A universal machine vision inspection device and a product surface defect detection method thereof

Abstract

The present invention discloses a general-purpose machine vision inspection device, including two material transfer mechanisms arranged in parallel and at intervals, a visual inspection mechanism arranged between the two material transfer mechanisms, and a sorting mechanism arranged vertically above the two material transfer mechanisms at their discharge ends; a coating mechanism is also arranged on one side of the discharge ends of the two material transfer mechanisms, and the two material transfer mechanisms are used to transport a number of materials to the inspection area of ​​the visual inspection mechanism in turn, so that the visual inspection mechanism can detect the surface defects of the materials; the sorting mechanism is used to transport qualified and unqualified materials to a coating mechanism respectively, and the coating mechanism is used to coat the inspected materials before unloading. The device has a reasonable design, compact structure, simple operation, and a high degree of automation. At the same time, it also provides a product surface defect detection method, through which rapid and comprehensive detection of material surface defects can be achieved, thereby improving detection efficiency.

Description

Technical Field

[0001] The present invention relates to the field of visual inspection technology, and in particular to a general-purpose machine vision inspection device and a product surface defect inspection method thereof. Background Art

[0002] With the rapid development of the mobile Internet industry and the rapid expansion of the market for electronic products such as mobile phones and tablets, the glass panels used to protect the displays of electronic products are becoming more and more diverse. The demand for glass panels for various electronic displays is increasing, and the quality control during their processing has also attracted much attention.

[0003] At present, the glass cover plate surface inspection equipment on the market is still at the stage of inspecting a certain defect or a certain area of ​​the glass cover plate. For example, after CNC processing, it only detects whether the glass cover plate has broken edges or corners. After silk-screen printing, it only detects whether there is ink shortage or ink overflow, etc., and the inspection efficiency is low. In addition, when using the above-mentioned equipment to inspect it, a large number of staff are required to cooperate with it to conduct manual inspection. Due to the subjectivity of manual inspection, the inspection standard is difficult to quantify and the inspection accuracy is not high. At the same time, when placing materials on the current inspection equipment on the market, most of them place the materials directly on the transparent glass plate. The surface of the transparent glass plate is easy to absorb dirty particles, which will cause scratches on the cover plate and other problems. This leads to interference and misjudgment of defect detection during the inspection process. Summary of the invention

[0004] The purpose of the present invention is to provide a general-purpose machine vision inspection equipment, which is equipped with a number of visual inspection modules, and can comprehensively detect various types of defects in materials. It has a wide inspection range, high inspection accuracy, and a reasonable overall design, compact structure, simple operation, and a high degree of automation. At the same time, a product surface defect detection method is also provided, through which rapid and comprehensive detection of material defects can be achieved, thereby improving detection efficiency.

[0005] In order to achieve the above purpose, the following technical solutions are adopted:

[0006] A general-purpose machine vision inspection equipment comprises two material transfer mechanisms arranged in parallel and at intervals, a visual inspection mechanism arranged between the two material transfer mechanisms, and a sorting mechanism arranged vertically above the two material transfer mechanisms at their discharge ends; a laminating mechanism is also arranged on one side of the discharge ends of the two material transfer mechanisms, and the two material transfer mechanisms are used to transport a number of materials alternately to the inspection area of ​​the visual inspection mechanism in sequence, so that the visual inspection mechanism can inspect the surface defects of the materials; the sorting mechanism is used to transport qualified and unqualified materials to a laminating mechanism respectively, and the laminating mechanism is used to laminarize the inspected materials before unloading.

[0007] Furthermore, an inkjet printer is provided at the end of one of the laminating mechanisms for receiving and inspecting unqualified materials, and the inkjet printer is used to print codes on the unqualified materials after lamination.

[0008] Furthermore, each material transfer mechanism includes a first translation module, a second translation module arranged perpendicular to the first translation module and slidably connected to the top of the first translation module, and a material receiving platform arranged on the top of the second translation module for carrying materials; one end of the material receiving platform is drivingly connected to the second translation module, and a first through hole is opened in the middle of the top of the other end of the material receiving platform; a number of fine molybdenum wires are arranged in the first through hole, and the material is placed on the number of fine molybdenum wires.

[0009] Furthermore, the visual inspection mechanism includes a first visual inspection module and a mounting frame; the first visual inspection module is arranged near the feed end of the two material transfer mechanisms and is located below the two material transfer mechanisms; the mounting frame is arranged on one side of one of the material transfer mechanisms, and a plurality of first lifting modules are also arranged in parallel and spaced apart in the length direction of one side of the mounting frame, and a second visual inspection module is installed on each first lifting module; the first lifting module is used to drive the second visual inspection module to lift and lower, and a plurality of second visual inspection modules are used to cooperate with the first visual inspection module to detect surface defects of the material.

[0010] Furthermore, the first visual detection module and the second visual detection module both include a camera component and a light source component.

[0011] Furthermore, the sorting mechanism includes a third translation module arranged vertically with two material transfer mechanisms and located above its discharge end, a second lifting module arranged on one side of the third translation module and slidably connected thereto, and a suction cup module for transferring materials which is drive-connected to the second lifting module.

[0012] Furthermore, the general-purpose machine vision inspection equipment also includes a frame, and the material transfer mechanism, the visual inspection mechanism, the sorting mechanism and the laminating mechanism are all arranged in the frame.

[0013] To achieve the above object, the present invention also provides a method for detecting surface defects of a product, comprising the following steps:

[0014] S1: Divide the material image into regions according to function, including silk screen area, screen area, camera area, IR hole area, earpiece area and character area;

[0015] S2: Obtain material image information and perform incoming material inspection and defect inspection of each area of ​​the material based on the image information;

[0016] S3: Based on the results of material defect detection in S2, classify, summarize and output them.

[0017] Furthermore, the incoming material detection in S2 specifically includes the following steps:

[0018] S21: Check whether there are materials placed on the carrying platform, whether the materials are placed upside down, and whether the materials are placed overlappingly;

[0019] S22: Detect whether different types of materials are placed on the carrying platform and whether the materials are placed beyond the field of vision;

[0020] Furthermore, the defect detection in S2 specifically includes the following steps:

[0021] S23: Matching and locating the material image according to the functional areas divided in S1 based on the shape matching algorithm;

[0022] S24: intercepting a portion of the image at the located position according to the size of the functional area, and performing threshold segmentation on the functional area contained in the intercepted image;

[0023] S25: Compare with the pre-saved material standard template and save the difference information;

[0024] S26: Extracting the defective area of ​​the image based on the difference information saved in S25.

[0025] By adopting the above scheme, the beneficial effects of the present invention are:

[0026] 1) With reasonable design and compact structure, it can comprehensively detect various types of defects of materials through several visual inspection modules, with wide detection range, high detection accuracy, simple operation and high degree of automation;

[0027] 2) Placing the material on a thin molybdenum wire can avoid detection blind spots and achieve comprehensive detection of the material;

[0028] 3) The sorting mechanism can realize automatic sorting of unqualified materials and qualified materials, avoiding the cumbersome manual operation and improving the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A perspective view of the present invention;

[0030] Figure 2 for Figure 1 A three-dimensional view of a part of the housing without the frame and protective cover;

[0031] Figure 3 is a three-dimensional diagram of the visual detection mechanism of the present invention;

[0032] Figure 4 A three-dimensional diagram of the material transfer mechanism of the present invention;

[0033] Figure 5 It is a three-dimensional diagram of the material receiving platform and the thin molybdenum wire of the present invention;

[0034] Figure 6 is a three-dimensional diagram of the sorting mechanism of the present invention;

[0035] Figure 7 It is a flow chart of the product surface defect detection method of the present invention;

[0036] The accompanying drawings illustrate:

[0037] 1—Material transfer mechanism; 2—Visual inspection mechanism;

[0038] 3—Sorting mechanism; 4—Laminating mechanism;

[0039] 5—Inkjet printer; 6—Frame;

[0040] 7—Detection platform; 8—Protective cover;

[0041] 11—first translation module; 12—second translation module;

[0042] 13—material receiving platform; 14—first through hole;

[0043] 15—fine molybdenum wire; 21—first visual inspection module;

[0044] 22—mounting frame; 23—first lifting module;

[0045] 24—second visual detection module; 31—third translation module;

[0046] 32—second lifting module; 33—suction cup module. DETAILED DESCRIPTION

[0047] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0048] Reference Figures 1 to 6 As shown, the present invention provides a general-purpose machine vision inspection equipment, including two material transfer mechanisms 1 arranged in parallel and at intervals, a visual inspection mechanism 2 arranged between the two material transfer mechanisms 1, and a sorting mechanism 3 arranged vertically above the two material transfer mechanisms 1 at their discharge ends; a coating mechanism 4 is also arranged on one side of the discharge ends of the two material transfer mechanisms 1, and the two material transfer mechanisms 1 are used to transport a number of materials alternately to the inspection area of ​​the visual inspection mechanism 2 in sequence, so that the visual inspection mechanism 2 can detect surface defects of the materials; the sorting mechanism 3 is used to transport qualified and unqualified materials to a coating mechanism 4 respectively, and the coating mechanism 4 is used to coat the inspected materials before unloading.

[0049] Among them, one of the coating mechanisms 4 for receiving and inspecting unqualified materials is also provided with an inkjet printer 5 at the end thereof, and the inkjet printer 5 is used to inkjet the unqualified materials after coating; each material transfer mechanism 1 includes a first translation module 11, a second translation module 12 arranged perpendicular to the first translation module 11 and slidably connected to the top thereof, and a material receiving platform 13 arranged on the top of the second translation module 12 for carrying materials; one end of the material receiving platform 13 is drivingly connected to the second translation module 12, and a first through hole 14 is opened in the middle of the top of the other end of the material receiving platform 13; a plurality of fine molybdenum wires 15 are arranged in the first through hole 14, and the materials are placed on the plurality of fine molybdenum wires 15; The visual inspection mechanism 2 includes a first visual inspection module 21 and a mounting frame 22; the first visual inspection module 21 is arranged near the feed end of the two material transfer mechanisms 1 and is located below the two material transfer mechanisms 1; the mounting frame 22 is arranged on one side of one of the material transfer mechanisms 1, and a plurality of first lifting modules 23 are also arranged in parallel and spaced apart in the length direction of one side of the mounting frame 22, and a second visual inspection module 24 is installed on each first lifting module 23; the first lifting module 23 is used to drive the second visual inspection module 24 to lift and lower, and a plurality of second visual inspection modules 24 are used to cooperate with the first visual inspection module 21 to detect surface defects of the material.

[0050] The first visual inspection module 21 and the second visual inspection module 24 both include a camera assembly and a light source assembly; the sorting mechanism 3 includes a third translation module 31 arranged vertically with two material transfer mechanisms 1 and located above the discharge end thereof, a second lifting module 32 arranged on one side of the third translation module 31 and slidably connected thereto, and a suction cup module 33 for transferring materials drivingly connected to the second lifting module 32; the general-purpose machine vision inspection equipment also includes a frame 6, in which the material transfer mechanism 1, the visual inspection mechanism 2, the sorting mechanism 3 and the laminating mechanism 4 are all arranged.

[0051] At the same time, refer to Figure 7 As shown, the present invention also provides a product surface defect detection method, comprising the following steps:

[0052] S1: Divide the material image into regions according to function, including silk screen area, screen area, camera area, IR hole area, earpiece area and character area;

[0053] S2: Obtain material image information and perform incoming material inspection and defect inspection of each area of ​​the material based on the image information;

[0054] S3: Based on the results of material defect detection in S2, classify, summarize and output them.

[0055] The incoming material detection in S2 specifically includes the following steps:

[0056] S21: Check whether there are materials placed on the carrying platform, whether the materials are placed upside down, and whether the materials are placed overlappingly;

[0057] S22: Detect whether different types of materials are placed on the carrying platform and whether the materials are placed beyond the field of vision;

[0058] The defect detection in S2 specifically includes the following steps:

[0059] S23: Matching and locating the material image according to the functional areas divided in S1 based on the shape matching algorithm;

[0060] S24: intercepting a portion of the image at the positioning position according to the size of the functional area, and performing threshold segmentation on the functional area contained in the intercepted image;

[0061] S25: Compare with the pre-saved material standard template and save the difference information;

[0062] S26: Extracting the defective area of ​​the image based on the difference information saved in S25.

[0063] Working principle of the present invention:

[0064] Continue to refer to Figure 1-2 As shown, in this embodiment, it also includes a detection platform 7, and the material transfer mechanism 1, the visual inspection mechanism 2, the sorting mechanism 3 and the laminating mechanism 4 are all arranged on the detection platform 7 and then placed in the frame 6; one side of the frame 6 is provided with a qualified material discharge port and an unqualified material discharge port corresponding to the two laminating mechanisms 4, and the inkjet printer 5 is installed on this side of the frame 6 and is located above the unqualified discharge port; the inkjet printer 5 can spray the unqualified material after lamination (such as the material is judged to be unqualified due to dirt and other problems) to spray the defects of the unqualified material on the film, so that the staff can check it in time and facilitate the next step of maintenance; the front of the frame 6 is also provided with a cabinet door, a touch screen, etc., which are easy to operate, and the top of the frame 6 is also provided with an indicator light, and the bottom is also provided with casters and feet for easy movement and fixation.

[0065] Material transfer mechanism 1: Figure 4-5As shown, the two material transfer mechanisms 1 are arranged in parallel and at intervals along the length direction of the detection platform 7. The two material transfer mechanisms 1 have the same structure and are used to alternately transfer materials to the detection area of ​​the visual detection mechanism 2 for detection. Through the cooperation of the two, the materials can be continuously transferred to improve the detection efficiency. When loading, the materials can be placed on the fine molybdenum wire 15 by an external manipulator or manually, and there is no restriction here. The first translation module 11 of the material transfer mechanism 1 includes a first linear motor assembly, and the second translation module 12 includes a first mounting seat arranged perpendicular to the first linear motor assembly and slidably connected to the top of the first mounting seat, a first screw rod assembly arranged therein along the length direction of the first mounting seat, a first motor driven by the first screw rod assembly, and a first Sliding seat; one end of the material receiving platform 13 is fixedly connected to the top of the first sliding seat, and a first through hole 14 is opened in the middle of the top of the other end; in this embodiment, two adjusting screws are respectively provided on both sides of the top of the material receiving platform 13 where the first through hole 14 is opened, and each fine molybdenum wire 15 is arranged between the two adjusting screws perpendicular to the length direction of the first through hole 14, and the adjusting screws can adjust the tension of the fine molybdenum wire 15; the material is directly placed on the fine molybdenum wire 15, and the fine molybdenum wire 15 has a small diameter. Under the condition of achieving stable support for the material, the part of the fine molybdenum wire 15 in contact with the bottom of the material can be ignored, thereby avoiding the existence of a detection blind spot (the fine molybdenum wire 15 is a transparent body and has a small diameter, thereby not blocking the light source, and avoiding secondary contamination caused by the contact between the material and the traditional support fixture), thereby achieving comprehensive detection of the material and avoiding missed detection.

[0066] Visual inspection mechanism 2: Figure 3As shown, a first mounting through hole is further provided in the middle of the detection platform 7 along its length direction, and the first mounting through hole is located between the two material transfer mechanisms 1; the first visual inspection module 21 is arranged close to the feeding end of the two material transfer mechanisms 1, and is installed in the first mounting through hole; the first visual inspection module 21 is located below the two material transfer mechanisms 1, and is mainly used to detect the character area located at the bottom of the material (in this embodiment, the material is a glass cover plate); the number of the first lifting module 23 and the second visual inspection module 24 are both set to 3, which are arranged in parallel and spaced apart on one side of the mounting frame 22 in the length direction of the detection platform 7 (a protective cover 8 is also provided on one side of the mounting frame 22, which can be The second visual inspection module 24 is wrapped to avoid damage by impact from foreign objects and improve safety); in this embodiment, the first lifting module 23 includes a first sliding module arranged on one side of the mounting frame 22 in the vertical direction, a second sliding seat slidably connected to the first sliding module, a second screw rod assembly inserted in the second sliding seat in the vertical direction and driven connected thereto, and a hand wheel driven and connected to the second screw rod assembly; the second visual inspection module 24 is installed on one side of the second sliding seat, and the second visual inspection module 24 can be lifted and lowered by rotating the hand wheel through the second screw rod assembly to drive the second sliding seat to focus the camera assembly of the second visual inspection module 24; Figure 3 As shown, the second visual inspection module 24 located on the far left is used to inspect the white area of ​​the material (the middle of the glass cover), and the other two second visual inspection modules 24 are used to inspect the end and tail of the material; through the mutual cooperation of multiple visual inspection modules, comprehensive inspection of the material can be achieved;

[0067] Sorting mechanism 3 and laminating mechanism 4: The third translation module 31 of the sorting mechanism 3 includes two mounting brackets, a mounting beam, and a second linear motor assembly; the two mounting brackets are respectively arranged on the two outer sides of the two material transfer mechanisms 1, and the mounting beam is arranged between the two mounting brackets; the second linear motor assembly is arranged on one side of the mounting beam, and the second lifting module 32 includes a first slide plate slidably connected to the second linear motor assembly, a lifting cylinder installed on the first slide plate, and a suction cup module 33 is drivingly connected to the lifting cylinder; the two-axis movement of the suction cup module 33 can be achieved through the mutual cooperation of the second linear motor assembly and the lifting cylinder, which is convenient for sucking and releasing materials; a laminating mechanism 4 is arranged on one side of the discharge end of each material transfer mechanism 1, and the laminating mechanism 4 can coat the inspected materials, which is simple and convenient.

[0068] In addition, the present invention also provides a product surface defect detection method, through which the defects of the glass cover plate can be quickly and comprehensively detected, including the detection of silk screen character LOGO defects, key light transmission detection, screen camera / earpiece hole position detection, proximity sensor light transmission hole detection, silk screen area detection (including 2.5D / 3D arc edge), missing printing, white spots, black spots, sawtooth, offset, crack, edge collapse, corner collapse, micro scratch detection, concave and convex points, silk screen defects, different colors, water ripples and other defects of the glass cover plate, with high detection efficiency and wide detection range. Specifically:

[0069] First, the glass cover is divided according to its functional areas, including the silk screen area, camera area, IR hole area, earpiece area and character area. When the cover is placed on the fine molybdenum wire 15 and driven by the material transfer mechanism 1, the first visual inspection module 21 and the three second visual inspection modules 24 will be triggered in sequence, and then take pictures of different areas of the cover, and transmit the images to the parallel processor in the equipment, and process each image in parallel respectively; the inspection of the cover includes incoming material inspection and defect inspection. The incoming material inspection mainly distinguishes whether there is material discharge, material reverse placement, material overlapping placement, material placement beyond the field of view and mixed materials (other different types of materials are placed). Specifically,

[0070] 1) No material, reversed, overlapped: The above situation is quite different from the normal situation. The silk-screen part can be clearly separated by the grayscale threshold. It only needs to set the area of ​​the specified type of mobile phone glass cover to determine whether there is material, reversed, and overlapped;

[0071] 2) Non-target model (mixed material): The subsequent positioning of the mobile phone glass cover is performed using a shape matching algorithm. If no match is found, the model is incorrect;

[0072] 3) Out of field of view: This means that the glass cover of the mobile phone is out of field of view or in contact with the edge of the image. The judgment is made by finding the intersection of the extracted silk-screen area and the edge of the image.

[0073] When detecting defects in materials, the shape matching algorithm can be used to locate the functional area of ​​the input image information, and the functional area can be segmented by threshold, and the segmented image can be accurately extracted, and then the image contrast can be enhanced and defects can be extracted. The multi-layer perceptron classifier can be used to perform defect classification operations. Specifically,

[0074] The cover plate is divided into a silk-screen area, a screen area, a camera area, an IR hole area, a handset area and a character area according to the functional areas. When the first visual inspection module 21 and the three second visual inspection modules 24 collect the image information, they will match and locate the above functional areas. After locating the area, the area will be extracted and compared with the pre-saved standard template. If there is a difference, it indicates that there is a defect in the functional area. The difference information is saved and the defect is extracted. If the defect is serious such as dirt, the defect detection result is directly output; if the defect feature is small, the defect is clustered and connected, and the defect discontinuity caused by the extraction is compensated, and then it is separated and classified, and then compared with the standard template to output the judgment result. This method can make each mechanism in a state of full utilization and high work efficiency, and it can be applied to the defect detection of different types of glass cover plates, with high work efficiency and strong versatility.

[0075] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A general-purpose machine vision inspection device, characterized in that: It comprises two material transfer mechanisms arranged in parallel and at intervals, a visual inspection mechanism arranged between the two material transfer mechanisms, and a sorting mechanism arranged vertically above the two material transfer mechanisms and at the discharge ends thereof; a laminating mechanism is arranged on one side of the discharge ends of the two material transfer mechanisms, and the two material transfer mechanisms are used to transport a number of materials alternately to the inspection area of ​​the visual inspection mechanism in sequence, so that the visual inspection mechanism can inspect the surface defects of the materials; the sorting mechanism is used to transport the materials that have passed the inspection and the materials that have failed the inspection to a laminating mechanism respectively, and the laminating mechanism is used to laminarize the inspected materials before unloading; A coding machine is also provided at the end of one of the laminating mechanisms for receiving and inspecting unqualified materials, and the coding machine is used to code the unqualified materials after lamination; Each material transfer mechanism comprises a first translation module, a second translation module arranged perpendicular to the first translation module and slidably connected to the top of the first translation module, and a material receiving platform arranged on the top of the second translation module for carrying materials; one end of the material receiving platform is drivingly connected to the second translation module, and a first through hole is opened in the middle of the top of the other end of the material receiving platform; a plurality of fine molybdenum wires are arranged in the first through hole, and the materials are placed on the plurality of fine molybdenum wires; The visual inspection mechanism includes a first visual inspection module and a mounting frame; the first visual inspection module is arranged near the feeding end of the two material transfer mechanisms and is located below the two material transfer mechanisms; the mounting frame is arranged on one side of one of the material transfer mechanisms, and a plurality of first lifting modules are arranged in parallel and spaced in a length direction on one side of the mounting frame, and a second visual inspection module is installed on each first lifting module; the first lifting module is used to drive the second visual inspection module to lift and lower, and the plurality of second visual inspection modules are used to cooperate with the first visual inspection module to detect surface defects of the material; The first translation module includes a first linear motor assembly, and the second translation module includes a first mounting seat arranged perpendicular to the first linear motor assembly and slidably connected to the top of the first linear motor assembly, a first screw assembly arranged inside the first mounting seat along the length direction thereof, a first motor drivingly connected to the first screw assembly, and a first sliding seat movably arranged on the top of the first mounting seat and drivingly connected to the first screw assembly; Two tightening screws are respectively arranged on both sides of the top of the material receiving platform where the first through hole is opened. Each thin molybdenum wire is arranged between the two tightening screws perpendicular to the length direction of the first through hole. The tightening screws can adjust the tension of the thin molybdenum wire.

2. The general-purpose machine vision inspection device according to claim 1, characterized in that: The first visual detection module and the second visual detection module both include a camera component and a light source component.

3. The general-purpose machine vision inspection device according to claim 1, characterized in that: The sorting mechanism includes a third translation module arranged vertically between two material transfer mechanisms and located above the material discharge end thereof, a second lifting module arranged on one side of the third translation module and slidably connected thereto, and a suction cup module for transferring materials which is drive-connected to the second lifting module.

4. The general-purpose machine vision inspection device according to claim 1, characterized in that: The general-purpose machine vision inspection equipment also includes a frame, and the material transfer mechanism, the visual inspection mechanism, the sorting mechanism and the laminating mechanism are all arranged in the frame.

5. A method for detecting surface defects of a product, using the general-purpose machine vision inspection device according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: Divide the material image into regions according to function, including silk screen area, screen area, camera area, IR hole area, earpiece area and character area; S2: Obtain material image information and perform incoming material inspection and defect inspection of each area on the material based on the image information; S3: Based on the results of material defect detection in S2, classify, summarize and output them; The incoming material detection in S2 specifically includes the following steps: S21: Check whether there are materials placed on the carrying platform, whether the materials are placed upside down, and whether the materials are placed overlappingly; S22: Detect whether different types of materials are placed on the carrying platform and whether the materials are placed beyond the field of vision; The defect detection in S2 specifically includes the following steps: S23: Matching and locating the material image according to the functional areas divided in S1 based on the shape matching algorithm; S24: intercepting a portion of the image at the positioning position according to the size of the functional area, and performing threshold segmentation on the functional area contained in the intercepted image; S25: Compare with the pre-saved material standard template and save the difference information; S26: Extracting the defective area of ​​the image based on the difference information saved in S25.

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