Flat surface defect detection machine vision system

Abstract

The utility model provides a visual system of a flat surface defect detection machine, which is used for detecting surface defects of a product and comprises a light source and a line scanning camera which are both arranged on one side of the product, the light source comprises linear strip light, a light spot area and a residual light area, the linear strip light emits light towards the product to generate the light spot area, and the residual light area emits light towards the product to generate the residual light area. The residual light area is located around the light spot area, and the line scanning camera scans and shoots the position, irradiated on the surface of the product, of the residual light area. According to the utility model, the linear camera is matched with the light source, so that the 3D defects on the surface of the product are sensed, the structure is simple, the cost is lower, the influence of light reflection is avoided, and the detection precision and efficiency are higher.

Description

[Technical field]

[0001] The utility model relates to the technical field of visual detection, in particular to a machine vision system for flat surface defect detection. [Background technology]

[0002] At present, 3D defects such as deformation, bruises, pits, bumps, scratches, etc. on the product surface are all detected manually. Since the slight degree of defect characteristics is difficult to identify with the naked eye, it is necessary to manually adjust the product angle repeatedly to achieve the purpose of observation. The detection efficiency is far behind the production speed.

[0003] Existing detection methods can be divided into two categories. One is to scan the product through 3D line laser, which has the disadvantages of high price and low detection efficiency; the other is to extract defect features through ordinary coaxial light source using the principle of light reflection, which has the disadvantage that the interference of scattered light will make minor defects unrecognizable. Both of the above detection methods cannot meet the detection needs of products and have the problems of high cost and low accuracy. [Utility Model Content]

[0004] The existing technology currently has technical problems of high cost and low precision. The utility model provides a machine vision system for flat surface defect detection to solve the above problems.

[0005] The utility model provides a machine vision system for flat surface defect detection, comprising a light source and a line scan camera, the light source comprising a linear strip light, a light spot area and a residual light area, the light source is arranged on one side of the product and irradiates the surface of the product, a light area is formed between the light source and the product, the linear strip light emits light toward the product, the light spot area is the light area between the linear strip light and the product, a strip light spot is formed on the surface of the product, the residual light area is located around the light spot area, the line scan camera is arranged on the same side of the product relative to the light source, and scans and photographs the position where the residual light area irradiates the surface of the product.

[0006] Compared with the prior art, the flat surface defect detection machine vision system provided by the utility model can present a pseudo 3D effect in the peripheral light area by setting the line scan camera, combining 3D defects, the flat area of ​​the product has uniform grayscale, the defect area has large grayscale changes and the effect is stable, the line scan camera is extremely sensitive to the height change of the product surface, and can obtain picture effects with different height sensitivity, so as to detect the defects on the flat surface of the product through the effect change of the picture, including 3D defects such as surface deformation, bruises, pits, bumps, scratches, etc. The system has a simple structure, low cost, and is not affected by light reflection, and has high detection accuracy and efficiency.

Brief Description of the Drawings

[0007] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0008] Figure 1 It is a structural schematic diagram of a flat surface defect detection machine vision system provided by the utility model. [Specific implementation method]

[0009] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0010] Please refer to Figure 1 The flat surface defect detection machine vision system 10 is used to detect surface defects of a product 20, and includes a light source 11, a line scan camera 13, and a control processor (not shown). The light source 11 includes a linear strip light 111, a light spot area 113, and a residual light area 115. The light source 11 is disposed on one side of the product 20 and irradiates the surface of the product 20. A light area is formed between the light source 11 and the product 20. The linear strip light 111 emits light toward the product 20. The light spot area 113 is a light area between the linear strip light 111 and the product 20, and a strip light spot is formed on the surface of the product 20. The residual light area 115 is located around the light spot area 113. The line scan camera 13 is disposed on the same side of the product 20 as the light source 11, and scans and photographs the position where the residual light area 115 irradiates the surface of the product 20. The control processor is connected to the linear light strip 111 and the line scan camera 13 respectively, controls the linear light strip 111 to emit light, and controls the line scan camera 13 to scan, take pictures and process them.

[0011] The light spot area 113 is a light area in the shape of a strip emitted by the linear light strip 111, and the residual light area 115 is a light area formed by the scattered light emitted by the linear light strip 111, and the overall structure is divergent. The light spot area 113 is at an angle of 30° to 60° relative to the product 20, and the angle at which the line scan camera 13 scans and photographs the product 20 is symmetrical to the angle of the light spot area 113 relative to the product 20. In this embodiment, the angle of the light spot area 113 relative to the product 20 is preferably 45°, so that the light source 11 cooperates with the line scan camera 13 to improve the scanning efficiency.

[0012] In this embodiment, the smooth surface defect detection machine vision system 10 also includes a transmission part (not shown), and the product 20 is arranged on the transmission part. The transmission part drives the product 20 to move relative to the light source 11 and the line scan camera 13, and the scanning and shooting position of the line scan camera 13 is fixed relative to the residual light area 115.

[0013] The working principle of the flat surface defect detection machine vision system 10 is briefly summarized as follows:

[0014] By utilizing the single-line scanning characteristic of the line scan camera 13 and combining it with 3D defects, a pseudo 3D effect can be presented in the peripheral light area 115. The product 20 moves under the control of the transmission member, and during the movement, the line scan camera 13 keeps its scanning position fixed in the peripheral light area 115 when shooting. After the line scan camera 13 completes shooting, the entire picture can be a pseudo 3D effect, with uniform grayscale in the flat area, large grayscale changes in the defective area and stable effect, and is extremely sensitive to height changes on the surface of highly reflective flat products.

[0015] In another embodiment, the flat surface defect detection machine vision system 10 further includes a rotating member (not shown), which is connected to the light source 11 and the line scan camera 13 respectively, and the rotating member controls the light source 11 and the line scan camera 13 to rotate relative to the product 20, and the scanning and shooting position of the line scan camera 13 is fixed relative to the residual light area 115. The setting of the rotating member has a similar technical effect to that of the transmission member, and can realize a comprehensive scan of the product 20, and ensure that the scanning position of the line scan camera 13 is fixed in the residual light area 115 during the movement.

[0016] Of course, the above technical effects can also be achieved by simultaneously providing the transmission machine and the rotating member, which is not limited here.

[0017] In addition, by adjusting the position of the scanning area of ​​the line scan camera 13 in the residual light area 115, image effects with different height sensitivities can be obtained. The farther away from the light spot area 113, the higher the height sensitivity of the image effect. Correspondingly, the less light the line scan camera 13 can receive, the slower the detection efficiency. Combined with the requirements of the defect limit sample and the detection efficiency, the position can be appropriately adjusted to achieve the best detection effect.

[0018] In the verification application, it was found that the flat surface defect detection machine vision system 10 is mainly suitable for highly reflective flat surface materials, such as metal, glass, plastic, coated mirrors, etc. The inspection speed of the product 20 depends on the degree of reflectivity of the surface of the product 20.

[0019] Compared with the prior art, the flat surface defect detection machine vision system 10 provided by the utility model can present a pseudo 3D effect in the peripheral light area 115 by setting the line scan camera 13, and the grayscale of the flat area of ​​the product 20 is uniform, and the grayscale of the defective area changes greatly and the effect is stable. The line scan camera 13 is extremely sensitive to the height change of the surface of the product 20, and can obtain picture effects with different height sensitivity, so as to detect the defects on the flat surface of the product 20 through the effect change of the picture, including 3D defects such as surface deformation, bruises, pits, bumps, scratches, etc. The system has a simple structure, low cost, and is not affected by light reflection, and has high detection accuracy and efficiency.

[0020] The above is only an implementation method of the present invention. It should be pointed out that a person skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements are all within the protection scope of the present invention.

Claims

1. A flat surface defect detection machine vision system for detecting surface defects of products, the characteristics of which include: A light source is provided on one side of the product and illuminates the surface of the product, a light zone is formed between the light source and the product, and the light source includes: a linear strip light emitting light toward the product; The light spot area is the light area between the linear light strip and the product, forming a light strip spot on the surface of the product; and A peripheral light area, located around the light spot area; and The line scan camera is arranged on the same side of the product as the light source, and scans and photographs the position where the residual light area illuminates the surface of the product.

2. A machine vision system for flat surface defect detection according to claim 1, characterized in that: The light spot area is a light area in a strip shape emitted by the linear light strip, and the residual light area is a light area formed by scattered light emitted by the linear light strip, and the whole structure is a divergent structure.

3. A machine vision system for flat surface defect detection according to claim 2, characterized in that: The angle between the light spot area and the product is 30° to 60°, and the angle at which the line scan camera scans and photographs the product is symmetrical to the angle between the light spot area and the product.

4. A machine vision system for flat surface defect detection according to claim 1, characterized in that: It also includes a control processor, which is connected to the linear light strip and the line scan camera respectively, controls the linear light strip to emit light, and controls the line scan camera to scan, take pictures and process them.

5. The flat surface defect detection machine vision system according to claim 1, characterized in that: It also includes a transmission member, the product is arranged on the transmission member, and the transmission member drives the product to move relative to the light source and the line scan camera. The scanning and shooting position of the line scan camera is fixed relative to the position of the residual light area.

6. A machine vision system for flat surface defect detection according to claim 1, characterized in that: It also includes a rotating part, which is respectively connected to the light source and the line scan camera. The rotating part controls the light source and the line scan camera to rotate relative to the product. The scanning and shooting position of the line scan camera is fixed relative to the position of the residual light area.

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