KR101218473B1

KR101218473B1 - Ultrasonic measurement device and ultrasonic measurement method

Info

Publication number: KR101218473B1
Application number: KR1020107016897A
Authority: KR
Inventors: 다카후미 오제키; 하지메 다카다
Original assignee: 제이에프이 스틸 가부시키가이샤
Priority date: 2008-02-20
Filing date: 2009-02-19
Publication date: 2013-01-04
Also published as: JP5402046B2; WO2009104811A9; CN102216767A; CN102216767B; WO2009104811A1; KR20100101683A; JP2010071971A

Abstract

The ultrasonic measuring apparatus transmits and receives ultrasonic waves toward the subject while scanning the focal point formed by the ultrasonic probe 10 with respect to the subject, and receives and receives the reflected wave from the internal defect of the subject (11). And 12) and using the reference propagation time obtained by treating the waveform of the ultrasonic wave propagating between the ultrasonic probe and the internal defect as the waveform of the ultrasonic wave synthesized on the entire surface of the transmitting / receiving surface, the signal received at each measuring point is opened. The opening synthesis processing means 14 which performs a synthesis process is provided.

Description

Ultrasonic Measuring Device and Ultrasonic Measuring Method {ULTRASONIC MEASUREMENT DEVICE AND ULTRASONIC MEASUREMENT METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic measuring device and an ultrasonic measuring method, and in particular, in an object of various shapes such as a plate, a tube, a cylinder, and the like made of metal, resin, etc., by using an ultrasonic flaw detection method, which is a kind of non-destructive testing method. It relates to the measurement of internal defects.

BACKGROUND ART Ultrasonic flaw detection, which is a kind of nondestructive inspection method, has been widely used for flaw detection of internal defects such as steel materials. In this internal defect flaw detection, in order to obtain more detailed internal defect information, high resolution of the ultrasound image is required. As a method of high resolution of the ultrasound image, there are the following conventional techniques.

(1) C Scan Ultrasonic Scanning

There is a C-scan ultrasonic flaw detection method that scans two-dimensionally an ultrasonic transceiver for transmitting and receiving a focused beam to a subject (for example, see Non-Patent Document 1), and this flaw detection method is widely used for detecting internal defects requiring high resolution.

(2) opening synthesis method

In addition to the C scan ultrasonic flaw detection described above, there is an aperture synthesis method as a technique for the purpose of high resolution imaging (see Patent Document 1 and Patent Document 2, for example). The principle of this aperture synthesis method will be described by taking a case where defect oscillation is brought into contact with the surface of the object 110 by vibrator array 120 shown in FIG. Ultrasonic waves are transmitted from each vibrator of the vibrator array 120 to detect defect echoes, and the beam path in the subject 110 of the defect echoes is measured from the time from the ultrasonic transmission to the echo reception. Since the ultrasonic waves transmitted and received from the individual vibrators 120p (p = 1, 2, ...) are spatially diffuse, the beam path of the echo detected by the vibrator 120p is Wp (p = 1, 2, ...). The reflection source exists somewhere in the directivity angle range of the ultrasonic wave transmitted and received by the vibrator 120p among the hollow spheres Sp (p = 1, 2, ...) having a radius Wp. If all the vibrators are used to detect an echo and the intersection point of the hollow sphere Sp is found, this intersection point becomes a defect image. In the example of FIG. 30, the state which synthesize | combines a defect image from the beam top of the echo which A, B, C, D, and E of the vibrator array 120 detected.

The aperture synthesis method using such an array type ultrasonic probe can synthesize a defect image in a predetermined area corresponding to the arrangement and shape of the array vibrator, and does not require mechanical scanning of the ultrasonic probe, so that ultrasonic scanning can be performed at high speed. have. When the focus is set at a certain depth position and the aperture combining process is performed, the same scanning as in the C scan ultrasonic flaw detection method using the focused beam of (1) can be performed.

(3) Opening synthesis method using focused beam

As a method which combined said (1) and (2), there exists an opening synthesis method using a focused beam (for example, refer patent document 3). In this method, a focused ultrasound probe is scanned, and the signal received at each measurement point is aperture synthesized to further increase resolution. As shown in Figure 31, divides the reconstructed image of the subject to smile element of the same size, each measurement point (P _{i, j)} each, which may be a defect echo source from the measuring beam exposed (W _{i, j)} smile factors As a method characterized by selecting (PF _{k, l, m} ), the resolution can be improved in flaw detection using a focused beam by this method.

The waveform obtained by focusing at a certain position using the array type ultrasonic probe and performing the opening synthesis of the above (2) using the signal of each vibrator is examined by using a focused beam of the focused ultrasonic probe. If it is equivalent to the obtained waveform, it can be combined with the aperture synthesis method using an array type ultrasonic probe.

Japanese Patent Application Laid-Open No. 8-62191 Japanese Laid-Open Patent Publication 2000-65808 Japanese Unexamined Patent Publication No. 2004-150875

Japan Nondestructive Testing Association Editing, Ultrasonic Testing Test II, Japan Nondestructive Testing Association, 2000, p. 151-152

The flaw detection method of said (1)-(3) has the following problems, respectively.

(1) C Scan Ultrasonic Scanning

The resolution of flaw detection using a focused beam can be expressed by the beam diameter dw at the focal point. The beam diameter dw can be approximated by the formula (1) using the focal length F, the wavelength λ, and the diameter D of the vibrator (ultrasonic transceiver) of the ultrasonic beam.

dw = (Fλ) / D... (One)

Therefore, to increase the resolution,

(a) Shorten the focal length (F).

(b) The wavelength λ is shortened.

(c) Increase the diameter (D) of the ultrasonic transceiver.

There are three ways called.

However, in the method of (a), there arises a problem that only a portion close to the surface of the subject can be inspected. In the method of (b), the attenuation of ultrasonic waves becomes large, and a problem arises that detection of a defect becomes difficult. In the method of (c), a problem arises in that the electrical impedance of the ultrasonic transceiver is too low to be used. Therefore, there is a limit to high resolution by using a focused beam.

(2) opening synthesis method

As shown in Fig. 30, this aperture synthesis method is different from the C-scan flaw detection method, in which an ultrasonic transceiver requires a wide direct angle to detect a defect echo over a wide range, and focuses the ultrasound beam in a narrow area. It has been regarded as a technique of commercial use.

(3) Opening synthesis method using focused beam

Also in this method, there was a problem that the resolution did not improve when a highly focused ultrasonic beam was used. Specifically, a focused ultrasound probe with a large ultrasonic vibrator or an array-type ultrasonic probe having a large area of the ultrasonic vibrator array string used for the opening synthesis process is used, and a focal length, a distance to a subject, and a contact medium from the probe are used. There was a problem when the converted distance was not long enough with respect to the size of the ultrasonic probe.

The reason is as follows.

In this method, it is assumed that the transmission and reception of ultrasonic waves is performed at one center of the ultrasonic vibrator, and the reciprocating propagation time from the ultrasonic probe to the microelement is shown from FIG. 32 to the microelement. Ultrasonic wave propagates on the only path | route phase of to calculate. However, in practice, the transmission and reception of the ultrasonic waves is performed on the entire surface of the ultrasonic vibrator. For this reason, especially when an ultrasonic vibrator uses a focused ultrasound probe with a large focal length, the internal defect imaging is performed by the technique described in Patent Document 3, because it greatly deviates from the assumption of transmission and reception at one point. It was difficult to increase the resolution.

DISCLOSURE OF INVENTION

The present invention improves the measurement resolution of internal defects in flaw detection using a focused ultrasound probe having a large ultrasonic vibrator and a short focal length, or an aperture synthesizer using a large area and a short focal length of the ultrasonic vibrator array array used for the opening synthesis process. The purpose.

In order to achieve the above object, the present invention provides an ultrasonic measuring device consisting of:

Transmitting and receiving means for scanning the focal point formed by the ultrasonic probe relative to the subject, transmitting ultrasonic waves toward the subject, and receiving reflected waves from the internal defects of the subject;

Opening synthesis processing of the signal received at each measurement position is performed using the reference propagation time obtained by treating the ultrasonic wave propagating between the ultrasonic probe and the internal defect as the waveform of the ultrasonic wave synthesized on the entire surface of the transmission / reception surface. Aperture synthesis processing means.

Moreover, it is preferable that the ultrasonic measuring apparatus which concerns on this invention is the following.

At each measurement position, it is provided with the propagation time measuring means which measures the propagation time to an internal defect based on the said reflected wave,

The opening synthesis processing means extracts the isoelectric time plane formed by linking the position inside the subject to which the reference propagation time is equal to the propagation time measured by the propagation time measurement means, and thus the position of the isoelectric time plane. Is the defect position.

Moreover, the ultrasonic measuring apparatus which concerns on this invention calculates the number of times extracted during the said scanning for every defect candidate position calculated | required by the said opening synthesis | combining processing means, and display means which displays the calculated number corresponding to a defect candidate position, and displays it. It is preferable to have.

Further, in the ultrasonic measuring apparatus according to the present invention, the aperture combining processing means delays the reflected wave received by the transmitting and receiving means according to the delay time calculated based on the reference propagation time, and then adds to generate a signal. It is desirable to.

Moreover, it is preferable that the ultrasonic measuring apparatus which concerns on this invention has display means which displays the signal data produced | generated by the said opening composition processing means.

Moreover, in the ultrasonic measuring apparatus according to the present invention, it is preferable to calculate the reference propagation time as follows:

Divide the entire surface of the transmitting and receiving surface of the ultrasonic probe into a plurality of regions,

Obtains the waveform of the ultrasonic wave transmitted and received between each divided region and the internal defect,

The reference propagation time is calculated from the waveform obtained by synthesizing the waveform with respect to the entire surface of the ultrasonic probe.

Using a subject having an internal defect manufactured artificially in advance, ultrasonic waves are transmitted toward the subject while relatively scanning the focal point formed by the ultrasonic probe and the subject, and from the internal defect of the subject The reference propagation time is obtained by receiving the reflected wave.

Moreover, in the ultrasonic measuring apparatus which concerns on this invention, it is preferable that the said ultrasonic probe is a focused ultrasonic probe.

Moreover, in the ultrasonic measuring apparatus which concerns on this invention, it is preferable that the said ultrasonic probe is an array type ultrasonic probe in which several vibrators were arranged. Moreover, it is preferable that the ultrasonic measurement apparatus which concerns on this invention has a signal processing means which focuses the signal of each said vibrator by opening synthesis | combination process, and uses it as the signal received by said each measuring point.

Moreover, it is preferable that the ultrasonic measuring apparatus which concerns on this invention has defect determination means which judges a defect using the signal synthesize | combined by the opening synthesis | combination process means by the said opening synthesis | combination processing means.

In addition, the ultrasonic measurement method according to the present invention,

Transmitting / receiving ultrasonic waves toward the subject and receiving reflected waves from internal defects of the subject;

Opening synthesis processing of the signal received at each measurement point is performed by using the reference propagation time obtained by treating the ultrasonic wave propagating between the ultrasonic probe and the internal defect as the waveform of the ultrasonic wave synthesized on the entire surface of the transmission and reception surface. An aperture synthesis treatment step.

According to the present invention, transmitting and receiving means for transmitting an ultrasonic wave toward the subject and receiving the reflected wave from the internal defect of the subject while scanning the focal point formed by the ultrasonic probe relative to the subject, the ultrasonic probe and Aperture synthesis processing means for performing aperture synthesis processing of the signal received at each measurement point, using the reference propagation time obtained by treating the waveform of the ultrasonic wave propagating between internal defects as the waveform of the ultrasonic wave synthesized on the entire surface of the transmission / reception surface. In this regard, the measurement resolution of the internal defect can be improved.

1 is a configuration diagram of an imaging apparatus for internal defects by ultrasonic waves according to Embodiment 1 of the present invention.
2 is an explanatory diagram of an isoelectric time plane of the present invention.
3 is a flowchart showing a processing method for obtaining ultrasonic wave propagation time by ultrasonic wave propagation analysis.
4C are explanatory drawing which showed the procedure of the method of obtaining propagation time.
5 is a flowchart illustrating a processing method when preparing an isoelectric time plane.
6 is an explanatory diagram showing a relationship between a change amount of propagation time and an isoelectric time plane.
7 is an example of data of an isoelectric time plane.
8 is a flowchart illustrating processing when synthesizing a defect image.
9 is an explanatory diagram of a water propagation time and a test subject propagation time.
FIG. 10 is an explanatory diagram of a method of drawing an isoelectric time plane at different propagation times using one isoelectric time plane. FIG.
11 is an explanatory diagram of an imaging process.
12A to 12C are views showing the effects of the embodiments of the present invention in comparison with the results of the conventional method.
It is explanatory drawing of opening synthesis in Embodiment 2 of this invention.
14 is a configuration diagram of an imaging apparatus for internal defects by ultrasonic waves according to Embodiment 3 of the present invention.
15 is an explanatory diagram of an isoelectric time plane of the present invention.
16 is a flowchart illustrating a processing method for obtaining ultrasonic wave propagation time by ultrasonic wave propagation analysis.
17 is a flowchart illustrating a processing method for acquiring the ultrasonic wave waveform at the defect position.
Fig. 18 is a flowchart showing a processing method for receiving an array type ultrasonic probe, performing aperture synthesizing to obtain an output waveform.
19 is an explanatory diagram showing a procedure of a method for obtaining a propagation time.
20 is a flowchart illustrating a processing method when preparing an isoelectric time plane.
21 is an explanatory diagram showing the relationship between the amount of change in propagation time and the isoelectric time plane.
22 is an example of data of an isoelectric time plane.
Fig. 23 is a flowchart showing processing when synthesizing a defect image.
It is explanatory drawing of the water propagation time and a test subject time.
FIG. 25 is an explanatory diagram of a method of drawing the isoelectric time planes at different propagation times using one isoelectric time plane. FIG.
26 is an explanatory diagram of an imaging process.
27A to 27C show the effects of the embodiment of the present invention in comparison with the results of the conventional method.
FIG. 28 is an explanatory diagram of a method of performing waveform resynthesis by constructing a delay time from the profile of the amount of change in propagation time in Embodiment 4 of the present invention. FIG.
29 is a diagram illustrating a linear focusing linear array ultrasonic probe.
30 is a principle explanatory diagram of a conventional aperture synthesizing method.
It is explanatory drawing of the defect image synthesis method in the prior art (patent document 3).
It is explanatory drawing which shows the path | route of the ultrasonic probe and a microelement in a prior art.

Carrying out the invention Form for

MEANS TO SOLVE THE PROBLEM In order to measure internal defects with high resolution, especially in order to measure a defect shape with the resolution of about tens to several hundred micrometers,

A focused ultrasound probe with a large measuring ultrasonic vibrator or an array type ultrasonic probe having a large area of the ultrasonic vibrator array array used for the opening synthesis process is used, and the focal length, the distance to the subject, and the contact medium conversion distance from the ultrasonic probe are ultrasonic. If it is not long enough for the size of the vibrator area for transmitting and receiving probes,

In the prior art, knowledge has been obtained that measurement cannot be performed with high resolution.

Specifically, if the conditions (focal length, object distance, contact medium conversion distance shown in the example of patent document 3 are about 8 times with respect to an oscillator area | region (size of the oscillator area to transmit / receive)), description of patent document 3 Even resolution is no problem. However, when the ratio of the focal length, the subject distance, and the contact medium conversion distance to the vibrator region becomes smaller than the conditions, it was found that the resolution becomes worse.

In addition, the contact medium conversion distance L is represented by the following formula, and when the ultrasonic wave propagates in a plurality of mediums, the actual distance to the ultrasonic probe and an arbitrary position (for example, a distance to an internal defect, etc.) The distance is expressed in terms of the distance from the medium in which the oscillator of the probe is in contact, and the conversion is performed geometrically in consideration of the refraction. Practically, it is a value equivalent to the focal length.

L = L1 + L2 × (C2 / C1) + L3 × (C3 / C1) + ----------

Provided that L1, L2, L3,... ; Medium 1, 2, 3,... (Media 1 is the actual propagation distance in contact medium),

C1, C2, C3,... ; Medium 1, 2, 3,... Sound velocity in (medium 1 is contact medium)

As a cause of the deterioration of resolution, in the conventional method, it is assumed that transmission and reception of ultrasonic waves is made at one point of the center of the area to be transmitted and received among the ultrasonic probes, and based on the propagation time from the center of the area to the minute element. Thus, the first half distance is calculated, and opening synthesis is performed on the spherical surface having the first half distance as a radius as a reflection source (internal defect) may exist. However, when the ratio of the focal length, the object distance, and the contact medium distance to the vibrator region becomes small, the distance between the internal defect and the center of the ultrasonic probe and the point other than the internal defect and the center of the ultrasonic probe (ends from the periphery of the center ( The difference in the case where the distance of the area | region to a part) differs becomes large with respect to a propagation distance.

In addition, it is conceivable that the transmission and reception of the ultrasonic waves is performed on the entire surface of the ultrasonic probe, and that the received signals are synthesized by the signals received in each area of the entire surface. In other words, in the conventional aperture synthesizing process, the propagation time itself is a propagation distance, and from one point of the center of the ultrasonic probe, a spherical surface is drawn with the radius of the propagation distance as the radius, and it is a position where a defect which is a reflection source may exist. Since the influence of the transmission and reception in the peripheral region other than the center of the ultrasonic probe is ignored, high resolution measurement becomes difficult under the conditions as described above.

Therefore, in order to perform high resolution measurement under the condition that the ratio of the focal length, the subject distance, and the contact medium distance to the vibrator area becomes small, the influence of the transmission and reception in the area from the periphery to the end other than the center of the ultrasonic probe is considered. I have found that there is a need.

As described above, the present invention, in the ultrasonic probe, note that the transmission and reception of the ultrasonic wave is performed on the entire surface of the ultrasonic probe, and according to the position of the ultrasonic probe and the position of the internal defect, the propagation time of the reflected wave from the internal defect is determined. This analysis is based on the knowledge that the aperture synthesis method can be combined in a flaw detection using a large-diameter, short-focused ultrasonic probe by analyzing in advance how it changes and performing signal processing using the analysis result. The specific example is demonstrated as Embodiment 1 and Embodiment 2, respectively.

Embodiment 1

1 is a block diagram showing a configuration of an ultrasonic imaging apparatus, which is an example of the ultrasonic measuring apparatus according to the first embodiment of the present invention.

In FIG. 1, 1 represents the test subject which is a test object. In this example, the subject 1 is a stationary subject and the medium uses water, and the internal defect is imaged using the immersion method. Denoted at 10 is a focused ultrasound probe (hereinafter also referred to simply as an ultrasonic probe) for transmitting and receiving a focused beam, which transmits the ultrasonic focused beam toward the subject 1 by a constant period of electric pulses from the transmission circuit 11; At the same time, reflected waves (echo) from the surface and the inside of the object 1 are received. The received signal is amplified by the receive amplifier 12 to an appropriate level suitable for later signal processing.

In addition, the transmission circuit 11 and the reception amplifier 12 correspond to the transmission / reception means of this invention. The ultrasonic probe 10 is subjected to two-dimensional scanning (xy scanning) on the subject 1 by suitable scanning means, the positions of which are respectively determined by the x-direction position detecting means 21 and the y-direction position detecting means 22, respectively. It is detected and sent to the reflection waveform data part 13. The ultrasonic probe 10 for transmitting and receiving the focused beam may be configured to form a focused beam with one ultrasonic vibrator having a curved transceiving surface, and arranged so that the plurality of ultrasonic vibrators have curvature. It is good also as a structure which forms a focusing beam.

The reflected waveform data section 13 reflects the reflected waveform corresponding to each position _{Pi and j} based on the outputs of the receiving amplifier 12, the x direction position detecting means 21 and the y direction position detecting means 22. The data is detected, and the output thereof is sent to the defect image composition processor 14. The defect image synthesizing processing section 14 corresponds to the aperture synthesizing means of the present invention and measures the propagation time of the ultrasonic waves. The difference in timing until the reception of the reflected pulse echo 51 from the transmission pulse and the object surface, that is, the water propagation time, is the difference between the reception timing of the surface echo 51 and the defect echo 52. That is, the total body time of an ultrasonic wave is measured. If the surface of the object and the scanning surface of the ultrasonic probe 10 are substantially parallel, the water propagation time may be considered to be constant. Therefore, if the water propagation time is measured once (or obtained from an arrangement relationship), It is only necessary to measure the subject propagation time which is the difference between the reception timings of the surface echo 51 and the defect echo 52. Each measured propagation time (hereinafter referred to as measurement propagation time) corresponds to the center position P _{i, j} of the ultrasonic probe 10 at this time (i: position in x direction, j: position in y direction). Are recorded.

In addition, it is assumed that the isoelectric time plane data unit 15 is configured with a storage device, and for example, data of the isoelectric time plane obtained in advance by the ultrasonic propagation analysis is stored. As shown in FIG. 2, this isoelectric time surface is a surface which was made | formed that the reciprocal propagation time from the surface of a probe to the micro defect in that point becomes equal. This isoelectric time plane changes according to the distance to the object surface of the ultrasonic probe 10 and the depth of the defect from the object surface, so that a plurality of isoelectric time plane data for each depth of the defect are prepared.

In the first embodiment, an isoelectric time plane by ultrasonic propagation analysis is created prior to the defect image synthesis process. In addition, this invention is not limited to this, The preparation of an isoelectric time surface may be performed during defect image synthesis.

Although preparation of the isoelectric time surface shown in FIG. 2 is required, the calculation procedure of the propagation time by the ultrasonic propagation analysis will be described based on the flowchart of FIG. 3 and the explanatory drawing of FIG. 4 as an example.

3 is a flowchart of a method of obtaining an ultrasonic propagation time (hereinafter referred to as reference propagation time) by ultrasonic propagation analysis, and FIG. 4 is an explanatory diagram showing a procedure of a method of obtaining a reference propagation time. In FIG. 4, the probe and the path are shown in two dimensions for convenience, but in the first embodiment, the probe and the path are interpreted as being in a three-dimensional space. However, this invention is not limited to this, You may process on two dimensions.

(S1) The surface of the ultrasonic probe is divided into regions of minute area (hereinafter referred to as minute elements).

(S2) An ultrasonic wave wave transmitted from the micro element is set.

(S3) The path | route from each area | region on the surface of an ultrasonic probe to a predetermined microdefect (corresponding to the set internal defect of this invention) is calculated | required. In the upper part of FIG. 4, the path | route is shown about four area | region A-D. In this case, the path is determined by transmitting and receiving at a point in the center of the minute element. In addition, A-D has shown a part of microelement for description.

(S4) The waveform when the ultrasonic wave transmitted from one area reaches the micro defect through the path | route is calculated | required. Consider the propagation time and attenuation when propagating on the path.

(S5) In the same manner as in the middle of FIG. 4, the calculation of the above-described (S4) is sequentially performed on all the minute elements (in the drawings, A to D in order), and the waveforms obtained sequentially are summed.

(S6) The above-described processes of (S4) and (S5) are repeated until the calculations are made for all the regions, and when the calculation for all the regions is finished, the process proceeds to the process (S7).

(S7) The ultrasonic waves of the waveforms obtained in the above (S5) are emitted from the microscopic defects.

(S8) Then, the waveform received in one area is obtained.

(S9) The obtained ultrasonic waves are summed.

(S10) As in the lower end of Fig. 4, the above calculations of S8 and S9 are repeated until all regions are performed.

(S11) The arrival time is read from the synthesized waveform obtained in the above (S9). At this time, a method of reading time includes a method of setting a threshold to obtain a rise time, a similarly acquiring threshold to acquire a fall time, or a time when a waveform becomes a peak value. Choose the appropriate method.

(S12) The first half time is obtained from the difference between the exit time from the probe and the arrival time. At this time, a method of reading time includes a method of setting a threshold to obtain a rise time, a method of acquiring a threshold to obtain a falling time, or a time of obtaining a waveform peak. Choose the appropriate method.

Next, a method of preparing data on an isoelectric time plane using the above method will be described. 5 is a flow chart illustrating the method. This procedure is shown below.

(S21) Set the water distance (see the top of FIG. 4).

(S22) The object distance (see the top of FIG. 4) is set.

(S23) The deviation between the internal defect of the object and the probe central axis (see the upper part of FIG. 4) is set.

(S24) Reference propagation time is calculated (see flow chart of FIG. 3).

(S25) The above-described operations (S23) and (S24) are repeated until the data enough to produce an isoelectric time plane is obtained by changing the deviation from the probe central axis in the range in which the defect signal can be received. do. In addition, it is preferable that the amount (shift pitch) which changes the deviation of a test subject and a probe central axis at once is less than the spatial resolution grade required for measurement, for example, and moves a probe to the range from which a signal from an internal defect is obtained. Just do it.

(S26) From the relationship between the deviation from the probe central axis obtained in the above (S23), (S24) and (S25) and the change amount of the reference propagation time, the position at which the reference propagation time is equal is determined using the propagation velocity of the ultrasonic wave. After that, we create the data for the time-domain of the isoelectric. For example, a difference in distance in the depth direction is obtained from the difference of the reference propagation time at each position of the probe central axis based on the time when the internal defect of the test object and the deviation of the probe central axis are zero, and the The depth position can be obtained from the difference in distance. As shown in FIG. 6, the equipotential time plane data is obtained by adjusting the depth of the microscopic defect so as to eliminate the increase and decrease of the reference propagation time. At this time, in the first embodiment, the reference propagation time and the isoelectric time plane are calculated as the difference from the value when the deviation from the probe central axis is zero. In addition, the calculation order of the isoelectric time surface is an example, and is not limited to this. For example, using not only the position of the probe center axis but also the internal defect depth, the reference propagation time may be obtained at a plurality of internal defect depths, and the position at which the reference propagation time becomes equal from the result may be the equipotential time plane. . Moreover, you may calculate | require by calculation and may be calculated | required by experiment.

(S27) From (S21) to (S26) described above until the equivalence time plane corresponding to all the number distances and subject distances that may be required (eg, assumed in the measurement object) is provided. Repeat the operation.

By the above-described method, it is possible to prepare an isoelectric time plane at all the distances and object distances that may be needed. However, the preparation method of the isoelectric time plane in this invention is not limited to the preparation method of the isoelectric time plane using the above-mentioned ultrasonic propagation analysis, and other analysis methods may be used and may be calculated | required by experiment.

FIG. 7 is an example of the isoelectric time plane data obtained as described above, which is stored in the isoelectric time plane data unit 15 of FIG. 1 to synthesize a defect image in the defect image synthesis processing unit 14. Used when In addition, in FIG. 7, the reference propagation time compared with the reference propagation time measured at the time of measurement is the propagation time corresponding to the column whose deviation with the probe center is zero.

Next, the operation of the ultrasonic imaging apparatus of FIG. 1 measured using the isoelectric time plane obtained as described above will be described.

FIG. 8 is a flowchart showing a process for synthesizing a defect image in the ultrasonic imaging apparatus of FIG. 1.

(S31) C scan flaw detection is performed by operating the ultrasonic probe 10, and the reflection waveform data part 13 is the receiving amplifier 12, the x direction position detection means 21, and the y direction position detection means 22. Based on the output of, the reflected waveform data corresponding to each position _Pi _{and j} is detected.

(S32) The defect image synthesis processing unit 14 detects the water propagation time and the object propagation time from the reflection waveforms at P _{i and j} having the largest defect echo among the reflected waveform data, as shown in FIG. 9, The number distance and the object distance (defect depth) are acquired from the measurement propagation time.

(S33) The defect image synthesizing processing unit 14 has a number distance and a subject distance described above in the data of the isoelectric time plane (refer to FIG. 7) stored and prepared in the isoelectric time plane data unit 15 (S32). Select the one close to the number distance and the object distance obtained in the In the first embodiment, as shown in FIG. 10, subsequent processing is performed using only one isoelectric time surface shape data selected here. 10 shows a method of drawing (obtaining) the isoelectric time plane at different reference propagation times using one isoelectric time plane data, which is applied to the isoelectric time plane data of the reference propagation time T2. On the other hand, even when the reference propagation time is different (T1, T3), if the error is not large, the equipotential time plane having the same shape as that of the reference propagation time T2 can be used only by changing the depth position. In this case, it is sufficient if there is data of one isoelectric time plane. In addition, when the depth range where the internal defect to be detected exists is wide and the isoelectric time plane cannot be handled as the same shape, the corresponding isoelectric time is referred to with reference to the reference propagation time corresponding to the measured propagation time. You can use the data of the face.

(S34) The defect image synthesizing unit 14 performs the imaging process using the data of the isoelectric time plane selected in the above (S33). 11 shows an imaging process method according to the first embodiment. Here, in FIG. 11, although described in two dimensions for convenience, in this Embodiment 1, it processes in three dimensions. However, this invention is not limited to this, You may process in two dimensions. The procedure of the imaging processing method in Embodiment 1 is shown below. In addition, it is assumed that the defect image synthesis processing unit 14 has an image memory corresponding to the configuration of FIG. 11.

(a) detects the respective positions (hereinafter also referred to, throughout the measuring time) (P _{i, j)} is a defect echo is detected in the probe center position (P _{i, j),} the first half hour as shown in FIG. 11 with respect to that.

(b) The area in which the defect may be present in the subject (1) is divided into microvolume elements, and each microvolume element has a three-dimensional address (Pf _{k, l, m} ) (k: position in the x direction, l: position in the y direction, m: the position in the Z direction).

(c) Calculate the number distance and the subject distance from the measurement propagation time at each position _Pi _{and j} , calculate the defect position (depth) when assuming that the defect was on the probe central axis, and calculate the defect Pf _{k, l, m} corresponding to the position are set as the center of the isoelectric time plane corresponding to the measurement propagation time as shown in FIG.

(d) Each minute element (Pf _{k, l, m} ) is formed from the center of the isoelectric time plane set in (c) above and corresponds to the position of the isoelectric time plane. ), The count 1 is added to the counters C _{k, l, m} formed in Pf _{k, l, m} .

(e) The above operations (c) and (d) are performed for all positions P _{i and j} in which defect echoes are detected.

(S35) The data obtained in the above (S34) is imaged. The imaging method in the first embodiment is as shown below.

(a) The maximum value (C _max (k, l)) of C _{k, l, m} when (k, l) is fixed to all of (k, l) is obtained, respectively.

(b) For each (k, l) where C _max (k, l) is equal to or greater than the threshold, another threshold is determined and the counter (C _{k, l, m} ) is checked from the smaller of m. M above the threshold is called m (k, l).

(c) Using the m (k, l) obtained in the above-mentioned (b), polygons in which each micro element corresponding to the angle (k, l, m (k, l)) are adjacent to each other in a line Configure

(d) The polygon obtained in the above-mentioned (c) is three-dimensionally displayed.

The imaging method is not limited to the three-dimensional polygon display method described above, but may be another three-dimensional display method or a two-dimensional display method.

Here, using an ultrasonic probe having a frequency of 50 MHz, a transceiver diameter of 6 mm, and an underwater focal length of 15 mm, an artificial hole having a diameter of 300 µm was drilled into the slab sample, and the hole was scanned as shown in FIG. An example of imaging by the defect image synthesizing method and displaying on the defect image display device 16 is shown in FIG. 12B. FIG. 12C is a diagram illustrating the imaging process by the method described in Patent Document 3 described above, and three-dimensional display by the method of the defect image synthesizing method (S35). In this embodiment, the underwater focal length and the contact medium conversion distance L are about 2.5 of the vibrator region (vibrator diameter). In FIG. 12C, the image of the artificial hole is flattened in the z direction, whereas in FIG. 12B, the curved surface of the artificial hole is reproduced, and the resolution of the shape is improved.

In addition, in the above description, an example of imaging by the defect image synthesizing method and displaying on the defect image display device 16 has been described. In the first embodiment, not only that, but also the defect determination device 17 is a defect image. The defect is determined based on the above-described signal that is subjected to the opening process by the synthesis processing unit 14. In addition, if only defect determination is made, the defect image display device 16 which images and displays the synthesis result may not necessarily be present, and the defect determination device 17 inputs the synthesis result from the defect image synthesis processing unit 14, and the determination is performed. It is good also as a structure which outputs only a result. On the contrary, the defect determination apparatus 17 may not be provided unless the automatic defect determination is made.

As described above, in the first embodiment, water is interposed between the focused ultrasound probe 10 and the subject 1, and the focused ultrasound probe 10 is relatively to the subject 1. In the transmission circuit 11 and the receiver amplifier 12 (transmission and reception means) which transmit an ultrasonic wave toward the test subject 1 and receive the reflected wave from the internal defect of the test subject 1, while scanning, in each measuring point The position of the defect candidate is determined by using the reflected waveform data section 13 (first half time measuring means) for measuring the first half time to the internal defect based on the reflected wave, and isoelectric time plane data corresponding to the measured first half time. The number of times extracted during the scanning of the defect image composition processing unit 14 (defect position extracting means) to be extracted for each of the positions is calculated, and the number of times calculated at the address corresponding to the position of the display image memory is calculated. The ultrasonic imaging apparatus of an internal defect provided with the defect image display apparatus 16 (display means) which displays an image, and is provided in the defect image synthesis | combination processing part 14 (defect position extraction means), The said isoelectric time surface The data divides the propagation time of the ultrasonic wave propagating between the focused ultrasound probe 10 and the set internal defect, and divides the entire surface of the transceiving surface of the focused ultrasound probe 10 into a plurality of regions, and the divided angles. The waveform of the ultrasonic wave transmitted and received between the area and the set internal defect is obtained, and the waveform is calculated from the signal waveform synthesized with respect to the entire surface of the focused ultrasonic probe 10, so as to calculate the focused ultrasonic probe 10 and the set inside. The amount of change in the propagation time with respect to the relative position of the defect is obtained, and the data formed by connecting the positions where the propagation time becomes equal based on the amount of change in the propagation time is obtained. Based on this data, the shape of the internal defect can be imaged with high resolution.

Embodiment 2 Fig.

This embodiment 2 is an example which made the defect image composition processing part 14 of FIG. 1 perform a process different from the above-mentioned calculation process. The defect image synthesis processing unit 14 of the second embodiment uses delay time data instead of the above-described equipotential time plane data. For this reason, instead of the isoelectric time plane data section 15, a storage device (not shown) in which delay time data is stored is formed. This delay time data (delay time group) is obtained from the change amount data of the propagation time (data before the conversion of Fig. 6). As shown in the conceptual diagram of Fig. 13, the longer the change amount data of the propagation time, the longer the delay time. The smaller the change amount data is, the larger the delay time is. In the same manner as the isoelectric time plane data, it is obtained corresponding to each value of the number distance and the defect depth and stored in the storage device.

The defect image synthesizing unit 14 differs in the details of the isoelectric time plane selection process S33 and the data imaging process S34 in the flowchart shown in FIG. 8, but the other processes are the same.

The equipotential time plane selection process S33 is a delay time data selection process. Specifically, a process of selecting delay time data (delay time group) corresponding to the number distance and the defect depth of the received waveform measured by the ultrasonic probe is performed.

The data imaging process S34 performs the aperture combining process as shown in Fig. 13 using the delay time data selected in the delay time data selection process.

Specifically, among a plurality of probe-scanned points, a predetermined number of adjacent probe positions (10 points in the example of FIG. 29) are selected, and selected delay time data (delay time group) with respect to the reflected waveform data measured at the 10 points. The waveform is delayed at each probe position. In the case shown in FIG. 13, the delay time is made small for the signal of the outer probe, and the delay time is made large for the inner probe. Thereby, if a defect exists below the probe located in the center among predetermined number of probes, a defect signal will be emphasized by aligning a defect waveform, and presence of a defect can be detected. On the other hand, if there is no defect under the probe located at the center, for example, if there is a defect immediately below the outer probe, the signal of the defect received by each probe is canceled out and not emphasized because the phase is not aligned even if delayed. The fault signal cannot be detected. In short, there is no defect directly under the center probe.

With respect to the data obtained by measuring a large number of such processes, a predetermined number of data is selected in order while moving the selection range, and the aperture synthesis waveform is obtained by repeating. When the delay time data (delay time group) is selected, the delay time data (delay time group) corresponding to the plurality of depths are selected, respectively, and the above-described calculation processing is repeated. And the obtained waveform is displayed by a suitable method (A scope, B scope, C scope, three-dimensional display).

In addition, while the second embodiment has also described an example of imaging by the defect image synthesizing method and displaying the image on the defect image display device 16, the defect determination device 17 is not only provided to the defect image synthesis processing unit 14. The defect is determined on the basis of the above-mentioned signal subjected to the opening process. In addition, if only defect determination is made, the defect image display device 16 which images and displays the synthesis result may not necessarily be present, and the defect determination device 17 inputs the synthesis result from the defect image synthesis processing unit 14, and the determination is performed. It is good also as a structure which outputs only a result. On the contrary, the defect determination apparatus 17 may not be provided unless the automatic defect determination is made.

As described above, in the second embodiment, water is interposed between the focused ultrasound probe 10 and the object 1, and the focused ultrasound probe 10 is relatively to the object 1. The transmitting circuit 11 and the receiving amplifier 12 (transmitting and receiving means) which transmit an ultrasonic wave toward the subject 1 and receive the reflected wave from the internal defect of the subject 1, scanning, and the received reflected wave A defect image composition processor 14 (signal generating means) for generating a signal by delaying and adding the delayed signal, and a defect image composition processor 14 (display means) for outputting and displaying the generated signal data to the image memory. As an ultrasonic imaging apparatus of an internal defect, in the defect image synthesizing unit 14 (signal generating means), a focused supersonic time is used to determine the propagation time of ultrasonic waves propagating between the focused ultrasound probe 10 and the set internal defect. The whole surface of the transmission / reception surface of the wave probe 10 is divided into a plurality of regions, and a waveform of ultrasonic waves transmitted and received between each divided region and the set internal defect is obtained, and the waveform is converted into the entirety of the focused ultrasound probe 10. The amount of change in propagation time with respect to the relative position of the focused ultrasound probe 10 and the set internal defect is determined by calculating the signal waveform synthesized with respect to the surface, and the delay time is obtained from the change amount of the propagation time. Accordingly, by delaying the reflected wave to generate an image signal of the internal defect, the internal defect can be imaged with high resolution.

Next, an embodiment in which the present invention is applied to an array type ultrasonic probe will be described.

In Embodiments 3 and 4 described below, instead of scanning the focused ultrasound probes of Embodiments 1 and 2 to obtain a received signal at each measurement point, the signals of the vibrators of the array type ultrasonic probe are focused by the opening synthesis process. And form the received signal at each measurement point. Then, the received signal at each measurement point is subjected to aperture combining again. In other words, similarly to the first and second embodiments, in the array type ultrasonic probe, it is noted that the transmission and reception of the ultrasonic waves is performed in the array rows of the plurality of vibrators, so that the array type ultrasonic probe is formed of the focal point formed by aperture synthesis or focusing. A probe having a large area and a short focal length of the entire array of ultrasonic vibrator arrays by analyzing in advance how the propagation time of the reflected wave from the internal defect changes according to the position and the position of the internal defect. And the finding that the resolution of flaw detection using the setting of aperture synthesis can be improved. The specific example is described as Embodiment 3 and Embodiment 4, respectively.

Embodiment 3:

14 is a block diagram showing a configuration of an ultrasonic imaging apparatus, which is an example of the ultrasonic measuring apparatus according to the third embodiment of the present invention. In FIG. 14, 1 represents the test subject which is a test object. In this example, the subject 1 is a stationary subject and the medium uses water, and the internal defect is imaged using the immersion method. 10a is an array type ultrasonic probe that transmits and receives ultrasonic waves, and the ultrasonic beam is transmitted by the electric signal transmitted to each vibrator by a certain period of electric pulses from the transmission circuit 111 passing through the drive element selection circuit 112. It transmits toward 1) and receives the reflected wave (eco) from the surface and the inside of the to-be-tested object 1. The received signal is aperture synthesized by the receiving circuit 113 and the array signal processing circuit 114 and amplified to an appropriate level suitable for later signal processing. The array type ultrasonic probe 10a is subjected to two-dimensional scanning (xy scanning) or one-dimensional scanning (y scanning) on the subject 1 by suitable scanning means, and the position thereof is the x-direction position detecting means 21 and Detected by the y-direction position detecting means 22, respectively, and sent to the output waveform data section 115.

The output waveform data unit 115 has an array type ultrasonic probe 10a at this time based on the outputs of the array signal processing circuit 114, the x direction position detecting means 21 and the y direction position detecting means 22. Output waveform data (output waveform data of the focused ultrasound probe in Embodiments 1 and 2) corresponding to the focal point P _{i, j} formed by aperture synthesis (i: position in x direction, j: position in y direction) , And the output is sent to the defect image composition processing unit 116. The defect image synthesis processing unit 116 measures the difference between the transmission time and the reception time of the defect echo 52, that is, the propagation time of the ultrasonic waves. The propagation time measured here is a difference between the transmission time and the reception time of the reflected surface echo 51 on the object surface, that is, the difference between the number propagation time and the reception timing of the surface echo 51 and the defect echo 52. That is, the total time of the subject of ultrasound. If the surface of the object and the scanning surface of the array type ultrasonic probe 10a are substantially parallel, the water propagation time may be considered to be constant. Therefore, if the water propagation time is measured once (or obtained from a placement relationship), Thereafter, only the object propagation time which is the difference between the reception timings of the surface echo 51 and the defect echo 52 may be measured. Each measured propagation time (hereinafter also referred to as measurement propagation time) is recorded in correspondence with each position _Pi _{and j} .

In addition, it is assumed that the isoelectric time plane data unit 117 stores the data of the isoelectric time plane obtained in advance by, for example, ultrasonic wave propagation analysis. As shown in FIG. 15, this isoelectric time surface is a surface which was made | formed that the round trip propagation time to the microdefect in that point obtained by aperture synthesis becomes equal. Since this isoelectric time surface changes with the depth of the defect with respect to the focal point of the array type ultrasonic probe 10a, the data of a plurality of isoelectric time surfaces for each depth of the defect are prepared. The output waveform data unit 115, the defect image synthesis processing unit 116, and the isoelectric time plane data unit 117 constitute the defect image reconstruction signal processing unit 200.

The array signal processing circuit 114 and the defect image synthesis processing unit 116 all have the same function in that they perform aperture synthesis processing. The array signal processing circuit 114 has each vibrator of the array type ultrasonic probe at each measurement point. Performing an aperture combining process on the received signal, thereby obtaining a signal received by the focused beam at each measurement point, thereby forming a focal point by the signal processing means according to claim 9 (the signal of each vibrator by the aperture combining process). And signal processing means used as signals received at the respective measuring points. On the other hand, the defect image synthesizing processing unit 116 synthesizes a defect image by opening synthesizing the signal subjected to the opening synthesizing processing in the array signal processing circuit 114 at each measurement point. Although the isoelectric time plane data of the present invention is essential in the defect image synthesis processing unit 116, since the oscillator is small in the array signal processing circuit 114, the conventional method does not need to use the isoelectric time plane data of the present invention. The synthetic aperture treatment (the reflection source exists at an equidistant distance from the center of the vibrator) may be used.

In addition, the array type ultrasonic probe 10a has been described as implementing all the vibrators included in the area range for transmitting and receiving, but not all of them, the vibrators transmitting and receiving at intervals at one or two intervals or the like. You may select and transmit / receive using it.

In the third embodiment, an isoelectric time plane is created by ultrasonic propagation analysis prior to the defect image synthesis process. In addition, this invention is not limited to this, The preparation of an isoelectric time surface may be performed during defect image synthesis.

Preparation of the isoelectric time surface shown in FIG. 15 can be performed by calculation of the propagation time W (referred to as a reference propagation time) by ultrasonic propagation analysis. This is demonstrated based on the flowchart of FIG. 16, FIG. 17, FIG. 18 and explanatory drawing of FIG.

FIG. 16 is a flow chart of the entire method of obtaining the reference propagation time by ultrasonic propagation analysis, FIG. 17 is a flowchart showing the details of the process S43 (acquisition of the ultrasonic waveform at the defective position) in FIG. 16, and FIG. 18 is FIG. 16 is a flow chart showing the details of the process S44 (acquisition received by the array probe and obtained by the aperture synthesis process), and FIG. 19 is an explanatory diagram showing a procedure of a method for obtaining a reference propagation time. Here, in FIG. 19, the two-dimensional analysis by the linear array probe is shown. However, this invention is not limited to this, The shape of an array probe may not be linear, and an analysis may be performed on three dimensions.

(S41) An ultrasonic wave wave transmitted from the vibrator is set.

(S42) The path | route from each vibrator of an ultrasonic probe to a predetermined microdefect (corresponding to the set internal defect of this invention) is calculated | required. In the upper part of FIG. 19, the path is shown about two vibrators.

(S43) Acquire an ultrasonic wave at the defect position.

As a detailed process of S43, as shown to the flowchart of FIG. 17, the following process is performed.

(S43-1) Initialization of Ultrasonic Waveform Data for Output

(S43-2) Determine the oscillator to calculate

(S43-3) The ultrasonic waveform at the minute defect position by the vibrator being calculated is calculated. At this time, when the timing of transmission differs according to the vibrator, it sets so that it may transmit at the time corresponding to a vibrator as shown in FIG. In addition, the propagation time and attenuation when propagating on the path are taken into consideration (see FIG. 19).

(S43-4) The obtained ultrasonic wave waveforms are sequentially added to the output ultrasonic wave wave data.

(S43-5) (S43-2) to (S43-4) are repeated until calculation is made for all the vibrators used for transmission.

(S43-6) Outputting ultrasonic wave wave data for output as an ultrasonic wave wave at the defect position

After such a process of FIG. 17, the process proceeds to process S44 of FIG. 16.

(S44) An output waveform received by the array probe and subjected to the aperture combining process is acquired.

As a detail of S44, as shown to the flowchart of FIG. 18, the following process is performed.

(S44-1) Emitting the Ultrasonic Waveform at the Defect Location from the Micro Defect Location

(S44-2) Initialize the received waveform data of all the vibrators used for reception

(S44-3) Determine the oscillator to calculate

(S44-4) Calculate the ultrasonic wave received from the vibrator being calculated (see FIG. 19)

(S44-5) The steps from (S44-3) to (S44-4) are repeated until calculations are made for all the vibrators used for reception.

(S44-6) Initialize output waveform data after focusing beam processing

(S44-7) Delay processing suitable for actual focused beam processing is performed on the received waveform data of all the vibrators (see FIG. 19).

(S44-8) Receive waveform data of all the vibrators subjected to the delay processing are added to the output waveform data, respectively (see FIG. 19).

After such a process of FIG. 18, the process proceeds to process S45 of FIG. 16.

(S45) The arrival time is read from the output waveform obtained in the above (S44). At this time, a method of reading the time includes a method of obtaining a rising time by setting a threshold value, a falling time by setting a threshold value, or obtaining a time when the waveform becomes a peak value, and the like. And use the appropriate method according to the obtained waveform and the like.

(S46) A reference propagation time is obtained from the difference between the exit time from the probe and the arrival time. At this time, a method of reading time includes a method of setting a threshold to obtain a rise time, a similarly acquiring threshold to acquire a fall time, or a time when a waveform becomes a peak value. Choose the appropriate method.

Next, a method of preparing data on an isoelectric time plane using the above method will be described.

20 is a flow chart illustrating the method. This procedure is shown below.

(S51) The number distance (see the upper part of FIG. 19) is set.

(S52) The object distance (see the top of FIG. 19) is set.

(S53) The aperture combined focal depth (for example, the depth position in the object under test, see the upper part in FIG. 19) is set.

(S54) The shift | offset | difference (in surface orthogonal to a depth direction) of an internal defect of a test object and an aperture combined focus is set.

(S55) The reference propagation time is calculated from the waveform subjected to the opening synthesis process (see the flow charts in FIGS. 16, 17, and 18).

(S56) The above-described processing (S54) until a data sufficient to produce an isoelectric time plane is obtained by changing the deviation in the plane orthogonal to the depth direction with the aperture synthesis focus in the range in which the defect signal can be received. , The operation of (S55) is repeated. In addition, it is preferable that the amount (shift pitch) which changes the shift | offset | difference of an object and aperture synthesis focal point at once is made into the spatial resolution degree required for measurement, for example, to the range from which a signal from an internal defect is obtained. Just move it.

(S57) The propagation velocity of the ultrasonic wave is determined from the relationship between the amount of change in the reference propagation time with respect to the deviation in the plane orthogonal to the depth direction of the subject and the aperture combined focal point obtained in the above-described processes (S54), (S55) and (S56). Using this method, the positions at which the reference propagation times become equal are obtained, and the data of the equipotential time planes are created following these positions. For example, the difference in the distance in the depth direction using the propagation velocity is obtained from the difference in the reference propagation time at each position of the probe central axis on the basis of the deviation between the internal defect of the subject and the opening composite focal point, and The depth position can be obtained from the difference of the distances. As shown in FIG. 21, the equipotential time plane data is obtained by adjusting the depth of the microscopic defect so as to eliminate the increase and decrease of the reference propagation time. At this time, in the third embodiment, the reference propagation time and the isoelectric time plane are calculated as the difference from the value when the deviation from the aperture synthesis focal axis is zero. In addition, the calculation order of the isoelectric time surface is an example, and is not limited to this. For example, using not only the position of the aperture combined focal point but also the internal defect depth, the reference propagation time can be obtained at a plurality of internal defect depths, and the position where the reference propagation time is equal from the result is also set as the isoelectric time plane. do.

(S58) The above-mentioned (S51) until the equivalence time plane corresponding to all the numerical distances, subject distances, and aperture combined focal depths that may be necessary (for example, to be assumed in the measurement object) are provided. The operation from to S57 is repeated.

By the above-described method, it is possible to prepare the isoelectric time plane at all the numerical distances, the subject distances, and the opening composite focal depths that may be needed. However, the preparation method of the isoelectric time plane in the present invention is not limited to the above-described method, and data based on actual measurements or ultrasonic propagation simulation may be used. In addition, the calculation method of a reference propagation time is not limited to the method shown by FIG. 16, FIG. 17, FIG. 18, and FIG.

In addition, when the area of each vibrator is sufficiently large with respect to the subject, the vibrator may be further divided into a plurality of micro regions, and the signal may be processed by adding signals of each micro region to each vibrator unit.

Further, even when the area is large in the direction of the array column and in the direction orthogonal to the plane of the sheet (inner plane in Fig. 20), it may be carried out by dividing into small areas in the orthogonal direction (for example, with a probe as shown in Fig. 17, Y). Divided into a plurality of directions).

In addition, although the vibrator is described as an example in which the oscillator is arranged only in the one-dimensional direction, the vibrator may be applied to an array-type probe arranged in two dimensions.

FIG. 22 is an example of the isoelectric time plane data obtained as described above, which is stored in the isoelectric time plane data unit 117 of FIG. 14 to synthesize a defect image in the defect image synthesis processing unit 116. It is used when In addition, in FIG. 22, the reference propagation time compared with the measured propagation time is the propagation time corresponding to the column where the shift | offset | difference with aperture synthesis focal point is zero.

Next, operation | movement of the ultrasonic imaging apparatus of FIG. 14 measured using the data of the isoelectric time surface calculated | required as mentioned above is demonstrated.

FIG. 23 is a flowchart showing processing when synthesizing a defect image in the ultrasonic imaging apparatus of FIG. 14.

(S61) The array waveform ultrasonic probe 10a, the drive element selection circuit, and the array signal processing circuit are operated to perform scanning while scanning the focus formed by the opening synthesis, and the output waveform data section 115 is a drive element selection circuit ( 112, corresponding to the respective positions _{Pi and j} based on the outputs of the receiving circuit 113, the array signal processing circuit 114, the x direction position detecting means 21 and the y direction position detecting means 22. One output waveform data is detected.

(S62) As shown in FIG. 24, the array signal processing circuit 114 or the defect image synthesizing processing unit 116 shows the first half time from the reflected waveform at P _{i and j} having the largest defect echo among the output waveform data. The object propagation time is detected, and the number of objects and the object distance (defect depth) are acquired from those propagation times.

(S63) The defect image synthesizing processing unit 116 stores the number of distances, the object distance, and the aperture synthesis focal depth in the data of the isoelectric time plane (refer to FIG. 22) stored and prepared in the isoelectric time plane data unit 117. The set value of is selected to be close to the number distance, the subject distance, and the aperture combined focal depth obtained in the above-mentioned (S62). In the third embodiment, as shown in FIG. 25, subsequent processing is performed using only one isoelectric time surface shape selected here. In FIG. 25, a method of drawing (obtaining) the isoelectric time plane at different reference propagation times using one isoelectric time plane, and for the isoelectric time plane of the reference propagation time T2, Even when the reference propagation time is different (T1, T3), if the difference in propagation time is not large, the isoelectric time plane having the same shape as that of the reference propagation time T2 can be used simply by changing the depth position ( In this case, there is enough data for one isoelectric time plane. In addition, when the depth range where the internal defect to be detected exists is wide and the isoelectric time plane cannot be handled as the same shape, the corresponding isoelectric time is referred to with reference to the reference propagation time corresponding to the measured propagation time. You can use the data of the face.

(S64) The defect image synthesizing processing unit 116 performs an imaging process using the data of the isoelectric time plane selected in the above-mentioned (S63). 26 shows an imaging process method according to the third embodiment. Here, in FIG. 26, although described in two dimensions for convenience, in Embodiment 3, it processes in three dimensions. However, this invention is not limited to this, You may process in two dimensions. The procedure of the imaging processing method in Embodiment 1 is shown below.

(a) At each focal position (P _i _, _j : the coordinates in the plane orthogonal to the depth direction also correspond to the center position of the oscillator group to transmit and receive) to the focal position (P _i _, _j ) where a defective echo is detected. On the other hand, the propagation time (hereinafter also referred to as measurement propagation time) is detected as shown in FIG. Detection of the measurement propagation time may be performed by the array signal processing circuit 114 in FIG. 14, may be performed by the defect image synthesis processing unit 116, and may be performed by the array signal processing circuit 114 in the present embodiment. have.

(c) The number distance and the subject distance are calculated from the measurement propagation time at each position (P _{i, j} ), and the coordinates in the plane orthogonal to the depth direction on the central axis of the oscillator group through which defects are transmitted and received are P The defect position (depth) is assumed to be in _{i, j} , and Pf _{k, l and m} corresponding to the defect position are set as the center of the isoelectric time plane corresponding to the measurement propagation time as shown in FIG. .

(d) Each minute region Pf _{k, l, m} which forms an isoelectric time plane (see Fig. 25) from the center of the isoelectric time plane set in the above (c) and corresponds to the position of the isoelectric time plane. ), The count 1 is added to the counters C _{k, l, m} formed in Pf _{k, l, m} .

(e) The above operations (c) and (d) are performed for all positions P _i _{and j} in which defect echoes are detected.

(S65) The data obtained in the above (S64) is imaged. The imaging method in Embodiment 3 is as follows.

(a) The maximum value (Cmax (k, l)) of _{Ck, l, m} when (k, l) is fixed to all (k, l) is calculated | required, respectively.

(b) For each (k, l) where Cmax (k, l) is greater than or equal to the threshold, another threshold is determined and the threshold (C _{k, l, m} ) is checked when m is checked from the smaller one. M above the value is called m (k, l).

(c) Using the m (k, l) obtained in the above-mentioned (b), a polygon is formed by connecting the centers of the micro-areas corresponding to the angles (k, l, m (k, l)) to each other in a line Configure

Here, an ultrasonic focusing array probe having a frequency of 50 MHz, an array pitch of 100 µm, the number of channels used for aperture synthesis, and a focal length of 15 mm of the focusing beam underwater (size in the direction perpendicular to the array array direction as shown in FIG. 29). A 10 mm vibrator surface has a curvature and focuses in that direction), an artificial hole having a diameter of 300 μm is drilled in the slab sample, the hole is inspected as shown in Fig. 27A, and imaged by the defect image synthesis method. One example is shown in FIG. 27B. In addition, FIG. 27B uses the isoelectric time plane created by dividing each vibrator into minute regions. FIG. 27C is a diagram illustrating the imaging process by the method described in Patent Document 3 described above, and three-dimensional display by the method of the defect image synthesis method (S65). In this embodiment, the underwater focal length and the contact medium conversion distance L are about 1.5 of the vibrator region (vibrator diameter). In FIG. 27C, the image of the artificial hole is flattened in the z direction, whereas in FIG. 27B, the curved surface of the artificial hole is reproduced, and the resolution of the shape is improved.

In addition, the third embodiment has also described an example of imaging by the defect image synthesizing method and displaying the image on the defect image display device 16. In addition, the defect determination device 17 is provided to the defect image synthesis processing unit 116. The defect is determined on the basis of the above-mentioned signal subjected to the opening process. Moreover, if only defect determination is made, the defect image display apparatus 16 which images and displays a composite result may not necessarily exist, and the defect determination apparatus 17 inputs the composite result from the defect image synthesis processing part 116, and the determination is carried out. It is good also as a structure which outputs only a result. On the contrary, the defect determination apparatus 17 may not be provided unless the automatic defect determination is made.

As described above, in the third embodiment, water is interposed between the array type ultrasonic probe 10a and the object 1 and formed by aperture synthesis processing the received signal of the array type ultrasonic probe 10a. A transmission / reception process of transmitting ultrasonic waves toward the subject 1 while receiving the focus relative to the subject 1, and receiving reflected waves from internal defects of the subject 1, and an array type ultrasonic probe ( A signal processing step of aperture-synthesizing the signals received by each vibrator of 10a), a signal generation step of delaying and adding the obtained aperture-synthesis waveform according to a set delay time to generate a signal, and displaying the generated signal An ultrasonic imaging method of an internal defect having a display process, wherein the delay time is calculated based on the opening synthesis waveform based on the array time. The amount of change in propagation time with respect to the focus of the aperture combining process and the relative position of the set internal defect performed on the received signal of each oscillator of the ultrasonic probe 10a is obtained, and the imaging signal of the internal defect is generated from the amount of change in the propagation time. Therefore, internal defects can be imaged with high resolution.

Embodiment 4.

The fourth embodiment is an example in which the defect image composition processing unit 116 in FIG. 14 performs a process different from the above-described calculation process. The defect image synthesis processing unit 116 of the fourth embodiment uses the delay time data instead of the above-described equipotential time plane data. For this reason, instead of the isoelectric time plane data section 117, a storage device (not shown) in which the delay time data is stored is formed. This delay time data (delay time group) is obtained from the change amount data of the propagation time (data before the conversion of FIG. 21). As shown in the conceptual diagram of FIG. 28, the larger the change amount of the propagation time, the smaller the delay time. The smaller the amount of change, the greater the delay time. In the same manner as the isoelectric time-plane data, it is obtained corresponding to each value of the number distance, the object distance, and the opening synthesis focal depth, and stored in the storage device.

The defect image synthesizing processing unit 116 differs in the details of the isoelectric time plane selection process S63 and the data imaging process S64 in the flowchart shown in FIG. 23, but the other processes are the same.

The equipotential time plane selection process (S63) is a delay time data selection process. Specifically, a process of selecting delay time data (delay time group) corresponding to the number distance and depth of defect of the received waveform measured by the array type ultrasonic probe is performed.

The data imaging process S64 performs waveform resynthesis processing as shown in FIG. 28 using the delay time data selected in the delay time data selection process.

Specifically, among a plurality of focus-scanned points, a predetermined number of adjacent focal positions (10 points in the example of FIG. 28) are selected, and the reflected waveform data (signal of each vibrator of the array type ultrasonic probe) measured at the 10 points is selected. As a signal subjected to aperture synthesis to form a focal point, corresponding to the output waveform data of the focused ultrasonic probes according to the first and second embodiments, corresponding signals to the selected delay time data (delay time group) are provided at respective probe positions. Delay the waveform. As shown in FIG. 28, the delay time is made small for the signal of the outer focus, and the delay time is made large for the inner focus. Thereby, if there is a defect above and below the focus located at the center of the predetermined number of focus positions, the defect waveform is aligned so that the defect signal is emphasized and the presence of the defect can be detected. On the other hand, if there are no defects above and below the focus located at the center, for example, if there is a defect immediately above or just below the outer focus, the signals of the defects received at each focus are canceled because the phases are not aligned even if delayed. Not highlighted, the defect signal cannot be detected. In short, there is no defect just above or just below the centrally located focal point.

In addition, while the fourth embodiment has also described an example of imaging by the defect image synthesizing method and displaying the image on the defect image display device 16, the defect determination device 17 is not only provided to the defect image synthesis processing unit 116. The defect is determined on the basis of the above-mentioned signal subjected to the opening process. Moreover, if only defect determination is made, the defect image display apparatus 16 which images and displays a composite result may not necessarily exist, and the defect determination apparatus 17 inputs the composite result from the defect image synthesis processing part 116, and the determination is carried out. It is good also as a structure which outputs only a result. On the contrary, the defect determination apparatus 17 may not be provided unless the automatic defect determination is made.

As described above, in the fourth embodiment, water is interposed between the array type ultrasonic probe 10a and the object 1 and formed by aperture synthesis processing the received signal of the array type ultrasonic probe 10a. Transmitting circuit 111 and driving element selecting circuit 112 for transmitting ultrasonic waves toward the subject 1 while receiving the focus relative to the subject 1 and receiving the reflected wave from the internal defect of the subject. ), The receiving circuit 113 (transmission / receiving means), the array signal processing circuit 114 (signal processing means) for aperture-synthesizing the signal received by each vibrator of the array type ultrasonic probe 10a, and the obtained aperture synthesis waveform. A defect image composition processing unit 116 (signal generating means) for delaying by the set delay time data and then adding and generating a signal, and outputting the generated signal data to the image memory for display. Is an ultrasonic imaging method of an internal defect provided with a defect image display device 16 (display means), wherein the delay time data is calculated based on the aperture synthesis waveform, and the array type ultrasonic probe 10a is used. The internal defect is generated from the amount of change in the propagation time with respect to the relative position of the focus and the set internal defect of the aperture synthesizing process performed on the received signal of each oscillator, and the video signal of the internal defect is generated from the amount of change in the propagation time. Imaging with high resolution is possible.

In addition, the present invention shown in Embodiments 1 to 4 may be applied even when the ratio of the focal length, the object distance, and the contact medium distance to the oscillator region is sufficiently large, but the focal length, the object distance, and the contact medium distance, The effect is remarkable on the condition that the ratio to the vibrator region becomes small. Specifically, the ratio of the focal length to the size of the oscillator to transmit and receive can be applied in the range of larger than 0.5 and smaller than 8, preferably larger than 0.5 and smaller than 6, more preferably larger than 0.5, A range less than 3 is suitable. In addition, the range of the ratio of the object distance and the contact medium distance to which the present invention is applied to the size of the oscillator to transmit and receive is also the same as the focal length.

In addition, although the description of Embodiment 1 thru | or 4 demonstrated as an imaging device which is one form of an ultrasonic measuring apparatus, the application of this invention is not limited to this, The waveform data synthesize | combined according to the calculated | required counter value and delay time, The present invention can also be applied to a defect detection device or the like that detects a defect by determining the kind or degree of the defect using these data.

Claims

Transmitting / receiving means for transmitting ultrasonic waves toward the subject, scanning the focal point formed by the ultrasonic probe relative to the subject, receiving the reflected wave from the internal defect of the subject, and acquiring the reflected waveform;
Reflected waveform of ultrasonic waves propagating between the ultrasonic probe and internal defects are treated as waveforms of ultrasonic waves synthesized on the entire surface of the transmission / reception surface to obtain a synthesized waveform, and a reference propagation time obtained using the synthesized waveform. Ultrasonic measuring device provided with aperture compounding means which performs aperture compounding process of the signal received in each measurement position using the above.

The method of claim 1,
At each measurement position, it is provided with the propagation time measuring means which measures the propagation time to an internal defect based on the said reflected wave,
The opening synthesis processing means extracts the isoelectric time plane formed by linking the position inside the subject to which the reference propagation time is equal to the propagation time measured by the propagation time measurement means, and thus the position of the isoelectric time plane. Ultrasonic measuring apparatus characterized by the above-mentioned.

The method of claim 2,
And display means for calculating the number of times extracted during the scanning for each defect candidate position determined by the aperture synthesizing means, and displaying the calculated number corresponding to the position.

The method of claim 1,
And the aperture synthesizing means delays the reflected wave received by the transmitting and receiving means according to the delay time calculated based on the reference propagation time, and adds to generate a signal.

The method of claim 4, wherein
An ultrasonic measuring apparatus comprising display means for displaying the signal data generated by the aperture synthesizing means.

6. The method according to any one of claims 1 to 5,
The reference propagation time divides the entire surface of the transmitting / receiving surface of the ultrasonic probe into a plurality of regions, obtains waveforms of ultrasonic waves transmitted and received between the divided regions and internal defects, and synthesizes the waveforms with respect to the whole surface of the ultrasonic probe. An ultrasonic measuring device, characterized in that it is calculated from one waveform.

6. The method according to any one of claims 1 to 5,
The reference propagation time transmits an ultrasonic wave toward the subject while relatively scanning the focal point formed by the ultrasonic probe and the subject, using a subject having an internally manufactured internal defect. It is obtained by receiving the reflected wave from the internal defect of the specimen.

6. The method according to any one of claims 1 to 5,
And the ultrasonic probe is a focused ultrasonic probe.

6. The method according to any one of claims 1 to 5,
The ultrasonic probe is an array type ultrasonic probe in which a plurality of vibrators are arranged.
Signal processing means for focusing the signal received by each oscillator by the aperture combining process and transferring the signal focused in the aperture combining process to the aperture combining processing means as a signal received at each measurement position. Ultrasonic measuring device comprising a.

6. The method according to any one of claims 1 to 5,
Ultrasonic measurement apparatus provided with defect determination means which judges a defect using the signal which carried out the aperture synthesis process by the said aperture synthesis process means.

Transmitting / receiving an ultrasonic wave toward the subject while scanning the focal point formed by the ultrasonic probe relative to the subject, receiving the reflected wave from the internal defect of the subject, and obtaining a reflected waveform;
By treating the reflected waveform of the ultrasonic wave propagating between the ultrasonic probe and the internal defect as the waveform of the ultrasonic wave synthesized on the entire surface of the transmission / reception surface, a synthesized waveform is obtained and using the reference propagation time obtained using the synthesized waveform, An ultrasonic measurement method comprising an aperture synthesis processing step of performing aperture synthesis processing of a signal received at each measurement point.