JP2011043416A - Ultrasonic inspection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the SN ratio of a detection signal from damage or the like present in an object, in an ultrasonic inspection system. <P>SOLUTION: The ultrasonic inspection system 10 is constituted of a laser drive device 12 for irradiating the object 50 with a laser beam to excite ultrasonic vibration in the object 50, a galvano scanner 14 for causing the laser beam to scan the surface of the object 50, ultrasonic probes 16 and 18 being a plurality of the receiving means arranged to the object 50, a control unit 30 or the like. The control unit 30 includes an individual imaging processing part 32 for imaging the ultrasonic vibration distribution in the object on a two-dimensional surface at every receiving means on the basis of the detection signal received by each of the receiving means corresponding to the scanning timing of the laser beam, and an image-enhancing processing part 34 for performing enhancement processing subjecting a plurality of image data at the same position to sum operation or integral operation with respect to a plurality of individual imaging data to obtain enhancement processing data at the position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ultrasonic inspection system, and more particularly, to an ultrasonic inspection system including a scanning unit that two-dimensionally moves and scans a position where an ultrasonic vibration is applied to an object.

  An apparatus for imaging the internal state of a solid material using ultrasonic vibration is based on a water immersion method in which an ultrasonic probe is directly scanned through water in an object such as a water tank. It is commercially available. The reason for passing water is that scanning with the subject not in contact can facilitate scanning and increase the scanning speed. In this case, the method cannot be applied to a subject that cannot be immersed in water, and in some cases, a large water tank is required. Therefore, another non-contact scanning method is desired. As another non-contact scanning method, it is known that laser light is scanned on the surface of a subject and ultrasonic waves generated by thermal excitation at the scanning point are used.

  For example, in Patent Document 1, as an imaging device for ultrasonic wave propagation, the surface of a subject is scanned with an oscillation laser, and a pulse laser beam is irradiated onto a plurality of measurement points along a scanning path. A thermal excitation ultrasonic wave is generated at a point, and this ultrasonic wave is detected in synchronization with a pulse of a laser beam irradiated by a receiving piezoelectric sensor attached to a subject and fixed, and the detected signal is detected by a digital oscilloscope or the like. It is disclosed that a / D converter records waveform waveform data in a personal computer, and the recorded waveform sequence data is imaged by modulating the amplitude value at each time with the personal computer.

  In addition, the inventors of the present invention, in Non-Patent Document 1, excite the Lamb wave as a guide wave with a laser and detect the Lamb wave A0 mode with an oblique probe at a distant point. We have disclosed that we have developed a method that can acquire the thickness information of the sheet.

JP 2006-300434 A

Hayashi et al., High Speed Thickness Measurement Using Guide Waves Excited by Oscillating Laser Scanning Method, Japan Nondestructive Inspection Association, Proc. Of the 16th Symposium on Nondestructive Evaluation of Materials by Ultrasonics, January 2009 29th, p107-111

  According to the prior art, the position where ultrasonic vibration is applied is two-dimensionally moved and scanned with respect to the object, ultrasonic vibration is detected by a probe arranged in advance fixed to the object, and the detected signal is processed. By doing so, the two-dimensional ultrasonic vibration distribution in the object can be imaged.

  However, when receiving ultrasonic vibrations, in non-contact scanning or contact scanning, as the reception point moves away from the scanning point, image distortion occurs due to ultrasonic attenuation, and a virtual image called artifact is caused by the influence of reflected waves. May occur. The reflected wave, which is one of the causes of such image disturbance, varies depending on the shape of the damage in the object, its size, the frequency of the ultrasonic wave used, and the like. In addition, ultrasonic attenuation, which is another cause of image distortion, is greatly affected by the propagation distance of ultrasonic vibration.

  When such image disturbance, virtual image, or the like occurs, noise is detected with respect to a detection signal from damage or the like present on the object, the SN ratio is lowered, and it is difficult to perform sufficient inspection.

  An object of the present invention is to provide an ultrasonic inspection system capable of improving the SN ratio of a detection signal from damage or the like existing in an object when receiving ultrasonic vibration.

  An ultrasonic inspection system according to the present invention includes a scanning unit that two-dimensionally moves and scans a position where ultrasonic vibration is applied to an object, and ultrasonic vibration that is disposed in a predetermined positional relationship with the object and propagates through the object. Based on a plurality of receiving means for receiving signals as detection signals and detection signals received by each receiving means corresponding to the timing of moving scanning, an ultrasonic vibration distribution in an object is imaged on a two-dimensional surface for each receiving means. For each of the individual imaging means and the plurality of two-dimensional imaging data obtained for each receiving means, a plurality of image data at the same position is processed to be enhanced processing data at that position, and each position is And an enhancement imaging means for imaging the enhancement processing data in a two-dimensional plane and outputting the image as an object inspection image.

  Further, in the ultrasonic inspection system according to the present invention, it is preferable that the enhancement image forming means performs a sum operation process or a product operation process on a plurality of pieces of image data at the same position to obtain enhancement process data at that position.

  In the ultrasonic inspection system according to the present invention, it is preferable that the enhanced imaging means includes a weighting means for weighting each of a plurality of image data at the same position according to a predetermined criterion.

  Further, in the ultrasonic inspection system according to the present invention, it is preferable that the scanning unit moves and scans a point to which the ultrasonic vibration is applied so as to propagate the Lamb wave as the ultrasonic vibration to the object.

  In the ultrasonic inspection system according to the present invention, it is preferable that the scanning unit includes a laser irradiation unit that irradiates an object with laser and excites ultrasonic vibration on the object.

  In the ultrasonic inspection system according to the present invention, the scanning means includes a mirror that receives and reflects the laser from the laser means and irradiates the object, and a means for tilting the mirror in accordance with the shape of the object. It is preferable to have tilting means for tilting the reflecting surface of the mirror so that the incident angle of the laser irradiated on the mirror becomes a predetermined angle.

  With the above-described configuration, the ultrasonic inspection system includes a plurality of receiving units that two-dimensionally move and scan the position where the ultrasonic vibration is applied to the object and receive the ultrasonic vibration signal propagating through the object as a detection signal. Then, for each receiving means, individual imaging means for imaging the ultrasonic vibration distribution in the object on a two-dimensional surface, and a plurality of two-dimensional surface imaging data obtained for each receiving means, Emphasis processing is performed to process the image data to make enhancement processing data at the position, image the enhancement processing data at each position on a two-dimensional surface, and output the image as an inspection image of the object.

  When ultrasonic vibration is detected and imaged by one receiving means, various noises are simultaneously detected depending on the propagation of the ultrasonic vibration, so the SN ratio of the detection signal from damage or the like existing in the object is It varies. When ultrasonic vibration is detected by a plurality of receiving means having different propagation paths, detection signals from damage or the like existing on the object are the same signal in all receiving means. On the other hand, the noise depending on the propagation path differs depending on each receiving means. According to the above-described configuration, the enhancement processing data at each position is processed into a two-dimensional plane by processing a plurality of image data at the same position to obtain enhancement processing data at that position, and therefore exists in the object. Detection signals from damage and the like are emphasized against noise. As a result, it is possible to improve the SN ratio of the detection signal from damage or the like existing on the object.

  In addition, imaging on a two-dimensional surface displays the amplitude distribution related to ultrasonic vibration by enabling the degree of ultrasonic vibration at each point constituting the two-dimensional surface to be displayed with a difference in shade, color, etc. Is to be able to do it. Such imaging display is similar to what is called a so-called C-scope method in the ultrasonic flaw detection technology.

  Further, in the ultrasonic inspection system, the enhanced imaging means performs a sum operation process or a product operation process on a plurality of pieces of image data at the same position to obtain enhancement process data at that position. For example, considering the use of four receivers, the S / N ratio of a detection signal from damage or the like existing in an object can be reduced to one image data by mutually performing a sum operation process on four image data at the same position. In terms of calculation, the signal-to-noise ratio is improved by a factor of four. By performing mutual product operation processing on the four image data at the same position, the SN ratio of the detection signal from damage or the like existing in the object is improved to the fourth power of the SN ratio in the case of calculation based on one image data. To do.

  In the ultrasonic inspection system, each of a plurality of image data at the same position is weighted according to a predetermined criterion. For example, even if the detection sensitivity may be different for each of a plurality of receiving means, if the detection sensitivity is examined in advance and weighting is performed according to the difference in the detection sensitivity, damage existing in the object It is possible to stably improve the SN ratio of the detection signal from the above.

  Further, in the ultrasonic inspection system, a point where ultrasonic vibration is applied is moved and scanned so that Lamb waves are propagated as ultrasonic vibration to an object. A Lamb wave is a wave that propagates along a plate while bending and expanding in a thin plate. Lamb waves tend to be generated when the ratio of the plate thickness to the wavelength of ultrasonic vibration (plate thickness / wavelength) is small, and propagates ultrasonic vibration mainly consisting of Lamb waves by entering at an oblique angle. Can be made. For example, the amplitude of a Lamb wave in a thin plate increases as the thickness of the thin plate decreases. By utilizing this fact and using an ultrasonic frequency band that generates Lamb waves, it is possible to effectively inspect that the plate thickness fluctuates locally due to damage or the like.

  In addition, since the ultrasonic inspection system has laser irradiation means for irradiating the object with laser and exciting the object with ultrasonic vibration, it is not possible to move and scan the object in a two-dimensional manner. It can be done in contact. Thereby, high-speed scanning is possible without using a water immersion method.

  Further, in the ultrasonic inspection system, the laser from the laser means is received by the mirror, reflected, and irradiated to the object, and the incident angle of the laser irradiated to the object is determined in advance according to the shape of the mirror. The reflecting surface of the mirror is tilted so that the angle becomes. Thus, even if the object is a curved surface, the laser can be appropriately incident on the curved object surface, so that an accurate ultrasonic inspection can be performed.

It is a figure explaining the composition of the ultrasonic inspection system of an embodiment concerning the present invention. In an embodiment concerning the present invention, it is a figure explaining an example of an object which is a candidate for inspection. 4 is a flowchart showing a procedure of ultrasonic inspection in the embodiment according to the present invention. In an embodiment concerning the present invention, it is a figure explaining an example of a received signal. In the embodiment according to the present invention, for each probe in the case where four probes are provided on the object to be inspected, the state of an example when each ultrasonic vibration distribution is imaged on a two-dimensional surface is shown. It is a figure explaining. In FIG. 5, it is a figure explaining a mode when the ultrasonic vibration distribution of one probe is imaged on a two-dimensional surface. In FIG. 5, it is a figure explaining a mode when the ultrasonic vibration distribution of another probe is imaged on the two-dimensional surface. It is a figure explaining a mode that the data which imaged each ultrasonic vibration distribution of the four probes demonstrated in FIG. 5 on the two-dimensional surface were emphasized by sum operation, and it was set as the image for a test | inspection. It is a figure explaining a mode that the data which imaged each ultrasonic vibration distribution of the four probes demonstrated in FIG. 5 on the two-dimensional surface were emphasized by product calculation, and were used as the image for an inspection. In the embodiment according to the present invention, another example of imaging each ultrasonic vibration distribution on a two-dimensional plane for each probe when four probes are provided on the object to be inspected. It is a figure explaining a mode when the ultrasonic vibration distribution of one probe is imaged on the two-dimensional surface. It is a figure explaining a mode when the ultrasonic vibration distribution of another probe is imaged on the two-dimensional surface in the example of FIG. In the example of FIG. 10, it is a figure explaining a mode that the data which imaged each ultrasonic vibration distribution of four probes on the two-dimensional surface were emphasized by sum operation, and it was set as the image for an inspection. In the example of FIG. 10, it is a figure explaining a mode that the data which imaged each ultrasonic vibration distribution of four probes on the two-dimensional surface are emphasized by product operation, and it was set as the image for an inspection. In embodiment which concerns on this invention, it is a figure explaining the example of the object which has a curved surface as a test object. In the example of FIG. 14, it is a figure explaining the mode of the surface which irradiates a laser. In the example of FIG. 15, for each probe when four probes are provided on the object to be inspected, one probe is used for an example in which each ultrasonic vibration distribution is imaged on a two-dimensional plane. It is a figure explaining a mode when the ultrasonic vibration distribution of a child is imaged on a two-dimensional surface. It is a figure explaining a mode when the ultrasonic vibration distribution of another probe is imaged on the two-dimensional surface in the example of FIG. In the example of FIG. 15, it is a figure explaining a mode that the data which imaged each ultrasonic vibration distribution of four probes on the two-dimensional surface were emphasized by sum operation, and it was set as the image for an inspection. In the example of FIG. 15, it is a figure explaining a mode that the data which imaged each ultrasonic vibration distribution of four probes on the two-dimensional surface were emphasized by product operation, and it was set as the image for an inspection.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In the following, a scanning unit that focuses on the surface of an object to be inspected, irradiates a laser, and excites ultrasonic waves inside the object will be described. However, other ultrasonic supply devices may be used. Good. For example, even if the focal point of laser irradiation is set away from the surface of the object, the plasma is generated by the laser starting from the position away from the surface of the structure, and the ultrasonic wave is excited on the object surface by the plasma. Good. At that time, laser light may be emitted in parallel to the surface of the object, and the focal point may be set away from the surface of the object. Further, ultrasonic excitation may be performed by discharge, microwave irradiation, or the like. Further, an ultrasonic transmission device using a piezoelectric element or the like may be configured to contact an object. Further, the object may be placed in a medium such as water or oil.

  In the following, a contact-type ultrasonic probe using a piezoelectric element will be described as the receiving means, but other ultrasonic vibration detection devices may be used. For example, a vibration detection device using a non-contact type laser interferometer, a so-called aerial ultrasonic sensor using a non-contact type piezoelectric element, a photoelectric vibration detection device, a capacitive vibration detection device, a magnetic vibration detection device, etc. May be used.

  Hereinafter, a case where four receiving units are used will be described. However, this is an example for explanation, and the number of receiving units may be plural. In addition, as an individual imaging method, laser scanning is performed for each receiving unit, but this is for explanation of imaging, and in an actual ultrasonic inspection system configuration, one scanning is performed. Thus, a plurality of receiving devices may be imaged simultaneously.

  In the following, the object to be inspected will be described as a flat object or an object having a curved surface. Of course, this is merely an example for explanation, and various shapes of objects, for example, objects with irregularities, through holes Or the like can be the inspection object.

  In addition, the materials, dimensions, material surface shapes, damage shapes, etc. described below are only examples for explanation, and may be changed as appropriate according to the characteristics of the materials subject to ultrasonic inspection and the inspection specifications. be able to.

  Below, the same code | symbol is attached | subjected to the same element in all the drawings, and the overlapping description is abbreviate | omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a diagram illustrating the configuration of the ultrasonic inspection system 10. FIG. 1 shows a part of an object 50 to be inspected, which is not a component of the ultrasonic inspection system 10. The object 50 to be inspected is not particularly limited as long as it propagates ultrasonic vibrations. However, in the following, the object 50 provided with appropriate simulated damage on a flat metal plate and the appropriate simulated damage on a metal plate having a curved surface will be described. A description will be given using the provided object 170. The contents of the objects 50 and 170 that are specifically inspected will be described later.

  The ultrasonic inspection system 10 changes the course of laser light from a laser driving device 12 for irradiating an object with a laser to excite ultrasonic vibrations on the object, and changes the path of laser light from the laser driving device 12 at a predetermined incident angle. , A galvano scanner 14 for scanning the surface of the laser beam, a plurality of ultrasonic probes 16, 18 arranged in a predetermined positional relationship on the object 50, and detection signals from the ultrasonic probes 16, 18. Is performed by the control device 30 and the control device 30 for processing the output data of the AD boards 24 and 26, the AD boards 24 and 26 for converting the analog signals of the amplifiers 20 and 22, the amplifiers 20 and 22 into digital signals, and the like. And a display device 36 for displaying the results of the data processing. The control device 30 and the display device 36 can be configured by an appropriate computer suitable for data processing.

  The laser driving device 12 is a device that outputs pulsed laser light at a predetermined interval, and for example, a YAG laser or the like can be used. Although the predetermined interval depends on the expected inspection speed, for example, the pulse laser beam can be output at a cycle of about 20 Hz to 1 kHz. A signal indicating the timing at which the laser driving device 12 outputs the pulse laser beam is transmitted to the control device 30 as a trigger signal using an appropriate signal line.

  The galvano scanner 14 is an optical device composed of a plurality of movable reflecting mirrors. By appropriately changing the reflection direction of the plurality of reflecting mirrors, the pulse laser light output from the laser driving device 12 is converted into the object 50. It has a function of scanning the surface according to a predetermined irradiation order trajectory. The galvano scanner 14 has a function of irradiating pulsed laser light at a predetermined incident angle with respect to the curved surface when the object 50 has a curved surface by appropriately changing the reflection directions of the plurality of reflecting mirrors. . In the example of FIG. 1, a state in which the pulse laser beam is scanned in the scanning region 60 with a zigzag moving locus 62 is shown.

  As the plurality of reflecting mirrors, a plane mirror, a curved mirror or the like can be used, and an actuator such as a small motor or an electrically driven plunger can be used to change the reflection direction of each reflecting mirror. The drive control of the galvano scanner 14 is executed by the control device 30 based on the trigger signal of the laser drive device 12 and the like.

  By irradiating the surface of the object 50 with the pulse laser light in this way, ultrasonic vibrations that are thermally excited in the object 50 are generated. The generated ultrasonic vibration propagates from the scanning point toward the periphery of the object 50. Therefore, the galvano scanner 14 is a scanning unit that two-dimensionally moves and scans the position to which the ultrasonic vibration is applied by the laser driving device 12 with respect to the object 50.

  The ultrasonic probes 16 and 18 are constituted by piezoelectric elements, and the object 50 is irradiated with pulsed laser light by the laser driving device 12 and the galvano scanner 14, whereby ultrasonic vibration generated at the scanning point propagates through the object 50. The ultrasonic vibration receiving means has a function of receiving an ultrasonic vibration signal as a detection signal. As the reception band of the piezoelectric element, for example, one having a center frequency of 1 MHz can be used.

  The ultrasonic probes 16 and 18 are arranged on the surface of the object 50 in a predetermined positional relationship. Specifically, the ultrasound probes 16 and 18 are in contact with the object 50 outside the scanning region 60 of the pulse laser beam on the surface of the object 50 and are disposed as fixed positions during the inspection. That is, the ultrasonic probes 16 and 18 do not detect ultrasonic vibration at a fixed position and scan and receive like pulse laser light.

  In FIG. 1, two ultrasonic probes 16 and 18 are arranged outside the scanning region 60, but the number of arrangement is preferably larger than two. In the following, the experimental results for an example in which four ultrasonic probes are arranged will be described. However, if only two ultrasonic probes that can be used are prepared, the inspection may be performed in two steps. Good. For example, as shown in FIG. 1, first, the ultrasonic probes 16 and 18 are arranged and fixed on the left and right sides of the scanning region 60, and an ultrasonic vibration detection signal by a pulse laser beam is used as the two ultrasonic probes 16. , 18. When the necessary detection signal data has been acquired, the two ultrasonic probes 16 and 18 are disposed on the upper and lower sides of the scanning region 60, for example, and the ultrasonic vibration detection signal by the pulse laser beam is used as the two ultrasonic signals. Acquired by the acoustic probes 16 and 18.

  In this manner, the ultrasonic vibration detection signals can be acquired at the four positions outside the scanning region 60 using the two ultrasonic probes 16 and 18. Similarly, even when only one ultrasonic probe can be prepared, the position to which ultrasonic vibration is applied is two-dimensionally moved and scanned with respect to the object by performing inspection in multiple times, and the object is determined in advance. The ultrasonic vibration signals propagating through the object can be received as detection signals at a plurality of reception positions in the predetermined positional relationship. In that sense, in the case of simultaneous reception, a plurality of reception means is literally arranged on the object 50, but in the case of performing a plurality of examinations, ultrasonic vibrations are received at a plurality of reception positions. It will include obtaining a detection signal.

  The amplifiers 20 and 22 are amplifiers that amplify analog detection signals from the ultrasonic probes 16 and 18. The AD boards 24 and 26 are circuits that convert analog signals amplified to an appropriate size by the amplifiers 20 and 22 into digital signals. The amplifier and the AD board are preferably provided independently for each ultrasonic probe that detects a detection signal. In the example of FIG. 1, since two ultrasonic probes 16 and 18 are provided at four reception positions, the amplifiers 20 and 22 and AD corresponding to the ultrasonic probes 16 and 18 are provided. Boards 24 and 26 are provided.

  In addition to having the function of scanning the galvano scanner 14 as described above, the control device 30 processes the output data of the AD boards 24 and 26, and the result is displayed on the display device 36 as a two-dimensional image 40. It has a function to display.

  As processing of the output data of the AD boards 24 and 26, the control device 30 performs two-dimensional analysis of the ultrasonic vibration distribution in the object for each receiving means based on the detection signal received by each receiving means corresponding to the timing of moving scanning. For individual imaging processing unit 32 for imaging on a plane and a plurality of two-dimensional plane imaging data obtained for each receiving means, enhancement is performed by processing a plurality of image data at the same position as enhancement processing data at that position. It is configured to include an enhancement imaging processing unit 34 that performs processing, images enhancement processing data at each position on a two-dimensional surface, and outputs the image as an inspection image of the object.

  Such a function can be realized by software, specifically, by executing corresponding ultrasonic inspection software. If necessary, some of these functions can be realized by hardware.

  Next, the contents of the object 50 to be inspected will be described. The object 50 is obtained by providing an appropriate simulated damage to a flat metal plate. Specifically, a straight groove 52 having a depth of 1.0 mm and a planar shape are formed on the back surface of an aluminum flat plate having a thickness of 3.0 mm. Is provided with a T-shaped groove 54, which is subjected to ultrasonic inspection to form simulated damage to be detected. Since a top view of the object 50 is shown in FIG. 2, the straight groove 52 and the T-shaped groove 54 are not visible, and are indicated by broken lines. The 60 mm × 100 mm scanning region 60 including the linear groove 52 and the 100 mm × 100 mm scanning region 61 including the T-shaped groove 54 are ranges in which the pulse laser beam is scanned by the galvano scanner 14.

  The reception positions 70, 72, 74, 76, 80, 83, 84, and 86 shown in FIG. 2 are positions where the ultrasonic probes 16 and 18 are installed. These receiving positions 70, 72, 74, 76, 80, 83, 84, 86 are set on the upper surface of the object 50, that is, the surface opposite to the surface on which simulated damage is provided. The reception positions 70, 72, 74, and 76 are positions where the ultrasonic probes 16 and 18 are installed to inspect the linear groove 52, and the reception positions 80, 82, 84, and 86 are T-shaped. This is the position where the ultrasonic probes 16 and 18 are installed to inspect the groove 54.

  FIG. 3 is a flowchart showing a procedure for inspecting the simulated damage of the object 50 using ultrasonic waves in the configuration of FIG. The object 50 has two simulated damages of the linear groove 52 and the T-shaped groove 54. Hereinafter, a case where the simulated damage of the linear groove 52 is inspected will be described as an example. In the example of FIG. 1, since two ultrasonic probes 16 and 18 are used, the inspection is divided into two times. First, the ultrasonic probes 16 and 18 are arranged at the receiving positions 70 and 74, and there. When the measurement is completed, the ultrasonic probes 16 and 18 are arranged at the receiving positions 72 and 76 and the remaining measurement is performed. In addition, when inspecting the simulated damage of the T-shaped groove 54, the inspection can be performed in the same procedure except that the reception position is different.

  First, the angle control of the galvano scanner 14 for laser scanning is calculated. Specifically, the coordinates of all laser scanning points in the scanning region 60 are determined, and the mirror angle of the galvano scanner 14 is calculated for each scanning point (S10). The scanning points are a plurality of points irradiated with pulsed laser light on the scanning movement locus 62. When the pulse laser beam is output at a predetermined time interval, the scanning point is different for each pulse laser beam. That is, when one pulse laser beam is output at a certain scanning point and irradiated on the surface of the object 50, the mirror angle of the galvano scanner 14 is changed next, and the next pulse laser beam is predetermined from the irradiation point. Irradiation is performed at the next irradiation point moved by a distance of. For example, assuming that the pulse interval of the pulse laser beam is 50 ms, the mirror angle of the galvano scanner 14 is changed during the pulse interval of 50 ms. And although an irradiation point moves on the surface of the object 50, it can be set as 1 mm as the movement amount. In this case, adjacent scanning points are separated from each other by 1 mm, and the pulse laser beam scans and moves on the surface of the object 50 at intervals of 1 mm every 50 ms.

  As described above, the mirror angle is calculated so that the irradiation point on the surface of the object 50, that is, the scanning point, has a predetermined distance on the predetermined movement locus 62. Specifically, the (x, y) coordinates of all the points to be moved and scanned on the movement locus 62 set two-dimensionally on the surface of the object 50 are obtained, and the corresponding mirror angle of the galvano scanner 14 is determined. Calculate each.

  Here, the mirror angle is an inclination angle with respect to the reference direction of the reflecting mirror constituting the galvano scanner 14. Since the galvano scanner 14 is composed of a plurality of reflecting mirrors, the mirror angle is calculated for each reflecting mirror. The calculation of the mirror angle is to calculate the mirror angle necessary for making the laser beam incident at a predetermined position on the plane. When operating, in order to move the pulse laser beam to a large number of points, it is preferable to obtain the mirror angles for all the points in advance by calculation. By doing so, the scanning time can be shortened.

  Since the calculation of the mirror angle for each scanning point is a typical scan when the flat plate is inspected, it is prepared by mapping in advance in association with the positional relationship between the galvano scanner 14 and the scanning region 60 of the object 50. It is possible. When the surface of the object to be inspected has a curved surface or complicated unevenness like an object 170 to be described later, a movement locus 62 is set in advance for the scanning region 60 on the surface of the object, and an appropriate movement locus 62 is set on the movement locus 62. The (x, y, z) coordinates of each point serving as the interval are obtained in advance, and the respective mirror angles with respect to the (x, y, z) coordinates are calculated.

  When mirror angles for all scanning points are prepared, laser scanning starts (S12). Specifically, the movement is first performed to the laser scanning initial position (S14). The laser scanning initial position is a start position of the movement locus 62 set in the scanning area 60 of the object 50. The galvano scanner 14 is driven so as to have a mirror angle corresponding to the start position, and in this state, the laser driving device 12 operates to output one pulse laser beam. The optical path of the output pulsed laser light is changed by the galvano scanner 14 so that the laser scanning initial position of the object 50 is irradiated at a predetermined incident angle.

  By irradiation with the pulse laser beam, ultrasonic vibration that is thermally excited in the object 50 is generated, and the ultrasonic vibration propagates from the scanning point toward the periphery of the object 50. The propagating ultrasonic vibration is detected by the ultrasonic probes 16 and 18 fixed in contact with a predetermined position outside the scanning region 60 and transmitted to the control device 30 as a detection signal of the ultrasonic vibration.

  Since the trigger signal is transmitted from the laser driving device 12 to the control device 30 when the pulse laser beam is output, the control device 30 acquires this trigger signal and detects the ultrasonic probes 16 and 18. With respect to the detection signal, the detection signal of the ultrasonic vibration by the pulse laser beam is specified, and the current received waveform corresponding to the trigger signal is recorded (S16).

  FIG. 4 shows an example of an ultrasonic vibration waveform detected by the ultrasonic probe 16. The horizontal axis in FIG. 4 is time, and the vertical axis is the amplitude of ultrasonic vibration. The origin of the horizontal axis, that is, t = 0 is the time when the trigger signal is acquired. The vertical axis is actually the voltage value at the output of the AD board 24.

  As shown in FIG. 4, the peak 90 of the amplitude appears about 50 ms after the trigger signal is acquired, that is, the pulse laser beam is irradiated. The waveform including this peak 90 is the waveform of the pulse laser beam. It is a waveform of ultrasonic vibration that has propagated from the irradiation point to the reception position of the ultrasonic probe 16 via the linear groove 52 that is simulated damage, and a peak 90 that is the maximum amplitude is the linear groove 52. The ultrasonic vibration from is shown. In addition to this peak 90, a slightly smaller peak appears at about 60 ms and about 80 ms, and a larger peak 92 appears at about 90 ms. These are due to the multiple reflected waves in the linear groove 52, which are simulated damages, and the reflected waves from the side surface of the object 50.

  As described above, noise peaks due to various reflected waves appear in the detection signal of the ultrasonic probe 16 in addition to the ultrasonic vibration peak 90 caused by the linear groove 52 which is simulated damage. As can be seen from FIG. 4, the noise peak due to the reflected wave appears at a time later than the peak 90 of the ultrasonic vibration caused by the linear groove 52 which is simulated damage. Therefore, by providing an appropriate windgate WG, it is possible to appropriately separate the ultrasonic vibration peak 90 caused by the linear groove 52 and the noise peak caused by the reflected wave.

  The windgate WG receives the shortest propagation time corresponding to the shortest propagation distance that is the position of the scanning region 60 closest to the reception position where the ultrasonic probe 16 is set, and the reception where the ultrasonic probe 16 is set. It can be set between the longest propagation time corresponding to the longest propagation distance corresponding to the farthest propagation distance which is the position of the scanning region 60 farthest from the position. In the example of FIG. 4, the wind gate WG is set with the shortest propagation time of 25 ms and the longest propagation time of 80 ms. By providing the wind gate WG in this way, it is possible to extract a direct reaching wave from the scanning position to the ultrasonic probe 16, and to include as few reflected waves as possible from the side whose arrival time is significantly different from the direct reaching wave. Can be.

Returning to FIG. 3 again, the maximum amplitude value in the windgate WG is acquired in the received waveform (S18). In the example of FIG. 4, the peak 92 is the maximum amplitude value on the screen, but is outside the windgate WG, so the amplitude value of the peak 90 is acquired as the maximum amplitude value in the windgate WG. The acquired amplitude maximum value is stored in an appropriate memory in association with the laser scanning position. For example the maximum amplitude as A _0, when the ultrasonic vibration including the amplitude maximum value A ₀ is the position on the object 50 which is excited (x _0, y _0), and _{A 0 (x 0, y 0} ) Are stored in association with each other.

  As described above, the maximum amplitude value in the wind gate WG in the ultrasonic probe 16 is acquired for each irradiation of the pulse laser beam. In the above example, since two ultrasonic probes are used, each window in each of the ultrasonic probes 16 and 18 installed at two locations for each irradiation of the pulse laser beam. The maximum amplitude value in the gate WG is acquired.

  When the maximum amplitude value in the wind gate WG is stored in association with the scanning position in each of the ultrasonic probes 16 and 18 as described above, it is next determined whether or not the laser scanning position is the last point (S22). ). In this case, since it is the laser scanning initial position, the result of the determination is negative, and the laser scanning position is moved to the next point (S24). That is, the mirror angle of the galvano scanner 14 is changed so that the next point of the initial position in the movement locus 62 set in the scanning region 60 is irradiated with the pulsed laser light, and then the next pulsed laser light is laser driven. Output from the device 12. In the above example, the position of the next point is 1 mm away from the initial position on the movement locus 62.

When the laser scanning position is moved and the pulsed laser light is irradiated to the moved position, steps S16 and subsequent steps are executed, and the maximum amplitude value at the next point is acquired. If the acquired maximum amplitude value is A ₁ and the corresponding scanning position is (x ₁ , y ₁ ), A ₁ and (x ₁ , y ₁ ) are stored in association with each other. In S22 again, it is determined whether or not the laser scanning position is the last point.

  If this is repeated and the maximum amplitude at the last point of the movement locus 62 set in the scanning region 60 is stored in association with the position of the last point, the determination result in S22 is affirmed and the process proceeds to S26. Here, it is determined whether or not another reception point is measured. As described with reference to FIG. 2, four reception positions 70, 72, 74, and 76 are provided for the scanning region 60. Therefore, there are four reception points corresponding to these four reception positions 70, 72, 74, and 76. In the above example, the ultrasound probes 16 and 18 are arranged at the reception positions 70 and 74, respectively. . Therefore, the measurement at the reception positions 72 and 76 is not yet performed, and the determination result at S26 is negative.

  In that case, the reception point is set as the next point (S28). Specifically, the ultrasound probes 16 and 18 are newly arranged at the reception positions 72 and 76. And the process after S14 is performed including S24.

  As a result, when the maximum amplitude value and the scanning position are stored in association with each other at all scanning positions even at the next reception point, the determination in S26 is performed again. If the determination result in S26 is affirmative, it is determined that all measurements have been completed (S30).

  When all the measurements are completed, data processing is performed on the maximum amplitude value data associated with the scan position, which is stored data. First, an individual imaging process (S32) is performed. This step is executed by the function of the individual imaging processing unit 32 of the control device 30. The individual imaging processing is based on the detection signals received by the ultrasonic probes 16 and 18 as the receiving means corresponding to the timing of the moving scanning of the pulse laser beam on the object 50, and the ultrasonic vibration of the object 50. This is a process of imaging the distribution on a two-dimensional surface for each receiving means.

  To image the ultrasonic vibration distribution in the object 50 on a two-dimensional surface for each receiving means, the degree of ultrasonic vibration at each point constituting the two-dimensional surface is displayed by a difference in density, a difference in color, etc. It is to be able to display a tomographic image related to vibration. Such display by imaging corresponds to what is called a so-called C-scope method in the ultrasonic flaw detection technology. In the above example, the maximum amplitude value at the point of the (x, y) coordinate of each scanning position in the movement locus 62 of the scanning region 60 is displayed by a difference in density, a difference in color, or the like. The density difference can also be indicated by an isodensity line.

  FIG. 5 is a schematic diagram schematically showing the distribution of the maximum amplitude value associated with the scanning position acquired at each of the four reception positions 70, 72, 74, 76 in the scanning region 60 with isodensity lines. is there. The density difference is indicated by the hatched density. The denser the hatched density, the higher the density, and the higher the density, the greater the maximum amplitude value.

  For example, as described with reference to FIG. 3, the individual imaging data 100 at the reception position 70 has the maximum amplitude value associated with the scanning position acquired by the ultrasonic probe 16 disposed at the reception position 70, etc. It is imaged on a two-dimensional surface with density lines. In this individual imaging data 100, there is a high density region corresponding to the linear groove 52 at the approximate center of the scanning region, and the nearest neighbor of the ultrasound probe 16 at the right end of the scanning region. It is shown that there are medium concentration regions corresponding to the regions, and some other low concentration regions.

  Further, in the individual imaging data 104 at the reception position 74, there is a high density area corresponding to the linear groove 52 at the approximate center of the scanning area, and an ultrasonic probe is provided at the left end of the scanning area. It is shown that there is an intermediate concentration region corresponding to the nearest region of the child 18, and there are several other low concentration regions.

  In addition, the individual imaging data 102 at the reception position 72 indicates the distribution state of the maximum amplitude value obtained by placing the ultrasonic probe 16 at the reception position 72 in the second measurement as described above. It is. Here, there is a high-density region at the center of the scanning region so as to correspond to the linear groove 52, and it corresponds to the nearest region of the ultrasound probe 16 at the lower end of the scanning region. It is shown that there is a medium concentration region and some other low concentration regions.

  Similarly, the individual imaging data 106 at the reception position 76 shows the distribution state of the maximum amplitude value obtained by placing the ultrasonic probe 18 at the reception position 76 in the second measurement as described above. Is. Here, there is a high concentration region at the center of the scanning region so as to correspond to the linear groove 52, and at the upper end of the scanning region so as to correspond to the nearest region of the ultrasonic probe 18. It is shown that there are medium density regions and some other low density regions.

  6 and 7 are detailed schematic diagrams of the individual imaging data 100 and 102. FIG. As described above, four receiving positions 70, 72, 74, and 76 are provided for the scanning region 60, and there are four individual imaging data. Of these, two of them are shown as representatives.

  In the individual imaging data 100 of FIG. 6, there is a high density region 112 at the center of the scanning region so as to correspond to the linear groove 52, and the ultrasound probe 16 is located at the right end of the scanning region. There is a medium concentration region 114 corresponding to the nearest region, and there are some other low concentration regions.

  The central high concentration region 112 corresponds to the position where the linear groove 52 is present. The straight groove 52 has a depth of 1.0 mm in the above example, and is a portion where the plate thickness is thinner in the object 50 than the plate thickness of 3.0 mm in other portions.

  Ultrasound excited by incidence of pulsed laser light on the thin plate-like object 50 tends to be Lamb waves. Since it is known that the amplitude of Lamb waves propagating through a flat plate increases when the plate thickness is thin, in the case of a 3 mm aluminum plate as described above, the Lamb waves are generated at the linear groove 52 that is simulated damage. It is considered that the amplitude becomes larger than other portions. Therefore, the detection signal of the ultrasonic probe 16 when the straight groove 52 is the scanning point is the detection signal of the ultrasonic probe 16 when the other plate thickness is 3.0 mm. The maximum amplitude value becomes larger than the detection signal. For this reason, in the imaging data of the two-dimensional surface, the portion corresponding to the linear groove 52 is a high density region.

  The middle density region 114 on the right end of the scanning region 60 corresponds to the nearest region of the ultrasound probe 16. In the middle density region 114, the shading is repeated in a wave shape, and it can be considered that a kind of artifact, that is, a virtual image is generated. Further, in the scanning region 60, the portion 116 farthest from the ultrasonic probe 16 across the high concentration region 112 has a low concentration, and the image is partially disturbed. This is presumably because the propagation of the ultrasonic vibration becomes longer, the attenuation of the ultrasonic vibration is large, and therefore the maximum amplitude value is small and the variation becomes large.

  Also in the individual imaging data 102 of FIG. 7, a high density region 122 is seen at the center of the scanning region so as to correspond to the linear groove 52. Further, at the right end of the scanning region, there is a wave-like medium concentration region 124 that is regarded as an artifact so as to correspond to the nearest region of the ultrasonic probe 16. Then, in the scanning region 60, image disturbance is seen at a portion 126 farthest from the ultrasonic probe 16 across the high density region 122.

  As can be seen by comparing FIG. 6 and FIG. 7, the individual imaging data is significantly different from the scanning region 60 only in the reception position. In particular, artifacts in the intermediate density regions 114 and 124, disturbances in the images 116 and 126 farthest from the ultrasound probe 16, and the like in the high density regions 112 and 122 corresponding to the linear grooves 52 are generated. There are considerable differences in the manner of occurrence.

  Returning to FIG. 3 again, when a plurality of pieces of individual imaged data are obtained, an emphasis calculation is performed on these data (S34), and an emphasis imaging process is performed to obtain a two-dimensional image (S36). The two-dimensional surface image 40 subjected to the enhanced image processing is output as an object inspection image and displayed on the display device 36. This completes the ultrasonic inspection. These steps are executed by the function of the enhanced image processing unit 34 of the control device 30.

  As described with reference to FIGS. 6 and 7, these processes are performed in order to solve the fact that the individual imaging data are considerably different from each other only in the reception position with respect to the scanning region 60. is there.

  As described with reference to FIGS. 6 and 7, the generation positions and generation modes of the high density regions 112 and 122 corresponding to the linear grooves 52 have little difference between the individual image data. On the other hand, artifacts, image disturbances, and the like are largely different between individual image data. The reason for this is that the linear groove 52, which is a simulated damage, is a common part in the detection signal at any reception position, while the others are those of ultrasonic propagation between the scanning position and the reception position. This is thought to be due to the difference in the situation.

  Therefore, it can be expected that an accurate ultrasonic vibration distribution with less noise can be obtained by superimposing a plurality of individual imaging data obtained at different reception positions. Furthermore, the signal corresponding to the linear groove 52 which is a common portion is set as signal data, the data corresponding to other portions is set as noise data, and the signal data is compared with the noise data to enhance (signal Data size / noise data size) = SNR can be greatly improved. In this way, the enhancement calculation processing is performed on the plurality of two-dimensional plane imaging data obtained for each receiving means, processing a plurality of image data at the same position to improve the SN ratio, and enhancing calculation processing data at that position. It is processing to.

  For example, considering the use of four receivers, the S / N ratio of a detection signal from damage or the like existing in an object can be reduced to one image data by mutually performing a sum operation process on four image data at the same position. In terms of calculation, the signal-to-noise ratio is improved by a factor of four. By performing mutual product operation processing on the four image data at the same position, the SN ratio of the detection signal from damage or the like existing in the object is improved to the fourth power of the SN ratio in the case of calculation based on one image data. To do.

  8 performs sum operation processing as enhancement operation processing on the four individual image data 100, 102, 104, and 106 having different reception positions described with reference to FIG. 5, and the result is imaged on a two-dimensional surface to form an enhancement image. It is a figure which shows a mode that it was set as the data 130. FIG. Specifically, a plurality of pieces of image data at the same position are added to each other with respect to a plurality of two-dimensional plane imaging data obtained for each receiving unit, and a sum calculation process is performed.

  8 performs sum operation processing as enhancement operation processing on the four individual image data 100, 102, 104, and 106 having different reception positions described with reference to FIG. 5, and the result is imaged on a two-dimensional surface to form an enhancement image. It is a figure which shows a mode that it was set as the data 130. FIG. Specifically, a plurality of pieces of image data at the same position are added to each other with respect to a plurality of two-dimensional plane imaging data obtained for each receiving unit, and a sum calculation process is performed. Since the image data at the same position corresponds to the maximum amplitude value at that position, it is substantially equivalent to adding the maximum amplitude values at the same position of the scanning region 60 to each other.

  In FIG. 8, an emphasized high density region 132 appears in which the high density region data of each individual imaged data is added at the center to obtain a higher density. In other regions, artifacts and image disturbances that appear at different locations in the four individual imaging data appear in the original locations without being added to each other. Therefore, as a result, compared with each of the individual imaged data 100, 102, 104, and 106, the emphasized high-density region 132 is conspicuous from the periphery in the center, and as a result, the linear groove 52 that is a simulated damage. The area of can be clearly identified.

  FIG. 9 shows a state in which product calculation processing is performed as enhancement processing on four individual imaging data 100, 102, 104, and 106 having different reception positions, and the result is imaged on a two-dimensional plane to form enhanced imaging data 134. FIG. Specifically, a plurality of image data at the same position are integrated with each other with respect to a plurality of two-dimensional plane imaging data obtained for each receiving means, and product operation processing is performed. The image data at the same position corresponds to the maximum amplitude value at that position. The maximum amplitude value is, for example, a voltage value, but can be multiplied as a unitless value excluding the unit in the product operation. Alternatively, the maximum amplitude value may be normalized to obtain a dimensionless number and multiplied by each other.

  In FIG. 9, an emphasized high density region 136 is obtained in which the high density area data of each individual imaged data is accumulated at the center portion to further increase the density. In other regions, artifacts and image disturbances appearing at different locations in the four individual imaging data are not accumulated, but rather multiplied by the background value to appear as a small value at the original location. Therefore, as a result, compared with FIG. 8, the emphasized high-concentration region 136 appears more conspicuously from the periphery, and this makes it possible to clearly identify the region of the linear groove 52 that is simulated damage.

  Note that reception performance such as reception sensitivity may differ between the ultrasonic probes 16 and 18, and the ultrasonic probes 16 and 18 are attached at the reception positions 70, 72, 74 and 76. The state may be different. In order to suppress the influence, it is preferable to weight each of the plurality of image data at the same position according to a predetermined standard. As the predetermined reference, standard reception sensitivity measured a plurality of times using a standard sample can be used.

  In the above, the inspection in the case where the linear groove 52 in FIG. 2 is simulated damage has been described. However, in the case where the T-shaped groove 54 in FIG. Emphasized imaging processing can be performed to output enhanced imaging data.

  FIG. 10 is a detailed schematic diagram of the individual imaging data 140 obtained when the ultrasound probe 16 is arranged at the reception position 80 in FIG. Here, as in FIG. 6, a high-concentration region 142 is seen at the center of the scanning region so as to correspond to the T-shaped groove 54. Further, at the right end of the scanning region, there is a wave-like medium concentration region 144 that is regarded as an artifact so as to correspond to the nearest region of the ultrasonic probe 16. Then, in the scanning region 60, image disturbance is seen at a place 146 farthest from the ultrasound probe 16 across the high density region 142.

  FIG. 11 is a detailed schematic diagram of the individual imaging data 150 obtained when the ultrasound probe 16 is disposed at the reception position 82 in FIG. Here, as in FIG. 7, a high-concentration region 152 is seen at the center of the scanning region so as to correspond to the T-shaped groove 54. In addition, a wave-like medium density region 154 that appears as an artifact corresponds to the nearest region of the ultrasound probe 16 at the lower end of the scanning region. Then, in the scanning region 60, image disturbance is seen at a place 156 farthest from the ultrasonic probe 16 across the high density region 152.

  In the inspection of the T-shaped groove 54, the ultrasonic probes 16 and 18 are arranged at the four reception positions 80, 82, 84, and 86, and four pieces of individual imaging data are obtained. In the enhancement calculation process or the like, a sum calculation process or a product calculation process is performed on these four individual image data.

  FIG. 12 is a diagram illustrating a state in which a sum operation process is performed as an emphasis operation process on four individual image data having different reception positions, and the result is imaged on a two-dimensional plane to form an emphasis image data 160. In FIG. 12, as in FIG. 8, an emphasized high density region 162 is obtained in which the high density region data of each individual imaging data is added at the central portion to obtain a higher density. In other regions, artifacts and image disturbances that appear at different locations in the four individual imaging data appear in the original locations without being added to each other. Therefore, as a result, compared with each of the individual imaging data 140 and 150 shown in FIGS. 10 and 11, the emphasized high density region 162 appears prominently from the periphery, and this causes T damage that is simulated damage. The region of the letter-shaped groove 54 can be clearly identified.

  FIG. 13 is a diagram illustrating a state where product calculation processing is performed as enhancement calculation processing on four individual imaging data having different reception positions, and the result is imaged on a two-dimensional plane to form enhancement imaging data 164. In FIG. 13, as in FIG. 9, an emphasized high density region 166 appears in which the high density region data of the individual imaged data is accumulated at the center portion to further increase the density. In other regions, artifacts and image disturbances appearing at different locations in the four individual imaging data are not accumulated, but rather multiplied by the background value to appear as a small value at the original location. Therefore, as a result, the emphasized high-concentration region 166 appears more conspicuously from the periphery as compared with FIG. 12, and this makes it possible to clearly identify the region of the T-shaped groove 54 that is simulated damage.

  In the above description, thin aluminum plate provided with simulated damage has been described as the object 50. However, an object having a curved surface is also subjected to individual imaging processing and enhanced imaging processing according to the procedure of FIG. can do.

  FIG. 14 is a diagram illustrating a state of an object 170 having a curved surface. This object 170 is obtained by cutting a cylindrical aluminum pipe having a thickness of 3.0 mm in half along the central axis. The object 170 is provided with a straight groove 176 having a depth of 1.0 mm and a T-shaped groove 178 having a depth of 1.0 mm as simulated damages on the concave inner surface. FIG. 14 shows the concave surface on the upper surface side so that the straight groove 176 and the T-shaped groove 178 which are simulated damages can be seen. However, ultrasonic inspection is performed using a pulse laser on the convex surface 174 side. This is done by irradiating light.

  FIG. 15 is a top view of the object 170 with the convex surface 174 irradiated with pulsed laser light as the top surface. Since the object 170 has a curved surface, both the scanning region 180 for the linear groove 176 and the scanning region 182 for the T-shaped groove 178 have a drum shape in the top view, but the object 170 is placed. The scanning area for the plane is rectangular. However, the scanning area on the curved surface can be made rectangular by calculating the mirror angle properly in advance. Four reception positions 190, 192, 194, and 196 are provided outside the scanning area 180 of the linear groove 176, and four reception positions 200, 202, 204, and 196 are provided outside the scanning area 182 of the T-shaped groove 178. 206 is provided.

  Even if the object 170 has a curved surface, the procedure of ultrasonic inspection in FIG. 3 is basically the same as that of the flat object 50. The difference is that the calculation of the mirror angle in S10 is more complicated than in the case of a flat plate. That is, the tilt angle of the reflecting surface of the mirror is calculated so that the incident angle of the pulsed laser light applied to the object 170 becomes a predetermined angle in accordance with the curved surface shape of the object 170. Specifically, a movement locus is set in advance for each of the scanning regions 180 and 182 on the surface of the object 170, and (x, y, z) coordinates of each point having an appropriate interval are obtained in advance on this movement locus, Each mirror angle with respect to each (x, y, z) coordinate is calculated.

  After the mirror angle is thus determined corresponding to the curved surface of the object 170, the maximum amplitude value associated with the scanning position is obtained in the same procedure as that for the flat object 50, and based on that, the individual amplitude values are obtained. Imaging data is obtained. Then, based on the obtained four individual imaged data, enhancement operation processing is performed using sum operation or product operation, and one emphasized imaged data is obtained.

  FIG. 16 shows a summation process performed as an emphasis calculation process on four individual imaged data with different reception positions for the linear groove 176 as simulated damage, and the result is imaged on a two-dimensional surface and the emphasis imaged data 210. FIG. In FIG. 16, as in FIGS. 8 and 12, an emphasized high density region 212 appears in which the high density region data of each individual imaged data is added at the central portion to further increase the density. In other regions, artifacts and image disturbances that appear at different locations in the four individual imaging data appear in the original locations without being added to each other. Therefore, as described in connection with FIGS. 8 and 12, as a result, compared to each of the individual imaged data, the emphasized high density region 212 appears prominently from the periphery, thereby causing simulated damage. This makes it possible to clearly identify the region of the linear groove 176.

  FIG. 17 shows a product calculation process as an emphasis calculation process on four individual imaging data having different reception positions for the linear groove 176 as a simulated damage, and the result is imaged on a two-dimensional surface and the emphasis imaging data 214. FIG. In FIG. 17, as in FIGS. 9 and 13, an emphasized high density region 216 is obtained in which the high density region data of each individual imaged data is accumulated in the central portion to obtain a higher density. In other regions, artifacts and image disturbances appearing at different locations in the four individual imaging data are not accumulated, but rather multiplied by the background value to appear as a small value at the original location. Therefore, as a result, as described with reference to FIGS. 9 and 13, the highlighted high-concentration region 216 appears more prominently from the surroundings, and thereby the region of the linear groove 176 that is simulated damage can be clearly identified. It becomes like this.

  FIG. 18 shows a T-shaped groove 178 as simulated damage, which is subjected to a sum operation process as an emphasis operation process on four individual imaged data having different reception positions, and the result is imaged on a two-dimensional surface to generate an enhanced imaged data. FIG. Again, the emphasized high-concentration region 220 appears prominently from the periphery in the center, and this makes it possible to clearly identify the region of the T-shaped groove 178 that is simulated damage.

  FIG. 19 is a diagram illustrating a state in which the enhanced imaging data 222 is obtained when product calculation processing is performed instead of sum calculation processing. Again, the highlighted high-concentration region 224 appears more prominently from the periphery in the center, and this makes it possible to clearly identify the region of the T-shaped groove 178 that is simulated damage.

  As shown in FIGS. 16 to 19, even when the object 170 has a curved surface, the procedure of FIG. 3 is executed in the ultrasonic inspection system 10 having the configuration of FIG. , Enhanced image data can be obtained. As a result, even when the object 170 has a curved surface, it is possible to improve the SN ratio of the detection signal from damage or the like existing in the object 170.

  The ultrasonic inspection system according to the present invention can be used for ultrasonic inspection for inspecting damage or the like contained in an object regardless of whether the shape of the object is a flat plate or a curved surface.

  DESCRIPTION OF SYMBOLS 10 Ultrasonic inspection system, 12 Laser drive apparatus, 14 Galvano scanner, 16, 18 Ultrasonic probe, 20, 22 Amplifier, 24, 26 AD board, 30 Control apparatus, 32 Individual imaging process part, 34 Weighted imaging Processing unit, 36 display device, 40 images, 50, 170 object, 52, 176 linear groove, 54, 178 T-shaped groove, 60, 61, 180, 182 scanning region, 62 movement locus, 70, 72, 74, 76, 80, 83, 84, 86, 190, 192, 194, 196, 200, 202, 204, 206 Reception position, 90, 92 peak, 100, 102, 104, 106, 140, 150 Individual imaging data, 112 122, 142, 152 High concentration region, 114, 124, 144, 154 Medium concentration region, 116, 126, 146, 15 (Farthest) portions, 130,134,160,164,210,214,218,222 emphasized image data, 132,136,162,166,212,216,220,224 emphasized high concentration region, 174 convex.

Claims (6)

Scanning means for two-dimensionally moving and scanning the position to which the ultrasonic vibration is applied to the object;
A plurality of receiving means that are arranged in a predetermined positional relationship with the object and receive an ultrasonic vibration signal propagating through the object as a detection signal;
Individual imaging means for imaging the ultrasonic vibration distribution in the object on a two-dimensional surface for each receiving means based on the detection signal received by each receiving means corresponding to the timing of moving scanning;
With respect to a plurality of two-dimensional plane imaging data obtained for each receiving means, a plurality of image data at the same position is processed to be enhanced processing data at that position, and the enhancement processing data at each position is two-dimensionally processed. An enhanced imaging means for imaging on a surface and outputting this as an image for inspection of an object;
An ultrasonic inspection system comprising: The ultrasonic inspection system according to claim 1,
Emphasized imaging means
An ultrasonic inspection system characterized in that a plurality of image data at the same position are subjected to mutual summation processing or product computation processing to obtain enhancement processing data at that position. The ultrasonic inspection system according to claim 2,
Emphasized imaging means
An ultrasonic inspection system comprising weighting means for weighting each of a plurality of image data at the same position according to a predetermined criterion. The ultrasonic inspection system according to claim 1,
An ultrasonic inspection system, wherein the scanning means moves and scans a point to which the ultrasonic vibration is applied so that a Lamb wave is propagated as ultrasonic vibration to the object. The ultrasonic inspection system according to claim 1,
The ultrasonic inspection system, wherein the scanning unit includes a laser irradiation unit that irradiates an object with laser and excites ultrasonic vibration on the object. The ultrasonic inspection system according to claim 5,
The scanning means
A mirror that receives and reflects the laser from the laser means to irradiate the object;
Means for inclining the mirror in accordance with the shape of the object, and inclining means for inclining the reflecting surface of the mirror so that the incident angle of the laser applied to the object is a predetermined angle;
An ultrasonic inspection system comprising:

Images