A real-time vision inspection system

Abstract

The utility model discloses a real -time visual inspection system, including conveying portion and two visual inspection module, visual inspection module includes light group and camera, light group includes four length direction with conveying portion conveying direction each other perpendicular's bar light, four bar light is two close to the chromatic aberration lamp of conveying portion and two far away the light supplement lamp of conveying portion, one chromatic aberration lamp's luminous surface is to camera tilt 40-50 DEG, another chromatic aberration lamp's luminous surface is to camera tilt 30 DEG. Can be compatible with the detection of large area object, and the space is small, and the detection object is in the conveying process synchronous completion positive and backside visual inspection process, and the detection efficiency is high. The light group is composed of two chromatic aberration lamps with different illumination angles and gray scales and two light supplement lamps for light supplement, which can ensure that each area of the detection object can be uniformly illuminated, reduce the shadow area, and improve the accuracy and reliability of detection.

Description

Technical Field

[0001] This utility model belongs to the field of visual inspection technology, and in particular relates to a real-time visual inspection system. Background Technology

[0002] Lighting arrangement is a crucial aspect of visual inspection system design, directly determining image acquisition quality and consequently affecting the accuracy and stability of the detection algorithm. Factors such as the choice of light source, brightness, uniformity, and illumination method significantly impact detection results through image contrast, feature sharpness, and noise levels. LED light sources, with their advantages of high power, long lifespan, low heat generation, and adjustable brightness and color, have become the ideal choice for machine vision. Their diverse illumination methods (such as ring light, coaxial light, and backlighting) can effectively highlight object features.

[0003] Chinese patent document CN221146420U discloses an illumination system, including a substrate, a first light source module, a second light source module, and a support frame. The first light source module includes a first fixed bracket and a first strip light source. The first fixed bracket is mounted on the substrate, and the first strip light source is rotatably mounted on the first fixed bracket. By rotating the first strip light source, the illumination angle of the first strip light source can be adjusted, enabling it to provide illumination light over a wider angle range in machine vision inspection. Furthermore, the second light source module can supplement the first strip light source and provide incident light at a higher angle to illuminate the object under test, which can, to some extent, compensate for the uneven illumination of some objects under test by the first strip light source, giving the illumination system better light source detection performance. For example, this illumination system can be applied to CPU pin inspection and PCB component inspection, showing good detection results for missing, sunken, warped, offset, and foreign object defects in CPU pins.

[0004] In the aforementioned patented solution, the four bar light sources are arranged in a circular pattern. While this can increase the imaging quality of the visual imaging system, it requires the product to be tested to be placed below the four bar light sources, which undoubtedly reduces the detection efficiency. Therefore, this method is only suitable for visual inspection of single or a small number of workpieces. When this technical solution is applied to a production line for real-time inspection of a large number of workpieces, the production line needs to stop intermittently to allow the image acquisition device to capture images, resulting in low detection efficiency. Moreover, due to its structure, the spatial interval between the four bar light sources is larger than the workpiece being inspected, thus the lighting system occupies a relatively large space, limiting its application conditions. Utility Model Content

[0005] To overcome the technical problems of existing visual imaging systems applied to production lines, where circumferentially distributed strip light sources improve image quality but reduce detection efficiency and occupy a large space, limiting application conditions, this invention aims to provide a real-time visual inspection system. This system uses four parallel strip light sources to provide illumination for image acquisition, reducing space requirements. Furthermore, the four strip light sources illuminate the image acquisition position at different angles, ensuring uniform illumination of the object being inspected, reducing shadow areas, and enabling the visual system to acquire stable and reliable image data, thereby improving the accuracy and reliability of the inspection.

[0006] To achieve the above objectives, this utility model adopts the following technical solution: a real-time visual inspection system, comprising a conveyor section mounted on a frame and two visual inspection modules respectively mounted on both sides of the conveyor section; a gap is provided on the conveyor section; each visual inspection module includes a light group mounted on the frame and at least one camera mounted on the frame on the side of the light group away from the conveyor section; the shooting direction of the camera is tilted towards the gap; the light group includes four strip lights whose length direction is perpendicular to the conveying direction of the conveyor section; wherein, the four strip lights are two color difference lights close to the conveyor section and two supplementary lights away from the conveyor section; the two color difference lights are respectively distributed on both sides of the shooting direction of the camera, the emitting surface of one color difference light is tilted at 40-50° to the camera, and the emitting surface of the other color difference light is tilted at 30° to the camera.

[0007] Furthermore, the grayscale of the strip light can be adjusted.

[0008] Specifically, the grayscale of the color difference lamp tilted at 40-50° is 30 higher than that of the fill light; the grayscale of the color difference lamp tilted at 30° is 20 lower than that of the fill light.

[0009] After adjusting the bar lights, the brightness of the solder resist in the camera scan image (such as a PCB board) will increase by about 10 gray levels compared to before, making the solder resist surface brighter and scratches more obvious.

[0010] Furthermore, in the same visual inspection module, the light-emitting surfaces of the two fill lights are tilted towards the camera; the intersection of the illumination directions of the two fill lights is located in the middle of the two color difference lamps.

[0011] Furthermore, the angle between the shooting direction of the camera and the direction of the conveying unit is an acute angle.

[0012] Furthermore, the color difference lamps tilted at 30° and the color difference lamps tilted at 40-50° are arranged linearly along the conveying direction of the conveying section.

[0013] Preferably, the shooting positions of the two vision detection modules located on both sides of the conveying section are staggered.

[0014] Furthermore, the conveying unit includes a first inclined plate that is inclinedly disposed on the frame, a track disposed at the lower end of the first inclined plate, and a pusher block that is reciprocally slidably connected to the lower part of the first inclined plate; the two vision inspection modules are respectively located on both sides of the first inclined plate; the vision inspection module includes a structural frame disposed on the first inclined plate; the camera and the light group are respectively disposed on the corresponding structural frame.

[0015] Specifically, one end of the structural frame is provided with a feeding section; the feeding section includes a second inclined plate that is inclinedly disposed on one side of the first inclined plate, a feed plate that is slidably connected to the second inclined plate, and a suction cup that is slidably connected to the other side of the first inclined plate.

[0016] Specifically, the other end of the structural frame is provided with a feeding section; the feeding section includes a conveyor belt horizontally disposed at the lower end of one side of the first inclined plate and a push rod slidably connected to the lower end of the other side of the first inclined plate.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0018] 1. The light assembly of this utility model consists of four strip lights that are perpendicular to the conveying direction of the conveying section in the length direction. It can accommodate large-area inspection objects, occupy little space, and has a wide range of application conditions. The inspection object can be visually inspected from the front and back simultaneously during the conveying process, resulting in high inspection efficiency.

[0019] 2. The lighting assembly of this utility model consists of two color difference lamps with different illumination angles and gray levels, and two supplementary lamps for supplementary lighting. This ensures that all areas of the object being inspected are uniformly illuminated, reduces shadow areas, enables the inspection equipment to clearly acquire image information, enhances the color difference detection effect, helps to discover subtle surface defects, and allows the camera to obtain stable and reliable image data, thereby improving the accuracy and reliability of the inspection.

[0020] 3. This utility model is specifically designed for judging surface defects (such as scratches, short circuits, open circuits, etc.) on PCB boards. Each strip light can adjust its light parameters and illumination angle, which can adapt to the inspection needs of different types and specifications of PCBs, as well as the specific inspection needs of different areas. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the structure of the visual inspection module of this utility model;

[0023] Figure 3 This is a side view of the visual inspection module of this utility model;

[0024] Figure 4 For the present utility model Figure 3 A schematic diagram of the lighting assembly in Section I;

[0025] In the diagram: 11. Frame; 12. First inclined support plate; 21. Conveyor belt; 22. Push rod; 31. Second inclined support plate; 32. Feed plate; 33. Suction cup; 41. Push block; 51. Structural frame; 52. Camera; 521. Shooting direction; 6. Lighting group; 61. Strip light; 7. PCB board. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0027] In the description of this utility model, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this utility model.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature. In this description of the utility model, "a number" means two or more, unless otherwise explicitly specified.

[0029] In this utility model, unless otherwise explicitly specified and limited, terms such as "set" and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0030] See Figures 1-4A real-time visual inspection system includes a conveyor section mounted on a frame 11 and two visual inspection modules respectively mounted on opposite sides of the conveyor section. A gap is provided on the conveyor section. Each visual inspection module includes a light group 6 mounted on the frame 11 and two cameras 52 mounted on the frame 11 on the side of the light group 6 furthest from the conveyor section. The shooting direction of each camera 52 is tilted towards the gap. The shooting direction of each camera 52 forms an acute angle with the direction of the conveyor section. (See attached diagram.) Figure 4 As shown, the camera's shooting direction is 521.

[0031] The light group 6 includes four strip lights 61 whose length direction is perpendicular to the conveying direction of the conveying section; as shown in the attached instruction manual. Figure 4 As shown, the object to be inspected (such as a PCB board) is conveyed from right to left. The light group 6 above names the strip lights 61 as A, B, C, and D in a clockwise direction. Among them, the four strip lights 61 are two color difference lights (A and D) close to the conveying part and two supplementary lights (B and C) away from the conveying part. The two color difference lights are respectively distributed on both sides of the shooting direction of the camera 52. The emitting surface of one color difference light A is tilted at 40-50° to the camera 52, and the emitting surface of the other color difference light D is tilted at 30° to the camera 52.

[0032] The grayscale of the strip light 61 can be adjusted. In the same visual detection module, the grayscale of the color difference light A is 30 higher than that of the fill light; the grayscale of the color difference light D is 20 lower than that of the fill light; the light-emitting surfaces of the two fill lights are tilted towards the camera 52; and the intersection of the illumination directions of the two fill lights is located in the middle of the two color difference lights.

[0033] The shooting positions of the two vision inspection modules located on both sides of the conveying section are staggered.

[0034] The conveying unit includes a first inclined plate 12 tilted on the frame 11, a track disposed at the lower end of the first inclined plate 12, and a pusher 41 reciprocatingly slidingly connected to the lower part of the first inclined plate 12; the two vision inspection modules are respectively located on both sides of the first inclined plate 12; the vision inspection module includes a structural frame 51 disposed on the first inclined plate 12; the camera 52 and the light group 6 are respectively disposed on the corresponding structural frame 51.

[0035] One end of the structural frame 51 is provided with a feeding part; the feeding part includes a second inclined plate 31 that is inclinedly disposed on the front side of the first inclined plate 12, a feed plate 32 that is slidably connected to the second inclined plate 31, and a suction cup 33 that is slidably connected to the back side of the first inclined plate 12.

[0036] The other end of the structural frame 51 is provided with a feeding section; the feeding section includes a conveyor belt 21 horizontally disposed at the lower end of the front side of the first inclined plate 12 and a push rod 22 slidably connected to the lower end of the back side of the first inclined plate 12.

[0037] Workflow: Taking the inspection of PCB board 7 as an example, the second inclined support plate 31 slides upward intermittently, pushing the PCB board 7 onto the first inclined support plate 12. After the suction cup 33 picks up the uppermost PCB board 7, it slides backward, causing the PCB board to move onto the track of the first inclined support plate 12 and lean against it. Then, the suction cup 33 releases. The reciprocating pusher block 41 pushes the PCB board 7 on the track through the two vision inspection modules. The two vision inspection modules simultaneously perform visual inspection on the front and back of the PCB board. After the inspection is completed, the push rod 22 extends forward, causing the lower end of the PCB board 7 to move onto the conveyor belt 21. Driven by the conveyor belt 21, the PCB board 7 is transported to the next station. This process repeats.

[0038] I. Lighting Principles and Basis

[0039] Multi-angle lighting: (with) Figure 4 Four strip lights, A, B, C, and D, are distributed at different positions along the PCB gaps and at different angles. This design is based on the fact that the PCB surface contains various components, circuits, and different surface characteristics (such as pads and solder mask layers). Illumination from a single angle can easily create shadows, affecting the inspection results. Multi-angle illumination ensures that all areas of the PCB surface are uniformly illuminated, reducing shadow areas and allowing the inspection equipment to clearly acquire image information of the PCB surface.

[0040] Uniform illumination: The four strip lights 61 on each side work together to achieve uniform illumination of the PCB surface. This is because in PCB inspection, uneven illumination can lead to excessive brightness differences in different areas of the image, thus interfering with the judgment of PCB surface defects (such as scratches, short circuits, open circuits, etc.). Uniform illumination enables the inspection equipment to acquire stable and reliable image data, improving the accuracy and reliability of the inspection.

[0041] II. Detection Principles and Basis

[0042] Enhanced Color Difference Detection: The design emphasizes enhanced color difference detection, and the key to achieving this is the independent brightness control of the four strip lights. Different PCB defects (such as oxidation, contamination, and solder joint quality issues) will exhibit different colors and brightness levels compared to normal areas under illumination. By independently adjusting the brightness of each strip light, the incident angle and intensity distribution of the light can be altered, thereby enhancing this color difference and enabling the inspection equipment to more accurately identify defects on the PCB surface. For example, when oxidation is present in a certain area, adjusting the brightness of a strip light at a specific angle can make the color contrast between the oxidized area and the normal area more pronounced, facilitating the detection of the problem.

[0043] Optimal Color Contrast: Achieving optimal color contrast helps in more accurately identifying minute defects and features on a PCB. During PCB manufacturing, some defects can be very subtle, such as tiny scratches or minor deformations of solder joints. By properly controlling the brightness and illumination angle of the four strip lights, the reflection and scattering of light on the PCB surface can be adjusted, creating a clear color contrast between these minute defects and the surrounding normal areas. This facilitates accurate analysis and judgment by inspection equipment.

[0044] III. Control Principles and Basis

[0045] Independent Brightness Control: Each strip light can have its brightness independently controlled. This design is primarily to adapt to the inspection needs of different types and specifications of PCBs. Different PCBs vary in material, color, and surface treatment processes, resulting in different lighting requirements. For example, some darker PCBs require stronger lighting to clearly display surface details, while smoother, more reflective PCBs require reduced light intensity to avoid glare interference. By independently controlling the brightness of each strip light, flexible lighting adjustments can be made for different PCB characteristics, improving the versatility and adaptability of the inspection system.

[0046] Flexible Lighting Adjustment: Since PCB inspection processes and priorities may vary, sometimes it's necessary to focus on inspecting a specific side or area of ​​the PCB. Independently controlled strip lights can quickly adjust the lighting scheme according to specific inspection needs. For example, when inspecting solder joints on a particular side of the PCB, the brightness of the relevant strip lights on that side can be increased while the brightness of other strip lights is decreased to highlight the inspection effect on the solder joint area, improving inspection efficiency and accuracy.

[0047] IV. Specific Control Process

[0048] The initial voltage values ​​of strip lights A, B, C, and D are the same by default. The brightness is changed by fine-tuning the lamp source voltage, and the change in light brightness affects the grayscale value. The voltage of strip light A is 20.5-21V, that of strip light B is 20.5-21V, that of strip light C is 20.8-21.2V, and that of strip light D is 21-21.5V.

[0049] The above description is only a specific embodiment of the present utility model, but the technical features of the present utility model are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present utility model are covered by the patent scope of the present utility model.

Claims

1. A real-time visual inspection system, characterized in that: The device includes a conveyor section mounted on a frame and two vision inspection modules respectively mounted on opposite sides of the conveyor section. A gap is provided on the conveyor section. Each vision inspection module includes a light group mounted on the frame and at least one camera mounted on the frame on the side of the light group away from the conveyor section. The camera's shooting direction is tilted towards the gap. The light group includes four strip lights whose length direction is perpendicular to the conveying direction of the conveyor section. Two of the four strip lights are two color difference lights near the conveyor section and two supplementary lights away from the conveyor section. The two color difference lights are distributed on opposite sides of the camera's shooting direction, with one color difference light's emitting surface tilted 40-50° towards the camera and the other color difference light's emitting surface tilted 30° towards the camera.

2. The detection system as described in claim 1, characterized in that: The grayscale of the strip light can be adjusted.

3. The detection system as described in claim 2, characterized in that: The grayscale of the color difference lamp tilted at 40-50° is 30 higher than that of the fill light; the grayscale of the color difference lamp tilted at 30° is 20 lower than that of the fill light.

4. The detection system as described in any one of claims 1-3, characterized in that: In the same visual inspection module, the light-emitting surfaces of the two fill lights are tilted towards the camera; the intersection of the illumination directions of the two fill lights is located in the middle of the two color difference lamps.

5. The detection system as described in any one of claims 1-3, characterized in that: The angle between the shooting direction of the camera and the direction of the conveying unit is an acute angle.

6. The detection system as described in any one of claims 1-3, characterized in that: The color difference lamps tilted at 30° and the color difference lamps tilted at 40-50° are arranged linearly along the conveying direction of the conveying section.

7. The detection system as described in any one of claims 1-3, characterized in that: The shooting positions of the two vision inspection modules located on both sides of the conveying section are staggered.

8. The detection system as described in any one of claims 1-3, characterized in that: The conveying unit includes a first inclined plate that is tilted on the frame, a track that is disposed at the lower end of the first inclined plate, and a pusher that is reciprocally slidably connected to the lower part of the first inclined plate; the two vision inspection modules are respectively located on both sides of the first inclined plate; the vision inspection module includes a structural frame disposed on the first inclined plate; the camera and the light group are respectively disposed on the corresponding structural frame.

9. The detection system as described in claim 8, characterized in that: One end of the structural frame is provided with a feeding section; the feeding section includes a second inclined plate that is inclinedly disposed on one side of the first inclined plate, a feed plate that is slidably connected to the second inclined plate, and a suction cup that is slidably connected to the other side of the first inclined plate.

10. The detection system as described in claim 9, characterized in that: The other end of the structural frame is provided with a feeding section; the feeding section includes a conveyor belt horizontally disposed at the lower end of one side of the first inclined plate and a push rod slidably connected to the lower end of the other side of the first inclined plate.

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