is defined in such a manner that the transducer number used for measurement and the measurement time can be distinguished. For example, in the reflection waveform signal data “φ _Ech (n, t)”, the time t (total measurement) is obtained at the nth vibrator (1 ≦ n ≦ N where the number of vibrators in the probe 1 is N). The peak value of the ultrasonic wave measured at 0 ≦ t ≦ T) with respect to time T is represented.

(2) Waveform Signal Analysis Process After ultrasonic measurement, as shown in FIG. 2, a waveform signal analysis process (S201 to S205) is performed.

First, an analysis condition input step S201 is performed to set and input analysis conditions such as an algorithm for performing back propagation analysis, forward propagation analysis, and forward propagation / back propagation combined operation and measurement time used for analysis. The input analysis conditions are stored in the measurement analysis condition storage mechanism 21 (for example, the analysis condition storage area of the measurement analysis condition storage mechanism 21). Note that this step S201 may be performed at the beginning of the analysis process, or may be performed simultaneously with the previous measurement condition input step S102.

The back propagation analysis and forward propagation analysis algorithms are not particularly limited as long as the analysis can be appropriately performed, and conventional analysis algorithms (for example, finite element method, finite integration method) can be suitably used. As an algorithm of forward propagation / back propagation merging operation, Hadamard product (also called Schur product, product per element) and summation are performed. Also, as the measurement time used for analysis, all the time data for each sampling interval Δt set in the previous measurement condition input step S102 may be used with the intention of improving analysis accuracy, or shortening of the analysis time Intentionally, time data for each integral multiple of the sampling interval Δt may be selectively used.

(2-1) Back propagation analysis process As a back propagation analysis process, back propagation analysis is performed on the object model using a reflected waveform signal to create back propagation still images aligned in a backward time series. Step S202 is performed. More specifically, the present step S202 includes a time-reversal waveform signal creation sub-step S202a for time-reversing the reflection waveform signal to create a time-reversal waveform signal, and performing the back propagation analysis based on the time-reversal waveform signal. It is a thing.

Specifically, the reflected waveform signal data “φ _Ech (n, t)” stored in the previous reflected wave measurement step S 103 is read out from the waveform signal storage mechanism 22, and the time is calculated by the propagation analysis mechanism 32 of the waveform signal analysis processing unit 30. Create an inverted waveform signal. The created time-reversal waveform signal is stored in the waveform signal storage mechanism 22 (for example, the time-reversal waveform signal storage area of the waveform signal storage mechanism 22). For example, time-inverted waveform signal data is stored as “φ _Inv (n, T−t)” (where 1 ≦ n ≦ N, 0 ≦ t ≦ T).

Next, the time inversion waveform signal data “φ _Inv (n, T−t)”, the test object model and the back propagation analysis algorithm are read out from the waveform signal storage mechanism 22 and the measurement analysis condition storage mechanism 21 respectively, The back propagation analysis is carried out in to create back propagation still image groups “{M _Rev (n, T−t)}” arranged in reverse time series. The generated back propagation still image group is stored in the image data storage mechanism 23 of the data storage unit 20 (for example, the back propagation still image storage area of the image data storage mechanism 23).

The still image / still image group expressed in the present invention is expressed by the line of sight of the measurer / observer in order to make the technology easy to understand, and shows the state in the case of display output or print output. It is a thing. However, image data in the computer is calculated as matrix data consisting of position data of each pixel constituting the image and pixel value data (brightness and color data, corresponding to peak value in the present invention). It is necessary to understand what is stored.

The back propagation analysis process will be described more specifically. FIG. 5 is a schematic view showing the relationship between the measured reflected waveform signal and its time-reversal waveform signal. As shown in FIG. 5, when the reflected waveform signal that received the echo at the time of “t = 10 × Δt” in the total measurement time “T = 40 × Δt” is time-reversed, “T−t = (40 × Δt A time-reversal waveform in which the echo is received in the inversion time of −) (10 × Δt) = 30 × Δt ”and the end time is“ T−t = (40 × Δt) − (0 × Δt) = 40 × Δt ” A signal is obtained.

Next, as described above, back propagation analysis is performed on the test object model (see FIG. 3) using the created time-reversal waveform signal (see FIG. 5), and back-propagated still image groups arranged in reverse time series Create The back propagation analysis in the present invention is basically the same as that of Patent Document 3 (WO 2014/167698 A1), and is an analysis for obtaining the propagation locus of ultrasonic waves from which the created time-reversal waveform signal can be obtained. . In other words, in order to obtain the generated time-reversal waveform signal, it is an analysis to determine how the wave front of the ultrasonic wave travels.

FIG. 6 is a schematic view showing an example of a back propagation still image group obtained as a result of back propagation analysis. In FIG. 6, the position of the wave front of the propagating ultrasonic wave is indicated by “●” on the nodal point of the test object model in order to facilitate technical understanding. However, in the actual analysis, the data of “●” includes not only the position of the wavefront but also the Mises stress and displacement amount corresponding to the amplitude (peak value) of the wavefront. The relationship between the time-reversal waveform signal and the back-propagating still image group will be described with reference to FIGS.

As shown in FIG. 5, no ultrasonic waves are observed as shown in FIG. 5 at the inversion time “T−t = 0 × Δt to 29 × Δt” of the time-reversal waveform signal. There is no "●" on the nodes of the body model.

Since ultrasonic waves are observed in FIG. 5 at the next inversion time “T−t = 30 × Δt” of the time inversion waveform signal, nodal points (0 , 1) to (0, 3) (the placement position of the probe) "● mark" is displayed.

Then, although the ultrasonic wave is not observed in FIG. 5 in the inversion time “T−t = 31 × Δt to 40 × Δt” of the time inverted waveform signal (although the ultrasonic wave is not observed at the installation position of the probe), In the back propagation still image group of FIG. 6, it is confirmed that the wavefront advances toward the inside of the test object model (to the right in the drawing).

The back propagation still image group “{M _Rev (n, T−t)}” created as described above is stored in the image data storage mechanism 23 as described above.

(2-2) Forward propagation analysis process Forward propagation analysis is performed on the object model. In the present invention, the forward propagation analysis process is not limited to the process performed after the back propagation analysis process, and after the above-described analysis condition input step S201, the forward propagation / back propagation combined operation process S204 described later If it is before, you may go at any timing. For example, it may be performed simultaneously with the analysis condition input step S201 and the measurement condition input step S102.

As a forward propagation analysis process, forward propagation analysis step S203 of performing forward propagation analysis on an object model using a waveform signal (incident waveform signal) of an incident wave to create a forward propagation still image group arranged in time series is performed. Do. More specifically, the present step S203 includes an incident waveform signal creation sub-step S203a for creating an incident waveform signal using the waveform signaling mechanism 12 of the measurement control unit 10, and forward propagation based on the created incident waveform signal It is an analysis.

The incident waveform signal may be a signal of a simulated waveform defined by a function (for example, Mexican hat function, French hat function) representing the center frequency band of the probe 1 to be used, or used The ultrasonic wave actually transmitted by the probe 1 may be separately measured and converted into a waveform signal. The created incident waveform signal “φ _Inc (n, t)” is stored in the waveform signal storage mechanism 22 (for example, the incident waveform signal storage area of the waveform signal storage mechanism 22).

Further, the forward propagation analysis in the present invention is performed on the assumption that there is no flaw inside the object to be inspected. In other words, the generation of echo due to flaws is not considered. Even when the probe 1 is scanned on the inspection subject, the incident waveform signal generation step S203 need not be repeated since the incident waveform signal is the same.

Specifically, the incident waveform signal data “φ _Inc (n, t)”, the test object model and the forward propagation analysis algorithm are read out from the waveform signal storage mechanism 22 and the measurement analysis condition storage mechanism 21 respectively. Forward propagation analysis is performed to create a forward propagation still image group “{M _For (n, t)}” arranged in time series. The created forward propagation still image group "{M _For (n, t)}" is stored in the image data storage mechanism 23 (for example, the forward propagation still image storage area of the image data storage mechanism 23).

The forward propagation analysis process will be described more specifically. FIG. 7 is a schematic view showing an example of the created incident waveform signal, and FIG. 8 is a schematic view showing an example of a forward propagation still image group obtained as a result of forward propagation analysis. In FIG. 8, as in FIG. 6, the position of the wavefront of the propagating ultrasonic wave is indicated by “●” on the nodal point of the object model. The relationship between the incident waveform signal and the forward propagation still image group will be described with reference to FIGS. 7-8.

In forward propagation analysis, it suffices to analyze the propagation time required for the incident wave to reach the farthest part of the inspection area. That is, here, “t = 0 × Δt ̃16 × Δt” may be analyzed.

First, at the time “t = 0 × Δt” of the incident waveform signal, since the probe oscillates the ultrasonic wave, the ultrasonic wave is observed in FIG. 7 and also in the forward propagation still image group in FIG. “●” is displayed on the nodes (0, 1) to (0, 3) of the test object model (the installation position of the probe).

Then, although the ultrasonic wave is not observed in FIG. 7 in the time “t = 1 × Δt to 16 × Δt” of the incident waveform signal (although the ultrasonic wave is not observed at the installation position of the probe), the order of FIG. In the propagation still image group, it is confirmed that the wavefront advances toward the inside of the test object model (to the right in the figure).

The forward propagation still image group “{M _For (n, t)}” created as described above is stored in the image data storage mechanism 23 as described above.

(2-3) Forward Propagation / Back Propagation Combined Operation Process Next, as a forward propagation / back propagation combined operation process, a forward propagation still image group “{M _For (n, t)}” and a back propagation still image group “{ A forward propagation / back propagation combined arithmetic processing step S204 is performed to create a single still image displaying a position where the arithmetic processing combining M _Rev (n, T−t)} is not performed. More specifically, the present step S 204 aligns the time origins of each still image of “{M _For (n, t)}” and each still image of “{M _Rev (n, T−t)}”. The operation-processed still image group creation sub-step S 204 a for generating the operation-processed still image group “{M _Ope (n, t)}” by taking the Hadamard product in the form, and the operation-processed still image group “{M _Ope ( n, t)}] to form a single still image “M _Sum (n)” by combining processing sub-step S 204 b.

Specifically, “{M _For (n, t)}” stored in forward propagation analysis step S 203, “{M _Rev (n, T−t)}” stored in back propagation analysis step S 202, and an arithmetic algorithm It reads from the image data storage mechanism 23 and the measurement analysis condition storage mechanism 21 respectively. In the calculation processing mechanism 34 of the waveform signal analysis processing unit 30, each still image of "{M _For (n, t)}" and each still image of "{M _Rev (n, T-t)}" The operation-processed still image group "{M _Ope (n, t)}" is created by taking the Hadamard product in a form in which t = 0 x? t. The created operation processing still image group “{M _Ope (n, t)}” is stored in the image data storage mechanism 23 (for example, the operation processing still image storage area of the image data storage mechanism 23).

The Hadamard product is an operation for obtaining a matrix which is determined by taking a product for each component with respect to a matrix of the same size. Further, as described above, since the image data is matrix data, a matrix representing a still image of "M _For (n, t)" and a matrix representing a still image of "M _Rev (n, T-t)" It is possible to take the Hadamard product of and the resulting matrix will represent the still image “M _Ope (n, t)” subjected to arithmetic processing. It will become like a formula (1) when it expresses with a formula.

Next, the arithmetic processing still image group “{M _Ope (n, t)}” and the arithmetic algorithm are read from the image data storage mechanism 23 and the measurement analysis condition storage mechanism 21 respectively, and the arithmetic processing still image group “{M _Ope (n , t)} ”to create a single still image“ M _Sum (n) ”. The single still image “M _Sum (n)” created is stored in the image data storage unit 23 (for example, an analysis result image storage area of the image data storage unit 23). In addition, if the arithmetic processing here is represented by numerical formula, it will become like Formula (2).

Finally, an analysis result output step S205 of outputting the obtained single still image "M _Sum (n)" by the output mechanism 42 of the input / output unit 40 is performed. There is no particular limitation on the output format of the analysis result, and it may be display output, print output, or any other output format.

The forward propagation / back propagation merging operation process will be described more specifically. FIG. 9 is a schematic diagram in which each still image of a forward propagation still image group and each still image of a back propagation still image group are arranged with their time starting points aligned.

Here, the time starting point will be briefly described. The ultrasound examination begins with the transmission of the incident wave as shown in FIG. 7 and ends after confirming receipt of the echo as shown in FIG. The total measurement time T has a certain degree of discretion because it is limited only that twice or more of the incident wave propagation time is preferable. Further, as shown in FIG. 5, the time-reversal waveform signal is obtained by reversing the time axis of the measured reflected waveform signal. Therefore, the time origin in the time inversion waveform signal is the total measurement time T. On the other hand, the time end point in the time-reversal waveform signal is the time start point of ultrasonic measurement (that is, the oscillation time of the incident wave “t = 0 × Δt”), which is the time determined at one point. From these things, in the present invention, the time start point (oscillation time of the incident wave) “t = 0 × Δt” of the ultrasonic measurement is defined as the time start point of the forward propagation / back propagation merging operation process.

The left column in FIG. 9 is a forward propagation still image group arranged in time series, and the right column is a back propagation still image group arranged so as to align time starting points. In other words, the same measurement time "t" is arranged in pairs. Since the time start points are aligned, the back propagation still image group in the right row is obtained by reversing the back propagation still image group shown in FIG.

In FIG. 9, when comparing the forward propagation still image and the back propagation still image (adjacent to each other in the figure) at the same measurement time “t”, “t = 0 × Δt ̃ other than“ t = 5 × Δt ” It can be seen that the wavefront positions of ultrasonic waves (the position of “●” on the nodal point of the object model) are different from each other by 4 × Δt ”and“ t = 6 × Δt ̃16 × Δt ”. A position that is not a wavefront (a position where there is no “●” on the nodal point) means that the pixel value data (the element of the matrix corresponding to the peak value) at that position is zero.

Then, if the Hadamard product is taken between the left and right still image pairs (if the Hadamard product between the matrix representing the forward propagation still image and the matrix representing the back propagation still image is taken), the wavefront positions do not match. In the calculation result (calculation processing still image), the pixel value data (elements of the matrix corresponding to the peak value) at all the nodes become zero. That is, a group of operation processing still images as shown in FIG. 10 is created. FIG. 10 is a schematic view showing an example of the operation processing still image group obtained as a result of the operation processing still image group creation sub-step.

Next, when the obtained operation-processed still image group is summed, a single still image as shown in FIG. 11 is created. FIG. 11 is a schematic view showing an example of a single still image obtained as a result of the uniting processing sub-step. The single static image of FIG. 11 is the same as the object model having the flaw shown in FIG. 4 and according to the forward propagation / back propagation merging operation process of the present invention, the ultrasound of the region other than the flaw position is It can be seen that the propagation trajectory can be canceled.

(Other embodiments)
FIG. 12 is a diagram showing an example of a result of performing a waveform signal analysis process of ultrasonic inspection according to the present invention on a test object model having two flaws different in position from each other (test object model diagram, analysis It is a result output figure). As shown in FIG. 12, even in the case where the test object model has a plurality of flaws (flaw A, flaw B) different in distance from the probe, the waveform signal analysis process of the present invention (in particular, forward order) As a result of performing propagation / back propagation combination calculation process, it is confirmed that the propagation locus of the ultrasonic wave in the area other than the flaw position can be canceled, and the plurality of flaws can be simultaneously displayed in one still image. .

The embodiments and examples described above are described in order to help the understanding of the present invention, and the present invention is not limited to only the specific configurations described. For example, it is possible to replace part of the configuration of the embodiment with the configuration of the common sense of the person skilled in the art, and it is also possible to add the configuration of the common sense of the person skilled in the art to the configuration of the embodiment. That is, the present invention may delete, add, or substitute other configurations to other configurations without departing from the technical concept of the invention with respect to a part of the configurations of the embodiments and examples of the present specification. It is possible.

100 ... ultrasonic inspection apparatus, 1 ... probe, 10 ... measurement control unit, 11 ... probe control mechanism, 12 ... waveform signal forming mechanism, 13 ... probe drive mechanism, 20 ... data storage unit, 21 ... Measurement analysis condition storage mechanism 22 waveform signal storage mechanism 23 image data storage mechanism 30 waveform signal analysis processor 31 inspection object model creation mechanism 32 propagation analysis mechanism 33 operation processing mechanism 40 ... input / output unit, 41 ... measurement analysis condition input mechanism, 42 ... output mechanism.

Claims

It is an ultrasonic inspection method which locates the flaw inside a to-be-inspected object using an ultrasonic wave,
A test object model preparation step of preparing a model of the test object;
A measurement condition input step of setting and inputting the measurement condition of the ultrasonic wave;
An ultrasonic measurement step of controlling a probe in accordance with the measurement conditions, transmitting an incident wave of the ultrasonic wave to the inside of the subject, and receiving a reflected wave of the incident wave by the probe;
Back propagation analysis step of performing back propagation analysis on the model using the waveform signal of the reflected wave to create a back propagation still image group arranged in a reverse time series;
A forward propagation analysis step of performing forward propagation analysis on the model using the waveform signal of the incident wave to create a forward propagation still image group arranged in time series;
Performing forward propagation / back propagation combined operation processing step of performing arithmetic processing combining the forward propagation still image group and the back propagation still image group to create a single still image displaying the position of the flaw; A method of ultrasound examination characterized by
In the ultrasonic examination method according to claim 1,
The forward propagation / back propagation merging operation processing step is
A process-processed still image group creation is performed by taking a Hadamard product by aligning time origins of each still image of the forward propagation still image group and each still image of the back-propagation still image group With substeps,
And e. Combining processing substeps of creating the single still image by summing the operation processing still images.
In the ultrasonic inspection method according to claim 1 or 2,
The back propagation analysis step includes a time inverted waveform signal creation substep of time inverting the waveform signal of the reflected wave to create a time inverted waveform signal, and performing the back propagation analysis based on the time inverted waveform signal And
The forward propagation analysis step includes an incident waveform signal creation sub-step for creating a waveform signal of the incident wave of the ultrasonic wave, and the forward propagation analysis is performed based on the created incident waveform signal. Ultrasound examination method.
An ultrasonic inspection apparatus that locates internal flaws in a subject using ultrasonic waves, comprising:
An input / output unit that inputs measurement conditions and analysis conditions of the ultrasonic wave and outputs an analysis result;
A measurement control unit configured to control a probe in accordance with the measurement condition, transmit an incident wave of the ultrasonic wave to the inside of the inspection object, and receive a reflected wave of the incident wave;
A data storage unit storing a model of the inspection object, the measurement condition, the analysis condition, a waveform signal of the reflected wave, a waveform signal of the incident wave, and an image based on the analysis;
And a waveform signal analysis processing unit that analyzes and processes the waveform signal of the incident wave and the waveform signal of the reflected wave according to the analysis condition on the model of the inspection object,
The waveform signal analysis processing unit
Back propagation analysis of creating a backward propagation still image group aligned in reverse time series using the waveform signal of the reflected wave, and order of creating a forward propagation still image group aligned in time series using the waveform signal of the incident wave Propagation analysis mechanism for propagation analysis,
Having an operation processing mechanism for performing forward propagation / back propagation combination arithmetic processing of combining the forward propagation still image group and the back propagation still image group to create a single still image displaying the position of the flaw; The ultrasonic inspection device that features it.
In the ultrasonic inspection apparatus according to claim 4,
The forward-propagation / back-propagation combining arithmetic processing is arithmetic processing still by taking a Hadamard product of each still image of the forward-propagating still image group and each still image of the back-propagating still image group in a form of aligning time origins An ultrasonic inspection apparatus comprising: an algorithm for creating an image group; and an algorithm for creating the single still image by summing the operation-processed still images.
In the ultrasonic inspection apparatus according to claim 5,
The data storage unit includes a measurement analysis condition storage mechanism that stores a model of the subject, the measurement condition, and the analysis condition.
A waveform signal storage mechanism for storing a waveform signal of the reflected wave, a time inverted waveform signal created by time inverting the waveform signal of the reflected wave, and a waveform signal of the incident wave;
An image data storage mechanism storing the back-propagated still images, the forward-propagated still images, the operation-processed still images, and the single still image as images based on the analysis. Ultrasonic examination device.
The ultrasonic inspection apparatus according to any one of claims 4 to 6.
The ultrasonic inspection apparatus, wherein the waveform signal analysis processing unit further includes a test object model creating mechanism that creates a model of the test subject.
The ultrasonic inspection apparatus according to any one of claims 4 to 7.
The measurement control unit controls a probe control mechanism for controlling transmission and reception of the ultrasonic wave of the probe, a waveform signaling mechanism for converting the received reflected wave into a waveform signal, position detection of the probe, and An ultrasonic inspection apparatus comprising: a probe drive mechanism responsible for a scan operation.