Defect inspection device and defect inspection method

Abstract

The defect inspection device (100) comprises: an excitation unit (1); a laser illumination (2); an interference unit (3) for causing laser light to interfere; an imaging unit (35) for capturing reflected light that has interfered; and a control unit (4) for measuring the spatial distribution of a physical quantity that is generated by the propagation of vibration of an inspection object and changes periodically based on the reflected light that has interfered captured by the imaging unit, and extracting a discontinuous portion of the vibration based on the spatial distribution of the physical quantity. The control unit is configured to perform control such that the extracted discontinuous portion of the vibration is displayed in an emphasized manner superimposed on a still image of the inspection object captured by the imaging unit.

Description

Technical Field

[0001] The present invention relates to a defect inspection device and a defect inspection method. Background Art

[0002] Conventionally, a defect inspection device is known. The defect inspection device is disclosed in, for example, International Publication No. 2017 / 221324.

[0003] The above-mentioned International Publication No. 2017 / 221324 discloses an acoustic wave propagation imaging device (defect inspection device), which comprises: an acoustic wave applying unit that applies acoustic waves (including all elastic waves propagating in gas, liquid, and solid) to the surface of the measured object; a pulsed laser light source that irradiates the measured object with pulsed laser light; a speckle shearing interferometer that causes interference of reflected light of the pulsed laser light from different positions of the measured object to which acoustic wave vibrations (hereinafter referred to as vibrations) are applied by the acoustic wave applying unit; an image sensor that captures the interfered reflected light; and a control processing unit that generates a motion image related to the propagation of vibrations of the measured object based on the interfered reflected light captured by the image sensor. Based on the motion image related to the propagation of vibrations generated by the acoustic wave propagation imaging device, the defects of the measured object are acquired.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2017 / 221324 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] The sound wave propagation imaging device (defect inspection device) of the above-mentioned International Publication No. 2017 / 221324 records that a portion where vibration propagation is discontinuous is detected as a defect. However, since a portion with a discontinuous shape and structure in a non-defective object will also produce discontinuity in vibration propagation, in order to determine whether the discontinuity in vibration propagation is actually a defect, it is necessary to compare the information on vibration propagation with the information on the shape and structure of the object.

[0009] The present invention is made to solve the problems mentioned above, and one object of the present invention is to provide a defect inspection device and a defect inspection method as follows: the position of the discontinuity of vibration propagation in the vibration inspection object can be easily grasped, and the shape and structure of the inspection object can be easily distinguished from defects.

[0010] Solutions for solving problems

[0011] In order to achieve the above-mentioned purpose, the defect inspection device of the first aspect of the present invention is constructed to include: an excitation unit, which excites the inspection object to cause the inspection object to generate acoustic wave vibrations; laser illumination, which irradiates the inspection object with laser; an interference unit, which causes interference of reflected light of the laser from different positions of the inspection object excited by the excitation unit; a camera unit, which captures the interfered reflected light; and a control unit, which measures the spatial distribution of a periodically changing physical quantity generated by the propagation of vibration of the inspection object based on the interfered reflected light captured by the camera unit, and extracts the discontinuous part of the vibration based on the spatial distribution of the physical quantity, wherein the control unit is configured to perform the following control: the extracted discontinuous part of the vibration is displayed in an emphasized manner in an overlapping manner on a still image of the inspection object captured by the camera unit.

[0012] In the defect inspection device of the first aspect of the present invention, a control unit is provided as described above, and the control unit performs the following control: the extracted discontinuous portion of the vibration is displayed in an emphasized manner in an overlapping manner on the still image of the inspection object captured by the camera unit. As a result, the shape and structure of the inspection object can be confirmed based on the still image, while the discontinuous portion of the vibration extracted from the spatial distribution of the physical quantity can be confirmed. As a result, the still image of the inspection object can be easily compared with the emphasized display of the discontinuous portion of the vibration, so the position of the discontinuous propagation of the vibration in the inspection object can be easily grasped. In addition, the shape of the inspection object can be confirmed based on the still image of the inspection object. As a result, the position of the discontinuous propagation of the vibration in the inspection object can be easily grasped, and the shape and structure of the inspection object can be easily distinguished from the defect.

[0013] In order to achieve the above-mentioned purpose, in the defect inspection method of the second aspect of the present invention, the inspection object is excited to cause the inspection object to generate acoustic wave vibrations, laser is irradiated to the inspection object to cause interference of reflected light of the laser from different positions of the excited inspection object, the interfered reflected light is photographed, and based on the photographed interfered reflected light, the spatial distribution of a periodically changing physical quantity generated by the propagation of the vibration of the inspection object is measured, and based on the spatial distribution of the physical quantity, the discontinuous part of the vibration is extracted, and the extracted discontinuous part of the vibration is displayed in an emphasized manner in an overlapping manner on a still image of the inspection object photographed.

[0014] In the defect inspection method of the second aspect of the present invention, the extracted discontinuous portion is displayed in an emphasized manner and overlapped on the still image of the inspection object taken as described above. As a result, the shape and structure of the inspection object can be confirmed based on the still image, while the discontinuous portion of the vibration extracted from the spatial distribution of the physical quantity can be confirmed. As a result, the still image of the inspection object can be easily compared with the emphasized display of the discontinuous portion of the vibration, so the position of the discontinuous propagation of the vibration in the inspection object can be easily grasped. In addition, the shape of the inspection object can be confirmed based on the still image of the inspection object. As a result, the following defect inspection method can be provided: the position of the discontinuous propagation of the vibration in the inspection object can be easily grasped, and the shape and structure of the inspection object can be easily distinguished from the defect.

[0015] Effects of the Invention

[0016] As described above, according to the present invention, the position where the propagation of vibration in the inspection object is discontinuous can be easily grasped, and the shape and structure of the inspection object can be easily distinguished from defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a block diagram showing the structure of a defect inspection device according to one embodiment of the present invention.

[0018] Figure 2 This is a diagram for explaining the display of defects by the defect inspection device according to one embodiment of the present invention.

[0019] Figure 3 This is a diagram showing an example of a display of a defect inspection device according to an embodiment of the present invention.

[0020] Figure 4 This is a flowchart for explaining defect display processing performed by a control unit of a defect inspection device according to one embodiment of the present invention.

[0021] Figure 5 This is a block diagram showing the structure of a defect inspection device according to a modified example of one embodiment of the present invention. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0023] (Structure of defect inspection device)

[0024] Reference Figure 1 and Figure 2 The structure of the defect inspection apparatus 100 according to one embodiment of the present invention will be described. The defect inspection apparatus 100 is an apparatus for inspecting defects of the inspection object 7 .

[0025] The defect inspection device 100 of this embodiment includes an oscillator 1, a laser illuminator 2, a speckle shearing interferometer 3, a control unit 4, a signal generator 5, and a display unit 6. The oscillator 1 is an example of an "excitation unit" of the present invention, and the speckle shearing interferometer 3 is an example of an "interference unit" of the present invention.

[0026] The oscillator 1 and the laser illumination 2 are connected to the signal generator 5 via cables.

[0027] The vibrator 1 excites the inspection object 7 to vibrate (acoustic vibration) the inspection object 7. Specifically, the vibrator 1 is arranged in contact with the inspection object 7, converts the AC signal from the signal generator 5 into mechanical vibration, and excites the inspection object 7 to vibrate (acoustic vibration) the inspection object 7.

[0028] The laser illumination 2 irradiates the inspection object 7 with laser light. The laser illumination 2 includes a laser light source and an illumination light lens (not shown). The illumination light lens is used to diffusely irradiate the laser light emitted from the laser light source to the entire measurement area of ​​the surface of the inspection object 7. In addition, the laser illumination 2 irradiates the laser light at a predetermined timing based on the electrical signal from the signal generator 5. That is, the laser illumination 2 irradiates the inspection object 7 with laser light corresponding to the vibration generated by the oscillator 1.

[0029] The speckle shearing interferometer 3 is configured to interfere reflected light of laser light from different positions of the inspection object 7 excited by the transducer 1. The speckle shearing interferometer 3 includes a beam splitter 31, a phase shifter 32, a first reflecting mirror 331, a second reflecting mirror 332, a focusing lens 34, and an image sensor 35. The image sensor 35 is an example of the “imaging unit” of the present invention.

[0030] The beam splitter 31 includes a half-transparent mirror. In addition, the beam splitter 31 is arranged at a position where the laser light reflected from the surface of the inspection object 7 is incident. In addition, the beam splitter 31 reflects the incident laser light toward the phase shifter 32 side, and transmits the incident laser light toward the second reflector 332 side. In addition, the beam splitter 31 reflects the incident laser light after being reflected from the second reflector 332 toward the condenser lens 34 side, and transmits the incident laser light after being reflected from the first reflector 331 toward the condenser lens 34 side.

[0031] The first reflecting mirror 331 is disposed on the optical path of the laser beam reflected by the beam splitter 31 at an angle of 45 degrees with respect to the reflecting surface of the beam splitter 31. The first reflecting mirror 331 reflects the laser beam reflected from the beam splitter 31 and incident thereon toward the beam splitter 31 side.

[0032] The second reflecting mirror 332 is arranged on the optical path of the laser beam transmitted through the beam splitter 31 at a slightly inclined angle from 45 degrees to the reflecting surface of the beam splitter 31. The second reflecting mirror 332 reflects the incident laser beam reflected from the beam splitter 31 toward the beam splitter 31 side.

[0033] The phase shifter 32 is disposed between the beam splitter 31 and the first reflection mirror 331, and changes (shifts) the phase of the transmitted laser light under the control of the control unit 4. Specifically, the phase shifter 32 is configured to change the optical path length of the transmitted laser light.

[0034] The image sensor 35 has a plurality of detection elements and is arranged to receive the laser light ( Figure 1 The straight line in the figure) and the laser light ( Figure 1 The image sensor 35 includes, for example, a CMOS image sensor or a CCD image sensor. The image sensor 35 is configured to capture incident laser light. In addition, the image sensor 35 is configured to capture reflected light that has interfered through the speckle shearing interferometer 3.

[0035] The condenser lens 34 is disposed between the beam splitter 31 and the image sensor 35, and is used to condense the laser light ( Figure 1 The straight line in the figure) and the laser light reflected by the beam splitter 31 ( Figure 1 The dotted line in the figure is used to focus light.

[0036] The laser light ( Figure 1 The straight line in the figure) and the laser light reflected at the position 742 on the surface of the inspection object 7 and the second reflecting mirror 332 ( Figure 1 The positions 741 and 742 are separated by a small distance. Similarly, the reflected light of the laser beam from different positions in each region of the inspection object 7 is guided by the speckle shearing interferometer 3 and incident on the image sensor 35.

[0037] The control unit 4 uses an actuator (not shown) to operate the phase shifter 32 disposed in the speckle shearing interferometer 3 to change the phase of the transmitted laser light. As a result, the phase difference between the laser light reflected at the position 741 and the laser light reflected at the position 742 changes. Each detection element of the image sensor 35 detects the intensity of the interference light after the two laser lights interfere with each other.

[0038] The control unit 4 controls the vibration of the oscillator 1 and the irradiation timing of the laser light of the laser illumination 2 via the signal generator 5, and captures images while changing the phase shift amount. The phase shift amount changes by λ / 4 each time, and a total of 37 images are captured at each phase shift amount (0, λ / 4, λ / 2, 3λ / 4), that is, 32 images captured corresponding to the timing j (j=0 to 7) of laser irradiation and 5 images before and after each phase shift amount (0, λ / 4, λ / 2, 3λ / 4) when the laser light is turned off. In addition, λ is the wavelength of the laser light.

[0039] The control unit 4 processes the detection signals from each detection element in the following process to obtain a moving image representing the state of vibration. The control unit 4 measures the spatial distribution of a physical quantity that changes periodically due to the propagation of the vibration of the inspection object 7 based on the reflected light that has interfered and is captured by the image sensor 35. For example, the control unit 4 generates a moving image related to the propagation of the vibration of the inspection object 7 based on the reflected light that has interfered and is captured by the image sensor 35.

[0040] The control unit 4 calculates the brightness values ​​I of the images (4 images) having the same laser irradiation timing j (j=0 to 7) and having phase shift amounts different by λ / 4. j0 ~I j3 , the optical phase (the phase difference between the two optical paths when the phase offset is zero) Φ is obtained by equation (1) j .

[0041] Φ j = -arctan{(I j3 -I j1 ) / (I j2 -I j0 )}…(1)

[0042] In addition, the control unit 4 calculates the optical phase Φ by the least square method. j The approximation coefficients A, θ, and C in equation (2) are obtained by performing sinusoidal wave approximation.

[0043] Φ j =Acos(θ+jπ / 4)+C=Bexp(jπ / 4)+C…(2)

[0044] Here, B is the complex amplitude, which is expressed as in equation (3).

[0045] B=Aexp(iθ): complex amplitude…(3)

[0046] In addition, the control unit 4 constructs and outputs a moving image (30 to 60 frames) showing the optical phase change at each phase moment ξ (0≤ξ<2π) of the vibration based on the approximate formula obtained by removing the constant term C from formula (3). In addition, in the above process, in order to remove noise, a spatial filter is appropriately applied to the complex amplitude B. In addition, the phase shift amount and the steps of laser irradiation timing (in the above example, λ / 4 and T / 8, respectively, where T is the period of vibration) are not limited to this. In this case, the calculation formula becomes a formula different from the above formulas (1) to (3).

[0047] The control unit 4 applies a spatial filter to detect the discontinuous area of ​​the vibration state from the above-mentioned motion image as the defective part 73 of the inspection object 7. That is, the control unit 4 extracts the discontinuous part of the vibration based on the spatial distribution of the physical quantity. In the case where the shape of the inspection object 7 itself includes concave and convex parts, the discontinuity of the vibration state sometimes occurs at the boundary between the plane part and the concave and convex part. The control unit 4 can also detect the defective part 73 in consideration of the shape information of the inspection object 7 to avoid detecting these as defects.

[0048] Here, in this embodiment, if Figure 2 As shown, the control unit 4 is configured to perform the following control: the extracted discontinuous portion of the vibration is displayed in an emphasized manner in an overlapping manner on the still image of the inspection object 7 captured by the image sensor 35. The control unit 4 is configured to obtain a still image based on a plurality of still images captured by the camera unit. Specifically, the control unit 4 is configured to obtain a still image by averaging a plurality of still images captured in order to generate a moving image related to the propagation of the vibration of the inspection object 7. In this still image, the changed portion 75 in the structure of the inspection object 7 can be confirmed. In addition, although the moving image related to the propagation of the vibration of the inspection object 7 can be used to confirm the vibration, it is difficult to confirm the structure of the inspection object 7 by visual observation. The control unit 4 is configured to perform the following control: the extracted discontinuous portion of the vibration is displayed in an emphasized manner in an overlapping manner on the still image obtained by averaging.

[0049] In addition, the control unit 4 is configured to perform the following control: according to the change of the physical quantity of the extracted discontinuous part of the vibration, the color of the superimposed display on the still image is changed to emphasize the display. Specifically, the control unit 4 is configured to perform the following control: according to the change of each phase moment of the extracted discontinuous part of the vibration, the color of the superimposed display on the still image is changed to emphasize the display. Specifically, the control unit 4 is configured to perform the following control: according to the change of each phase moment of the extracted discontinuous part of the vibration, the color of the superimposed display on the still image is changed to emphasize the display. Figure 3 As in the display example shown in FIG. 1 , the color of the highlighted image is changed and displayed superimposed on the still image. In addition, the frame interval of the actual moving image displayed superimposedly is different from that of the moving image displayed superimposedly. Figure 3 The control unit 4 is configured to control the color tone to be eliminated at a certain time when the color displayed in the still image is changed in accordance with the change in the physical quantity of the discontinuous part of the extracted vibration. Figure 3 In the example of π / 2 and 3π / 2, the color tone of the highlighted part disappears. In this case, the structure of the discontinuous part of the vibration of the inspection object 7 can be easily confirmed by visual observation based on the still image. In addition, the extracted discontinuous part of the vibration changes periodically. As a result, the highlighted part of the vibration is displayed in a flashing manner while changing color relative to the still image. For example, in Figure 3 In the example of 0, π / 4, 7π / 4 and π, 5π / 4, 3π / 4, the highlighted hue is displayed in reverse. Figure 3 The example shows an example in which the phases of discontinuous parts of a plurality of vibrations are displayed in the same manner, but the phases of the changes may differ depending on the part.

[0050] The display unit 6 is used to display a moving image showing the vibration state of the inspection object 7 and an image obtained by superimposing the extracted discontinuous portion of vibration on a still image in an emphasized manner, which is generated by the control unit 4. The display unit 6 includes a liquid crystal display or an organic EL display.

[0051] The inspection object 7 is a coated steel plate obtained by coating a coating film 72 on the surface of a steel plate 71. The defective portion 73 includes cracks, peeling, and the like.

[0052] (Defect display processing)

[0053] Next, refer to Figure 4 , the defect display processing performed by the defect inspection device 100 of this embodiment is described based on the flowchart. In addition, the defect display processing is performed by the control unit 4.

[0054] exist Figure 4 In step 101, vibration is applied to inspection object 7 from vibrator 1. Inspection object 7 is thereby excited to vibrate. In step 102, laser light is irradiated from laser illuminator 2 to a measurement region of inspection object 7.

[0055] In step 103, interference data is acquired while changing the offset of the phase shifter 32. That is, a plurality of images that interfere with each other by changing the phase are captured. Thus, the phase shifter 32 of the speckle shearing interferometer 3 is operated so that the phase of the laser light changes by λ / 4 each time, and the intensity of the interference light of the laser light at each phase is detected (captured) by the image sensor 35.

[0056] In step 104, the application of vibration from vibrator 1 to inspection object 7 is terminated. In step 105, a moving image related to the propagation of vibration of inspection object 7 is generated.

[0057] In step 106, a discontinuous portion of vibration is extracted based on the moving image related to the propagation of vibration of the inspection object 7. In step 107, one still image is acquired based on the plurality of still images.

[0058] In step 108, the extracted discontinuous portion of vibration is displayed superimposed on the still image in an emphasized manner. Thereafter, the defect display process is terminated by input of a termination instruction from the user (operator) or the like.

[0059] (Effects of this embodiment)

[0060] In this embodiment, the following effects can be obtained.

[0061] In the present embodiment, a control unit 4 is provided, and as described above, the control unit 4 performs the following control: the extracted discontinuous portion of the vibration is displayed in an emphasized manner in an overlapping manner on the still image of the inspection object 7 captured by the image sensor 35. As a result, the shape and structure of the inspection object 7 can be confirmed based on the still image, while the discontinuous portion of the vibration extracted from the spatial distribution of the physical quantity can be confirmed. As a result, the still image of the inspection object 7 can be easily compared with the emphasized display of the discontinuous portion of the vibration, so the position of the discontinuous propagation of the vibration in the inspection object 7 can be easily grasped. In addition, the shape of the inspection object 7 can be confirmed based on the still image of the inspection object 7. As a result, the position of the discontinuous propagation of the vibration in the inspection object 7 can be easily grasped, and the shape and structure of the inspection object 7 can be easily distinguished from defects.

[0062] In addition, in the present embodiment, the control unit 4 is configured to perform the following control as described above: the physical quantity that changes periodically in the discontinuous part of the extracted vibration is displayed in the form of a moving image superimposed on the still image. Thus, the change of the physical quantity that changes periodically can be easily confirmed based on the moving image superimposed on the still image.

[0063] In addition, in the present embodiment, the control unit 4 is configured to perform the following control as described above: the color displayed superimposed on the still image is changed according to the change in the physical quantity of the extracted discontinuous portion of vibration to perform emphasized display. Thus, the color of the discontinuous portion of vibration changes according to the change in the physical quantity of the discontinuous portion of vibration, so that the discontinuous portion of vibration can be easily confirmed.

[0064] In addition, in the present embodiment, the control unit 4 is configured as described above to control the color tone to be eliminated at a timing when the color displayed in a superimposed manner on the still image changes according to the change in the physical quantity of the extracted discontinuous portion of vibration. As a result, the color tone of the discontinuous portion of vibration disappears, and the discontinuous portion of vibration in the still image can be confirmed without being displayed in a superimposed manner, so that the discontinuous portion of vibration in the still image can be easily confirmed by visual observation.

[0065] In addition, in the present embodiment, as described above, the control unit 4 is configured to perform control such that the extracted discontinuous portion of the vibration is displayed in an emphasized manner superimposed on a single still image acquired based on a plurality of still images captured by the image sensor 35. Thus, the capturing of an image for generating a moving image related to the propagation of the vibration of the inspection object 7 and the capturing of a still image can be performed simultaneously, and thus, unlike the case where the capturing is performed separately, it is possible to suppress the increase in the capturing time.

[0066] [Modifications]

[0067] In addition, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the patent claims, not by the description of the above embodiments, and the scope of the present invention also includes all changes (modifications) within the meaning and scope equivalent to the patent claims.

[0068] For example, in the above embodiment, a configuration example is shown in which a plurality of still images captured to generate a moving image related to the propagation of vibration of the inspection object are averaged to obtain a still image, and the extracted discontinuous portion of the vibration is displayed in an emphasized manner superimposed on the obtained still image, but the present invention is not limited thereto. In the present invention, if Figure 5 As in the modified example shown in FIG. 1 , an incoherent illumination 21 for irradiating incoherent light to the inspection object 7 may be provided. Furthermore, the control unit 4 may be configured to perform the following control: the extracted discontinuous portion of the vibration is displayed in an emphasized manner in an overlapping manner on a still image captured by the image sensor 35 (camera unit) in a state where light is irradiated from the incoherent illumination 21. Thus, unlike the case where a still image is captured by coherent illumination, it is possible to suppress local darkening or interference fringes in the still image caused by interference of light due to the shape, structure, dirt, dust, etc. of the inspection object 7. In addition, incoherent light is light with inconsistent amplitude and phase, and is light in which no interference is observed.

[0069] Alternatively, the extracted discontinuous portion of vibration may be displayed in an emphasized manner by overlapping one still image among a plurality of still images captured to generate a moving image related to the propagation of vibration of the inspection object. Alternatively, a still image may be captured individually for a plurality of still images captured to generate a moving image related to the propagation of vibration of the inspection object, and the extracted discontinuous portion of vibration may be displayed in an emphasized manner by overlapping one still image captured individually.

[0070] In addition, in the above embodiment, an example of a structure in which the signal generator, the oscillator (excitation unit), and the laser illumination are connected via cables (wired), but the present invention is not limited thereto. In the present invention, the signal generator, the excitation unit, and the laser illumination may also be connected wirelessly.

[0071] In addition, in the above-mentioned embodiment, an example in which a speckle shearing interferometer is used as the interference unit is shown, but the present invention is not limited to this. In the present invention, other optical interferometers may be used as the interference unit.

[0072] In addition, in the above-mentioned embodiment, an example is shown in which the vibrator (excitation unit) is used in a manner of contacting the surface of the inspection object, but the present invention is not limited to this. In the present invention, it is also possible to use the excitation unit in a manner of separating the excitation unit from the surface of the inspection object. For example, a powerful speaker or the like may be used as the excitation unit.

[0073] In the present invention, in order to protect optical components, improve the SN ratio of the device, etc., a window or various optical filters may be arranged on the optical path until the reflected light from the inspection object enters the imaging unit.

[0074] In addition, in the above-mentioned embodiment, for the convenience of explanation, the processing action of the control unit of the present invention is explained using a flow chart of a process-driven type that is processed sequentially according to the processing flow, but the present invention is not limited thereto. In the present invention, the processing action of the control unit can also be performed by an event-driven type of processing that performs processing in units of events. In this case, the processing action can be performed by using a complete event-driven type, or by combining event-driven and process-driven processing to perform the processing action.

[0075] Description of Reference Numerals

[0076] 1: oscillator (excitation part); 2: laser illumination; 3: speckle shearing interferometer (interference part); 4: control part; 7: inspection object; 21: incoherent illumination; 35: image sensor (camera part); 73: defect part; 100: defect inspection device.

Claims

1. A defect inspection device comprising: an exciting unit for exciting the inspection object to cause the inspection object to generate acoustic wave vibration; laser illumination for irradiating laser light to the inspection object; an interference unit that causes reflected light of laser light from different positions of the inspection object excited by the exciting unit to interfere; A camera unit for capturing the reflected light that has interfered; as well as a control unit that measures a spatial distribution of a physical quantity that changes periodically due to propagation of vibration of the inspection object based on the reflected light that interferes and is captured by the imaging unit, and extracts a discontinuous portion of the vibration based on the spatial distribution of the physical quantity, The control unit is configured to perform the following control: the extracted discontinuous portion of the vibration is displayed in an emphasized manner superimposed on the still image of the inspection object captured by the imaging unit; The control unit is configured to perform control to display the periodically changing physical quantity in the extracted discontinuous portion of the vibration in the form of a moving image in a superimposed manner on the still image.

2. The defect inspection device according to claim 1, characterized in that: The control unit is configured to perform control to change the color of the image displayed in a superimposed manner on the still image in accordance with the change in the physical quantity of the extracted discontinuous portion of the vibration to perform emphasized display.

3. The defect inspection device according to claim 2, characterized in that: The control unit is configured to perform control so that there is a timing at which the color tone is eliminated when the color displayed in a superimposed manner on the still image changes according to the change in the physical quantity of the extracted discontinuous portion of the vibration.

4. The defect inspection device according to any one of claims 1 to 3, characterized in that: The control unit is configured to perform control to display the extracted discontinuous portion of the vibration in an emphasized manner superimposed on one still image acquired based on the plurality of still images captured by the imaging unit.

5. The defect inspection device according to any one of claims 1 to 3, characterized in that: further comprising incoherent illumination, wherein the incoherent illumination irradiates the inspection object with incoherent light, The control unit is configured to perform control so as to display the extracted discontinuous portion of the vibration in an emphasized manner superimposed on a still image captured by the imaging unit in a state where light is emitted from the incoherent illumination.

6. A defect inspection method, in which: Exciting the inspection object to cause the inspection object to generate acoustic vibrations, irradiating the inspection object with laser light, causing reflected light of the laser beam from different positions of the excited inspection object to interfere with each other, Shooting the reflected light that interferes with the light Based on the captured reflected light that has interfered, a spatial distribution of a physical quantity that changes periodically due to the propagation of vibration of the inspection object is measured, Extract the discontinuous part of the vibration based on the spatial distribution of the physical quantity, The extracted discontinuous portion of the vibration is displayed in an emphasized manner by overlapping with the still image of the inspection object taken. The physical quantity that changes periodically in the extracted discontinuous portion of the vibration is displayed in the form of a moving image superimposed on the still image.

Images