Inspection device and inspection method

Abstract

This inspection device provides an option to determine appropriate exposure conditions without repeated trial and error. A light probe generates an image of the surface to be inspected. Relationship information, representing the relationship between the characteristic values ​​of multiple optically cut-off images obtained by photographing the surface to be inspected under multiple exposure conditions and adjustment information to adjust the exposure conditions so that the characteristic values ​​of each of the multiple optically cut-off images of the sample approach the target value, is stored in a memory unit. A control unit controls the light probe. Under the first exposure condition, the control unit activates the light probe to acquire an image of the surface to be inspected. Based on the characteristic values ​​of the optically cut-off images in the acquired image, the relationship information stored in the memory unit, and the first exposure condition, a second exposure condition is determined. Under the second exposure condition, the light probe is activated to acquire an image of the surface to be inspected.

Description

[Technical Field]

[0001] This invention relates to an inspection device and an inspection method. [Previous Technology]

[0002] An apparatus for inspecting the inner surface of a tubular body is known (Patent Document 1). This apparatus irradiates the inner surface of the tubular body with a ring-shaped beam to capture an image of the inner surface. Information such as the inner diameter is obtained by analyzing the optically cut-off image in the resulting image. The analysis of the optically cut-off image includes, for example, a procedure for detecting the peak position of the brightness distribution in the thickness direction of the optically cut-off image. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-60722 [Summary of the Invention]

[0004] [Problem to be Solved by the Invention] In order to accurately detect the peak position of the brightness distribution, it is necessary to appropriately adjust the exposure (shutter speed, aperture, gain) when acquiring the image. For example, if the exposure is too low, the brightness of the cut-off image will be close to the noise level, and the peak position will be easily affected by noise. If the exposure is too high, the brightness near the peak position of the cut-off image will exceed the saturation value, making it impossible to detect the peak position accurately.

[0005] Furthermore, the surface of the object is affected by deviations in various manufacturing conditions (processing conditions, heat treatment conditions, etc.), thus the brightness recorded in the image will also vary depending on the object. According to the inventors' assessment, due to deviations in processing conditions or heat treatment conditions, the appropriate shutter speed may differ by approximately 1000 times between objects. To determine the appropriate exposure conditions, repeated trial and error is necessary. The object of this invention is to provide an inspection device and method that can determine the appropriate exposure conditions without repeated trial and error. [Technical Means for Solving the Problem]

[0006] According to one aspect of the present invention, an inspection apparatus is provided, comprising: a light probe for generating an image of the inspected surface of an object; a memory unit for storing relational information, the relational information representing the relationship between feature values ​​of multiple optically cut-off images obtained by photographing the inspected surface of a sample under multiple exposure conditions and adjustment information for adjusting the exposure conditions so that the feature values ​​of each of the multiple optically cut-off images of the sample are close to a target value; and a control unit for controlling the light probe, wherein the control unit causes the light probe to operate under a first exposure condition to acquire an image of the inspected surface of the object, determines a second exposure condition based on the feature values ​​of the optically cut-off images in the acquired image, the relational information stored in the memory unit, and the first exposure condition, and causes the light probe to operate under the second exposure condition to acquire an image of the inspected surface of the object.

[0007] According to another aspect of the present invention, an inspection method is provided, wherein an image of the inspected surface of an object is acquired under a first exposure condition, a second exposure condition is determined based on relationship information indicating the relationship between the characteristic values ​​of multiple optically cut-off images obtained by photographing the inspected surface of a sample under multiple exposure conditions and adjustment information that adjusts the exposure conditions so that the characteristic values ​​of each of the multiple optically cut-off images of the sample are close to a target value, the characteristic values ​​of the optically cut-off images in the acquired image, and the first exposure condition, and an image of the inspected surface of the object is acquired under the second exposure condition.

[0008] According to another aspect of the present invention, an inspection apparatus is provided, comprising: a light probe for generating an image of the inspected surface of an object; a memory unit for storing relational information, which represents the relationship between the characteristic quantity of the optically cut-off image obtained from the sample and adjustment information for adjusting the current exposure conditions to suitable exposure conditions; and a control unit having the function of controlling the light probe and obtaining the batch ID of the object to be inspected next. The control unit, before inspecting an object having the same batch ID as the object to be inspected next, activates the light probe under a first exposure condition to obtain an image of the inspected surface of the object. Based on the characteristic quantity of the optically cut-off image in the obtained image, the relational information stored in the memory unit, and the first exposure condition, a second exposure condition is determined. Under the second exposure condition, the light probe is activated to obtain an image of the inspected surface of the object. If objects with the same batch ID as the objects to be inspected have already been inspected, an image of the inspected surface of the object is obtained under the same exposure conditions used when inspecting objects with the same batch ID. [Effects of the Invention]

[0009] If the image of the surface to be inspected of the object is obtained under the first exposure condition, the appropriate second exposure condition can be determined without repeated trial and error.

Implementation Method

[0011] [First Embodiment] Referring to Figures 1 to 5, the inspection apparatus and inspection method of the first embodiment will be described. Figure 1 is a schematic diagram of the inspection apparatus of the first embodiment. The inspection apparatus of the first embodiment irradiates the inner peripheral surface of the object 60 to be inspected with an annular beam of light to inspect the inner peripheral surface.

[0012] A workpiece setting section 52 is provided on a support plate 51 disposed within the internal space of the housing 50. For example, the object to be inspected, i.e., a tubular object 60, is held by the workpiece setting section 52. The object 60 is fixed in an orientation in which its central axis is parallel to the vertical direction. The optical probe 10 is supported by a support mechanism 18 so that it can move along the central axis of the object 60. During inspection, the optical probe 10 descends and enters the space inside the object 60 along its central axis. When the inspection is completed, the optical probe 10 rises and exits from the space inside the object 60.

[0013] The optical probe 10 includes an optical module 11, a camera device 12, and an optical module fixing member 13. The position of the optical module 11 relative to the camera device 12 is fixed by the optical module fixing member 13.

[0014] The housing 50 houses a laser light source 15 and a control box 42. The laser light source 15 is, for example, a laser diode that outputs a laser beam with a wavelength in the range of 370nm to 1100nm. Laser light is guided from the laser light source 15 to the optical module 11 via an optical fiber 16. The control box 42 controls the laser light source 15 and the support mechanism 18 according to instructions from the upper control unit 40. Images captured by the camera device 12 are input to the control unit 40 for image analysis. During image analysis, information stored in the memory unit 41 is utilized. Based on the results of the image analysis, the inner diameter of the object 60 can be measured.

[0015] The housing 50 is able to move on the ground by means of the wheels 53.

[0016] Next, referring to FIG2, the positional relationship between the optical module 11, the object 60 and the camera device 12 and the function of the optical probe 10 will be explained.

[0017] Figure 2 is a schematic perspective view of the optical probe 10. The optical probe 10 includes an optical module 11 and an imaging device 12. The optical module 11 includes a collimating lens 11A and a reflector 11B. The reflector 11B is fixed relative to the collimating lens 11A, for example, by means of a transparent member (not shown) or multiple pillars.

[0018] Laser light is guided from laser source 15 to optical module 11 via optical fiber 16. The laser light output from the output end of optical fiber 16 is collimated by collimating lens 11A.

[0019] A reflector 11B is positioned at the incident position of the collimated light. The reflector 11B has a conical reflecting surface. The axis of rotation of this conical surface is aligned with the optical axis of the collimated light (the optical axis of the collimating lens 11A). The reflector 11B reflects the collimated light, generating an annular beam 20 that extends in a circumferential direction along the inner circumferential surface of the object 60.

[0020] When the apex angle of the conical reflecting surface of the reflector 11B is 90°, the annular beam 20 expands into a disk shape (sheet shape). The inner circumferential surface of the object 60 is a rough surface with unevenness having a size equal to or greater than the wavelength of the annular beam 20. If the annular beam 20 is incident on the inner circumferential surface of the object 60, diffuse reflection will occur. The part where diffuse reflection occurs is called the diffuse reflection part 21. The diffuse reflection part 21 is along the intersection of a plane orthogonal to the central axis of the object 60 and the inner circumferential surface of the object 60. When the inner circumferential surface is a cylindrical surface, the diffuse reflection part 21 is circumferential in shape. A portion of the reflected light 22 diffusely reflected at the diffuse reflection part 21 is incident on the imaging device 12. The imaging device 12 receives the reflected light 22 and generates image data (sometimes simply referred to as "image"). That is, the optical probe 10 generates an image of the inner circumferential surface (inspected surface) of the object 60.

[0021] The generated image is input to the control unit 40 (Fig. 1). The control unit 40 obtains information about the inner circumferential surface of the object 60 by performing image analysis, such as the inner diameter, the shape of the cut surface, and whether there are scratches on the surface. The memory unit 41 (Fig. 1) stores information used to determine the exposure conditions (shutter speed, aperture, gain) of the imaging device 12.

[0022] Next, the function of the control unit 40 will be explained. The control unit 40 has the function of activating the light probe 10 under the first exposure condition to acquire an image of the inspected surface of the object 60 from the light probe 10. The memory unit 41 stores relational information, which represents the relationship between the characteristic values ​​of multiple optical cut-off images obtained by photographing the inspected surface of the sample under multiple exposure conditions and adjustment information that adjusts the exposure conditions so that the characteristic values ​​of each of the multiple optical cut-off images of the sample are close to the target value. The relational information stored in the memory unit 41 will be explained later with reference to Figures 4A and 4B. The control unit 40 further has the function of determining an appropriate second exposure condition based on the characteristic values ​​of the optical cut-off images in the acquired image, the relational information stored in the memory unit 41, and the first exposure condition. The method for determining the second exposure condition will be explained later with reference to Figures 4A and 4B. Furthermore, the control unit 40 has the function of activating the light probe 10 under the second exposure condition to acquire an image of the inspected surface of the object 60.

[0023] Next, referring to Figures 3A to 3D, the cut-off image and brightness distribution will be explained. Figures 3A and 3C are diagrams showing an example of the cut-off image 30. When the inner circumferential surface of the object 60 is a cylindrical surface, the cut-off image 30 is circumferential. Figures 3B and 3D are graphs showing the brightness distribution 31 in the radial direction of the cut-off images shown in Figures 3A and 3C, respectively. Figure 3C is a cut-off image obtained by slowing down the shutter speed compared to Figure 3A. Here, "shutter speed" refers to the time when the shutter of the imaging device 12 is open, and "slow shutter speed" means that the shutter is open for a long time.

[0024] The inner circumferential surface of the object 60 is inspected by detecting the position of the peak of the brightness distribution 31 in the radial direction r, for example, by measuring the inner diameter. To improve inspection accuracy, the position of the peak of the brightness distribution 31 must be detected with high precision. To detect the peak position of the brightness distribution 31 with high precision, sub-pixel processing can be used, for example. When measuring the average inner diameter, a fitting method can be used to find the circumference of the circle that best fits the closed curve connecting the peak positions of the brightness distribution 31.

[0025] As shown in Figure 3B, if the shutter speed is too fast, the peak of the brightness distribution becomes lower, and the detected peak position is easily affected by noise. As shown in Figure 3D, if the shutter speed is too slow, the peak of the brightness distribution 31 will exceed the saturation level Bsat. If the peak exceeds the saturation level Bsat, it is difficult to accurately detect the peak position. In particular, in the case of asymmetrical brightness distribution 31, the offset of the inferred peak position will become larger. In the first embodiment, a better shutter speed for high-precision peak position detection can be determined by a simple method.

[0026] Next, referring to Figures 4A and 4B, the "relationship information that represents the relationship between the characteristic quantity of the light cut-off image obtained from the sample and the adjustment information used to adjust the exposure conditions at that time to suitable exposure conditions" stored in the memory unit 41 will be explained.

[0027] For a sample manufactured under the same manufacturing conditions as the object 60, images of the inspected surface were acquired at various shutter speeds, and the number of pixels Ngt in the cut-off image within the image was counted. Figure 4A is a graph showing an example of the relationship between shutter speed and the number of pixels Ngt for evaluating the sample. The horizontal axis represents shutter speed on a logarithmic scale, and the vertical axis represents the number of pixels Ngt on a logarithmic scale. The relationship between shutter speed and the number of pixels Ngt obtained for the sample is represented by the thick solid line NS (hereinafter referred to as the exposure condition-pixel count relationship). The thin solid line NX in the graph represents the exposure condition-pixel count relationship in the object 60. However, the exposure condition-pixel count relationship in the object 60 is unknown.

[0028] If the shutter speed increases, the brightness of the cut-off image increases, and the pixel count Ngt increases. Even for products manufactured under the same manufacturing conditions, deviations in the reflectivity and scattering angle of the inner circumferential surface (the surface being inspected) can occur due to manufacturing variations. As a result, the amount of light incident on the imaging device 12 changes. Therefore, the curve representing the exposure condition-pixel count relationship varies from product to product. Therefore, the exposure condition-pixel count relationship (solid line NS) obtained for the sample and the exposure condition-pixel count relationship (solid line NX) obtained for the object 60 may not necessarily be the same.

[0029] The inventors of this application focus on the characteristic quantity of the optically cut-off image as an indicator for determining a better shutter speed. By adjusting the shutter speed so that the characteristic quantity of the optically cut-off image obtained at a certain shutter speed is close to a target value, a suitable shutter speed that can improve inspection accuracy is determined. In the first embodiment, the characteristic quantity of the optically cut-off image is the number of pixels (hereinafter referred to as the number of pixels Ngt) among the pixels constituting the optically cut-off image that have a brightness exceeding a predetermined threshold value.

[0030] First, for a single sample, the number of pixels Ngt required to obtain a brightness distribution 31 (Fig. 3B, Fig. 3D) that enables high-precision detection of the peak position of the brightness distribution was determined. The results of the same evaluation experiment for other samples clearly showed that this number of pixels Ngt was almost identical for all samples. The number of pixels Ngt required to obtain a brightness distribution 31 that enables high-precision detection of the peak position of the brightness distribution was set as the target value NT for the number of pixels.

[0031] As shown in Figure 4A, for a sample, the shutter speed when the number of pixels Ngt becomes the target value NT is marked as SST. The number of pixels Ngt when the shutter speed is set to SS1 is marked as N1.

[0032] For the object 60, the shutter speed when the number of pixels Ngt becomes the target value NT is denoted as ST, and the shutter speed when the number of pixels Ngt becomes N1 is denoted as S1. Assuming that among multiple objects 60, due to the different reflectivity or scattering angle of the inner peripheral surface (the surface being inspected), the amount of light incident on the imaging device 12 is different, and the brightness of the light-cut image changes according to the amount of light, it can be considered that the exposure condition-pixel count relationship (solid line NX) for the object 60 is obtained by stretching the exposure condition-pixel count relationship (solid line NS) for the sample in the horizontal axis direction. Based on the inventor's various evaluation experiments, it was confirmed that this assumption is satisfied.

[0033] Assuming that stretching the solid line NS in the horizontal direction yields the solid line NX, then the following equation holds. If equation (1) is modified, the following equation can be obtained. The shutter speed SST is a fixed value determined in advance, but the shutter speed SS1 varies according to the number of pixels N1. Therefore, (SST / SS1) in equation (2) is a function of the number of pixels N1. This function can be determined in advance based on the exposure conditions for the sample and the pixel count relationship (solid line NS).

[0034] If the number of pixels N1 of the cut-off image of the object 60 acquired at shutter speed S1 is known, then (SST / SS1) can be determined. By multiplying (SST / SS1) by shutter speed S1, the target shutter speed ST can be calculated. The coefficient (SST / SS1) multiplied by shutter speed S1 is called the shutter speed adjustment coefficient.

[0035] Figure 4B is a graph illustrating an example of the relationship between the number of pixels Ngt and the shutter speed adjustment factor (SST / SS1). The horizontal axis represents the number of pixels Ngt on a logarithmic scale, and the vertical axis represents the shutter speed adjustment factor (SST / SS1) on a logarithmic scale. As can be seen from Figure 4A, if the number of pixels Ngt increases, the shutter speed SS1 also increases. Therefore, if the number of pixels Ngt increases, the shutter speed adjustment factor (SST / SS1) decreases.

[0036] The number of pixels Ngt is one of the feature quantities of the light cut-off image obtained from the sample, and the shutter speed adjustment factor (SST / SS1) is one of the adjustment information used to adjust the shutter speed. That is, "the relationship information that represents the relationship between the feature quantity of the light cut-off image obtained from the sample and the adjustment information" is defined, for example, by the curve shown in Figure 4B.

[0037] The relationship information shown in Figure 4B includes the relationship between the feature quantity (number of pixels Ngt) and the exposure conditions (shutter speed SS1) when acquiring an optically cut-off image of the sample under various exposure conditions, and the exposure condition sample value (shutter speed SST) when acquiring an optically cut-off image of the sample suitable for inspection. The exposure condition sample value (shutter speed SST) is set to the maximum brightness of the optically cut-off image not exceeding the saturation level of the light-receiving element of the acquired image, and the position where the brightness distribution in the coarse direction of the optically cut-off image becomes the largest is not affected by noise.

[0038] Since the exposure condition sample value (shutter speed SST) is set in this way, the shutter speed ST calculated by formula (2) for the object 60 also satisfies the condition that the maximum brightness of the light cut-off image does not exceed the saturation level and the position where the brightness distribution in the roughness direction of the light cut-off image becomes the largest is not affected by noise.

[0039] Next, referring to FIG5, the inspection method of the first embodiment will be described. FIG5 is a flowchart showing the procedure of the inspection method of the first embodiment.

[0040] First, the shutter speed is set to the first shutter speed to acquire an image of the object 60 (step SA1). Next, the feature quantity of the light cut-off image in the acquired image is calculated (step SA2). As this feature quantity, the number of pixels Ngt with a brightness of the determination threshold value Bth or higher in the brightness distribution 31 (Figs. 3B and 3D) in the coarseness direction of the light cut-off image can be used.

[0041] Next, based on the calculated feature quantity, the first shutter speed at the time of execution step SA1, and the relational information stored in the memory unit 41 (Figure 4B), an appropriate shutter speed for inspection is determined (step SA3). For example, the shutter speed adjustment factor (SST / SS1) is determined based on the number of pixels Ngt and the relational information (Figure 4B). If the shutter speed adjustment factor (SST / SS1) is determined, the shutter speed ST is calculated according to equation (2). Here, the shutter speed S1 in equation (2) is equivalent to the first shutter speed, and the shutter speed ST is equivalent to the shutter speed for inspection. Next, the actual inspection is performed using the determined shutter speed ST for inspection (step SA4).

[0042] Next, the superior effects of the first embodiment will be explained. In the first embodiment, by setting the shutter speed to a first shutter speed to obtain an image of the surface to be inspected of the object 60 (step SA1), the appropriate shutter speed for inspection can be determined immediately without repeated trial and error (step SA3). For example, as shown in FIG4A, where the horizontal axis represents shutter speed on a logarithmic scale, repeated trial and error would require changing the shutter speed by approximately 1 / 100 to 100 times. Therefore, the number of repeated trial and error attempts could become extremely large. In the first embodiment, there is no need to repeatedly perform trial and error to find the appropriate shutter speed, thus improving inspection efficiency.

[0043] In the first embodiment, an example of inspecting the inner circumferential surface of a cylindrical object 60 is shown. However, the method for adjusting the exposure conditions used in the inspection method of the first embodiment can be applied to inspections using a more general optical cut-off method. The inspection method of the first embodiment can also be applied to the determination of the shape of the outer surface of an object, etc.

[0044] Next, a variation of the first embodiment will be described. In the first embodiment, shutter speed is used as the exposure condition to be adjusted, but aperture value or gain can also be used. In this case, the relationship between aperture value or gain and the number of pixels Ngt shown in FIG4A can be used instead of the relationship between shutter speed and the number of pixels Ngt. As the relationship information shown in FIG4B, it is sufficient to define the relationship between the number of pixels Ngt and the aperture value adjustment coefficient or the relationship between the number of pixels Ngt and the gain adjustment coefficient. More generally, as the relationship information, it is sufficient to define the relationship between the number of pixels Ngt and the exposure condition adjustment coefficient. In addition, as an example, shutter speed can be easily adjusted in the range of 10μs to 1s, which is a wider range than aperture value or gain. Therefore, if shutter speed is used as the exposure condition to be adjusted, it is advantageous from the viewpoint of having a wider range of adjustable exposure conditions.

[0045] When using any one of shutter speed, aperture value, and gain as the exposure conditions, in step SA1, an image of the surface to be inspected of the object 60 is acquired under the first exposure condition. In step SA3, the second exposure condition is determined simply based on the relationship information representing the relationship between the feature quantity (number of pixels Ngt) and the adjustment information, the feature quantity of the light cut-off image in the acquired image, and the first exposure condition. In step SA4, the inspection is performed simply by acquiring an image of the surface to be inspected of the object under the second exposure condition.

[0046] In the first embodiment, the brightness of the optically cut-off image obtained with high inspection accuracy is changed by adjusting the exposure conditions of the imaging device 12. Alternatively, the brightness of the optically cut-off image can also be changed by adjusting the output of the laser light source 15.

[0047] In the first embodiment, the number of pixels Ngt among the pixels constituting the light-cut-off image that have a brightness of a determination threshold value Bth or higher was used as a feature quantity, but other feature quantities may also be used. For example, a feature quantity that increases or decreases monotonically with respect to shutter speed, as shown in the curve of FIG4A, may be used as a feature quantity of the light-cut-off image.

[0048] For example, the average, median, dispersion, standard deviation, and other statistical quantities of the brightness values ​​of all pixels constituting the optical cut-off image or all pixels including the annular region of the optical cut-off image can also be used as the characteristic quantities of the optical cut-off image.

[0049] Alternatively, the values ​​described below can also be used as feature quantities. In fact, the light-cut-off image is formed into multiple arc-shaped images separated in the circumferential direction because the light is blocked by the components supporting the reflector 11B (FIG. 2), the light module fixing component 13 (FIG. 1), etc. For each of the multiple arc-shaped images, the contour lines of the regions with brightness values ​​of a critical value or higher are obtained. Alternatively, contour lines containing a certain number of pixels or more can be extracted, and the ratio of the total number of pixels in the region surrounded by these contour lines to the total perimeter of these contour lines can be used as the feature quantity of the light-cut-off image.

[0050] [Second Embodiment] Next, referring to Figures 6 and 7, the inspection device of the second embodiment will be described. Hereinafter, the description of the structure common to the inspection device of the first embodiment (Figures 1 to 5) will be omitted.

[0051] Figures 6 and 7 are schematic diagrams of the inspection device according to the second embodiment. In the first embodiment (Figure 1), in the standby state when no inspection is being performed, the optical probe 10 is positioned above the object 60. In the inspection device of the second embodiment, the optical probe 10 is positioned below the object 60 (below the support plate 51), and during inspection, the optical probe 10 rises and enters the space inside the object 60. The user moves the object 60 in and out of the housing 50 through the opening 50C provided in the housing 50.

[0052] The support mechanism 18 realizes an insertion state in which at least a portion of the optical probe 10 is disposed within the cylindrical portion of the object 60, and a standby state in which it is disposed outside the cylindrical portion. FIG6 shows the inspection device when the optical probe 10 is in the insertion state, and FIG7 shows the inspection device when the optical probe 10 is in the standby state. The inspection device of the second embodiment includes a proximity suppression device that prevents a user from approaching the object 60 when the optical probe 10 is in the insertion state. The proximity suppression device will be described in detail below.

[0053] The proximity suppression device prevents the user from approaching the object 60 installed on the inspection device. For example, if the user removes the object 60 while the optical probe 10 is in the inserted state, there is a risk that the object 60 will come into contact with the optical probe 10, causing damage to the optical probe 10. If the user is prevented from approaching the object 60 while the optical probe 10 is in the inserted state, damage to the optical probe 10 can be prevented.

[0054] As one of the proximity suppression devices, the inspection device includes an indicator 71. The operation of the indicator 71 is controlled by the control unit 40. When the optical probe 10 is in the insertion state, the indicator 71 informs the user that the optical probe 10 is in the insertion state. For example, the indicator 71 is a warning light that illuminates red and green lights. When the optical probe 10 is in the insertion state (Fig. 6), the indicator 71 illuminates the red light or makes it flash, and when the optical probe 10 is in the standby state (Fig. 7), the indicator 71 illuminates the green light.

[0055] By checking the illuminated color of the indicator 71, the user can easily determine whether the light probe 10 is in an inserted state or a standby state. If the indicator 71 is illuminated in red, the user will be careful not to approach the object 60. This helps to prevent damage to the light probe 10.

[0056] As one of the proximity suppression devices, the inspection device includes a door 54 that blocks the opening 50C of the housing 50. The user approaches the object through the opening 50C. The door 54 can be opened, closed, and locked. As the door 54, a sliding door, a swing door, etc. can be used. The control unit 40 locks and unlocks the door 54. When the optical probe 10 is in the inserted state, the door 54 is locked, and when the optical probe 10 is in the standby state, the door 54 is unlocked.

[0057] When the optical probe 10 is in the inserted state, the door 54 is locked, so the user cannot open the door 54 and approach the object 60. This prevents damage to the optical probe 10.

[0058] As one of the proximity suppression devices, the inspection device includes a detector 72 for detecting objects that intrude into the housing 50 through the opening 50C and an alarm transmitter 73. The control unit 40 activates the alarm transmitter 73 based on the detection result of the detector 72. When the optical probe 10 is in the inserted state, if the detector 72 detects an object intruding into the housing, the alarm transmitter 73 will sound an alarm. The detector 72 can be, for example, a light curtain or a zone sensor. The alarm transmitter 73 can be, for example, a sounder that outputs an alarm sound. In addition to the sounder, a display screen that shows an image to attract the user's attention can also be configured.

[0059] When performing maintenance, the door 54 is left unlocked. If the detector 72 detects an object intruding into the housing while the optical probe 10 is in the inserted state, the alarm transmitter 73 will sound an alarm, thus alerting the user that the optical probe 10 is in the inserted state and preventing them from approaching the object 60. This helps to prevent damage to the optical probe 10.

[0060] Alternatively, regardless of whether the optical probe 10 is in the inserted state or in the standby state, the detector 72 may emit a sound to alert the user when it detects an object entering the housing. The user will then carefully consider the possibility of the object 60 coming into contact with the optical probe 10 and perform the operation accordingly. This will help prevent damage to the optical probe 10.

[0061] [Third Embodiment] Next, referring to FIG8, the inspection device of the third embodiment will be described. Hereinafter, the description of the structure common to the inspection device of the first embodiment (FIGs 1 to 5) will be omitted.

[0062] The control unit 40 (FIG. 1) of the inspection device in the third embodiment has the function of obtaining the batch ID of the object 60. The batch ID can be obtained by means of reading the embossed text marked on the object 60 and manually inputting it by the user, by taking a picture of the embossed text with a camera and performing image analysis, by reading the barcode affixed to the object 60, or by reading the IC tag installed on the object 60.

[0063] Figure 8 is a flowchart showing the inspection procedure performed by the inspection device of the third embodiment. The control unit 40 determines whether other objects 60 in the same batch as the object 60 to be inspected have already been inspected (step SB1). If the objects 60 in the same batch have not yet been inspected, the inspection is performed using the same procedure as steps SA1 to SA4 in Figure 5.

[0064] If the objects 60 in the same batch as the objects 60 to be inspected have already been inspected, the control unit 40 performs the inspection under the same shutter speed used when inspecting the same batch of objects 60 (step SB2).

[0065] Next, the superior effects of the third embodiment will be explained. Since the inspection method of the first embodiment (Fig. 5) is used for inspecting the first object 60 in the same batch, the inspection can be completed in a short time without repeated trial and error. Since the second and subsequent objects 60 in the same batch are inspected under the already adjusted exposure conditions, the inspection time can be further shortened. In addition, regarding the objects 60 in the same batch, it can be assumed that the quality is consistent to some extent, so the shutter speed determined when inspecting the first object 60 can be applied to the second and subsequent objects 60.

[0066] Next, the inspection apparatus of the modified example of the third embodiment will be described. In the third embodiment, shutter speed is used as the exposure condition to be adjusted, but aperture value, gain, etc. can also be used in addition to this.

[0067] The above embodiments are examples, and of course, partial substitutions or combinations of the structures shown in different embodiments can be made. The same effects of the same configurations in multiple embodiments will not be mentioned individually for each embodiment. Furthermore, the present invention is not limited to the above embodiments. For example, the inventive should be able to make various changes, improvements, combinations, etc. This application claims priority based on Japanese Patent Application No. 2024-122572, filed on July 29, 2024. The entire contents of that Japanese application are incorporated herein by reference. [Simplified Explanation of the Diagram]

[0010] [Fig. 1] is a schematic diagram of the inspection apparatus of the first embodiment. [Fig. 2] is a schematic perspective view of the optical probe 10. [Fig. 3] In this diagram, Fig. 3A and Fig. 3C are diagrams showing an example of the optical cut-off image 30, and Fig. 3B and Fig. 3D are graphs showing the brightness distribution 31 in the radial direction of the optical cut-off image shown in Fig. 3A and Fig. 3C, respectively. [Fig. 4] In this diagram, Fig. 4A is a graph showing an example of the relationship between the shutter speed for sample evaluation and the number of pixels Ngt, and Fig. 4B is a graph showing the relationship between the number of pixels Ngt and the shutter speed adjustment factor (SST / SS1). [Fig. 5] is a flowchart showing the procedure of the inspection method of the first embodiment. [Fig. 6] is a schematic diagram of the inspection apparatus of the second embodiment. [Fig. 7] is a schematic diagram of the inspection apparatus of the second embodiment. [Fig. 8] is a flowchart showing the procedure of the inspection apparatus of the third embodiment performing the inspection.

Claims

1. An inspection apparatus comprising: a light probe for generating an image of an inspected surface of an object; a memory unit for storing relational information, the relational information representing a relationship between feature values ​​of multiple optically cut-off images obtained by photographing the inspected surface of a sample under multiple exposure conditions and adjustment information for adjusting the exposure conditions so that the feature values ​​of each of the multiple optically cut-off images of the sample are close to a target value; and a control unit for controlling the light probe, wherein the control unit operates the light probe under a first exposure condition to acquire an image of the inspected surface of the object, determines a second exposure condition based on the feature values ​​of the optically cut-off images in the acquired image, the aforementioned relational information stored in the memory unit, and the first exposure condition, and operates the light probe under the second exposure condition to acquire an image of the inspected surface of the object.

2. The inspection device as described in request item 1, wherein, The aforementioned object includes a cylindrical portion, and the aforementioned inspection device further includes: a support mechanism that supports the aforementioned optical probe to realize an insertion state in which at least a portion of the aforementioned optical probe is disposed within the aforementioned cylindrical portion and a standby state in which it is disposed outside the aforementioned cylindrical portion; and a proximity suppression device that suppresses the user from approaching the aforementioned object when the aforementioned optical probe is in the aforementioned insertion state.

3. The inspection device as described in request item 1, wherein, The aforementioned characteristic quantity refers to the number of pixels with brightness above the critical value.

4. The inspection device as described in claim 2, wherein, The aforementioned proximity suppression device includes a notification device that informs the user when the aforementioned optical probe is in the aforementioned insertion state.

5. The inspection device as claimed in claim 2 or 4, further comprising a housing, the housing defining a space for receiving the object and having an opening for the user to approach the object, the approach inhibition device comprising a door that can be opened, closed and locked to block the opening, the control unit locking the door when the optical probe is in the aforementioned insertion state and unlocking the door when in the aforementioned standby state.

6. The inspection device as described in claim 5, wherein, The aforementioned proximity suppression device includes: a detector for detecting objects that intrude into the aforementioned housing through the aforementioned opening; and an alarm transmitter for issuing an alarm when the aforementioned optical probe is in the aforementioned inserted state, if the aforementioned detector detects an object that has intruded into the aforementioned housing.

7. An inspection method, wherein, Under the first exposure condition, an image of the inspected surface of the object is acquired. Based on the relationship information indicating the relationship between the characteristic quantities of multiple optical cut-off images obtained by photographing the inspected surface of the sample under multiple exposure conditions and the adjustment information that adjusts the exposure conditions so that the characteristic quantities of the multiple optical cut-off images of the sample are close to the target value, the aforementioned characteristic quantities of the optical cut-off images in the acquired image, and the aforementioned first exposure condition, a second exposure condition is determined. Under the aforementioned second exposure condition, an image of the inspected surface of the object is acquired.

8. As in the inspection method for request item 7, where, The aforementioned relational information includes the relationship between the aforementioned characteristic quantities and exposure conditions when obtaining optically cut-off images of the aforementioned samples under various exposure conditions, and the sample values ​​of exposure conditions when obtaining optically cut-off images of the aforementioned samples suitable for inspection.

9. As in the inspection method for request item 8, where, The aforementioned exposure condition sample value is set such that the maximum brightness of the aforementioned light-cut image does not exceed the saturation level of the light-receiving element of the acquired image, and the location where the brightness distribution in the coarse direction of the aforementioned light-cut image becomes the largest is not affected by noise.

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