Inspection image generation device, inspection image generation method, control program, and gloss inspection system

Abstract

The present invention generates an inspection image by which an inspection of gloss can be executed with higher accuracy. An inspection image generation device according to an aspect of the present disclosure comprises: an acquisition unit that acquires a plurality of first images captured by illuminating an object from any of a plurality of different illumination directions; and a generation unit which, on the basis of an average value of the luminance values of each pixel in the plurality of first images and at least one luminance value higher than the average value among the luminance values of each of the plurality of pixels of the plurality of first images, generates an inspection image for carrying out an inspection pertaining to the gloss of the object.

Description

Inspection image generating device, inspection image generating method, control program, and gloss inspection system

[0001] The present disclosure relates to an inspection image generating device that generates an inspection image used to inspect the gloss of an object.

[0002] Inspection devices used to inspect the gloss of an object are known, and in such inspection devices, inspection is performed using an inspection image generated from an image captured by illuminating the object, as in the technique disclosed in Patent Document 1.

[0003] Japanese Patent Application Publication No. 2018-63207

[0004] An inspection image generating device according to one aspect of the present disclosure includes an acquisition unit that acquires a plurality of first images captured by illuminating an object from one of a plurality of different illumination directions, and a generation unit that generates an inspection image for inspecting the gloss of the object based on the average value of the brightness of each pixel in the plurality of first images and at least one brightness of each pixel in the plurality of first images that is higher than the average value.

[0005] An inspection image generating method according to one aspect of the present disclosure includes an acquisition step of acquiring a plurality of first images captured by illuminating an object from one of a plurality of different illumination directions, and a generation step of generating an inspection image for inspecting the gloss of the object based on an average value of the luminance of each pixel in the plurality of first images and at least one luminance of each pixel of the plurality of first images that is higher than the average value.

[0006] The inspection image generating device according to each aspect of the present disclosure may be realized by a computer. In this case, the control program for the inspection image generating device that causes the computer to operate as each part (software element) of the inspection image generating device to realize the inspection image generating device, and the computer-readable recording medium on which it is recorded, also fall within the scope of the present disclosure.

[0007] A gloss inspection system according to one aspect of the present disclosure comprises an illumination unit capable of illuminating an object from any one of a plurality of different illumination directions, a camera for capturing images of the object, and an inspection image generation device for illuminating the object from any one of the plurality of different illumination directions using the illumination unit to acquire a plurality of first images captured by the camera, and generating an inspection image for inspecting the gloss of the object based on an average value of the brightness of each pixel in the plurality of first images and at least one brightness of each pixel of the plurality of first images that is higher than the average value.

[0008] 1 is a block diagram showing the configuration of a gloss inspection system according to an embodiment of the present disclosure; FIG. 2 is a side view of an imaging device according to an embodiment of the present disclosure; FIG. 3 is a view of the imaging device as seen from above; FIG. 4 is an image of an image of an object; FIG. 5 is a first image of the object; FIG. 6 is an example of an image generated by multiplying the average value of the luminance of each pixel calculated by a first calculation unit according to an embodiment of the present disclosure by a coefficient, and using that value as the luminance of each pixel; FIG. 7 is an example of an image generated by multiplying the average value of the luminance of each pixel of a plurality of first images by a coefficient; FIG. 8 is a diagram showing an example of an inspection image generated by an image generation unit according to an embodiment of the present disclosure; and FIG. 9 is a flowchart showing an example of the flow of processing performed by an inspection image generation device according to an embodiment of the present disclosure.

[0009] An object of one aspect of the present disclosure is to realize an inspection image generation device or the like that can generate an inspection image that allows for more accurate gloss inspection. According to one aspect of the present disclosure, it is possible to generate an inspection image that allows for more accurate gloss inspection.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A gloss inspection system 1 according to an embodiment of the present disclosure is a system for inspecting whether or not there is an abnormality in gloss on the surface of an object.

[0011] (Configuration of gloss inspection system 1) Fig. 1 is a block diagram showing the configuration of the gloss inspection system 1. As shown in Fig. 1, the gloss inspection system 1 includes an imaging device 10, an inspection image generation device 20, and an inspection device 40.

[0012] The imaging device 10 captures an image to be used to generate a gloss inspection image (described later) by the inspection image generation device 20. Hereinafter, the image captured by the imaging device 10 and used to generate the gloss inspection image will be referred to as a first image. In the following description, the gloss inspection image will also be simply referred to as an inspection image.

[0013] Fig. 2 is a side view of the imaging device 10. Fig. 3 is a view of the imaging device 10 as seen from above. As shown in Figs. 2 and 3, the imaging device 10 includes a base 11 on which an object W to be inspected is placed, a camera 12, a first illumination unit 13, and a second illumination unit 16.

[0014] The camera 12 captures an image of the target W placed on the base 11. The camera 12 is disposed vertically above the base 11. The optical axis 12A of the camera 12 is perpendicular to the base 11. Therefore, the optical axis direction of the camera 12 is in the up-down direction. For example, a CCD (Charge-Coupled Device) camera or a CMOS (Complementary Metal-Oxide Semiconductor) camera can be used as the camera 12. In this embodiment, the target W1 is placed on the base 11 when the camera 12 captures the image. However, the gloss inspection system of the present disclosure is not limited to this. In one aspect of the present disclosure, the target W1 may be held by a holding mechanism (not shown) when the camera 12 captures the image. For example, the inner diameter hole of the target W1 may be chucked to hold the target W1.

[0015] The first illumination unit 13 is an illumination device that illuminates the target W placed on the base 11. As shown in FIG. 3 , the first illumination unit 13 includes a housing 14. The housing 14 is ring-shaped. The center of the housing 14 is located on the optical axis 12A of the camera 12, and the housing 14 is arranged in a plane perpendicular to the optical axis 12A. A plurality of light sources 15 are arranged inside the housing 14. In the present embodiment, eight light sources 15 are arranged in the first illumination unit 13. In the following description, the eight light sources 15 may be referred to as light source 15A to light source 15H in order to distinguish them from one another. The light sources 15A to 15H are each capable of emitting light independently. The light sources 15A to 15H are arranged on a circumference centered at the intersection of the optical axis 12A and a plane perpendicular to the optical axis of the camera 12. This allows the target W to be illuminated from multiple directions.

[0016] The number of light sources arranged in the first illumination unit 13 is not limited to eight. The number of light sources arranged in the first illumination unit 13 may be four or more. The multiple light sources 15 may be arranged evenly inside the housing 14.

[0017] The first illumination unit 13 is movable in the vertical direction. In this embodiment, as shown in FIG. 2 , the vertical height of the first illumination unit 13 is described as being adjustable between three levels: height H1, height H2, and height H3. In this case, the first illumination unit 13 can illuminate from any of a plurality of positions on three different planes perpendicular to the optical axis of the camera 12. The height position of the first illumination unit 13 is not limited to three levels. The first illumination unit 13 only needs to be able to illuminate at at least two heights. By using the first illumination unit 13 to illuminate from any of a plurality of positions on at least three different planes perpendicular to the optical axis of the camera 12, the contrast in the inspection image, described below, can be increased. The first illumination unit 13 can be moved vertically by a user directly or by a driving mechanism such as an actuator. In the gloss inspection system 1 of this embodiment, the first illumination unit 13 is configured to illuminate from any of a plurality of positions on a plane perpendicular to the optical axis of the camera 12 by using any of a plurality of light sources 15 arranged inside the housing 14 of the ring-shaped first illumination unit 13, but this is not limited to this. In one aspect of the present disclosure, a configuration may be adopted in which a single light source is moved to illuminate from any of a plurality of positions on a plane perpendicular to the optical axis of the camera 12. In another aspect of the present disclosure, a configuration may be adopted in which a light source that illuminates from any of a plurality of positions on a plane perpendicular to the optical axis of the camera 12 is provided at each of the plurality of positions.

[0018] The second illumination unit 16 is disposed on the optical axis of the camera 12. The second illumination unit 16 illuminates the object W by irradiating the object W with light coaxially with the optical axis 12A of the camera 12.

[0019] The inspection image generating device 20 generates an inspection image that is used by the inspection device 40 (described later) to inspect whether or not there is a gloss abnormality on the surface of an object, in other words, to inspect for gloss abnormalities. As shown in FIG. 1 , the inspection image generating device 20 includes a control unit 30, a memory unit 21, an input unit 22 that accepts input to the inspection image generating device 20, and a display unit 23 that displays various information. The memory unit 21 stores various data used by the control unit 30. The input unit 22 may be, for example, a keyboard or a mouse. The display unit 23 may be, for example, a display device such as a monitor.

[0020] The control unit 30 comprehensively controls each unit of the inspection image generating device 20. The control unit 30 includes an acquisition unit 31 and a generation unit 32.

[0021] The acquisition unit 31 acquires, from the imaging device 10, first images captured by the imaging device 10. In the gloss inspection system 1 of this embodiment, the acquisition unit 31 acquires, as the first images, the following 25 first images captured when illuminated from 25 different illumination directions: Eight images captured when the height of the first illumination unit 13 is set to height H1 and the target W is illuminated by any of the light sources 15A to 15H; Eight images captured when the height of the first illumination unit 13 is set to height H2 and the target W is illuminated by any of the light sources 15A to 15H; Eight images captured when the height of the first illumination unit 13 is set to height H3 and the target W is illuminated by any of the light sources 15A to 15H; An image captured when the target W is illuminated by the second illumination unit 16.

[0022] The 25 first images are images captured without changing the position of the camera 12 or the position of the target W. Therefore, in the 25 first images, the target W is captured at the same position.

[0023] FIG. 4 is an image of an object W1. As shown in FIG. 4, the object W1 has a member that is roughly parallelogram-shaped in a plan view. The following description will use as an example a method for identifying an abnormal gloss location in the parallelogram-shaped member of the object W1. As shown in FIG. 4, an abnormal gloss location 100 exists in the object W1. The abnormal gloss location 100 appears whitish in the image shown in FIG. 4. The abnormal gloss location 100 in the object W1 is a location where the PVD (Physical Vapor Deposition) coating was not properly formed when the coating was applied, and fine irregularities are formed on the surface. Therefore, light irradiated onto the abnormal gloss location 100 is diffusely reflected by the abnormal gloss location 100. Furthermore, the object W1 also has a dirty location 101 where dirt is attached. The dirty location 101 absorbs the light irradiated onto it, and therefore appears black in the image shown in FIG. 4. In the object W1, a portion that is neither an abnormal gloss portion 100 nor a dirty portion 101 is a normal portion 102. Illuminated light is specularly reflected in the normal portion 102. The object W1 has a triangular shape with each corner tilted toward the depth of the page, and appears white in the image shown in FIG.

[0024] FIG. 5 shows 25 first images P1 to P25 of the target W1. The first images P1 to P8 shown in FIG. 5 are images captured when the height of the first illumination unit 13 is set to height H1 and the light sources 15A to 15H are sequentially switched to illuminate the target W1. The first images P9 to P16 shown in FIG. 5 are images captured when the height of the first illumination unit 13 is set to height H2 and the light sources 15A to 15H are sequentially switched to illuminate the target W1. The first images P17 to P24 shown in FIG. 5 are images captured when the height of the first illumination unit 13 is set to height H3 and the light sources 15A to 15H are sequentially switched to illuminate the target W1. The image P25 shown in FIG. 5 is an image captured when the target W1 is illuminated by the second illumination unit 16. For example, the first image P1, the first image P9, and the first image P17 are images captured by illuminating with the same light source 15A at different elevation angles by changing the height of the first illumination unit 13 to height H1, height H2, and height H3.

[0025] As shown in FIG. 5 , the brightness (luminance) of each pixel in each of the first images P1 to P25 varies depending on the illumination direction of the target W1. Specifically, the normal area 102 has a high luminance in at least one of the first images P1 to P25. This is because, when illuminated from any of the 25 illumination directions, specularly reflected light reaches the camera 12 at the normal area 102. The gloss abnormal area 100 has a luminance above a certain level in each of the first images P1 to P25 due to diffuse reflection of the illuminated light, but the luminance is lower than the maximum luminance of the pixel corresponding to the normal area 102. Therefore, the maximum luminance of the pixel corresponding to the gloss abnormal area 100 is lower than the maximum luminance of the pixel corresponding to the normal area 102. The luminance of the stained area 101 is lower in each of the first images P1 to P25 because the illuminated light is absorbed by the stain.

[0026] The generation unit 32 generates an inspection image based on the average luminance value and the maximum luminance value for each pixel in the plurality of first images P1 to P25 acquired by the acquisition unit 31. The generation unit 32 includes a first calculation unit 32A, a second calculation unit 32B, and an image generation unit 32C.

[0027] The first calculation unit 32A calculates the average value of the luminance for each pixel of the plurality of first images. In this embodiment, the first calculation unit 32A calculates the average value of the luminance for each pixel of the 25 first images P1 to P25.

[0028] The second calculation unit 32B calculates the difference between the value obtained by multiplying the average luminance value for each pixel calculated by the first calculation unit 32A by a coefficient and the maximum luminance value for each pixel. In this embodiment, the second calculation unit 32B calculates the difference by subtracting the maximum luminance value for each pixel from the value obtained by multiplying the average luminance value for each pixel calculated by the first calculation unit 32A by a coefficient. In this case, the coefficient may be set, for example, so that the difference for pixels corresponding to the abnormal gloss portion 100 is greater than 0. The coefficient may also be set so that the difference for pixels corresponding to the normal portion 102 is close to 0.

[0029] Image generator 32C generates an inspection image in which the difference calculated by second calculator 32B is used as the luminance of each pixel. The inspection image has the same number of pixels as first images P1 to P25.

[0030] Fig. 6 is an example of an image generated by multiplying the average luminance value for each pixel calculated by the first calculation unit 32A by a coefficient, and setting the luminance value for each pixel as the luminance. Fig. 7 is an example of an image generated by multiplying the maximum luminance value for each pixel of the multiple first images P1 to P25 as the luminance value for each pixel. Fig. 8 is a diagram showing an example of an inspection image generated by the image generation unit 32C.

[0031] As described above, the irradiated light is diffusely reflected at the gloss abnormality area 100, while the irradiated light is specularly reflected at the normal area 102. Therefore, as shown in FIG. 6 , the average luminance values ​​of the pixels corresponding to the gloss abnormality area 100 and the normal area 102 are substantially the same. Because the irradiated light is absorbed by the dirt at the stained area 101, as shown in FIG. 6 , the average luminance value of the pixels corresponding to the stained area 101 is smaller than the average luminance values ​​of the pixels corresponding to the gloss abnormality area 100 and the normal area 102. Because the irradiated light is diffusely reflected at the gloss abnormality area 100, while the irradiated light is specularly reflected at the normal area 102, as shown in FIG. 7 , the maximum luminance value of the pixels corresponding to the gloss abnormality area 100 is smaller than the maximum luminance value of the pixels corresponding to the normal area 102. Therefore, the difference calculated by the second calculation unit 32B for the pixels corresponding to the gloss abnormality area 100 is larger than the difference calculated by the second calculation unit 32B for the pixels corresponding to the normal area 102. 8, in the inspection image generated by the image generating unit 32C, the pixels corresponding to the abnormal gloss area 100 are displayed brighter than the pixels corresponding to the normal area 102. As for the pixel corresponding to the stained area 101, the maximum brightness value exceeds the average brightness value, and therefore the pixel is displayed dark in the inspection image.

[0032] The inspection image shown in FIG. 8 is an image generated by setting the coefficients so that the difference for pixels corresponding to normal area 102 is near 0. Therefore, the brightness of pixels corresponding to dirty area 101 and normal area 102 is near 0, and only pixels corresponding to abnormal gloss area 100 are displayed brightly, resulting in a large difference in brightness between dirty area 101 and normal area 102 and abnormal gloss area 100. This makes it easier to identify abnormal gloss area 100 in the inspection image. Furthermore, as in the inspection image shown in FIG. 8, the inspection image generation device 20 of this embodiment can generate an inspection image in which the influence of unevenness is reduced when unevenness is present on object W1, thereby generating an inspection image that can detect abnormal gloss with greater accuracy.

[0033] The inspection device 40 inspects whether or not there is a gloss abnormality on the surface of the object using the inspection image generated by the inspection image generation device 20. Specifically, the inspection device 40 identifies pixels in the inspection image output from the inspection image generation device 20 whose luminance is greater than a predetermined threshold. These pixels correspond to pixels whose maximum luminance value in the plurality of first images is smaller than the other pixels, i.e., locations where gloss abnormality locations 100 exist. Hereinafter, pixels in the inspection image whose luminance is greater than a predetermined threshold will be referred to as gloss abnormal pixels.

[0034] The inspection device 40 may determine that the object W is defective if there are abnormal gloss pixels in the inspection image. Alternatively, the inspection device 40 may determine that the work has abnormal gloss and classify it as defective if the proportion of pixels identified as abnormal gloss pixels is a predetermined proportion or more of the total number of pixels in the inspection image.

[0035] (Processing Performed by Inspection Image Generating Apparatus 20) The flow of processing (inspection image generating method) performed by the inspection image generating apparatus 20 will be described below with reference to Fig. 9. Fig. 9 is a flowchart showing an example of the flow of processing performed by the inspection image generating apparatus 20.

[0036] In the process performed by the inspection image generating device 20, the acquisition unit 31 first acquires a first image captured by the imaging device 10 from the imaging device 10 (step S1, acquisition step). In this embodiment, as described above, the height of the first illumination unit 13 is set to one of heights H1 to H3. The acquisition unit 31 then acquires 24 images captured when the target W is illuminated by one of the light sources 15A to 15H, and an image captured when the target W is illuminated by the second illumination unit 16. In the gloss inspection system 1 according to one aspect of the present disclosure, the 24 first images may be acquired excluding the image captured when the target W is illuminated by the second illumination unit 16. In the image captured when the target W is illuminated by the second illumination unit 16, the surface of the target W perpendicular to the optical axis 12A of the camera 12 is bright. Therefore, by acquiring a first image including an image captured when the object W is illuminated by the second illumination unit 16, the difference between the abnormal gloss area 100 and the normal area 102 in the plane perpendicular to the optical axis 12A of the camera 12 can be increased in the generated inspection image.

[0037] Next, the first calculation unit 32A calculates the average luminance value for each pixel of the 25 first images by multiplying it by a coefficient (step S2). Specifically, the first calculation unit 32A calculates the average luminance value for each pixel of the 25 first images, and the second calculation unit 32B calculates the average luminance value for each pixel calculated by the first calculation unit 32A by a coefficient. Next, the second calculation unit 32B calculates the maximum luminance value for each pixel of the 25 first images (step S3). Next, the second calculation unit 32B calculates the difference between the average luminance value for each pixel multiplied by the coefficient and the maximum luminance value for each pixel (step S4). Next, the second calculation unit 32B generates an inspection image in which the calculated difference is used as the luminance of each pixel (step S5). Steps S2 to S5 are generation steps for generating an inspection image for inspecting the gloss of the object W based on the luminance and maximum luminance values ​​for each pixel in the 25 first images.

[0038] (Effects of the Gloss Inspection System 1) Here, if the object W has unevenness, the image captured by illuminating the object W from one direction will have shadows due to the unevenness, making it impossible to perform gloss inspection on the shadowed areas. For this reason, in conventional gloss inspection systems, the shape of the object W is determined in advance, and for the shadowed areas, gloss inspection is performed using an image captured by illuminating from another direction that does not cast a shadow when illuminated. For this reason, it is necessary to determine the shape of the object W, and in order to inspect multiple types of object W, it is necessary to set the illumination direction for each object W. This results in a complex optical system, which poses the problem of time-consuming setup for inspection.

[0039] In contrast, in the gloss inspection system 1 of this embodiment, the inspection image generating device 20 includes: (1) an acquisition unit 31 that acquires multiple first images captured by illuminating the target W from one of multiple different illumination directions; and (2) a generation unit 32 that generates an inspection image based on the average luminance value and the maximum luminance value for each pixel in the multiple first images. According to this configuration, the acquisition unit 31 acquires multiple first images captured by illuminating the target W from one of multiple different illumination directions. Even if the target W has irregularities, in at least one of the multiple first images, the luminance of the pixel corresponding to the normal portion 102 increases due to light specularly reflected from the normal portion 102. On the other hand, because light is diffusely reflected from the abnormal gloss portion 100, the maximum luminance value of the pixel corresponding to the abnormal gloss portion 100 is small in all of the multiple first images. Therefore, the maximum luminance value differs greatly between the abnormal gloss portion 100 and the normal portion 102. The generation unit 32 generates an inspection image based on the average brightness value where the difference between the abnormal gloss area 100 and the normal area 102 is small and the maximum brightness value where the difference between the abnormal gloss area 100 and the normal area 102 is large. This allows the generation of an inspection image that is independent of the shape of the object W. As a result, the gloss inspection system 1 of this embodiment can generate an inspection image without setting the illumination direction according to the shape of the object W. Furthermore, since the inspection image is an image in which the influence of unevenness on the object W is reduced, the inspection device 40 can perform high-precision inspection. As a result, the inspection threshold can be appropriately set, thereby improving product yield. Furthermore, the gloss inspection system 1 of this embodiment can generate an inspection image that can detect gloss abnormalities on curved surfaces and / or undulating portions, even if the object W1 is not composed solely of flat surfaces but also has curved surfaces and / or undulating portions. Alternatively, the gloss inspection system 1 of this embodiment can generate an inspection image that can accurately inspect the gloss level, even if the object W1 is not composed solely of flat surfaces but also has curved surfaces and / or undulating portions.

[0040] In this embodiment, the generation unit 32 generates an inspection image in which the luminance of each pixel is the difference between the average luminance of each pixel calculated by the first calculation unit 32A multiplied by a coefficient and the maximum luminance of each pixel. This reduces the luminance of pixels corresponding to normal areas 102 and increases the luminance of pixels corresponding to abnormal gloss areas 100. This makes the pixels corresponding to abnormal gloss areas 100 appear brighter in the inspection image, making them easier to visually identify. Furthermore, with the above configuration, the luminance of pixels corresponding to dirty areas 101 in the inspection image appears darker, similar to the luminance of pixels corresponding to normal areas 102. Therefore, even when dirt is present on the target W, an inspection image can be generated in which only the pixels corresponding to abnormal gloss areas 100 appear brighter.

[0041] In one aspect of the present disclosure, as described above, the coefficient may be set so that the difference for pixels corresponding to the normal portion 102 is close to 0. This makes it possible to generate an inspection image in which only pixels corresponding to the gloss abnormal portion 100 are displayed brightly, making the gloss abnormal portion 100 easier to see.

[0042] In the gloss inspection system 1 according to the present embodiment, the first illumination unit 13 is moved vertically to illuminate from one of a plurality of positions at different distances from the target W1 in the optical axis direction of the camera 12. However, this is not limited to this. In one aspect of the present disclosure, a single light source may be moved to illuminate from one of a plurality of positions at different distances from the target W1 in the optical axis direction of the camera 12. Also, in one aspect of the present disclosure, a light source may be provided at each of a plurality of positions at different distances from the target W1 in the optical axis direction of the camera 12. In another aspect of the present disclosure, multiple light sources emitting the same amount of light may be evenly arranged in a hemispherical dome shape, and the multiple light sources may emit light in divided increments. This allows multiple first images to be acquired without moving the light source or the illumination unit.

[0043] In the gloss inspection system 1 according to one aspect of the present disclosure, the generator 32 may generate an inspection image in which the luminance of each pixel is the difference between the maximum luminance of each pixel and the average luminance of each pixel calculated by the first calculator 32A. In this case, an inspection image can be generated in which the normal areas 102 are displayed brightly and the abnormal gloss areas 100 are displayed darkly.

[0044] Although the gloss inspection system 1 of the present embodiment is configured to generate an inspection image based on the average luminance value and the maximum luminance value for each pixel in the multiple first images, the gloss inspection system 1 of the present disclosure is not limited to this configuration. In one aspect of the gloss inspection system 1 of the present disclosure, the generation unit 32 may generate an inspection image based on the average luminance value for each pixel in the multiple first images and at least one luminance value higher than the average value among the luminance values ​​for each pixel in the multiple first images. For example, the generation unit 32 may calculate an average value of multiple luminance values ​​higher than the average value among the luminance values ​​for each pixel in the multiple first images. Hereinafter, the "average value of multiple luminance values ​​higher than the average value among the luminance values ​​for each pixel in the multiple first images" will be referred to as the "first luminance." The generation unit 32 may generate an inspection image in which the luminance of each pixel is the difference obtained by subtracting the first luminance from the average luminance value for each pixel calculated by the first calculation unit 32A. This allows the generation unit 32 to generate an inspection image in which pixels corresponding to abnormal gloss areas 100 appear brighter than pixels corresponding to normal areas 102. In the gloss inspection system 1 according to one aspect of the present disclosure, the generator 32 may calculate, as the first luminance, an average value of the luminances of the pixels in the plurality of first images whose difference from the average value of the luminances of the pixels in the plurality of first images is equal to or greater than a predetermined threshold. The generator 32 may generate an inspection image in which the luminance of each pixel is the difference obtained by subtracting the first luminance from the average value of the luminances of the pixels calculated by the first calculator 32A.

[0045] Here, if the brightness of the first image captured by the camera 12 is saturated at the upper limit of the sensor equipped in the camera 12 or the upper limit of the image bit rate format, the actual brightness of the target W cannot be obtained from the first image captured by the camera 12. Therefore, the generation unit 32 cannot generate an inspection image based on the actual brightness of the target W. In this case, using the inspection image generated by the generation unit 32 would result in detection errors in detecting the gloss abnormality area 100 and reduced inspection accuracy. Therefore, in one aspect of the gloss inspection system 1 of the present disclosure, the inspection image generation device 20 may analogize the brightness of the saturated brightness area based on brightness gradient information of areas surrounding the saturated brightness area in the first image and generate an inspection image using the analogized result. This allows the inspection image generation device 20 to generate an inspection image based on a brightness that approximates the actual brightness of the target W. As a result, detection errors in detecting the gloss abnormality area 100 can be reduced, enabling more accurate detection of the gloss abnormality area 100.

[0046] In the present embodiment, the inspection image generated by the inspection image generating device 20 is used to inspect whether or not there is an abnormal gloss on the surface of the object, but the present disclosure is not limited to this. In a unique aspect of the present disclosure, the inspection image generated by the inspection image generating device 20 may be used to inspect the degree of gloss on the surface of the object. That is, the inspection image may be an inspection image for inspecting the degree of gloss on the object. In this case, the inspection device 40 may be configured to inspect the degree of gloss on the surface of the object by calculating the degree of gloss of the object W based on the brightness of each pixel of the inspection image output from the inspection image generating device 20.

[0047] The gloss inspection system 1 according to an embodiment of the present disclosure can be applied to inspecting the gloss of a surface of a large object W1, such as a vehicle, by enlarging the imaging device 10. As another example, the gloss inspection system 1 according to an embodiment of the present disclosure can be applied to checking the progress of polishing in a polishing process, in particular, checking the progress of polishing an object W1 having a curved and / or undulating portion on its surface.

[0048] [Example of implementation using software] The functions of the inspection image generating device 20 (hereinafter referred to as the "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device (particularly each part included in the control unit 30).

[0049] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The functions described in each of the above embodiments are realized by executing the program using the control device and storage device.

[0050] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0051] In addition, some or all of the functions of each of the control blocks can be realized by logic circuits. For example, integrated circuits in which logic circuits that function as each of the control blocks are formed are also included in the scope of the present disclosure. In addition, the functions of each of the control blocks can also be realized by, for example, a quantum computer.

[0052] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be variously changed, modified, or modified within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. For example, the functions contained in each component, etc. can be rearranged so as not to cause logical contradictions, and multiple components, etc. can be combined into one or divided. In other words, it should be noted that those skilled in the art can easily make various modifications or alterations based on the present disclosure. It should also be noted that these modifications, alterations, or alterations are included within the scope of the present disclosure.

[0053] [Summary] The inspection image generating device according to aspect 1 of the present disclosure includes an acquisition unit that acquires a plurality of first images captured by illuminating an object from one of a plurality of different illumination directions, and a generation unit that generates an inspection image for inspecting the gloss of the object based on the average value of the luminance of each pixel in the plurality of first images and at least one luminance of each pixel in the plurality of first images that is higher than the average value.

[0054] An inspection image generating device according to aspect 2 of the present disclosure may be configured in the above-mentioned aspect 1 such that the generation unit generates the inspection image based on the difference between the average brightness and a first brightness calculated based on at least one brightness higher than the average brightness among the brightnesses of each of the plurality of pixels in the plurality of first images.

[0055] An inspection image generating device according to aspect 3 of the present disclosure may be configured in the above-mentioned aspect 1 such that the generation unit generates as the inspection image an image in which the brightness of each pixel is set based on the difference between a value obtained by multiplying the average brightness of each pixel by a coefficient and a first brightness calculated based on at least one brightness among the brightnesses of each pixel of the plurality of first images that is higher than the average brightness.

[0056] In the inspection image generating device of aspect 4 of the present disclosure, in the above-mentioned aspect 3, the coefficient may be set so that the difference between pixels at gloss abnormality locations where gloss abnormalities exist on the surface of the object is greater than 0.

[0057] An inspection image generation device according to aspect 5 of the present disclosure may be configured such that, in any of aspects 1 to 4 above, the generation unit generates the inspection image based on the average value and the maximum brightness value for each pixel in the plurality of first images.

[0058] An inspection image generating device according to aspect 6 of the present disclosure may be configured such that, in any of aspects 1 to 5 above, the acquisition unit acquires the plurality of first images, each of which includes an image captured when the object is illuminated from one of a plurality of positions on a plane perpendicular to the optical axis of a camera that captures the object.

[0059] An inspection image generating device according to aspect 7 of the present disclosure may be configured in the above-described aspect 6 such that the acquisition unit acquires the plurality of first images each including an image captured when illuminated from any of at least eight positions on a circumference centered at the intersection of a plane perpendicular to the optical axis and the optical axis.

[0060] The inspection image generating device according to aspect 8 of the present disclosure may be configured in any one of aspects 1 to 7 above, wherein the acquisition unit acquires the plurality of first images each including an image captured when the object is illuminated from one of a plurality of positions at different distances from the object on the optical axis of a camera capturing the object.

[0061] An inspection image generating device according to aspect 9 of the present disclosure may be configured in the above-mentioned aspect 8 such that the acquisition unit acquires the plurality of first images, each of which includes an image captured when illuminated from any of a plurality of positions in at least three different planes perpendicular to the optical axis.

[0062] The inspection image generating device according to aspect 10 of the present disclosure may be configured such that, in any of aspects 1 to 9 above, the acquisition unit acquires the plurality of first images including images captured by illuminating the object from a light source located on the optical axis of a camera that captures the object.

[0063] In an inspection image generating device according to aspect 11 of the present disclosure, in any of aspects 1 to 10 above, the inspection image may be an inspection image for inspecting gloss abnormalities in the object.

[0064] In the inspection image generating device according to aspect 12 of the present disclosure, in any one of aspects 1 to 10 above, the inspection image may be an inspection image for inspecting the degree of gloss of the object.

[0065] An inspection image generation method according to aspect 13 of the present disclosure includes an acquisition step of acquiring a plurality of first images captured by illuminating an object from one of a plurality of different illumination directions, and a generation step of generating an inspection image for inspecting the gloss of the object based on the average value of the luminance of each pixel in the plurality of first images and at least one luminance of each pixel in the plurality of first images that is higher than the average value.

[0066] A control program according to aspect 14 of the present disclosure is a control program for causing a computer to function as an inspection image generation device that includes an acquisition unit that acquires a plurality of first images captured by illuminating an object from one of a plurality of different lighting directions, and a generation unit that generates an inspection image for inspecting the gloss of the object based on an average value of the brightness of each pixel in the plurality of first images and at least one brightness of each pixel in the plurality of first images that is higher than the average value, and is a program for causing a computer to function as the acquisition unit and the generation unit.

[0067] A gloss inspection system according to aspect 15 of the present disclosure comprises an illumination unit capable of illuminating an object from any one of a plurality of different illumination directions, a camera for capturing images of the object, and an inspection image generation device for illuminating the object from any one of the plurality of different illumination directions using the illumination unit, acquiring a plurality of first images captured by the camera, and generating an inspection image for inspecting the gloss of the object based on an average value of the brightness of each pixel in the plurality of first images and at least one brightness of each pixel of the plurality of first images that is higher than the average value.

[0068] REFERENCE SIGNS LIST 1 Gloss inspection system 10 Imaging device 12 Camera 12A Optical axis 13 First illumination unit (illumination unit) 16 Second illumination unit (illumination unit) 20 Inspection image generating device 31 Acquisition unit 32 Generation unit

Claims

1. An acquisition unit that acquires a plurality of first images captured by illuminating an object from any one of a plurality of different illumination directions; and a generation unit that generates an inspection image for inspecting the gloss of the object based on an average value of luminance for each pixel in the plurality of first images and at least one luminance higher than the average value among the luminances of the plurality of pixels in the plurality of first images. An inspection image generation apparatus comprising:

2. The inspection image generation apparatus according to claim 1, wherein the generation unit generates the inspection image based on a difference between the average value of the luminance and a first luminance calculated based on at least one luminance higher than the average value among the luminances of the plurality of pixels in the plurality of first images.

3. The inspection image generation apparatus according to claim 1, wherein the generation unit generates, as the inspection image, an image in which the luminance of each pixel is set based on a difference between a value obtained by multiplying the average value of the luminance per pixel by a coefficient and a first luminance calculated based on at least one luminance higher than the average value among the luminances of the plurality of pixels in the plurality of first images.

4. The inspection image generation apparatus according to claim 3, wherein the coefficient is set such that the difference of the pixels at a gloss abnormality location where there is a gloss abnormality on the surface of the object is greater than 0.

5. The inspection image generation apparatus according to any one of claims 1 to 4, wherein the generation unit generates the inspection image based on the average value and the maximum value of the luminance for each pixel in the plurality of first images.

6. The inspection image generation apparatus according to any one of claims 1 to 5, wherein the acquisition unit acquires the plurality of first images including images respectively captured when illuminating from any one of a plurality of positions on a plane perpendicular to the optical axis of the camera that images the object.

7. The inspection image generation apparatus according to claim 6, wherein the acquisition unit acquires the plurality of first images including images respectively captured when illuminating from any one of at least eight positions on a circumference centered at an intersection of the plane perpendicular to the optical axis and the optical axis.

8. The inspection image generation apparatus according to any one of claims 1 to 7, wherein the acquisition unit acquires the plurality of first images including images respectively captured when illuminating from any one of a plurality of positions at different distances from the object on the optical axis of the camera that images the object.

9. The inspection image generation apparatus according to claim 8, wherein the acquisition unit acquires the plurality of first images including images respectively captured when illuminating from any one of a plurality of positions in at least three different planes perpendicular to the optical axis.

10. The inspection image generation apparatus according to any one of claims 1 to 9, wherein the acquisition unit acquires the plurality of first images including an image captured by illuminating from a light source on the optical axis of a camera that images the object.

11. The inspection image generation apparatus according to any one of claims 1 to 10, wherein the inspection image is an inspection image for inspecting gloss abnormality in the object.

12. The inspection image generation apparatus according to any one of claims 1 to 10, wherein the inspection image is an inspection image for inspecting the degree of gloss of the object.

13. An inspection image generation method including: an acquisition step of acquiring a plurality of first images captured by illuminating an object from any one of a plurality of different illumination directions; and a generation step of generating an inspection image for inspecting the gloss of the object based on an average value of luminances for each pixel in the plurality of first images and at least one luminance higher than the average value among the luminances for each pixel in the plurality of first images.

14. A control program for causing a computer to function as an inspection image generation apparatus including: an acquisition unit that acquires a plurality of first images captured by illuminating an object from any one of a plurality of different illumination directions; and a generation unit that generates an inspection image for inspecting the gloss of the object based on an average value of luminances for each pixel in the plurality of first images and at least one luminance higher than the average value among the luminances for each pixel in the plurality of first images, the control program for causing the computer to function as the acquisition unit and the generation unit.

15. A gloss inspection system comprising: an illumination unit capable of illuminating an object from any one of a plurality of different illumination directions; a camera that images the object; and an inspection image generation device that illuminates the object from any one of the plurality of different illumination directions by the illumination unit, acquires a plurality of first images imaged by the camera, and generates an inspection image for performing an inspection regarding the gloss of the object based on an average value of luminance for each pixel in the plurality of first images and at least one luminance higher than the average value among the luminances for each pixel of the plurality of first images.

Images