Inspection device

Abstract

To provide an inspection device capable of performing inspection in an optimum position corresponding to a state of a flaw.SOLUTION: An inspection device includes two parallel illumination devices 3 that are provided along a direction of a straight line and apply light to an inspection object 9, multiple area cameras 5 provided in a gap of between the two illumination devices 3, and a conveyance apparatus 21 for conveying the inspection object 9, acquires an image of a boundary area 62 between a regular reflection area 61 and a non-regular reflection area 63 from the inspection object 9 that travels by using a moving device 2 by using the area cameras 5 in a state in which an area below the illumination device 3 is set as the regular reflection area 61 and an area in the side of the illumination device 3 is set as the non-regular reflection area 63, and inspects the inspection object 9 by using the acquired image.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an inspection apparatus for inspecting the appearance of an article, and more particularly to an inspection apparatus that can perform inspection with high accuracy by changing illumination conditions. [Background technology]

[0002] In general, when inspecting the formation state of an object to be inspected, an illumination device such as a coaxial epi-illumination or ring illumination is used to irradiate the object with light, and the reflected light is captured by a camera to perform the inspection. In this case, with a coaxial epi-illumination, the flat surface of the object to be inspected can be brightened by capturing specularly reflected light, and with a ring illumination, the surface of the object to be inspected can be irradiated with light obliquely, making it possible to inspect the normal surface dark (Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-66274 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such an inspection device, the reflected light irradiated from the inspection object to the camera includes specular reflected light and diffused light, and the specular reflected light is received by the camera more strongly than the diffused light.

[0005] When an image of a flaw is obtained by such reflected light, the direction of specular reflection of the flaw formed on the surface of the object to be inspected changes depending on the inclination of the flaw surface, so that in the specular reflection area, the light from the flaw is no longer in specular reflection state and appears black, and in the non-specular reflection area, the light from the flaw is in specular reflection state and appears white. Note that in this specular reflection area, if the specular reflection area is enlarged by, for example, increasing the size of the light source, the flaw may not be clearly visible due to the light from the light source irradiated from various places.

[0006] On the other hand, if the scratch is far from the specular reflection area, it will not appear white unless the inclination of the scratch surface becomes large. In other words, the further away from the specular reflection area the scratch is, the less likely it is to appear white.

[0007] For this reason, in the past, it was necessary to perform inspection at the optimum position depending on the state of the scratch, including the regular reflection area and other areas.

[0008] Therefore, the present invention has been made in consideration of the above-mentioned problem, and has an object to provide an inspection device that enables inspection at an optimal position depending on the state of the scratch. [Means for solving the problem]

[0009] In other words, in order to solve the above-mentioned problems, the present invention is configured to include an illumination device that is arranged along a linear direction and irradiates light onto an object to be inspected, an area camera that acquires reflected light of the light irradiated from the illumination device, a moving device that moves the object to be inspected, and an inspection unit that uses the area camera to acquire an image of the boundary area between the specular reflection area and the non-specular reflection area from the object to be inspected that is moved using the moving device, with the area below the illumination device being a specular reflection area and the areas to the sides of the specular reflection area being non-specular reflection areas, and inspects the quality of the object to be inspected based on the acquired image.

[0010] With this configuration, it is possible to inspect the flaw at the optimum position according to its condition, and for example, for small flaws, it is possible to inspect the flaw by making it conspicuous in the boundary area beside the regular reflection area, thereby improving the inspection accuracy.

[0011] In the invention, a plurality of the illumination devices are provided in parallel, and a plurality of the boundary regions are set within the angle of view of the area camera.

[0012] With this configuration, the boundary area on either side of the regular reflection area is reduced in a conventional large lighting device, but by providing multiple lighting devices arranged in a linear direction, the boundary area can be increased, making defects easier to see.

[0013] Furthermore, a plurality of the area cameras are provided along the linear direction of the lighting devices.

[0014] With this configuration, it becomes possible to simultaneously inspect a wide range using an area camera with a small angle of view and high resolution.

[0015] Furthermore, when inspection is performed using the inspection unit, the inspection is configured to compare defect information stored in a memory unit with defect information based on images acquired by the area camera, and the defect information stored in the memory unit is stored and updated for each inspection.

[0016] With this configuration, when performing inspections under different lighting conditions, normally, reference information based on defect-free images of good products corresponding to those lighting conditions is stored and then inspection is performed. However, when performing inspections under different lighting conditions, there is no need to store reference information based on images of good products corresponding to each lighting condition. This makes it possible to search for and inspect scratch information similar to past scratch information, and the reference information can be learned to perform inspections with high accuracy. Effect of the Invention

[0017] According to the present invention, the inspection object is inspected by passing it through the boundary area on the side of the regular reflection area, so that the inspection can be performed at the optimum position according to the state of the scratch, and for example, for small scratches, the scratch can be made conspicuous in the boundary area on the side of the regular reflection area, thereby improving the inspection accuracy. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic diagram of an inspection device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic plan view of the inspection device in the same embodiment; [Diagram 3] Functional block diagram of the inspection device in the same configuration. [Figure 4] The same shape shows scratches due to lighting conditions in the specular reflection area. [Diagram 5] The same configuration shows that the damage caused by lighting conditions is in the non-specular reflection area. [Figure 6] The same morphology shows scratches in the border area due to lighting conditions. [Figure 7] A flowchart showing the inspection process in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] The inspection device 1 in this embodiment is capable of inspecting defects formed on the surface of an object, and is configured to include a moving device 2 that moves an inspection object 9 in a horizontal direction, an illumination device 3 that irradiates light onto the inspection object 9 moved by the moving device 2, an area camera 5 that acquires reflected light from the light irradiated by the illumination device 3, and an inspection unit 7 that inspects the state of the inspection object 9 from the image acquired by the area camera 5. Characteristically, the inspection object 9 passes through a boundary area 62 on the side of a regular reflection area 61 that receives regular reflection light, and a plurality of area cameras 5 with a small angle of view and high resolution are arranged so that the quality of the inspection object 9 can be inspected. The inspection device 1 in this embodiment will be described in detail below. In this embodiment, the transport direction of the inspection object 9 is defined as the X-axis direction, the direction perpendicular to the X-axis along the plane of the transport direction is defined as the Y-axis direction, and the normal direction of the XY plane is defined as the Z direction, and the description will be given using the X-axis, Y-axis, and Z-axis directions, respectively.

[0021] First, the moving device 2 for moving the inspection object 9 transports the inspection object 9 along the X-axis direction, and in this example is configured with a transport device 21 for transporting the inspection object 9 configured in a planar shape. This transport device 21 is configured to rotate an endless belt 23 on rollers 22 provided on the upstream and downstream sides, place the inspection object 9 on the endless belt 23, and transport it using a motor (not shown).

[0022] The illumination device 3 is provided above the inspection object 9 (above the Z-axis direction) and irradiates the inspection object 9 with light. In this example, as shown in FIG. 2, a plurality of illumination devices 3 are provided along the Y-axis direction. The illumination device 3 is configured by providing a plurality of LEDs 32 below a substrate 31 provided in a straight line, and further providing a diffusion plate 33 below the LEDs 32. Two illumination devices 3 are provided in parallel with a predetermined gap 4 in the X-axis direction, and light is irradiated onto the inspection object 9. At this time, of the light irradiated by the illumination device 3, as shown in FIG. 1, a region that is specularly reflected toward the area camera 5 becomes a specular reflection region 61, and a region where the specularly reflected light from the illumination device 3 does not reach the area camera 5 becomes a non-specular reflection region 63, and a region beside the specular reflection region 61 and a vague region between the non-specular reflection region 63 becomes a boundary region 62. With respect to the brightness of the specular reflection region 61, boundary region 62, and non-specular reflection region 63, when the average illuminance of the specular reflection region 61 is taken as 100, the non-specular reflection region 63 can be defined as a region with an average illuminance of 25 to 50, and the boundary region 62 can be defined as a region with an average illuminance of 50 to 75. With respect to the areas of the specular reflection region 61, boundary region 62, and non-specular reflection region 63, the areas of the specular reflection region 61, boundary region 62, and non-specular reflection region 63 can be set to a ratio of 20% to 40% within the angle of view of one area camera 5, and the ratio of the boundary region 62 can be made relatively large when focusing on inspection of small scratches, and the non-specular reflection region 63 can be made large when focusing on inspection of color defect detection, and the ratios of the specular reflection region 61, boundary region 62, and non-specular reflection region 63 can be changed in various ways.

[0023] The area camera 5 acquires reflected light from the light irradiated from the lighting device 3, and is composed of a camera having a pixel resolution of at least about 30 to 40 μm / pixel. The area camera 5 is set so that a boundary area 62 between a specular reflection area 61 and a non-specular reflection area 63 falls within one viewing angle, and a plurality of area cameras 5 are arranged in the Y-axis direction as shown in Fig. 2, so that images of a wide range of inspection areas can be acquired at once. When acquiring images with the area camera 5, images are acquired for each sampling time for the inspection object 9 being transported.

[0024] The image acquired by the area camera 5 in this way is inspected by the inspection unit 7 for the presence or absence of defects. Usually, when inspecting whether or not there is a defect in an acquired image, reference information based on one good product is stored for one illumination condition, and the reference information of the good product is compared with information based on the image acquired from the inspection target 9 to perform inspection. However, when the illumination state changes within the angle of view of the area camera 5 as in this embodiment, it is necessary to store the reference image according to each illumination state. However, when the illumination state changes continuously as in this embodiment, it becomes difficult to set the reference information according to the continuously changing illumination state. Also, when the reference information of a good product is stored, only inspection based on the reference information of the good product can be performed, and when there is a defect that cannot be inspected by the reference information of the good product, it becomes difficult to extract the defect. Therefore, in this embodiment, instead of storing the reference information for the good product, a plurality of defect information is stored in the storage unit 8, and this defect information is sequentially learned each time an inspection is performed, and whether or not there is a defect similar to the learned defect information can be inspected using artificial intelligence.

[0025] Specifically, when inspection is performed using this inspection unit 7, an image acquired by the area camera 5 is output to the inspection unit 7, and the image is searched for to determine whether or not there is information that has a correlation with the defect information stored in the memory unit 8. If, for example, a defect with a high correlation value is present, it is determined that there is a defect, and the position of the defect is also output. If it is determined that there is a defect, the defect information is stored in the memory unit 8, and is sequentially accumulated as defect information to be used during the next inspection.

[0026] Next, the appearance of defects depending on the lighting conditions when performing such an inspection will be described with reference to FIGS.

[0027] First, as shown in FIG. 4, when a small scratch (a dent indicated by a small elliptical region) exists on the surface in the specular reflection region 61, even if the scratch exists, the normal surface continues to be in a specular reflection state, so the scratch is not noticeable. On the other hand, as shown in FIG. 5, when the scratch exists in the non-specular reflection region 63, the specular reflection light from the lighting device 3 does not reach the area camera 5, so the normal surface becomes dark, and the scratch becomes inconspicuous only by being in a slightly specular reflection state. On the other hand, in the boundary region 62, which is the side of the specular reflection region, as shown in FIG. 6, the normal surface without the scratch is not in a specular reflection state, so the brightness decreases, while the reflected light from the scratch is in a specular reflection state and appears white. On the other hand, for a long scratch on the surface (a scratch indicated by a long elliptical region), as shown in FIG. 4, the scratch is in a specular reflection state and appears black, and as shown in FIG. 5, there is almost no specular reflection light from the normal surface, so the scratch is only slightly visible in a weak specular reflection state. On the other hand, as shown in FIG. 6, the specular reflection light that begins to decrease on the normal surface and the weak specular reflection light from the scratch become the same level, so the contrast disappears and it becomes difficult to see. The appearance of these scratches changes depending on the position of the lighting device 3 and the condition of the scratches, so the inspection object 9 is transported little by little in the X-axis direction and the lighting conditions are reversed on the upstream and downstream sides, and light is irradiated from the opposite direction along the X-axis direction to change the lighting conditions for inspection.

[0028] Next, a flow of inspecting the inspection object 9 for scratches using the inspection device 1 configured as above will be described with reference to FIG.

[0029] First, when inspecting the inspection object 9, the planar inspection object 9 is placed on the endless belt 23 of the moving device 2 and is transported downstream along the X-axis direction (step S1).

[0030] Then, the inspection object 9 passes through the specular reflection region 61, boundary region 62, and non-specular reflection region 63 below the upstream lighting device 3, and at this time, the area camera 5 captures an image including the specular reflection region 61, boundary region 62, and non-specular reflection region 63 within one angle of view at each sampling time (step S2). At this time, in the specular reflection region 61, an image based on specular reflected light out of the light irradiated from the lighting device 3 is captured by the area camera 5, and at this time, for small scratches, the influence of specular reflected light from the surroundings is strong, so that the image is captured in a state in which the scratches are not obscured. On the other hand, for large scratches, the influence of the scratches is relatively strong, so that the image is captured in a state in which the scratches are made noticeable.

[0031] On the other hand, in the boundary region 62, the specularly reflected light from the normal surface does not reach the area camera 5, making the normal surface dark, whereas for small scratches, the specularly reflected light from the scratches reaches the area camera 5. As a result, an image is acquired in which the normal surface appears dark and the scratches appear bright.

[0032] In addition, in the non-specular reflection area 63 set below the gap 4 between the lighting devices 3, the specular reflected light from the lighting device 3 and the specular reflected light from the scratches do not reach the area camera 5, so the images acquired from the scratches and normal surfaces are also dark. Note that in this non-specular reflection area 63, strong light reaches the area camera 5, just like a glossy surface such as a metal surface, so it is possible to inspect the gloss state, color, etc.

[0033] The image thus obtained is output to the inspection unit 7, which then performs inspection (step S3). When inspection is performed by this inspection unit 7, it uses artificial intelligence to determine whether or not similar defect information exists in the storage unit 8, and if similar defect information exists, it outputs information that "there is a defect" (step S4), and if no defect information exists (step S6), it outputs information that "there is no defect" (step S7).

[0034] Furthermore, if a defect is found in this inspection (step S3), the defect information is stored in the storage unit 8 as new defect information (step S5), and the defect information is successively learned to improve the quality of the next inspection. Note that in the initial inspection, the inspection is performed with a plurality of pieces of defect information stored in the storage unit 8 in advance.

[0035] Thereafter, in the same manner, the inspection object 9 is transported downstream (step S1), light is irradiated from the illumination device 3 on the opposite side onto the inspection object 9, and an image based on the reflected light is acquired (step S2). Then, inspection is performed by the inspection unit 7 based on the acquired image (steps S3 to S6).

[0036] As described above, according to the embodiment, the inspection system includes the lighting device 3 that is provided along a straight line and irradiates light onto the inspection object 9, the area camera 5 that acquires an image based on the reflected light of the light irradiated from the lighting device 3, the transport device 21 that transports the inspection object 9, and the inspection unit 7 that acquires an image including the boundary area 62 between the specular reflection area 61 and the non-specular reflection area 63 from the inspection object 9 that is moved by the transport device 21 using the area camera 5 in a state in which the area below the lighting device 3 is a specular reflection area 61 and the sides of the specular reflection area 61 are non-specular reflection areas 63, and inspects the quality of the inspection object 9 based on the acquired image. Therefore, the inspection can be performed at an optimal position according to the state of the flaw, and for example, for small flaws, the flaw can be inspected by making it stand out in the boundary area 62 beside the specular reflection area. This makes it possible to improve the inspection accuracy.

[0037] The present invention is not limited to the above-described embodiment, but can be embodied in various forms.

[0038] For example, in the above embodiment, two lighting devices 3 are installed in parallel, but three or more lighting devices 3 may be installed for inspection with a gap 4 provided therebetween. In this case, the other lighting devices 3 may have different colors or illuminance of the LEDs 32 so that inspection can be performed under different lighting conditions.

[0039] In the above embodiment, the conveying device 21 constituted by the endless belt 23 or the like has been described as an example of the moving device 2, but the inspection object 9 may be gripped by a robot arm and moved in a horizontal direction. In this case, if the inspection object 9 is a three-dimensional object, the three-dimensional object may be moved while being rotated by the robot arm.

[0040] Furthermore, in the above embodiment, the inspection unit 7 stores defect information as reference information and updates the reference information by successively learning from it, but as in the past, information based on defect-free images of non-defective products may be stored as reference information and the presence or absence of defects may be inspected by comparing with this reference information. Alternatively, until a certain amount of defect information is accumulated, inspection may be performed using reference information based on non-defective images, and after the "defect information" obtained at that time has been accumulated, inspection may be performed based on the reference information based on the "defect information". [Explanation of symbols]

[0041] 1. Inspection equipment 2. Mobile device 21. Transport device 22 Roller 23... Endless belt 3. Lighting equipment 31... Substrate 32 LEDs 33 Diffusion plate 4. Gap 5. Area camera 61... specular reflection area 62...boundary area 63...Non-specular reflection area 7. Inspection Department 8...Storage section 9. Inspection object

Claims

1. An illumination device that is provided along a linear direction and irradiates light onto an object to be inspected; an area camera for acquiring reflected light of light emitted from the lighting device; A moving device that moves the inspection object; an inspection unit that, with a region below the illumination device defined as a specular reflection region and a region to the side of the specular reflection region defined as a non-specular reflection region, acquires an image of a boundary region between the specular reflection region and the non-specular reflection region from an object to be inspected that is moved by the moving device using the area camera, and inspects the quality of the object to be inspected based on the acquired image; An inspection device comprising:

2. A plurality of the illumination devices are provided in parallel, 2. The inspection device according to claim 1, wherein a plurality of said boundary regions are included within the angle of view of said area camera.

3. 2. The inspection device according to claim 1, wherein a plurality of the area cameras are provided along a linear direction of the lighting device.

4. the inspection unit performs inspection by comparing defect information stored in a storage unit with defect information based on an image acquired by the area camera, 2. The inspection apparatus according to claim 1, wherein the defect information stored in said memory section is updated for each inspection.

Images