TW202020433A - Automatic optical inspection system for defects of mirror metal plate - Google Patents

Abstract

The invention provides an automatic optical inspection system for defects of mirror metal plate, comprising a base, an annular light source, a hemispherical cover, a camera and a black baffle. The base has an opening. The annular light source is disposed on an upper surface of the base, and the annular light source includes a plurality of illuminators disposed around the opening; the hemispherical cover is disposed on the upper surface of the base, and the hemispherical cover is provided with an assembly hole, the hemisphere The inner surface of the mask has a hemispherical reflecting surface; the camera is coupled to the assembly hole, and the black baffle is disposed in the hemispherical cover, and the black baffle is symmetrically disposed on two sides of the hemispherical cover with the camera. This optimizes the image quality of optical inspection.

Description

Automatic optical detection system for defects of mirror metal plate

The invention relates to an optical detection system, in particular to an automatic optical detection system of a mirror metal plate.

Metal sheet is widely used in various industries, and the detection of surface defects of products is one of the important quality control items. Among them, the surface quality of mirror metal plates such as mirror stainless steel plates and chrome plated steel plates is the highest. The current quality inspection method is that the quality control personnel conduct visual inspection on the production line. In order to check the mirror stainless steel plate and other mirror metal plates produced from the production line, they must be stopped to manually check whether the steel plate is defective on the production line. The steel plate produced will have oily residues and sharp burrs, and the steel plate produced is also at a relatively high temperature. The production staff will test the production line to cause hidden safety concerns, and the product demand and production capacity are constantly increasing. The development of an automated defect inspection system to replace manual visual inspection is an important issue today.

Among the related automated inspection technologies, one of the prior technologies is disclosed in the invention patent of the Republic of China Announcement No. I373614 "Inspection Device and Method for Obtaining Inspection Images", which is the lens inspection technology in optoelectronic products. The field to be explored is slightly different, and the method is only partially similar to the present invention. The patent discusses that the light source that is often encountered in the detection situation directly emits too much light, which causes the lens under test to reflect light, so the small flaws are masked and cannot be recognized; but if the light is insufficient, the image may also be too Dark and incomparable situation.

However, the structure of this patent is too complicated, and two sets of detection systems must be installed to obtain two different images for comparison, and the illumination unit and the imaging unit are both installed outside the lampshade. The imaging port of the lampshade prevents light leakage in the lampshade. Evenly reflected light is created inside, and this conventional technology may not be able to obtain good balanced lighting due to poor reflection control of light, and the detection accuracy cannot be improved. Therefore, it is necessary to improve the conventional structure and system to Solve the problems of conventional technology.

The purpose of the present invention is to provide an automatic optical inspection system for mirror metal plate defects that can optimize the optical inspection image quality.

Another object of the present invention is to provide an automatic optical detection system for defects of mirror metal plates that can improve the detection accuracy.

In order to achieve the above-mentioned object, in one embodiment, the automatic optical inspection system for mirror metal plate defects of the present invention includes a base, an annular light source, a hemispherical mask, a camera, and a black mask. An opening is provided in the center of the base, and a ring-shaped light source is arranged on the upper surface of the base. The ring-shaped light source includes a plurality of light-emitting bodies surrounding the opening; a hemispherical cover is provided on the upper surface of the base, and the hemispherical cover is provided with an assembly hole, The inner surface of the cover has a hemispherical reflecting surface; the camera is combined with the assembly hole, and the black mask is disposed in the hemispherical cover, and the black mask and the camera are symmetrically disposed on both sides of the hemispherical cover, by This can optimize the image quality of optical inspection to improve inspection accuracy.

In an embodiment, the plurality of luminous bodies are respectively disposed on the plurality of bases, The plurality of bases respectively include a bearing platform and a fixed seat, and the bearing platform is pivotably arranged on the fixed seat at an adjustable angle. In this way, the angle of illumination of the luminous body can be changed by adjusting the angle of the carrier.

In one embodiment, it further includes a ring-shaped base, and the plurality of bases are equidistantly disposed on the ring-shaped base. In this way, the ring light source combined with the ring base becomes a modular product, simplifying the installation process.

In an embodiment, the first angle between the camera's photographic axis and the central axis of the hemispherical mask is equal to the first angle between the vertical axis of the mask of the black mask and the central axis of the hemispherical mask The two included angles allow the black mask to form a dark field in the camera's imaging and eliminate excessively reflected strong light.

In one embodiment, the first included angle between the photographic axis of the camera and the central axis of the hemispherical cover is 45 degrees.

In one embodiment, the surface of the hemispherical reflecting surface in the hemispherical cover is coated with a matting paint, so that the light of the ring light source diffuses on the hemispherical reflecting surface to obtain uniform light source illumination.

In one embodiment, it further includes a computer and image processing software. The computer can receive images shot by the camera and perform image processing through the image processing software.

In an embodiment, the processing procedures of the image processing software are image gray scale, image binarization, and noise removal, respectively.

In one embodiment, it further includes a light source controller electrically connected to the plurality of light-emitting bodies, and the light source controller can control the brightness of each light-emitting body separately.

The invention is provided with a ring light source in a hemispherical cover, which forms an ideal diffuse standard transmission and obtains a uniform light source similar to the principle of an integrating sphere. The black mask is used to establish a dark field at the symmetrical position of the camera, which is beneficial to highlight the mirror stainless steel plate or For all kinds of sunken defects on mirror metal plates, the feature point area of the smallest sunken defects can be detected is 0.188mm ² , and it can also be adapted to the detection of surface defects on mirror metal plates with oil drops or oil films. Subsequent applications of the present invention can capture images of flaws through the system developed by the present invention to search for flaw contours, and display the coordinates of the flaws found, so that field personnel can quickly eliminate defective products.

10‧‧‧Base

11‧‧‧ opening

20‧‧‧Ring light source

21‧‧‧ luminous body

22‧‧‧Dock

23‧‧‧Carrying platform

24‧‧‧Fixed seat

25‧‧‧ Ring seat

30‧‧‧Hemispherical cover

31‧‧‧Hemispherical reflecting surface

32‧‧‧Assembly hole

40‧‧‧Camera

41‧‧‧Lens

42‧‧‧Photosensitive coupling

50‧‧‧Black mask

60‧‧‧Object to be tested

A1‧‧‧The first angle

A2‧‧‧Second included angle

L1‧‧‧Central axis

L2‧‧‧photography axis

L3‧‧‧Mask vertical axis

1,2,3‧‧‧defect

FIG. 1 shows a top perspective exploded perspective view of an embodiment of an automatic optical inspection system for defects on a mirror-surface metal plate of the present invention.

FIG. 2 shows an exploded perspective view of an embodiment of an automatic optical detection system for flaws in a mirror metal plate of the present invention.

FIG. 3 shows a perspective view of the combination of a luminous body and a base of an embodiment of an automatic optical inspection system for mirror surface metal plate defects of the present invention.

FIG. 4 shows a schematic diagram of the adjustable angle of the base of the embodiment of the automatic optical inspection system for the mirror surface metal plate defects of the present invention.

FIG. 5 shows a combined top view of an embodiment of an automatic optical inspection system for defects on a mirror-surface metal plate of the present invention.

Fig. 6 shows a cross-sectional view taken along the line A-A in Fig. 5.

FIG. 7 shows a schematic diagram of the positional relationship between the camera and the black mask in the embodiment of the automatic optical inspection system for the mirror metal plate defects of the present invention.

8a to 8d show schematic diagrams of metal plate defect classification of an embodiment of an automatic optical inspection system for mirror plate metal defects of the present invention.

FIG. 9 shows an original image of a metal plate defect image of an embodiment of an automatic optical inspection system for a mirror metal plate defect of the present invention.

FIG. 10 shows a schematic diagram of an image of a metal plate defect image processed by an image processing software according to an embodiment of an automatic optical inspection system for a mirror metal plate defect of the present invention.

In order to make the purpose, features, and advantages of the present invention clearly understandable, the following will give a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The following embodiments illustrate possible implementation forms of the present invention, but are not intended to be limiting The scope of protection of the present invention.

Please refer to FIG. 1, FIG. 2 and FIG. 5 and FIG. 6, FIG. 1 shows an exploded perspective perspective view of an embodiment of an automatic optical inspection system for mirror metal sheet defects of the present invention, and FIG. 2 shows an embodiment of an automatic optical inspection system of mirror metal sheet defects of the present invention. FIG. 5 shows an exploded perspective view of the bottom angle of the present invention. FIG. 5 shows a combined top view of an embodiment of an automatic optical inspection system for defects on a mirror metal plate of the present invention. FIG. 6 shows a cross-sectional view taken along the line AA in FIG. 5. In order to achieve the purpose of the invention, the mirror sheet metal automatic defect detection system of the present invention in a preferred embodiment includes a base 10, a ring light source 20, a hemispherical cover 30, a camera 40 and a black mask 50 .

An opening 11 is provided in the center of the base 10, and the size of the opening 11 depends on the size of the object to be measured or the set size of the detection capture. A test object 60 is placed under the opening 11. The test object 60 has a highly reflective surface, such as a mirror stainless steel plate, a mirror metal plate, a chrome plated metal plate, and the like.

The ring light source 20 is disposed on the upper surface of the base 10, and the ring light source 20 includes a plurality of luminous bodies 21 around the opening 11; the hemispherical cover 30 is disposed on the upper surface of the base 10, and the hemispherical cover 30 is provided with an assembly hole 32 , The inner surface of the hemispherical cover 30 has a hemispherical reflective surface 31; the camera 40 is coupled to the assembly hole 32, and the black mask 50 is disposed in the hemispherical cover 30, the black mask 50 and the camera 40 are symmetrically disposed on both sides of the hemispherical cover 30, thereby optimizing the optical Inspection image quality to improve inspection accuracy.

The plurality of luminous bodies 21 included in the ring light source 20 can be directly arranged on the upper surface of the base 10 and surround the opening 11. The luminous body 21 is preferably an LED. The LED can be directly arranged on the upper surface of the base 10. The base 10 can be A printed circuit board. Or, as shown in the figure, the plurality of luminous bodies 21 are respectively disposed on the plurality of bases 22, and then the plurality of bases 22 are equally spaced on an annular base 25, and the annular base 25 is combined with the base 10 again.

The hemispherical cover 30 is provided with an assembling hole 32. The inner surface of the hemispherical cover 30 has a hemispherical reflecting surface 31. The hemispherical reflecting surface 31 is a true spherical surface, so as to obtain a uniform reflected light effect similar to an integrating sphere; the camera 40 is combined with the assembly hole 32, the black mask 50 is disposed in the hemispherical cover 30, the black mask 50 and the camera 40 are symmetrically disposed on both sides of the hemispherical cover 30, so that the black mask 50 can be produced Dark field effect. This dark field effect can absorb the excessive reflected light on the mirror stainless steel plate or various mirror metals, thereby optimizing the image quality of the optical inspection and improving the detection accuracy.

The black mask 50 is a plate with a low reflection coefficient, and the surface preferably has matt black or dark-colored paint. It can be fixed in the hemispherical mask 30 by sticking or screwing or using a clamp. As the opposite side of the camera 40, by the principle that the incident angle is equal to the reflection angle, it can resist the reflection of the hemispherical reflective surface 31 on the opposite side of the angle between the camera 40 and the object to be measured 60.

The camera 40 is preferably equipped with a high-resolution CMOS industrial camera 40. The structure of the camera 40 usually includes a lens 41 and a photosensitive coupling member 42 (CCD). The photosensitive coupling member 42 can be connected to a computer to transfer the captured images to the computer Perform image processing.

Please refer to FIGS. 3 and 4. FIG. 3 shows the combined perspective view of the luminous body 21 and the base 22 of the embodiment of the mirror metal plate defect automatic optical inspection system of the present invention. FIG. 4 shows the embodiment of the mirror metal plate defect automatic optical inspection system of the present invention. A schematic diagram of the adjustable angle of the base 22. More preferably, the plurality of bases 22 may include a carrying platform 23 and a fixing base 24 respectively, so that the carrying platform 23 can be pivotably mounted on the fixing base 24 at an adjustable angle. Thereby, the irradiation angle of the luminous body 21 can be changed by adjusting the angle of the supporting table 23.

Referring to FIG. 6, the bearing table 23 and the fixing base 24 in the figure are set at 90 degrees, so that the luminous body 21 exhibits a horizontal irradiation angle to illuminate the light toward the hemispherical reflection surface 31, and the data obtained through experiments are displayed as The horizontal illumination angle can obtain a lighting effect that is closer to the integrating sphere, but not limited to this. In the present invention, the angle setting can be adjusted by the carrier 23 and the fixed base 24, so that the luminous body 21 can be performed according to the nature of the object 60 to be measured Adjust the irradiation angle to obtain the most ideal inspection image.

As mentioned above, an annular base 25 may be further included. As shown in FIG. 1, the plurality of bases 22 are equidistantly arranged on the annular base 25. In this way, the ring light source 20 and the ring base 25 become modular products, which can simplify the installation procedure.

The ring base 25 may be made of non-conductive material such as wood, bakelite, or plastic. The luminous body 21 may be directly fixed on the ring base 25 at an equal distance. However, in this embodiment, the irradiation angle of the luminous body 21 cannot be adjusted.

Please refer to FIG. 7, in this embodiment, the detection system of the present invention is suitable for detecting a test object 60, the test object 60 has a highly reflective surface, such as mirror stainless steel plate, mirror metal plate, chrome plated metal plate, etc. . The present invention defines a straight line that perpendicularly passes through the object to be measured 60, and at the same time, the line at the center of the hemispherical cover 30 is the central axis L1, and defines the center of the camera 40 The axis is the photographic axis L2, and a vertical line defining the black mask 50 is a mask vertical axis L3. The first angle A1 between the photographic axis L2 of the camera 40 and the central axis L1 of the hemispherical mask 30 is equal to the distance between the vertical axis L3 of the black mask 50 and the central axis L1 of the hemispherical mask 30 The second included angle A2, according to the principle that the incident angle is equal to the reflection angle, causes the black mask 50 to block the reflected light from the area of the hemispherical reflective surface 31 behind it, which can cause the dark field effect in the imaging of the camera 40 and eliminate the excessively reflected strong light.

In this embodiment, preferably, the first included angle A1 between the photographing axis L2 of the camera 40 and the central axis L1 of the hemispherical cover 30 is 45 degrees. The second included angle A2 between the vertical axis L3 of the black mask 50 and the central axis L1 of the hemispherical mask 30 is also preferably 45 degrees. The experimental data shows that the setting of this angle can make the metal Defects on the surface of the board are highlighted.

In this embodiment, the surface of the hemispherical reflecting surface 31 in the hemispherical cover 30 may be coated with a matting paint, so that the light emitted by the ring light source 20 diffuses on the hemispherical reflecting surface 31 to form a uniform light source illuminance.

In this embodiment, a light source controller may be further electrically connected to the plurality of light-emitting bodies 21, and the light source controller may individually control the brightness of each light-emitting body 21. The light source controller (not shown) can use software such as Arduino to independently control the lighting of each single luminous body 21, so that the hemispherical cover 30 can achieve the uniform light effect inside the integrating sphere as much as possible.

The present invention uses the black mask 50 to establish a dark field at the symmetrical position of the camera 40, which is beneficial to highlight the concave defects of the mirror stainless steel plate or various mirror metal plates. The experimentally proved that the minimum concave defect feature point area is 0.188mm ² It can also be adapted to the detection of surface defects of mirror metal plates with oil droplets or oil films. Subsequent applications of the present invention can capture images of flaws through the system developed by the present invention to search for flaw contours, and display the coordinates of the flaws found, so that field personnel can quickly eliminate defective products.

In this embodiment, the luminous body 21 is preferably an LED. The LED light source is directed to an integrating sphere-like hemispherical cover 30. The light is reflected by the hemispherical reflective surface 31 inside the hemispherical cover 30 after multiple diffuse reflections at the exit The end (the lens 41 of the camera 40) obtains a light source with uniform illuminance, which can reduce the reflection problem of metal products during detection.

In this embodiment, it also includes a computer and image processing software. The computer can receive images captured by the camera 40 and perform image processing through the image processing software.

After being processed by image processing software, the four most common defects (sags, indentations, scratches, convex hulls) in mirror stainless steel plates are easily highlighted. 8a to 8d, it shows a schematic diagram of metal plate defect classification of an embodiment of the mirror plate metal plate defect automatic optical inspection system of the present invention, wherein FIG. 8a is a concave type defect, which shows that the mirror plate metal plate has a spot-shaped depression; FIG. 8b is Indentation type defects, showing sheet-like indentations on the surface of the mirror metal plate; Figure 8c is scratch type defects, showing linear scratches on the mirror metal plate surface; Figure 8d is convex hull type defects, showing the mirror metal plate A convex point hull is formed on the surface.

The processing procedures of the image processing software are image gray scale, image binarization and noise removal. Among them, the image gray scale is to process the image that has been loaded in the image processing software, to perform the image gray scale processing, and to store the processed image. Then carry out the image binarization process. In this binarization process, double threshold binarization processing can be performed, the minimum and maximum values of the binarization are set, the two images are processed separately and then the images are merged, and the binarization Archive the displayed image and reverse binarize it to convert the black and white part of the binarized image to white and black. In some cases, it is easier to observe the defects on the mirror stainless steel plate.

Please refer to FIG. 9 and FIG. 10, FIG. 9 shows the original image of the metal plate defect image of the embodiment of the mirror metal plate defect automatic optical inspection system of the present invention, and FIG. 10 shows the metal plate defect of the embodiment of the mirror metal plate defect automatic optical inspection system of the present invention Schematic diagram of the image after the image is processed by the image processing software. After the original image of the metal plate defect image captured by the camera 40 is processed by the image processing software, it is easier to observe various defects 1, 2, 3 on the mirror metal plate.

The above-mentioned embodiments are only to illustrate the technical ideas and features of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, but should not limit the patent scope of the present invention Any changes or modifications made in accordance with the spirit of the present invention and the content of the description should be covered by the patent scope of the present invention.

10‧‧‧Base

11‧‧‧ opening

20‧‧‧Ring light source

21‧‧‧ luminous body

22‧‧‧Dock

23‧‧‧Carrying platform

24‧‧‧Fixed seat

25‧‧‧ Ring seat

30‧‧‧Hemispherical cover

31‧‧‧Hemispherical reflecting surface

40‧‧‧Camera

50‧‧‧Black mask

60‧‧‧Object to be tested

A1‧‧‧The first angle

A2‧‧‧Second included angle

L1‧‧‧Central axis

L2‧‧‧photography axis

L3‧‧‧Mask vertical axis

Claims (9)

An automatic optical detection system for the defects of mirror metal plates, comprising: a base with an opening in the center; an annular light source arranged on the upper surface of the base, the annular light source including a plurality of luminous bodies arranged around the opening; hemispherical cover, cover Set on the upper surface of the base, the hemispherical cover is provided with an assembly hole, the inner surface of the hemispherical cover has a hemispherical reflecting surface; a camera is integrated into the assembly hole; and a black mask is provided in the hemispherical cover The black mask and the camera are arranged symmetrically on both sides of the hemispherical mask. The automatic optical inspection system for the defects of mirror metal plates as described in item 1 of the patent application scope, wherein the plurality of luminous bodies are respectively arranged on a plurality of bases, and the plurality of bases respectively include a bearing table and a fixing seat, the bearing The table is pivotably arranged on the fixing seat at an adjustable angle. As described in item 2 of the patent application scope, the automatic optical inspection system for the defects of mirror metal plates further includes a ring-shaped base, and the plurality of bases are arranged at equal distances on the ring-shaped base. An automatic optical inspection system for defects in mirror metal plates as described in item 1 of the patent scope, wherein the first angle between the camera's photographic axis and the central axis of the hemispherical mask is equal to the vertical mask of the black mask The second angle between the axis and the central axis of the hemispherical cover. As described in item 4 of the patent application scope, an automatic optical detection system for defects in mirror metal plates, wherein the first included angle between the photographic axis of the camera and the central axis of the hemispherical cover is 45 degrees. An automatic optical inspection system for defects in mirror metal plates as described in item 1 of the patent application scope, wherein the surface of the hemispherical reflective surface in the hemispherical cover is coated with a matting paint. As described in item 1 of the patent scope, the automatic optical inspection system for mirror metal plate defects includes a computer and image processing software. The computer receives images captured by the camera and performs image processing through the image processing software. As described in item 7 of the patent application scope, an automatic optical inspection system for defects in mirror metal plates, wherein the processing procedures of the image processing software are image gray scale, image binarization, and noise removal, respectively. The automatic optical inspection system for the defects of mirror metal plates as described in item 1 of the scope of the patent application further includes a light source controller electrically connected to the plurality of luminous bodies, and the light source controller controls the brightness of each luminous body separately.

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