Defect Detection Equipment

Abstract

To provide a defect detection device with which it is possible to easily compare a position between a plurality of images that are used in defect detection.SOLUTION: A defect detection device (10) comprises: an excitation unit (12) that adds vibration to an inspection object; a vibration state display image creation unit (163) that measures by optical means the vibration state in a measurement region on the surface of the inspection object to which vibration is added, and creates, on the basis of the measurement results, one or a plurality of vibration state display images that represent the vibration state in the measurement region; an optical image acquisition unit (164) that acquires an optical image in the measurement region; an image display unit (19) that displays the image; and a display control unit (166) that exercises control, regarding the same display region within the measurement region, to display two images out of the one or plurality of vibration state display images and the optical image simultaneously on the image display unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a defect detection apparatus for detecting defects present in an object to be inspected. [Background technology]

[0002] Defect detection devices have been proposed in the past that excite elastic waves in an object to detect defects present in the object. The defect detection device described in Patent Document 1 uses speckle interferometry or speckle shearing interferometry to detect defects. Speckle interferometry involves splitting laser light from a laser light source into illumination light and reference light, irradiating the illumination light onto an inspection area, and obtaining an interference pattern between the reference light and light reflected from each point on the surface of the object within the inspection area. Speckle shearing interferometry involves irradiating the inspection area with laser light from a laser light source (without splitting the reference light) and obtaining an interference pattern between light reflected from two nearby points on the surface of the object within the inspection area.

[0003] The conventional defect detection device described in Patent Document 1 applies a vibrator to an object under inspection and vibrates it to excite elastic waves in the object. A strobe light illuminated in synchronization with the elastic waves is then used to measure the out-of-plane (perpendicular to the surface) displacement of each point at a certain phase of the elastic waves (speckle interferometry) or the relative out-of-plane displacement between two adjacent points (speckle shearing interferometry). This operation is performed for at least three different phases of a sinusoidal elastic wave, and the data obtained can be used to reproduce the vibration state throughout the entire inspection area as a moving image or to display the spatial amplitude distribution as a still image using different colors. At the location of a defect, the moving image shows a spatial discontinuity in the vibration state, while the still image of the amplitude distribution shows a different amplitude from other locations, enabling the detection of defects within the inspection area. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-219318 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional defect detection devices described above, not only defects but also non-defective parts, such as steps inherent in the object being inspected, may appear in a dynamic image or a still image showing the amplitude as vibrations similar to defects. Therefore, conventional defect detection devices separately acquire optical images of the inspection area and, by performing a predetermined operation, allow the image displayed on the display device to be switched between the optical image, the dynamic image, and the still image. This allows an operator to compare the dynamic image or the still image with the optical image and confirm whether or not something other than a defect exists in a position that appears to be a defect in the dynamic image or the still image. However, with conventional defect detection devices, an operator must determine which positions in the dynamic image or the still image showing the vibration state correspond to which positions in the optical image based on the positions of the defects, steps, etc. that appear in those images, which may result in misidentification of the positions.

[0006] Furthermore, in order to detect defects more reliably, the operator determines whether or not there is a defect based on both moving images and still images. However, even in this case, there is a risk of misidentifying the position for the same reasons as when comparing with still images described above.

[0007] An object of the present invention is to provide a defect detection apparatus that can easily compare positions among a plurality of images used for defect detection. [Means for solving the problem]

[0008] The defect detection device according to the present invention, which is made to solve the above problems, is an excitation unit that applies vibration to the object to be inspected; The vibration state in a measurement area on the surface of the object to be inspected to which the vibration is applied is measured by an optical means, and based on the measurement results, a vibration state in the measurement area is represented. A moving image, a vibration distribution image showing the distribution of vibration amplitude, and a wavelength distribution image showing the distribution of vibration wavelengths. a vibration state display image creating unit that creates a plurality of types of vibration state display images; an optical image acquisition unit that acquires an optical image within the measurement area; an image display unit that displays an image; For the same display area within the measurement area, duplication Several vibration status display images At least two images of and the optical image The images are displayed at different positions within the image display unit. simultaneous Shown in a display control unit that controls the display of the Equipped with. [Effects of the Invention]

[0009] According to the defect detection device of the present invention, two (or three or more) images of one or more types of vibration state display images and optical images used for defect detection are simultaneously displayed on the image display unit in the same display area, so that the positions of these images can be easily compared. Here, the vibration state display image refers to an image that shows the vibration state of the inspected object, and examples thereof include a moving image, a still image showing the amplitude distribution, and a still image showing the wavelength distribution. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram showing an embodiment of a defect detection device according to the present invention; [Figure 2] 5A and 5B are diagrams for explaining a method for determining the displacement of the surface of an object to be inspected in the defect detection apparatus of the present embodiment. [Figure 3] 3A and 3B are diagrams conceptually showing a method for acquiring a moving image and an optical image in the defect detection device of the present embodiment. [Figure 4] FIG. 10 is a diagram showing an example of an optical image. [Figure 5] FIG. 10 is a diagram showing an example of a moving image. [Figure 6] FIG. 10 is a diagram showing an example of an amplitude distribution image. [Figure 7] FIG. 10 is a diagram showing an example of a wavelength distribution image. [Figure 8] 10A and 10B are diagrams showing an example in which an optical image, a moving image, an amplitude distribution image, and a wavelength distribution image are all displayed simultaneously. [Figure 9] 10A and 10B are diagrams showing an example of simultaneously displaying two images from among an optical image, a moving image, an amplitude distribution image, and a wavelength distribution image. [Figure 10] 10A and 10B are diagrams showing an example of displaying a frame for specifying a display area within a vibration state display image and an optical image displayed on a display unit. [Figure 11] 11 is a diagram showing an example of displaying a vibration state display image and an optical image in a display area enlarged by the frame shown in FIG. 10. FIG. [Figure 12] 10A and 10B are diagrams showing an example of displaying marks indicating regions of interest within a vibration state display image and an optical image displayed on a display unit. [Figure 13] 10A and 10B are diagrams showing an example of an operation for determining the distance between two points in a vibration state display image or an optical image displayed on a display unit. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of a defect detection device according to the present invention will be described with reference to FIGS.

[0012] (1) Configuration of the defect detection device of this embodiment The defect detection device 10 of this embodiment includes a signal generator 11, an oscillator 12, a pulsed laser light source 13, an illumination lens 14, a speckle shearing interferometer 15, a control unit 16, a memory unit 17, an input unit 18, and a display unit 19.

[0013] The signal generator 11 is connected to the vibrator 12 by a cable, and generates and transmits an AC electric signal to the vibrator 12. The vibrator 12 is used by being in contact with the object S to be inspected, and receives the AC electric signal from the signal generator 11, converts it into mechanical vibrations having the same frequency (vibration number) as the AC electric signal, and applies the mechanical vibrations to the object S to be inspected. This excites elastic waves in the object S to be inspected. The signal generator 11 and vibrator 12 correspond to the excitation unit described above.

[0014] The signal generator 11 is also connected to a pulsed laser light source 13 via a cable separate from the cable connecting to the oscillator 12, and transmits a pulsed electric signal (pulse signal) to the pulsed laser light source 13 at a timing when the AC electric signal has a predetermined phase. The pulsed laser light source 13 is a light source that outputs a pulsed laser light when it receives a pulse signal from the signal generator 11. The illumination light lens 14 is arranged between the pulsed laser light source 13 and the object S to be inspected, and is made of a concave lens. The illumination light lens 14 serves to spread the pulsed laser light from the pulsed laser light source 13 over the entire measurement area on the surface of the object S to be inspected. In this way, the measurement area on the surface of the object S to be inspected is illuminated with a strobe.

[0015] The speckle shearing interferometer 15 has a beam splitter 151, a first reflecting mirror 1521, a second reflecting mirror 1522, a phase shifter 153, a condenser lens 154, and an image sensor 155. The beam splitter 151 is a half mirror arranged at a position where illumination light reflected from a measurement region on the surface of the object S to be inspected is incident. The first reflecting mirror 1521 is arranged on the optical path of the illumination light reflected by the beam splitter 151, and the second reflecting mirror 1522 is arranged on the optical path of the illumination light passing through the beam splitter 151. The phase shifter 153 is arranged between the beam splitter 151 and the first reflecting mirror 1521 and changes (shifts) the phase of the light passing through the phase shifter 153, and the amount of phase change is variable. Image sensor 155 is disposed on the optical path of illumination light that is reflected by beam splitter 151, then reflected by first reflecting mirror 1521, and transmitted through beam splitter 151, and illumination light that is transmitted through beam splitter 151, then reflected by second reflecting mirror 1522, and then reflected back by beam splitter 151. Collecting lens 154 is disposed between beam splitter 151 and image sensor 155.

[0016] First reflecting mirror 1521 is positioned so that its reflecting surface is at an angle of 45° with respect to the reflecting surface of beam splitter 151. In contrast, second reflecting mirror 1522 is positioned so that its reflecting surface is at an angle slightly inclined from 45° with respect to the reflecting surface of beam splitter 151. Due to the arrangement of first reflecting mirror 1521 and second reflecting mirror 1522, in image sensor 155, the illumination light reflected by point A on the surface of object S to be inspected and first reflecting mirror 1521 (dash-dotted line in FIG. 1) and the illumination light reflected by point B, which is slightly shifted from point A on the surface, and second reflecting mirror 1522 (dashed line in FIG. 1) are incident on the same position on image sensor 155 and interfere with each other. At this time, the phase of the illumination light reflected by first reflecting mirror 1521 changes by the amount of change set by phase shifter 153, and therefore the phase difference with the illumination light reflected by second reflecting mirror 1522 also changes accordingly.

[0017] Image sensor 155 has a large number of detection elements, and light incident on image sensor 155 from a large number of points (point A) on the surface of inspected object S through first reflecting mirror 1521 and phase shifter 153 is detected by different detection elements. Similarly, light incident on image sensor 155 from a large number of points through second reflecting mirror 1522 is detected by different detection elements for point B.

[0018] In this embodiment, the image sensor 155 of the speckle shearing interferometer 15 is used to create the vibration state display image as well as to create the optical image. The optical image is created based on the intensity of the interference light between the illumination light reflected by the first reflecting mirror 1521 and the illumination light reflected by the second reflecting mirror 1522, detected by the image sensor 155 (details will be described later). In this case, light is incident on each detection element of the image sensor 155 from two points on the surface of the object S to be inspected. However, because these two points are located close to each other, it can be considered that light is incident on each detection element from a single point on the surface of the object S to be inspected, as in a normal optical image. Note that instead of using the image sensor 155, a separate camera for capturing optical images may be provided to acquire the optical images.

[0019] The memory unit 17 is a device that stores measurement data such as the intensity values ​​of the detection signals obtained from each detection element of the image sensor 155, data such as the values ​​of the out-of-plane displacement for each position calculated by the displacement calculation unit 162, and software that executes control by the control unit 16. The input unit 18 is an input device such as a keyboard, mouse, touch panel, or a combination thereof through which an operator inputs predetermined information. The display unit 19 corresponds to the image display unit described above and is a display that simultaneously displays multiple images from one or more types of vibration state display images and optical images (actual images). In addition to the function of displaying multiple vibration state display images and optical images, the display unit 19 also has the function of displaying only one of these images and the function of displaying information other than images.

[0020] The control unit 16 has, as functional blocks, a measurement operation control unit 160, an input receiving unit 161, a displacement calculation unit 162, a vibration state display image creation unit 163, an optical image acquisition unit 164, a display area designation unit 165, a display control unit 166, a region of interest setting unit 167, and a distance calculation / display unit 168. The control unit 16 is embodied by hardware such as a CPU and software that executes each operation. Each unit (functional block) of the control unit 16 will be described below.

[0021] The measurement operation control unit 160 controls the operation of each unit when performing measurement, particularly the operation of the signal generator 11 and the speckle sharing interferometer 15 .

[0022] The input receiving unit 161 receives information input by the operator using the input unit 18 to select an image to be displayed on the display unit 19, information to set the display area of ​​the image, information to set the area of ​​interest, information to set the interval for calculating the distance, etc., and transmits this information to each unit that performs the display and setting.

[0023] The displacement calculation section 162 performs processing to find the displacement in the out-of-plane direction for each position on the surface of the object S to be inspected, based on the detection signals obtained from each detection element of the image sensor 155 .

[0024] The vibration state display image creation unit 163 performs processing to create a vibration state display image showing the vibration state of the object S to be inspected, based on the out-of-plane displacement calculated by the displacement calculation unit 162. In this embodiment, three types of images are created as the vibration state display image: a moving image, a vibration distribution image showing the distribution of vibration amplitudes, and a wavelength distribution image showing the distribution of vibration wavelengths. Corresponding to these three types of images, the vibration state display image creation unit 163 has a moving image creation unit 1631, an amplitude distribution image creation unit 1632, and a wavelength distribution image creation unit 1633.

[0025] The optical image acquisition unit 164 acquires an intensity signal for each detection element detected by the image sensor 155 when the phase shifter 153 is set so that the phase difference between the illumination light reflected by the first reflecting mirror 1521 and the illumination light reflected by the second reflecting mirror 1522 is 0, and acquires an optical image based on the intensity signal.

[0026] The display area designation unit 165 is composed of an area designation screen display control unit 1651 and a display area designation operation control unit 1652. The area designation screen display control unit 1651 performs processing to display a rectangular frame 41 (described later) of the same shape and size at the same position on each of two or more types of images consisting of one or more types of vibration state display images and / or optical images displayed on the display unit 19. The display area designation operation control unit 1652 controls the operation of designating the area within the frame 41 as the display area by the operator enlarging, reducing, or moving the frame 41 using the mouse or the like of the input unit 18 on one of the two or more types of images displayed on the display unit 19 by the display control unit 166, which will be described next.

[0027] The display control unit 166 controls the simultaneous display of two or more of the multiple vibration state display images created by the vibration state display image creation unit 163 and the optical images acquired by the optical image acquisition unit 164 on the display unit 19. At this time, the display areas of the two or more images displayed simultaneously are set to be the same. When the images are first displayed, the display area is set to a predetermined area (which may be the entire measurement area or a part of it), and when an area is designated by the display area designation unit 165, that area is used as the display area for processing.

[0028] The display control unit 166 further has a display image selection processing unit 1661. The display image selection processing unit 1661 displays a plurality of buttons, each corresponding to a plurality of vibration state display images and optical images, on the display unit 19, and then performs processing to select, as an image to be displayed on the display unit 19, an image corresponding to a button clicked by the operator using the input unit 18.

[0029] Region of interest setting unit 167 is composed of region of interest setting control unit 1671 and region of interest display control unit 1672. Region of interest setting control unit 1671 controls the operator to perform a predetermined operation (e.g., moving the mouse cursor to draw a closed curve) on a certain region in one of two or more types of images displayed on display unit 19, thereby setting the position as a region of interest in which the operator is interested, such as for the presence or absence of a defect. Region of interest display control unit 1672 controls the display of a mark (e.g., a closed curve, arrow, or triangle mark indicating the outer edge of the region of interest) indicating that the region set by region of interest setting control unit 1671 is a region of interest in all of two or more types of images displayed on display unit 19. Note that the mark indicating the region of interest may be displayed only on some of the two or more types of images displayed on display unit 19.

[0030] The distance calculation / display unit 168 is composed of a distance calculation position setting unit 1681, a distance calculation unit 1682, and a distance display control unit 1683. When the operator performs an operation to specify two points using the input unit 18 in one of two or more types of images displayed on the display unit 19, the distance calculation position setting unit 1681 sets the distance between those two points as a calculation target. The distance calculation unit 1682 calculates the distance on the image between the two points set by the distance calculation position setting unit 1681 and then divides the calculated distance by the display magnification of the image to calculate the distance between the two points on the surface of the object S to be inspected (rather than the distance on the image). The distance display control unit 1683 performs processing to display the value of the distance calculated by the distance calculation unit 1682 on the display unit 19.

[0031] (2) Operation of the defect detection device of this embodiment First, the operator places the object to be inspected S at a predetermined position in the defect detection device 10, and then brings the vibrator 12 into contact with the object to be inspected S. Then, when the operator performs a predetermined operation using the input unit 18, the defect detection device starts operating.

[0032] The measurement operation control unit 160 controls the signal generator 11 so that the signal generator 11 transmits an AC electric signal having a predetermined frequency to the vibrator 12. As a result, vibration is applied to the object S to be inspected from the vibrator 12, and elastic waves are excited.

[0033] While exciting elastic waves in the object to be inspected S in this manner, the measurement operation control unit 160 further causes the signal generator 11 to send a pulse signal to the pulse laser light source 13 at the timing when the AC electric signal reaches a predetermined phase. As a result, the pulse laser light source 13 repeatedly outputs illumination light, which is a pulse laser beam, every time it receives a pulse signal (i.e., every time the vibration of the object to be inspected S determined by the AC electric signal reaches the predetermined phase) (strobe illumination). The diameter of this illumination light is expanded by the illumination light lens 14, and it is irradiated onto the entire measurement area on the surface of the object to be inspected S.

[0034] The illumination light is reflected from the surface of the object to be inspected S and enters the beam splitter 151 of the speckle shearing interferometer 15. A portion of the illumination light is reflected by the beam splitter 151, passes through the phase shifter 153, and then is reflected by the first reflecting mirror 1521. After passing through the phase shifter 153 again, a portion of the illumination light passes through the beam splitter 151 and enters the image sensor 155. The remainder of the illumination light that entered the beam splitter 151 passes through the beam splitter 151 and is reflected by the second reflecting mirror 1522, and a portion of the illumination light is reflected by the beam splitter 151 and enters the image sensor 155. In the image sensor 155, the illumination light reflected from many points on the surface of the object to be inspected S is detected by different detection elements.

[0035] While the illumination light, which is a pulsed laser beam, is repeatedly output, the phase shifter 153 changes (shifts) the phase of the illumination light passing through the phase shifter 153 (i.e., the illumination light reflected at point A). This changes the phase difference (phase shift amount δα) between the illumination light reflected at point A and the illumination light reflected at point B. During this change, each detection element of the image sensor 155 detects the interference light resulting from the interference of these two illumination lights and calculates its intensity. The upper part of Figure 2 shows a graph of an example of the phase shift amount by the phase shifter 153 and the intensity of the interference light detected by the detection elements of the image sensor 155 when the vibration of the inspected object S is at a certain phase φ1. Note that while Figure 2 shows a continuous curve representing the sinusoidal change in the detected intensity versus the phase shift amount, what is actually observed is discrete data, and a continuous sinusoidal waveform is reconstructed from the observed data using a least-squares method or the like. To achieve this, the intensity is detected at at least three different phase shift amounts δα.

[0036] The above operation is performed for a plurality of cases where the phase of vibration of the object S to be inspected is different (phases φ2, φ3, ...) by changing the timing of irradiating the pulsed laser light. In FIG. 2, an example is shown in which interference light is detected at three phases in total, namely, phase φ2 = φ1 + 2π / 3 and phase φ3 = φ1 + 4π / 3 in addition to phase φ1. However, it is sufficient to detect interference light at three or more phases, and it may be performed at three phases different from this example, or at four or more phases. The three or more vibration phases (the number is assumed to be n) are as follows: to To smoothly play back the moving image described below, it is preferable to use equal intervals (for example, 2π / 3 as in the above example when n=3), but unequal intervals are also acceptable.

[0037] When the phase difference δα of the irradiated light generated by the phase shifter 153 is 0, the moving image generating unit 1631 changes the phases φ1, φ2, . . . φ of each vibration. n For each of the n still images (n is 3 or more), a still image is created based on the detection intensity of the image sensor 155 (see FIG. 3). By sequentially playing back the n still images created in this way at time intervals corresponding to the intervals between the vibration phases (for example, if the vibration phases are equally spaced, the time intervals are also equally spaced), a moving image showing the vibrations in the measurement area on the surface of the object S to be inspected can be obtained.

[0038] Furthermore, each of the n still images created by the moving image creation unit 1631 corresponds to an optical image obtained by capturing a measurement area on the surface of the object to be inspected S at a certain vibration phase. The optical image acquisition unit 164 acquires one of the n still images as an optical image.

[0039] The displacement calculation unit 162 calculates, for each detection element of the image sensor, maximum output phase shift amounts δφ1, δφ3, δφ3... at which the output of the detection element is maximized while the phase shift amount by the phase shifter 153 is changed for each vibration phase φ1, φ2, φ3..., and further calculates the difference in maximum output phase shift amounts between different phases based on the calculated maximum output phase shift amounts. For example, in the example shown in FIG. 2, the differences in the three maximum output phase shift amounts (δφ3-δφ1), (δφ3-δφ3), and (δφ1-δφ3) are obtained. These differences in maximum output phase shift amounts are calculated by calculating the relative displacement of points A and B in the out-of-plane direction from three or more sets of data with different vibration phases (i.e., different times) of the vibrator 12. in Based on these three or more sets of relative displacements, three parameter values ​​that indicate the vibration state of the object S to be inspected are obtained: the vibration amplitude, the vibration phase, and the vibration center value (DC component) at each point in the measurement area. The amplitude distribution image creation unit 1632 creates an amplitude distribution image based on the vibration amplitude values ​​at each point in the measurement area calculated by the displacement calculation unit 162. Specifically, colors corresponding to amplitude values ​​are defined in advance, and data indicating the coordinates of each point in the measurement area and the color corresponding to the amplitude value at that point is stored in the storage unit 17 as amplitude distribution image data.

[0040] The wavelength distribution image creation unit 1633 performs a fast Fourier transform on one of the n still images created by the moving image creation unit 1631, for each point in the measurement area, using data on the intensity values ​​of multiple points within a predetermined range from each point, and stores the data in the memory unit 17 as data on a distribution image representing the difference in wavelength in the planar direction.

[0041] Through the operations up to this point, an optical image, a moving image representing the vibration state, an amplitude distribution image, and a wavelength distribution image are obtained for the entire measurement region on the surface of the object to be inspected S. FIGS. 4 to 7 show examples of an optical image 21, a moving image 22, an amplitude distribution image 23, and a wavelength distribution image 24. In this example, the optical image 21 shows a groove 201 (which is not a defect) that was originally provided on the surface of the object to be inspected S, and nothing else in particular can be seen other than the groove 201. The groove 201 also appears in the moving image 22, the amplitude distribution image 23, and the wavelength distribution image 24. Since the optical image 21, the moving image 22, the amplitude distribution image 23, and the wavelength distribution image 24 all display the entire measurement region, a comparison of the images shows that they display the same region.

[0042] Although the moving image 22 is represented by a static striped pattern in FIG. 5, it is actually represented as a moving image in which the position of the stripes changes over time. Within the moving image 22, discontinuous regions can be seen, such as a striped region 251 that does not change over time and a region 252 where a striped pattern is formed at a different spacing than the surrounding area. The striped region 251 indicates that no vibration is occurring due to the formation of cracks inside the inspected object S. The region 252 with different stripe spacing indicates that the inspected object S itself is vibrating at a different wavelength due to peeling of the coating formed on the surface of the inspected object S. These cracks and peeling of the coating cannot be seen visually or in the optical image 21.

[0043] The amplitude distribution image 23 and the wavelength distribution image 24 show a groove 201, a region 251 where a crack is formed, and a region where the coating film is peeling off, respectively. region 252 oscillates with an amplitude and wavelength different from other regions.

[0044] When the operator performs a predetermined operation using the input unit 18 (e.g., clicks a button displayed on the display unit 19 with a mouse), the display control unit 166 controls the display unit 19 to simultaneously display four images: the optical image 21, the moving image 22, the amplitude distribution image 23, and the wavelength distribution image 24. FIG. 8 shows an example in which these four images are simultaneously displayed on the display unit 19. As described above, these four images display the same region. Therefore, by comparing these four images, the operator can confirm whether an object is displayed at the same position in the optical image 21 corresponding to a discontinuous region in any of the moving image 22, the amplitude distribution image 23, and the wavelength distribution image 24. Based on this, it can be determined whether the discontinuous region is due to a defect or is not a defect but is actually a groove or other inherent feature of the object to be inspected S. In the example of FIG. 8, the region denoted by reference numeral 201 is shown to be a groove in the optical image 21, and therefore can be determined to be different from a defect. On the other hand, since no grooves or holes appear in the areas 251 and 252 in the optical image 21, it can be determined that the discontinuities appearing in those areas in the moving image 22 and the like are due to defects.

[0045] Furthermore, by comparing the vibration state display images, i.e., the moving image 22, the amplitude distribution image 23, and the wavelength distribution image 24, it may be possible to discover a defect that is not clearly visible in one of the images based on the other images, thereby enabling more reliable defect detection.

[0046] In the example shown in FIG. 8 , in addition to the four images described above, image display selection buttons 31 (optical image display selection button 311, moving image display selection button 312, amplitude distribution image display selection button 313, and wavelength distribution image display selection button 314) are displayed to select whether or not to display each image. The display image selection processing unit 1661 performs processing to display these selection buttons, and also performs processing to switch between displaying and hiding the image corresponding to one of these selection buttons each time the operator clicks the button once using the input unit 18. FIG. 9 shows an example in which “display” is selected for the optical image display selection button 311 and the wavelength distribution image display selection button 314 (the buttons are colored in response to this selection), and “hide” is selected for the moving image display selection button 312 and the amplitude distribution image display selection button 313 (the buttons are not colored). In accordance with this selection, the display image selection processing unit 1661 performs processing to display only the optical image 21 and the wavelength distribution image 24 on the display unit 19. Of course, the combination of images to be displayed is not limited to that shown in FIG. 9 , and any combination is possible.

[0047] In the example shown in FIG. 8, further displayed are a video playback start / stop button 32, a display area designation operation button 33, a region of interest setting button 34, and a distance calculation operation button 35, which are buttons for performing predetermined operations on the displayed image.

[0048] The video playback start / stop button 32 operates so that when clicked once, playback of the video 22 starts, and when clicked once more, playback of the video 22 stops and a still image at the time of stopping is displayed.

[0049] The display area specification operation buttons 33 consist of a frame setting button 331, a display area enlargement button 332, and a display area enlargement cancellation button 333. When the operator clicks the frame setting button 331 using the input unit 18, the area specification screen display control unit 1651 controls the display of rectangular frames 41 in the same corresponding positions on all (up to) four images currently displayed (FIG. 10). When the operator uses the input unit 18 to move or change the vertical and horizontal lengths of the frame 41 on one of the four images, the display area specification operation control unit 1652 controls the display of the frame 41 to change the position, shape, and size on that image and to display the frame 41 in the same position, shape, and size on the other (up to) three images. After setting the position, shape, and size of the frame 41 in this way, when the operator clicks the display area enlargement button 332 using the input unit 18, the display control unit 166 controls the display of the four images by enlarging (increasing the magnification) the area within the frame 41 (FIG. 11). From this state, the operator can perform a similar operation to further enlarge the image. On the other hand, if the operator clicks the display area enlargement cancel button 333 using the input unit 18, the image immediately preceding the image currently being displayed, i.e., an image with a lower magnification, is displayed.

[0050] Region of interest setting button 34 is a button used when the operator performs an operation to display a region of interest in (up to) four images. After clicking region of interest setting button 34 using a mouse, which is input unit 18, the operator performs an operation to draw a closed curve indicating the region of interest in one of the four images while pressing the mouse button. Region of interest display control unit 1672 draws the closed curve in the one image and also draws the same image at the same corresponding position in (up to) three other images. When the operator releases the mouse button, region of interest setting control unit 1671 sets the drawn closed curve as a region of interest and stores it in memory unit 17.

[0051] For example, when an operator draws a rectangle in one of the four images while pressing the mouse button, which is the input unit 18, the rectangle and a closed curve such as an ellipse inscribed in the rectangle (a perfect circle when a square is drawn) are displayed in all four images. The rectangle or ellipse may also be tilted by operating the mouse. In the example shown in FIG. 12, the closed curve and perfect circle formed by tilting the ellipse are displayed as the region of interest 42.

[0052] By displaying the regions of interest thus set in the four images, the operator can know the regions to which attention should be paid when viewing those images thereafter.

[0053] The distance calculation operation button 35 is used to calculate the distance between two points on the surface of the object to be inspected S. When the operator clicks the distance calculation operation button 35 using the input unit 18 and then clicks two points 431 and 432 in one of (a maximum of) four images as shown in FIG. 13 , the distance calculation position setting unit 1681 sets the two points 431 and 432 as distance calculation targets. Then, the distance calculation unit 1682 calculates the distance on the image between the two points set by the distance calculation position setting unit 1681 and divides the calculated distance by the display magnification of the image, thereby calculating the distance between the two points on the surface of the object to be inspected S. The distance display control unit 1683 superimposes and displays the value of the distance calculated by the distance calculation unit 1682 on the image in which the points 431 and 432 are set.

[0054] Conventionally, when determining the distance between two points displayed on the moving image 22 and the amplitude distribution image 23, a scale with graduations is displayed on the images, and the operator reads the graduations. In contrast, in this embodiment, the distance between two points on the surface of the object S to be inspected can be easily determined by simply setting two points using the input unit 18.

[0055] (3) Modifications The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0056] For example, in the above embodiment, a speckle shearing interferometer is used to acquire the vibration state display image, but a speckle interferometer may be used instead.

[0057] In the above embodiment, three vibration state display images are created and displayed: a moving image, an amplitude distribution image, and a wavelength distribution image. However, it is also possible to create and display only one or two of these, or to display other vibration state display images.

[0058] The method for setting and changing the display area is not limited to the above example. For example, the display area may be set and changed by dragging the image on the display unit 19 using the mouse or the like of the input unit 18 to determine the center position of the image to be displayed, and then clicking the "Enlarge" or "Reduce" button to enlarge or reduce the image by a predetermined magnification, or by inputting a numerical value for the magnification.

[0059] The region of interest setting unit 167 and the distance calculation / display unit 168 are not essential components in the present invention and may be omitted.

[0060] In addition, various configurations shown in the above embodiments and modifications may be combined as appropriate.

[0061] [Aspect] It will be apparent to those skilled in the art that the above-described exemplary embodiments are examples of the following aspects.

[0062] (Item 1) The defect detection device according to item 1 is an excitation unit that applies vibration to the object to be inspected; a vibration state display image creation unit that measures, by optical means, the vibration state within a measurement area on the surface of the object to be inspected to which the vibration is applied, and creates one or more types of vibration state display images that represent the vibration state within the measurement area based on the measurement results; an optical image acquisition unit that acquires an optical image within the measurement area; an image display unit that displays an image; a display control unit that controls the image display unit to simultaneously display two images selected from the one or more vibration state display images and the optical image for the same display area within the measurement area; and Equipped with.

[0063] According to the defect detection device of paragraph 1, two (or three or more) images of one or more types of vibration state display images and optical images used for defect detection are displayed simultaneously on the image display unit in the same display area, making it easy to compare the positions of those images.

[0064] The combination of images to be simultaneously displayed on the image display unit may be a combination of one or more of the vibration state display images with an optical image, or may be a combination of more than one of the vibration state display images without including an optical image.

[0065] The vibration state display image may be, for example, a moving image showing the vibration state, or an amplitude display image in which the amplitude of vibration is color-coded (including color-coded by grayscale shading) for each position in the display area and displayed as a still image. A wavelength display image, which will be described next, may also be used as the vibration state display image.

[0066] (Item 2) The defect detection device according to item 2 is the defect detection device according to item 1, wherein the one or more types of vibration state display images include wavelength display images that are displayed as still images, with differences in vibration wavelengths color-coded for each position within the display area.

[0067] According to the defect detection device of paragraph 2, by displaying the vibration wavelength for each position in the display area using different colors, it is possible to identify positions that vibrate at a different wavelength than other positions due to the presence of defects, thereby detecting defects. Furthermore, defects that occur in inspected objects come in a variety of different forms, such as cracks and peeling paint on the surface of the inspected object, and these forms have different vibration transmission speeds and therefore different wavelengths. Therefore, it is possible to distinguish between defect forms based on differences in vibration wavelength.

[0068] (Item 3) The defect detection device according to item 3 is the defect detection device according to item 1 or 2, further comprising: an area designation screen display control unit that controls the display of one of the one or more types of vibration state display images and the optical image on the image display unit, and the superimposition of a display area designation image that is an image indicating a display area on the image displayed on the image display unit; a display area designation operation control unit that sets the size and position of the display area designation image through an input operation by an operator; Equipped with The display control unit controls the display area set by the control of the display area designation operation control unit to be the same display area, and controls the image display unit to simultaneously display two images of the one or more vibration state display images and the optical image.

[0069] According to the defect detection device of the third aspect, the operator can set a desired display area by inputting an input operation.

[0070] (4) The defect detection device according to 4 is the defect detection device according to any one of 1 to 3, further comprising: a region of interest setting control unit that displays one of the one or more vibration state display images and the optical image on the image display unit, and controls setting of a region of interest within the image displayed on the image display unit by an input operation by an operator; a region of interest display control unit that controls displaying a mark indicating a region corresponding to the region of interest in one of the two images in the display region displayed by the display control unit; Equipped with.

[0071] According to the defect detection device of paragraph 4, a mark indicating a region of interest, which is a region in which the operator is interested, is displayed on one of two or more images (or two or more images, which may be all images displayed here) in the display area displayed on the image display unit. This allows the operator to compare two or more images by focusing on the region of interest. The mark indicating the region of interest may be a closed curve indicating the outer edge of the region of interest, or a symbol indicating the region of interest such as an arrow or a triangle.

[0072] (Item 5) The defect detection device according to item 5 is the defect detection device according to any one of items 1 to 4, further comprising: a distance calculation position setting unit that sets the positions of two points in one of two or more images in a display area displayed on the image display unit through an input operation by an operator; a distance calculation unit that calculates the distance between two points corresponding to the positions of the two points on the surface of the object to be inspected; Equipped with.

[0073] According to the defect detection device of paragraph 5, the operator can determine the distance between the corresponding two points on the surface of the actual object to be inspected simply by setting the positions of two points in one of two or more images displayed in the display area of ​​the image display unit. This makes it possible to easily measure the size of defects that appear in the image in the display area. [Explanation of symbols]

[0074] 10...Defect detection device 11...Signal generator 12...Oscillator 13...Pulse laser light source 14...Illumination lens 15...Speckle shearing interferometer 151...Beam splitter 1521…1st reflector 1522…Second reflector 153...Phase shifter 154...Condenser lens 155...Image sensor 16...Control unit 160...Measurement operation control section 161...input reception section 162...Displacement calculation unit 163...Vibration status display image creation unit 1631...Video Production Department 1632...Amplitude distribution image creation unit 1633...Wavelength distribution image creation unit 164...Optical image acquisition unit 165...Display area specification section 1651...Area designation screen display control unit 1652...Display area designation operation control unit 166...Display control unit 1661...display image selection processing unit 167...region of interest setting unit 1671...region of interest setting control unit 1672...region of interest display control unit 168...Distance calculation / display section 1681...Distance calculation position setting unit 1682...Distance calculation unit 1683...Distance display control unit 17...Storage section 18...Input section 19...Display section 201...Groove 21...Optical image 22...Video 23...Amplitude distribution image 24...Wavelength distribution image 251... Streaky area 252: Area with striped patterns formed at intervals different from the surrounding area 31...Image display selection button 311...Optical image display selection button 312...Moving image display selection button 313...Amplitude distribution image display selection button 314... Wavelength distribution image display selection button 32...Video playback start / stop button 33...Display area specification operation button 331...Frame setting button 332…Display area enlargement button 333…Display area enlargement cancel button 34...Region of interest setting button 35...Distance calculation operation button 41...frame 42...Area of ​​interest 431, 432...Points to calculate distance

Claims

1. an excitation unit that applies vibration to the object to be inspected; a vibration state display image creation unit that measures, by optical means, the vibration state within a measurement region on the surface of the object to be inspected to which the vibration is applied, and creates, based on the measurement results, a plurality of types of vibration state display images from among a moving image showing the vibration state within the measurement region, a vibration distribution image showing the distribution of vibration amplitudes, and a wavelength distribution image showing the distribution of vibration wavelengths; an optical image acquisition unit that acquires an optical image within the measurement area; an image display unit that displays an image; a display control unit that controls the simultaneous display of at least two of the plurality of vibration state display images and the optical image at different positions within the image display unit for the same display area within the measurement area; A defect detection device comprising:

2. 2. The defect detection device according to claim 1, wherein the plurality of types of vibration state display images include wavelength display images that are displayed as still images with different colors representing differences in vibration wavelength for each position within the display area.

3. moreover, an area designation screen display control unit that controls superimposition display of at least two images of the plurality of types of vibration state display images displayed on the image display unit and a display area designation image that is an image indicating a display area on the optical image; a display area designation operation control unit that sets the size and position of the display area designation image through an input operation by an operator; Equipped with The defect detection device described in claim 1 or 2, wherein the display control unit controls the display area set by the control of the display area designation operation control unit to be the same display area and controls the image display unit to simultaneously display at least two images of the multiple types of vibration state display images and the optical image.

4. moreover, a region of interest setting control unit that controls setting of a region of interest in at least two of the plurality of vibration state display images displayed on the image display unit and the optical image by an input operation by an operator; a region of interest display control unit that controls displaying a mark indicating a region corresponding to the region of interest in at least two of the plurality of vibration state display images displayed on the image display unit and in the optical image; The defect detection device according to any one of claims 1 to 3, comprising:

5. moreover, a distance calculation position setting unit that sets the positions of two points in at least two of the plurality of vibration state display images and one of the optical images, which are displayed on the image display unit, by an input operation by an operator; a distance calculation unit that calculates the distance between two points corresponding to the positions of the two points on the surface of the object to be inspected; The defect detection device according to any one of claims 1 to 4, comprising:

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