JP5183422B2 - Three-dimensional ultrasonic imaging method and apparatus - Google Patents

Description

  The present invention relates to a three-dimensional ultrasonic imaging method and apparatus for non-destructively inspecting the inside of an inspection object three-dimensionally using a two-dimensional array type ultrasonic sensor.

  Conventionally, defect inspection methods for various structural materials include inspection and transmission of ultrasonic waves using a single ultrasonic sensor, detection of reflected echoes reflected from defects inside the inspection object, etc. Defects have been detected based on the position of the sonic sensor. In addition, the ultrasonic sensor has been scanned to determine the position at which the reflected echo from the defect is obtained, and the defect size has been identified by integrating the difference in reception time of the reflected echo from the bottom surface or surface and the material sound velocity. This method has a simple principle and the apparatus is relatively simple, so it is often used for general defect inspection. However, the ultrasonic echo is measured and the defect is evaluated from the reception time of the reflected echo. Therefore, in order to perform a highly accurate inspection, a skilled inspector is required and time is also required.

  In recent years, a flaw detection method has been developed for imaging and inspecting the inside of an inspection object with high accuracy, and a phased array method, an aperture synthesis method, and the like are well known. The phased array method is based on the principle that an ultrasonic sensor in which a plurality of piezoelectric vibration elements are arranged is used, and the wave front of the ultrasonic signal transmitted from each piezoelectric vibration element interferes to form a composite wave front and propagates. ing. By shifting the ultrasonic transmission timing of each piezoelectric vibration element by delay control, the incident angle of the ultrasonic wave can be controlled or the ultrasonic wave can be focused. Further, at the time of ultrasonic reception, the reflected ultrasonic waves received by the respective piezoelectric vibration elements are added while being shifted on the time axis, so that the ultrasonic waves can be received with the same focus as at the time of transmission. The phased array method can scan the ultrasonic wave at high speed without scanning the ultrasonic sensor, and can arbitrarily control the position of the incident angle of the ultrasonic wave and the focusing depth without replacing the ultrasonic sensor. This technology enables high-speed and high-precision inspection. A linear scan method that linearly scans a piezoelectric vibrator, a sector scan method that changes a transmission / reception direction of ultrasonic waves in a fan shape, and the like are generally known.

  On the other hand, in the aperture synthesis method, ultrasonic waves are transmitted so that they are widely diffused inside the inspection object, and reflected ultrasonic signals are received. The position of the defect, which is the received reflected ultrasonic source, is based on the principle that exists on an arc whose radius is the propagation distance of the reflected ultrasonic wave around the position of the piezoelectric vibrating element that has transmitted and received ultrasonic waves. The ultrasonic wave is transmitted and received by changing the position sequentially, and the received waveform at each position is expanded in an arc shape by calculation on the electronic computer, so that the intersection of the arcs is concentrated at the defective position that becomes the ultrasonic reflection source. Then, the position of the defect is specified and imaged. In actuality, this is a technique that uses a position of an ultrasonic sensor and an ultrasonic waveform signal at that position to perform high-resolution imaging by performing arithmetic processing on an electronic computer. The contents of the arithmetic processing are described in Non-Patent Document 1.

  Furthermore, in recent years, matrix array sensors in which the array of piezoelectric transducers inside the array-type ultrasonic sensor is arranged in a matrix and ring array sensors (including division in the circumferential direction) arranged in a concentric manner have been developed. Devices capable of transmitting and receiving ultrasonic waves using a multi-element piezoelectric vibrator have been put into practical use. As a result, the inside of the inspection object directly under the sensor can be imaged three-dimensionally without scanning the ultrasonic sensor. As a technique, two-dimensional array type ultrasonic sensors transmit ultrasonic waves one by one at the time of ultrasonic transmission, and receive by all elements at the time of reception, and three-dimensional aperture synthesis processing so that received echoes overlap. A technique is known in which the interior of the inspection object is converted into a three-dimensional image by performing (see, for example, Patent Document 1).

JP 2005-315582 A Co-authored by Masamasa Kondo, Yoshimasa Ohashi, and Akuro Mimori, “Digital Signal Processing Series, Volume 12, Digital Signal Processing in Measurements and Sensors”, Shosodo, May 20, 1993, pages 143 to 186

  However, in the above prior art, in order to obtain focused three-dimensional flaw detection data in the whole three-dimensional space, a data processing table (focal law, delay, etc.) corresponding to the number of coordinate positions of each three-dimensional flaw detection data is obtained. Therefore, there is a physical limit to the number, and the size of the 3D imaging area and the spatial resolution are in a trade-off relationship. Therefore, in order to convert a wide area into a three-dimensional image with high resolution, it is necessary to divide the flaw detection area a plurality of times, and it is necessary to repeatedly read, reset, and measure the data processing table.

  In addition, in the above-described prior art, accuracy and sensitivity are good when imaging directly under a two-dimensional array type ultrasonic sensor, but there is a problem that both accuracy and sensitivity decrease when imaging a position outside the ultrasonic sensor. It was. For this reason, when the inspection target range is wide, it is necessary to carry out flaw detection in a plurality of times in order to cover the entire area.

  Further, in the above-described conventional technology, since the size of the piezoelectric vibration element inside the two-dimensional array type ultrasonic sensor is small, energy at the time of ultrasonic transmission from each element is weak and transmission is performed by one element at the time of transmission. Therefore, the spatial energy of the ultrasonic wave was weakened. Also, since the reception energy per element is weak at the time of reception, it is easily affected by noise such as electrical noise, and the ultrasonic echo intensity is weak when the inspection target is thick or in the case of a high attenuation material. Thus, there is a problem that the SN ratio of the received echo is lowered.

  An object of the present invention is to use a set of data processing tables (focal law) in an inspection using a two-dimensional array type ultrasonic sensor, even if the inspection object range is wide. Even in the case of attenuating materials, a 3D ultrasonic imaging method and apparatus capable of forming a 3D image with 3D flaw detection data with a high resolution and a high S / N ratio in a wide area and handling it as a single 3D flaw detection data. It is to provide.

(1) In order to achieve the above-described object, the present invention transmits ultrasonic waves focused to an arbitrary depth from a two-dimensional array type ultrasonic sensor, and further changes the incident angle to three-dimensionally examine the inside of the inspection object. To record the waveform data, convert the obtained waveform data into voxel format 3D flaw detection data, sequentially move the installation position of the array type ultrasonic sensor to record the 3D flaw detection data, The three-dimensional flaw detection data obtained at each flaw detection position is synthesized while shifting by the amount of movement of the array type ultrasonic sensor to form a three-dimensional image.
By this method, even when the inspection target range is wide in the inspection using the two-dimensional array type ultrasonic sensor, only one set of data processing table (focal law) is used, and the inspection target is thick or a high attenuation material. Even in this case, a wide range can be collectively converted into a three-dimensional image with high-resolution and high S / N ratio three-dimensional flaw detection data, and can also be handled as one three-dimensional flaw detection data.

  (2) In the above (1), preferably, the surface shape of the inspection object is measured, and the incident angle of the ultrasonic wave is changed while following the surface shape of the inspection object to obtain the three-dimensional flaw detection data inside the inspection object. Recording, sequentially moving the installation position of the array-type ultrasonic sensor to detect flaws, and obtaining the obtained three-dimensional flaw detection data at each flaw detection position while shifting the movement amount and rotation angle of the array-type ultrasonic sensor The 3D flaw detection data is combined into a 3D image.

  (3) In the above (1), preferably, as an ultrasonic scanning method for performing three-dimensional flaw detection inside the inspection object by changing the incident angle of the ultrasonic wave oscillated from the two-dimensional array type ultrasonic sensor, rotational scanning, Either tilt scanning or wedge-shaped tilt scanning is used.

  (4) In the above (1), preferably, the three-dimensional flaw detection data is synthesized by adding or averaging the three-dimensional flaw detection data into an image.

(5) In order to achieve the above object, the present invention provides a transmission signal between a two-dimensional array type ultrasonic sensor having a plurality of piezoelectric vibration elements and each piezoelectric vibration element of the array type ultrasonic sensor. A pulsar to transmit, a receiver to transmit and receive a received signal, a delay control unit for performing time control by changing a delay time for each of the piezoelectric vibration elements to the transmission signal and the received signal, and an ultrasonic wave by the array type ultrasonic sensor A data recording unit that records transmitted and received waveforms, a sensor moving unit that scans the array-type ultrasonic sensor, a scan control unit that controls the data, a movement amount detection unit that measures the movement amount of the array-type ultrasonic sensor, , converted from from the waveform data to the three-dimensional flaw detection data of the voxel format and shifted by the movement amount measured by the movement amount detecting unit of the array-probe ultrasonic sensor synthesizing a plurality of three-dimensional flaw detection data And calculation unit is obtained by such a display unit for displaying the inspection data the composite.
With such a configuration, in the inspection using the two-dimensional array type ultrasonic sensor, even if the inspection object range is wide, only one set of data processing table (focal law) is used, and the inspection object is thick or a high attenuation material. Even in this case, a wide range can be collectively converted into a three-dimensional image with high-resolution and high S / N ratio three-dimensional flaw detection data, and can also be handled as one three-dimensional flaw detection data.

  (6) In the above (5), preferably, the sensor includes a sensor moving means that scans following the surface shape of the inspection object, a scanning control unit, and a movement amount detection unit, and the detected movement amount of the array type ultrasonic sensor. And a computer that synthesizes the three-dimensional flaw detection data while shifting it by the movement amount and angle of the array type ultrasonic sensor based on the measured value or the design value of the surface shape of the object.

  (7) In the above (5), preferably, flaw detection data obtained by normal flaw detection using the maximum value among flaw detection data sequentially obtained by movement of the array-type ultrasonic sensor as the flaw detection data is combined with the display unit. The data processing switching means for switching and displaying the flaw detection data obtained by the above is provided.

  According to the present invention, in an inspection using a two-dimensional array type ultrasonic sensor, even if the inspection object range is wide, only one set of data processing table (focal law) is used. Even in the case of an attenuating material, a wide range can be collectively converted into a three-dimensional image with high-resolution and high S / N ratio three-dimensional flaw detection data, and can also be handled as one three-dimensional flaw detection data.

Hereinafter, the configuration and operation of the three-dimensional ultrasonic imaging apparatus according to the first embodiment of the present invention will be described with reference to FIGS.
First, the configuration of the three-dimensional ultrasonic imaging apparatus according to the present embodiment will be described with reference to FIG.
FIG. 1 is a block diagram showing a configuration of a three-dimensional ultrasonic imaging apparatus according to the first embodiment of the present invention.

  The three-dimensional ultrasonic imaging apparatus of the present embodiment includes a two-dimensional array type ultrasonic sensor 101 that makes an ultrasonic wave incident on an inspection object 100, a transmission / reception unit 102, and a display unit 103 that displays a received signal and three-dimensional flaw detection data. A scanning means control unit 105 that scans the two-dimensional array type ultrasonic sensor 101, a movement amount detection unit 106 that detects a movement amount of the array type ultrasonic sensor 101, and a scan that scans the two-dimensional array type ultrasonic sensor 101. Sensor scanning means 107.

  As shown in the figure, the array type ultrasonic sensor 101 is composed of a piezoelectric vibration element 104 that generates ultrasonic waves. The array-type ultrasonic sensor 101 is set on the flaw detection surface of the inspection object 100, generates an ultrasonic wave 108 by a drive signal supplied from the transmission / reception unit 102, propagates this into the inspection object 100, and a reflected echo that appears thereby And the received signal is input to the transmitting / receiving unit 102.

  The transmission / reception unit 102 includes a computer 102A, a delay time control unit 102B, a pulsar 102C, a receiver 102D, and a data recording unit 102E. The pulser 102C supplies a drive signal to the array probe 101, and the receiver 102D processes the reception signal input from the array type ultrasonic sensor 101. Here, the computer 102A controls the delay time control unit 102B, the pulsar 102C, the receiver 102D, and the data recording unit 102E so as to obtain necessary operations.

  The delay time control unit 102B controls the timing of the drive signal output from the pulsar 102C and also controls the input timing of the received signal by the receiver 102D, thereby the operation of the two-dimensional array type ultrasonic sensor 101 by the phased array method. Is obtained. As the operation of the two-dimensional array type ultrasonic sensor 101 by the phased array method, the focal depth of the ultrasonic wave 108 is controlled, and the incident angle 109 is three-dimensionally controlled in the inspection object 100 to generate ultrasonic waves. Send and receive.

  Then, the data recording unit 102E processes the reception signal supplied from the receiver 102D and supplies it to the computer 102A. The computer 102A processes the recorded flaw detection data and displays it on the display unit 103.

  The processing content in the computer 102A and the operation of the display unit 103 will be described in detail later. In the computer 102A, the waveform obtained by each piezoelectric vibration element is synthesized according to the delay time, and each ultrasonic wave The waveform at each incident angle is processed into three-dimensional flaw detection data and displayed on the display unit 103 as three-dimensional flaw detection data 103B.

  Further, a plurality of three-dimensional flaw detection data 103B obtained at the respective positions are synthesized (added or averaged) in accordance with the operations of the scanning means control unit 105 and the movement amount detection unit 106, which will be described later, and the display hand unit. 103 is displayed as a three-dimensional processed video 103C. The display unit 103 has a function of displaying the received waveform 103A corresponding to the position of an arbitrary ultrasonic incident angle 103F in the flaw detection data as well as displaying the three-dimensional flaw detection data as described above.

  FIG. 1 shows a case where a defect 110 exists on the bottom surface side to be inspected. If the defect 110 exists on the bottom surface side, the dimensional inspection data 103B and the three-dimensional processing image 103C include A defect corner echo 103K, a defect tip echo 103J, and a bottom echo 103I to be inspected are observed on the bottom surface position 103E. When performing the depth sizing of the defect on the bottom surface side, the sizing is performed using the distance between the bottom surface position 103E and the defect tip echo position 103D obtained in the three-dimensional processing data 103C. In addition, reflected echoes 103J and 103K corresponding to these echoes are also observed in the combined waveform 103A at an arbitrary ultrasonic incident angle.

  The position control unit of the scanning means control unit 105 receives a movement signal composed of a movement speed and a movement amount from the computer 102A, and drives the sensor movement means 107 based on this to move the installation position of the two-dimensional array type ultrasonic sensor. To do. The sensor moving means 107 is connected to the movement amount detection unit 106 and measures the movement amount that the array type ultrasonic sensor has actually moved. This figure shows the case where the array type ultrasonic sensor installation position 101A at the start of flaw detection moves to the array type ultrasonic sensor installation position 101C at the end of flaw detection.

  The measured movement amount is sent to the computer 102A and used for processing flaw detection data. Although details will be described later, the movement amount at each flaw detection position of the array-type ultrasonic sensor 101 is measured, and the data in the three-dimensional flaw detection data is shifted and synthesized in the computer 102A by this movement amount ( Used to perform addition or averaging).

  Since the ultrasonic imaging apparatus of the present embodiment can also perform a conventional flaw detection operation using a two-dimensional array type ultrasonic sensor, processing of this operation mode and the above-described synthesis (addition or averaging) of the three-dimensional flaw detection data is performed. It is necessary to switch the operation mode. In the conventional operation mode, synthesis processing is not performed. In the conventional operation mode, along with the movement of the two-dimensional array type ultrasonic sensor, each flaw detection data is obtained for the same defect at each movement position, but the maximum value is obtained among the obtained flaw detection data. And displayed as flaw detection data. Therefore, the ultrasonic imaging apparatus according to the present embodiment has a means for switching the processing content on the display unit 103 as a processing content switching means in the computer 102A. Since this is for switching the processing content of the software, it is a switch or button type processing content switching means such as 103L in the display unit. The processing content switching means 103L switches between the conventional flaw detection mode and the processing mode of addition or averaging.

Next, the operation of the two-dimensional array type ultrasonic sensor used in the three-dimensional ultrasonic imaging apparatus according to the present embodiment will be described with reference to FIG.
FIG. 2 is an operation explanatory diagram of the two-dimensional array type ultrasonic sensor used in the three-dimensional ultrasonic imaging apparatus according to the first embodiment of the present invention.

  As described above, the two-dimensional array type ultrasonic sensor 101 is composed of a plurality of piezoelectric vibration elements 104, which vibrate due to the piezoelectric effect by the electrical signal sent from the transmission / reception unit 102, thereby generating ultrasonic waves 108. Oscillates. Here, the electric signal 201 transmitted to each piezoelectric vibration element is driven by being given a time delay by the delay time control unit. As a result, the wavefront of each ultrasonic wave generated by each piezoelectric vibration element interferes to form a synthetic wavefront, and the ultrasonic wave is focused at an arbitrary depth position or the incident angle 204 of the ultrasonic wave is controlled. .

  In FIG. 2, in order to explain the operation of the two-dimensional array type ultrasonic sensor, in consideration of the readability of the figure, only one row of the plurality of piezoelectric vibrators 104 and the transmitting / receiving unit 102 are connected. Although the state is shown, all the vibrators of the piezoelectric vibrator 104 and the transmission / reception unit 102 are actually connected. In addition, here, the case of a matrix array sensor in which piezoelectric vibrators are arranged in a matrix is shown. However, a two-dimensional array type that can be focused three-dimensionally inside the inspection object and can control the incident angle three-dimensionally. Any sensor may be used as long as it is an ultrasonic sensor.

  About the setting method of the focal depth at the time of implementing this embodiment, a focus is arbitrarily set to a position in consideration of the plate thickness of an inspection object. Thereby, the diffusion attenuation of the ultrasonic wave which becomes a problem when the aperture synthesis method is applied can be suppressed, and the flaw detection can be performed with a high SN ratio even when the propagation distance of the ultrasonic wave is long. Furthermore, the incident angle range of ultrasonic waves used for flaw detection is a solid angle within an angle range in which ultrasonic waves can be transmitted and received with high sensitivity, and the pitch of the ultrasonic incident angles is a delay time that can be set by the delay control unit. It is set arbitrarily in consideration of the allowable range of numbers.

Next, using FIG. 3 to FIG. 5, the operation of 3D ultrasonic scanning (volume scanning) by the 2D array in the 3D ultrasonic imaging apparatus according to the present embodiment will be described.
3 to 5 are operation explanatory diagrams of three-dimensional ultrasonic scanning (volume scanning) by a two-dimensional array in the three-dimensional ultrasonic imaging apparatus according to the first embodiment of the present invention.

  Here, the focal point is set at a fixed distance with reference to the center of the two-dimensional array type ultrasonic sensor as a reference, and the ultrasonic wave is focused and transmitted / received within the range of the incident angle of the ultrasonic wave used for flaw detection.

  FIG. 3 is an explanatory diagram of tilt scanning. A scanning method in which the distance to the focal point 301 of ultrasonic waves is constant and the angle θ (angle pitch Δθ) is continuously changed in an angle range 302 within a certain plane in the three-dimensional space is called a sector scanning method. The sector scan is further performed so as to continuously draw a plane within an angle range 303 at an angle φ (angle pitch Δφ). Thereby, three-dimensional ultrasonic scanning becomes possible.

  FIG. 4 is an explanatory diagram of rotational scanning. The scanning method in which the angle θ ′ (angle pitch Δθ ′) is continuously changed in the angle range 402 in a certain plane in the three-dimensional space with the distance to the ultrasonic focal point 401 being constant is called a sector scanning method. This sector scan is further scanned so as to rotate in the angle range 403 in the direction of angle φ ′ (angle pitch Δφ ′). As a result, by rotating the angle range 403 of φ ′ from 0 to 180 degrees, three-dimensional ultrasonic scanning becomes possible.

  Further, FIG. 5 is an explanatory diagram of tilt scanning with wedges. Conventionally, wedges (shoes) are used to adjust the directivity of ultrasonic waves in a direction in which defects can be easily detected. However, in the case of a two-dimensional array type ultrasonic sensor, flaw detection using wedges is also possible. . Also in this case, as in the case of tilt scanning described with reference to FIG. Then, the sector scan is further performed so as to draw a plane continuously at an angle φ ″ (angle pitch Δφ ″) in an angle range 503. In selecting the three-dimensional ultrasonic scanning, an optimal investigation method is selected and used in accordance with the nature and size of the defect.

Next, processing of 3D flaw detection data in the 3D ultrasonic imaging apparatus according to the present embodiment will be described with reference to FIGS.
6 and 7 are explanatory diagrams of the operation of the processing of the three-dimensional flaw detection data in the three-dimensional ultrasonic imaging apparatus according to the first embodiment of the present invention.

  The processing of the three-dimensional flaw detection data shown in FIG. 6 is performed by the computer 102A. FIG. 6 schematically shows the contents of the processing of the three-dimensional flaw detection data in the computer 102A.

  For simplification, only flaw detection data of an arbitrary y section in the xyz coordinate system is shown here. In the computer 102A shown in FIG. 1, the waveform obtained by each piezoelectric vibration element 104 is synthesized according to the delay time, and an appropriate interpolation process is applied to the waveform for each incident angle of each ultrasonic wave. The data is converted into voxel-format three-dimensional flaw detection data in units of a three-dimensional cubic lattice called a voxel, and the three-dimensional flaw detection data is processed using this. However, the three-dimensional flaw detection data used here represents an RF waveform.

Assuming that the array type ultrasonic sensor 101 is moved horizontally by the movement amount x from the position of the three-dimensional flaw detection data 600 obtained at the direction flaw detection start position 101A, the recording range of the three-dimensional flaw detection data is the same. Deviation occurs. In order to correct this, a measurement value obtained by the movement amount detection unit 106 is used. Assuming that the sensor movement amount is x, in the three-dimensional flaw detection data, a shift corresponding to Δ occurs in the x-axis direction. Here, is the value of the voxel address of the three-dimensional processing data 603, and is the value of the voxel address of the m-th three-dimensional flaw detection data. In addition, the following formula | equation (1) has shown the thing at the time of addition.

  Here, in order to schematically show the contents of processing, an example is shown in which three sets of three-dimensional flaw detection data 600, 601, and 602 are added to obtain three-dimensional processing data 603.

  FIG. 7 shows the contents of the processing described with reference to FIG. 6 together with the actual flaw detection situation.

  The first three-dimensional flaw detection data (1) 701A is three-dimensional flaw detection data at the flaw detection start position 101A, and the i-th three-dimensional flaw detection data (i) 701B is the flaw detection position 101B and the m-th three-dimensional flaw detection data (m ) 701C corresponds to the flaw detection position 101C, and m sets of three-dimensional flaw detection data 701 obtained at each position are obtained. In this example, the surface where the two-dimensional array type ultrasonic sensor 101 is installed and the bottom surface are parallel, that is, the parallel plate and the axial direction of the pipe are shown. A reflected echo 103I from the bottom surface is obtained immediately below the position where the ultrasonic sensor is installed, and when there is a defect from the bottom surface side, a defect corner echo 103K and a defect tip echo 103J are observed.

  As shown in FIG. 6, when these three-dimensional flaw detection data are shifted or added by the number of voxels corresponding to the moving amount of the array type ultrasonic sensor, three-dimensional processing data 702 is obtained. In addition, the defect tip echo 103K and the defect corner echo 103J selectively leave only the signal of the defect 110 due to the superposition of the wavefronts of ultrasonic waves incident from various angles. This is based on the same principle as the aperture synthesis method. The three-dimensional processing data is displayed on the display means 103 and is used for checking the defect position and evaluating the defect depth.

Next, 3D ultrasound imaging processing in the 3D ultrasound imaging apparatus according to the present embodiment will be described with reference to FIGS. 8 and 9.
8 and 9 are flowcharts showing the contents of the 3D ultrasound imaging process in the 3D ultrasound imaging apparatus according to the first embodiment of the present invention.

  In FIG. 8, first, the flaw detection range, the focal depth of the two-dimensional array type ultrasonic sensor, and the ultrasonic incident angle range are set by the transmission / reception unit 102, and the flaw detection is started (step S800). Next, the ultrasonic sensor 101 is installed on the inspection target (step S801), and the three-dimensional ultrasonic scan (volume scan) is performed by changing the incident angle of the ultrasonic wave (step S802). The waveform is recorded by the transmission / reception unit 102, converted into three-dimensional flaw detection data by the computer 102A (step S803), and displayed on the display unit 103 as three-dimensional flaw detection data. If all the flaw detection ranges have not been completed, the two-dimensional array type ultrasonic sensor is moved by the scanning means 107 (step S804), and the three-dimensional ultrasonic scan and the three-dimensional flaw detection data conversion processing are performed. This is repeated m times until the flaw detection is completed (step S805).

  When the flaw detection is completed in the entire flaw detection range (from flaw detection start position 101A to flaw detection end position 101C), the recorded three-dimensional flaw detection data is added by shifting the movement amount of two-dimensional array type ultrasonic sensor 101 by computer 102A or Averaging is performed (step S806). The added or averaged three-dimensional processing data (processing data 702) obtained in this way is displayed on the display unit 103 (step S807), and the flaw detection is terminated (step S808).

  Next, the second procedure will be described with reference to FIG. In the second procedure, there is also a procedure in which each time three-dimensional flaw detection data processing is recorded, it is added or averaged one after another and displayed.

  First, the flaw detection range, the focal depth of the two-dimensional array type ultrasonic sensor, and the incident angle range of the ultrasonic wave are set by the transmission / reception unit 102, and the flaw detection is started (step S900). Next, the ultrasonic sensor 101 is installed on the inspection target (step S901), and the three-dimensional ultrasonic scan (volume scan) is performed by changing the incident angle of the ultrasonic wave (step S902). The waveform is recorded and a computer performs a three-dimensional flaw detection data step (S903).

  When there are two or more three-dimensional flaw detection data sets, the computer 102A shifts the moving amount of the two-dimensional array type ultrasonic sensor and adds or averages them (step S906) and displays them on the display unit 103. If the flaw detection in all flaw detection ranges has not been completed, the array type ultrasonic sensor is moved by the scanning means 107 (step S904), and the three-dimensional ultrasonic scanning (volume scan) and the three-dimensional flaw detection data conversion processing are all performed. It is repeated m times until the flaw detection is completed (step S905).

  When the flaw detection in the entire flaw detection range (from the flaw detection start position 101A to the flaw detection end position 101C) is completed, the flaw detection is terminated (step S908).

  As described above, according to the present embodiment, the inside of the inspection object is three-dimensionally scanned by changing the incident angle of the ultrasonic wave oscillated from the two-dimensional array ultrasonic sensor, and sequentially the two-dimensional array ultrasonic wave The three-dimensional data obtained at each flaw detection position while shifting the sensor installation position or ultrasonic transmission / reception position and shifting the obtained three-dimensional flaw detection data by the movement amount of the two-dimensional array type ultrasonic sensor or the ultrasonic transmission / reception position By adding or averaging the flaw detection data into an image, 3D processing data can be constructed by superimposing ultrasonic waves incident from various angles, so there are many data processing tables (focal law, delay time) memory Therefore, it is possible to obtain an ultrasonic focusing effect. As a result, high-resolution three-dimensional processing data can be obtained at almost all positions, so that highly accurate nondestructive inspection can be performed.

  Furthermore, with regard to ultrasonic diffusion attenuation, which was a problem with the aperture synthesis method, by focusing and scanning with ultrasonic waves from an array-type ultrasonic sensor, the inspection object is thick and the ultrasonic propagation distance is long. However, since the diffusion and attenuation of ultrasonic waves can be suppressed, the SN ratio of the three-dimensional flaw detection data can be improved. Similarly, random noise such as electrical noise can be reduced by adding or averaging the three-dimensional flaw detection data, so that the SN ratio of the three-dimensional flaw detection data can be improved. Also, in the inspection using a two-dimensional array type ultrasonic sensor, even if the inspection target range is wide, only one set of data processing table (focal law) is used. In FIG. 3, a wide range is collectively converted into a three-dimensional image with high-resolution and high S / N ratio three-dimensional flaw detection data, and can be further handled as one three-dimensional flaw detection data.

Next, the configuration and operation of the three-dimensional ultrasonic imaging apparatus according to the second embodiment of the present invention will be described with reference to FIGS. 10 and 11. Note that the 3D ultrasonic imaging apparatus according to the present embodiment is the same as that shown in FIG.
FIG. 10 is an explanatory diagram of the operation of the processing of 3D flaw detection data in the 3D ultrasonic imaging apparatus according to the second embodiment of the present invention. FIG. 11 is a flowchart showing the contents of 3D ultrasound imaging processing in the 3D ultrasound imaging apparatus according to the second embodiment of the present invention.

  Compared with FIG. 7 according to the first embodiment, the embodiment shown in FIG. 10 is different in that the two-dimensional array type ultrasonic sensor is also scanned in the y-axis direction which is the depth direction on the paper surface, and the inspection range is wider. Used in cases where Two-dimensional scanning methods using mechanical scanning means include a zigzag scanning method and a comb type scanning in which scanning is performed once in one axial direction, then returned once, moved by a scanning pitch in another axial direction, and scanned again. .

  The first three-dimensional flaw detection data (1, 1) 1001A is three-dimensional flaw detection data at the flaw detection start position 101A, and the i × j th three-dimensional flaw detection data (i, j) 1001B is the flaw detection position 101B, m × n. The third three-dimensional flaw detection data (m × n) 1001C corresponds to the flaw detection position 101C, and m × n sets of three-dimensional flaw detection data 1001 obtained at each position are obtained. In these three-dimensional flaw detection data, a reflected echo 103I from the bottom surface is obtained immediately below the installation position of the two-dimensional array type ultrasonic sensor, and when there is a defect from the bottom surface side, the defect corner echo 103K and the tip of the defect are detected. An echo 103J is observed.

  When these three-dimensional flaw detection data are shifted or added by the number of voxels corresponding to the movement amount and direction of the array-type ultrasonic sensor, three-dimensional processing data 1002 is obtained. In addition, the defect tip echo 103K and the defect corner echo 103J selectively leave only the signal of the defect 110 by superimposing the wavefronts of the ultrasonic waves incident from various angles in three dimensions. This is based on the same principle as the three-dimensional aperture synthesis method. The three-dimensional processing data is displayed on the display means 103 and is used for checking the defect position and evaluating the defect depth.

  Next, the contents of the three-dimensional ultrasonic imaging process will be described with reference to FIG.

  First, the transmitter / receiver 102 sets the flaw detection range, the focal depth of the two-dimensional array type ultrasonic sensor, and the ultrasonic incident angle range, and starts flaw detection (step S1100). Next, the ultrasonic sensor 101 is installed on the inspection target (step S1101), and the three-dimensional ultrasonic scan (volume scan) is performed by changing the incident angle of the ultrasonic wave (step S1102). The waveform is recorded by the transmitting / receiving unit 102, converted into three-dimensional flaw detection data by the computer 102A (S1103), and displayed on the display unit 103 as three-dimensional flaw detection data.

  If all the flaw detection ranges have not been completed, the two-dimensional array type ultrasonic sensor is moved by the scanning means 107 (step S1104), and the three-dimensional ultrasonic scan and the three-dimensional flaw detection data conversion processing are performed. This is repeated m × n times until the flaw detection is completed (step S1105).

  When the flaw detection is completed in the entire flaw detection range (from flaw detection start position 101A to flaw detection end position 101C), the recorded three-dimensional flaw detection data is added by shifting the movement amount of two-dimensional array type ultrasonic sensor 101 by computer 102A or Averaging is performed (step S1106).

  The added or averaged three-dimensional processing data (processing data 1002) obtained in this way is displayed on the display unit 103 (step S1107), and the flaw detection is terminated (step S1108).

  As described above, according to the present embodiment as well, the inside of the inspection object is scanned three-dimensionally by changing the incident angle of the ultrasonic wave oscillated from the two-dimensional array type ultrasonic sensor, and sequentially the two-dimensional array type ultrasonic sensor. 3D flaw detection obtained at each flaw detection position while shifting the installation position of the ultrasonic wave or ultrasonic transmission / reception position and shifting the obtained 3D flaw detection data by the amount of movement of the 2D array type ultrasonic sensor or the transmission / reception position of ultrasonic waves By adding or averaging the data and visualizing it, 3D processing data can be constructed by superimposing ultrasonic waves incident from various angles, so a large number of data processing tables (focal law, delay time) are stored in memory. Therefore, it is possible to obtain an ultrasonic focusing effect. As a result, high-resolution three-dimensional processing data can be obtained at almost all positions, so that highly accurate nondestructive inspection can be performed.

  Furthermore, with regard to ultrasonic diffusion attenuation, which was a problem with the aperture synthesis method, by focusing and scanning with ultrasonic waves from an array-type ultrasonic sensor, the inspection object is thick and the ultrasonic propagation distance is long. However, since the diffusion and attenuation of ultrasonic waves can be suppressed, the SN ratio of the three-dimensional flaw detection data can be improved. Similarly, random noise such as electrical noise can be reduced by adding or averaging the three-dimensional flaw detection data, so that the SN ratio of the three-dimensional flaw detection data can be improved. Also, in the inspection using a two-dimensional array type ultrasonic sensor, even if the inspection target range is wide, only one set of data processing table (focal law) is used. In FIG. 3, a wide range is collectively converted into a three-dimensional image with high-resolution and high S / N ratio three-dimensional flaw detection data, and can be further handled as one three-dimensional flaw detection data.

Next, the configuration and operation of the three-dimensional ultrasonic imaging apparatus according to the third embodiment of the present invention will be described with reference to FIGS. Note that the 3D ultrasonic imaging apparatus according to the present embodiment is the same as that shown in FIG.
FIG. 12 is a diagram for explaining the operation of the processing of 3D flaw detection data in the 3D ultrasonic imaging apparatus according to the third embodiment of the present invention. FIG. 13 is a flowchart showing the contents of 3D ultrasound imaging processing in the 3D ultrasound imaging apparatus according to the third embodiment of the present invention.

  In the embodiment shown in FIG. 12, the inspection object is a curved surface such as the circumferential direction of the pipe or a complicated object in comparison with the inspection object having the planar shape of FIG. 7 according to the first embodiment and FIG. 10 according to the second embodiment. An application example in the case of a shape is shown.

  In the curved surface inspection object 1200 of FIG. 12, the first three-dimensional flaw detection data (1) 1201A is the three-dimensional flaw detection data measured at the flaw detection start position 101A, and the i-th three-dimensional flaw detection data (i) 1201B is The flaw detection position 101B and the m-th three-dimensional flaw detection data (m) 1301C correspond to the flaw detection position 101C. When three-dimensional ultrasonic scanning (volume scan) is performed at each position, m sets of three-dimensional flaw detection data 1201 are obtained. can get. In this example, since an inspection target having a curved surface shape such as a pipe is assumed, the surface on which the array type ultrasonic sensor 101 is installed is substantially parallel to the bottom surface, so that it is directly below the installation position of the array type ultrasonic sensor. When the echo 103I from the bottom surface is obtained and a defect has entered from the bottom surface side, a defect corner echo 1202A and a defect tip echo 1202B are observed corresponding to the position of each defect 1202, respectively.

  These three-dimensional flaw detection data are added or averaged while being shifted by the number of pixels corresponding to the movement amount of the two-dimensional array type ultrasonic sensor. Here, the difference from the first and second embodiments is that the object to be inspected has a curved surface shape, and it is necessary to correct the influence of the inclination due to this shape when processing the three-dimensional flaw detection data. It is. Therefore, in the present embodiment, the surface shape data of the inspection object that has been measured in advance, or the addition of the three-dimensional flaw detection data by adding the tilt measurement function of the two-dimensional array type ultrasonic sensor to the movement amount detection unit (or (Grading) is performed. Specifically, the computer shifts the 3D flaw detection data by the amount of movement of the center position of the array-type ultrasonic sensor from the flaw detection start position, and rotates it by the rotation angle from the flaw detection start position to add or average. As a result, the processed three-dimensional flaw detection data 1203 is obtained.

  In addition, in the inclination correction of each voxel, addition or averaging is performed after matching each voxel position by performing an appropriate complementing process as a pre-processing. In the three-dimensional flaw detection data 1203, only the signal of the true defect position selectively remains in the defect corner echo 1202A and the defect tip echo 1202B by superimposing the wavefronts of the ultrasonic waves incident from various angles, and this is used as the defect position echo. Used for confirmation of defects and evaluation of defect depth. Furthermore, even when the surface shape is complicated, three-dimensional processing data can be created by performing the same processing as described above.

  Next, the contents of the three-dimensional ultrasonic imaging process will be described with reference to FIG.

  First, the flaw detection range, the focal depth of the two-dimensional array type ultrasonic sensor, and the ultrasonic incident angle range are set, and a flaw detection start step is performed (S1300). Next, a step of installing a two-dimensional ultrasonic sensor on the inspection target (S1301), a step of performing a three-dimensional ultrasonic scan (volume scan) (S1302), and recording a waveform at an incident angle of each ultrasonic wave, The computer generates three-dimensional flaw detection data (step S1303).

  When the flaw detection of all flaw detection ranges has not been completed, the two-dimensional array type ultrasonic sensor is moved along the surface to be inspected by the scanning means (step S1304), and the three-dimensional ultrasonic scanning and the three-dimensional flaw detection data are performed. Is repeated m times until all the flaw detection is completed (step S1305).

  When all the flaw detection areas have been detected, the 3D flaw detection data recorded in the computer is shifted by the amount of movement of the two-dimensional array type ultrasonic sensor from the flaw detection start position, and the tilt angle from the flaw detection start position. Addition or averaging is performed by rotating by the amount (step S1306). The result is displayed on the display unit (step S1307), and the flaw detection is terminated (step S1308).

  As described above, according to the present embodiment as well, the inside of the inspection object is scanned three-dimensionally by changing the incident angle of the ultrasonic wave oscillated from the two-dimensional array type ultrasonic sensor, and sequentially the two-dimensional array type ultrasonic sensor. 3D flaw detection obtained at each flaw detection position while shifting the installation position of the ultrasonic wave or ultrasonic transmission / reception position and shifting the obtained 3D flaw detection data by the amount of movement of the 2D array type ultrasonic sensor or the transmission / reception position of ultrasonic waves By adding or averaging the data and visualizing it, 3D processing data can be constructed by superimposing ultrasonic waves incident from various angles, so a large number of data processing tables (focal law, delay time) are stored in memory. Therefore, it is possible to obtain an ultrasonic focusing effect. As a result, high-resolution three-dimensional processing data can be obtained at almost all positions, so that highly accurate nondestructive inspection can be performed.

Furthermore, with regard to ultrasonic diffusion attenuation, which was a problem with the aperture synthesis method, by focusing and scanning with ultrasonic waves from an array-type ultrasonic sensor, the inspection object is thick and the ultrasonic propagation distance is long. However, since the diffusion and attenuation of ultrasonic waves can be suppressed, the SN ratio of the three-dimensional flaw detection data can be improved. Similarly, random noise such as electrical noise can be reduced by adding or averaging the three-dimensional flaw detection data, so that the SN ratio of the three-dimensional flaw detection data can be improved. Also, in the inspection using a two-dimensional array type ultrasonic sensor, even if the inspection target range is wide, only one set of data processing table (focal law) is used. In FIG. 3, a wide range is collectively converted into a three-dimensional image with high-resolution and high S / N ratio three-dimensional flaw detection data, and can be further handled as one three-dimensional flaw detection data.

It is a block diagram which shows the structure of the three-dimensional ultrasonic imaging apparatus by the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the two-dimensional array type ultrasonic sensor used for the three-dimensional ultrasonic imaging apparatus by the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the three-dimensional ultrasonic scan (volume scan) by the two-dimensional array in the three-dimensional ultrasonic imaging apparatus by the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the three-dimensional ultrasonic scan (volume scan) by the two-dimensional array in the three-dimensional ultrasonic imaging apparatus by the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the three-dimensional ultrasonic scan (volume scan) by the two-dimensional array in the three-dimensional ultrasonic imaging apparatus by the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the process of the three-dimensional flaw detection data in the three-dimensional ultrasonic imaging apparatus by the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the process of the three-dimensional flaw detection data in the three-dimensional ultrasonic imaging apparatus by the 1st Embodiment of this invention. It is a flowchart which shows the content of the three-dimensional ultrasonic imaging process in the three-dimensional ultrasonic imaging apparatus by the 1st Embodiment of this invention. It is a flowchart which shows the content of the three-dimensional ultrasonic imaging process in the three-dimensional ultrasonic imaging apparatus by the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the process of the three-dimensional flaw detection data in the three-dimensional ultrasonic imaging apparatus by the 2nd Embodiment of this invention. It is a flowchart which shows the content of the three-dimensional ultrasonic imaging process in the three-dimensional ultrasonic imaging apparatus by the 2nd Embodiment of this invention. It is operation | movement explanatory drawing of the process of the three-dimensional flaw detection data in the three-dimensional ultrasonic imaging apparatus by the 3rd Embodiment of this invention. It is a flowchart which shows the content of the three-dimensional ultrasonic imaging process in the three-dimensional ultrasonic imaging apparatus by the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Inspection object 101 ... Two-dimensional array type ultrasonic sensor 101A ... Flaw detection start position 101B ... Flaw detection position 101C ... Flaw detection end position 102 ... Transmission / reception unit 102A ... Computer 102B ... Delay time control unit 102C ... Pulser 102D ... Receiver 102E ... Data recording Part 103 ... Display part 103A ... Waveform 103B of arbitrary ultrasonic incident angle ... Three-dimensional flaw detection data 103C ... Three-dimensional processing data 103D ... Defect tip position 103E ... Bottom face position 103F ... Arbitrary ultrasonic incident angle in three-dimensional flaw detection data 103I ... bottom echo 103J ... defect tip echo 103K ... defect corner echo 103L ... processing content switching means 104 ... piezoelectric vibration element 105 ... scanning means control section 106 ... movement amount detection section 107 ... scanning means 108 ... ultrasonic wave 109 ... ultrasonic incidence Angle swing 110 ... defect

Claims (7)

Sending ultrasonic waves focused to an arbitrary depth from a two-dimensional array type ultrasonic sensor,
Furthermore, the incident angle is changed and the inside of the inspection object is scanned three-dimensionally to record waveform data.
Convert the obtained waveform data into 3D flaw detection data in voxel format ,
Move the installation position of the array type ultrasonic sensor sequentially to record 3D flaw detection data,
A three-dimensional ultrasonic imaging method characterized by combining three-dimensional flaw detection data obtained at each flaw detection position while shifting by an amount of movement of the array type ultrasonic sensor to form a three-dimensional image. The three-dimensional ultrasound imaging method according to claim 1,
Measure the surface shape of the inspection object, follow the surface shape of the inspection object, change the incident angle of the ultrasonic wave and record the 3D flaw detection data inside the inspection object,
Sequentially move the installation position of the array type ultrasonic sensor to detect flaws,
Three-dimensional imaging characterized by synthesizing three-dimensional flaw detection data obtained at each flaw detection position while shifting the obtained three-dimensional flaw detection data by the moving amount and rotation angle of the array-type ultrasonic sensor to form a three-dimensional image Ultrasound imaging method. The three-dimensional ultrasound imaging method according to claim 1,
As an ultrasonic scanning method for three-dimensional flaw detection inside the inspection object by changing the incident angle of the ultrasonic wave oscillated from the two-dimensional array type ultrasonic sensor, one of rotation scanning, tilt scanning, and wedged tilt scanning is used. A three-dimensional ultrasonic inspection method characterized by that. The three-dimensional ultrasound imaging method according to claim 1,
The three-dimensional flaw detection data is synthesized by adding or averaging the three-dimensional flaw detection data to form an image. A two-dimensional array type ultrasonic sensor including a plurality of piezoelectric vibration elements;
A pulsar that transmits a transmission signal to and from each piezoelectric vibration element of the array-type ultrasonic sensor and a receiver that transmits and receives a reception signal;
A delay control unit for performing time control by varying a delay time for each of the piezoelectric vibration elements in the transmission signal and the reception signal;
A data recording unit that records waveforms transmitted and received by the array-type ultrasonic sensor;
Sensor moving means for scanning the array-type ultrasonic sensor and a scanning control unit for controlling the sensor moving means;
A movement amount detector for measuring the movement amount of the array-type ultrasonic sensor;
A computer that converts the recorded waveform data into three-dimensional flaw detection data in the voxel format, and synthesizes a plurality of three-dimensional flaw detection data by shifting the movement amount measured by the movement amount detection unit of the array type ultrasonic sensor,
A three-dimensional ultrasonic imaging apparatus comprising a display unit for displaying the synthesized flaw detection data. The three-dimensional ultrasonic imaging apparatus according to claim 5,
Sensor moving means for scanning following the surface shape of the inspection object, a scanning control unit, and a movement amount detection unit,
A computer is provided that synthesizes the three-dimensional flaw detection data while shifting by the movement amount and angle of the array type ultrasonic sensor based on the detected movement amount of the array type ultrasonic sensor and the measured value or design value of the surface shape of the target. A three-dimensional ultrasonic imaging apparatus characterized by that. The three-dimensional ultrasonic imaging apparatus according to claim 5,
The display unit switches and displays flaw detection data obtained by normal flaw detection using the maximum value among flaw detection data sequentially obtained by movement of the array-type ultrasonic sensor and flaw detection data obtained by synthesis processing. A three-dimensional ultrasonic imaging apparatus comprising data processing switching means.

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