An integrated multi-parameter testing device and method for the appearance quality of glass tubes

Abstract

This invention provides an integrated multi-parameter inspection device and method for the appearance quality of glass tubes. The inspection device includes at least one set of measuring units, each including an industrial camera, a grating, and an LED surface light source. The industrial camera is located on one side of the glass tube to be tested, with its lens facing the tube. The LED surface light source is located radially along the glass tube to be tested on the opposite side of the tube relative to the industrial camera. The grating is located between the LED surface light source and the glass tube, and is covered with alternating black and white geometric patterns formed by parallel lines. In this invention, by combining the industrial camera, lens, grating, and LED surface light source, the outer diameter, inner diameter, wall thickness, and defects of the glass tube to be tested can be simultaneously detected using optical inspection principles. This results in high inspection efficiency and is beneficial for improving the production efficiency of glass tubes.

Description

Technical Field

[0001] This invention belongs to the field of glass tube testing technology, and specifically relates to an integrated multi-parameter testing device and method for the appearance quality of glass tubes. Background Technology

[0002] The physical appearance quality of glass tubes is an important aspect of glass tube quality assurance. The physical appearance quality of glass tubes is mainly reflected in the accuracy of the outer diameter and wall thickness, as well as the absence of defects inside or on the surface of the glass tube. Traditionally, these quality inspections of glass tubes are carried out by direct manual measurement or by visual inspection under light to check for defects on the surface or inside the tube. Obviously, this method has great limitations, low efficiency, and cannot achieve online inspection, thus failing to effectively improve product quality and production efficiency.

[0003] With the development of laser technology, various instruments and methods for laser detection of the outer diameter or wall thickness of glass tubes have been developed both domestically and internationally and applied in glass tube drawing production lines. Laser technology is also used to detect defects such as stones on the surface of glass tubes. However, none of the above methods have achieved the simultaneous detection of the outer diameter, wall thickness, and surface defects of glass tubes based on a single detection device, nor have they achieved the detection of a wider range of defect types.

[0004] Industrial cameras have been widely used to detect the outer diameter and surface defects of flat glass, glass bottles, and glass tubes. The main application involves using dynamic light boxes or structured light to generate variable black and white light for measuring the wall thickness of transparent glass tubes or detecting surface defects. However, this variable structured light requires controlling the exposure time for switching between black and white fields, which in turn requires the camera to control its exposure time. This places high demands on the control system, especially since defects only exhibit boundary deformation when they are located at the boundary between black and white fields. When defects fall in the middle of the black or white field, there is no boundary deformation effect, and continuous images of defect boundary deformation cannot be obtained, thus failing to fully extract this deformation information and affecting the determination of the defect type.

[0005] How to design an integrated multi-parameter testing device and method for the appearance quality of glass tubes, and how to increase the efficiency of glass tube quality testing, are urgent problems to be solved. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an integrated multi-parameter detection device and method for the appearance quality of glass tubes, so as to solve the problem of low efficiency in the quality detection of glass tubes in the prior art.

[0007] To achieve the above objectives, the present invention provides an integrated multi-parameter inspection device for the appearance quality of glass tubes, comprising at least one set of measuring units, wherein the measuring units include an industrial camera, a grating, and an LED surface light source;

[0008] The industrial camera is located on one side of the glass tube under test, and the lens of the industrial camera is facing the glass tube under test.

[0009] The LED surface light source is located on the opposite side of the glass tube to be tested relative to the industrial camera, along the radial direction of the glass tube under test.

[0010] The grating is located between the LED surface light source and the glass tube under test;

[0011] The grating is covered with alternating black and white geometric patterns, which are formed by parallel lines.

[0012] This technical solution involves placing the glass tube under test between a grating and the lens of an industrial camera. The LED surface light source is then activated. Under the influence of the grating, the edges of the glass tube exhibit distinct boundary features. Simultaneously, the image captured by the industrial camera shows a grayscale difference between the images where light passes through and does not pass through the glass tube. The outer diameter of the glass tube can be calculated using these boundary features and grayscale differences. Furthermore, when the glass tube is placed between the grating and the camera lens, the parallel light emitted by the LED surface light source, after passing through the grating, refracts upon reaching the glass tube. The luminous flux attenuates most at the inner diameter of the tube walls, forming two distinct black lines. The distance between these two black lines is then used to calculate the outer diameter of the glass tube. The wall thickness of the glass tube under test can be calculated from its outer diameter. When parallel light emitted from the LED surface light source passes through a black and white grating and is transmitted through the glass tube, it presents a regular, distorted grating image with alternating bright and dark areas on the photosensitive image of the industrial camera. When there are defects on the surface of the glass tube, the grating image will be distorted at the defect, and the distortion position will move with the movement of the glass tube, showing continuous image movement characteristics accompanied by boundary changes and disturbance characteristics. The type of defect can be determined based on the feature changes, defect size, and defect grayscale. In this way, the quality inspection of the glass tube under test can be completed simultaneously by using an industrial camera, lens, grating, and LED surface light source, increasing the efficiency of quality inspection of the glass tube under test.

[0013] In one embodiment of the present invention, the position of the grating between the glass tube under test and the LED surface light source is adjustable.

[0014] By adopting this technical solution, the adjustable focal length requirement between the grating and the LED surface light source can be met. This ensures that by adjusting the distance between the grating and the LED surface light source, the clarity of the image formed by the light from the industrial camera passing through the grating, the glass tube under test, and the lens can be changed, thus enabling quality inspection of the glass tube under test.

[0015] In one embodiment of the present invention, the measuring units are configured as three groups and evenly distributed along the circumference of the glass tube to be tested.

[0016] By adopting this technical solution, three sets of measuring units work together to simultaneously detect defects in the circumference of the glass tube under test, thereby increasing the efficiency of quality inspection of the glass tube under test and accurately determining the location of defects on the glass tube under test.

[0017] This invention provides a detection method for a multi-parameter integrated detection device for the appearance quality of glass tubes, comprising the following steps:

[0018] S1. Place the glass tube to be tested between the lens and the grating, turn on the LED surface light source, and the parallel light emitted by the LED surface light source passes upward through the grating, the glass tube to be tested and the lens in sequence, so that the industrial camera can acquire the corresponding inspection image.

[0019] S2. Adjust the position of the grating between the glass tube under test and the LED surface light source so that the industrial camera can obtain a clear inspection image;

[0020] S3. The clear detection image shows obvious boundary features on the edge of the glass tube to be tested, and the distance between the two boundary features is the outer diameter D of the glass tube to be tested.

[0021] S4. Adjust the grating away from the glass tube under test. Stop when two equal-width black lines appear on the detection image. The two equal-width black lines correspond to the points where parallel light rays are tangent to the inner diameters on both sides of the glass tube under test. The distance between the two equal-width black lines is the inner diameter d of the glass tube under test. Therefore, using the difference between the outer diameter and the inner diameter of the glass tube under test, the wall thickness t of the glass tube under test can be calculated, i.e., the wall thickness.

[0022] S5. Observe whether the image of the grating corresponding to the detection image is distorted. Determine whether there are defects in the glass tube under test based on whether the grating image is distorted. If there are defects, move the glass tube under test. The image distortion position shows continuous movement characteristics and accompanied by boundary change disturbance characteristics. Extract these features and determine the type of defect based on feature changes, defect size and defect grayscale.

[0023] In one embodiment of the present invention, the defect size in step S5 is calculated according to the following formula:

[0024]

[0025] Where: L (x,y)Let denoted as , and let (x, y) be the length of the defective block on the arc surface of the glass tube. Let (x, y) be the coordinates of the centroid of the defective block on the circumference, R be the radius of the outer diameter of the glass tube, x1 be the coordinates of the left boundary of the defective block along the cross-sectional direction of the glass tube in the image, x2 be the coordinates of the right boundary of the defective block along the cross-sectional direction of the glass tube in the image, and δ be the coordinates of the defective block. y This is the correction value for the image pixel size along the y-direction.

[0026] By adopting this technical solution: due to the transparency of the glass tube under test, defects can be detected on the entire circumference of the glass tube. However, due to the different distances between the glass tube and the industrial camera, the pixel size of the industrial camera will vary at different locations on the entire circumference of the glass tube, which will affect the size of the defects and the subsequent judgment of the defect type. Therefore, by calculating and correcting the length of the defect in the arc direction using this calculation formula, the size of the defect can be obtained.

[0027] As described above, the integrated multi-parameter inspection device and method for the appearance quality of glass tubes of the present invention has the following beneficial effects: by combining an industrial camera, lens, grating and LED surface light source, the outer diameter, inner diameter, wall thickness and defects of the glass tube under test can be detected simultaneously through optical inspection principle, which has high inspection efficiency and is conducive to improving the production efficiency of glass tubes; its widespread application has good economic and social benefits. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the device arrangement of the present invention.

[0029] Figure 2 This is a schematic diagram illustrating the principle of measuring the outer diameter of the glass tube to be measured according to the present invention.

[0030] Figure 3 This is a schematic diagram illustrating the principle of measuring the wall thickness of the glass tube to be measured according to the present invention.

[0031] Figure 4 This is a schematic diagram of the method for correcting the radial size of defects on the surface of the glass tube to be tested according to the present invention.

[0032] Figure 5 This is a schematic diagram of the all-around defect detection of the glass tube under test according to the present invention.

[0033] In the image: 1. Industrial camera; 2. Lens; 3. Grating; 4. LED surface light source. Detailed Implementation

[0034] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0035] Please see Figure 1-5 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0036] Please see Figure 1 An integrated multi-parameter inspection device for the appearance quality of glass tubes includes at least one set of measurement units. Each measurement unit includes an industrial camera 1, a grating 3, and an LED surface light source 4. The industrial camera 1 is located on one side of the glass tube to be tested, with its lens 2 facing the tube. The LED surface light source 4 is located radially along the glass tube to be tested on the opposite side of the tube opposite to the industrial camera 1. The grating 3 is located between the LED surface light source 4 and the glass tube to be tested. The grating 3 is covered with alternating black and white geometric patterns formed by parallel lines. The industrial camera 1, lens 2, grating 3, and LED surface light source 4 form a set of measurement units. After the glass tube to be tested is placed between the lens 2 and the grating 3, its outer diameter, inner diameter, and wall thickness can be directly obtained through optical inspection. Simultaneously, the presence of defects can be determined based on whether the image of the grating 3 acquired by the industrial camera 1 is distorted. This provides sufficient conditions for judging the type of defects, enabling simultaneous detection of the outer diameter, inner diameter, wall thickness, and surface defects of the glass tube to be tested, thus increasing the efficiency of quality inspection of the glass tube.

[0037] Furthermore, by evenly distributing three sets of these measuring units around the periphery of the glass tube under test, it is possible to detect defects on the entire circumference of the glass tube under test, thereby increasing the efficiency of quality inspection of the glass tube under test and accurately determining the location of defects on the glass tube under test.

[0038] Please see Figure 2-5 A detection method for a multi-parameter integrated detection device for the appearance quality of glass tubes includes the following steps:

[0039] S1. Place the glass tube to be tested between the lens 2 and the grating 3. Adjust the position and orientation of the industrial camera 1 connected to the lens 2 so that the image of the industrial camera 1 is orthogonal to and centered with the glass tube to be tested. Turn on the LED surface light source 4 and adjust the brightness. The parallel light emitted by the LED surface light source 4 passes through the grating 3, the glass tube to be tested and the lens 2 in sequence, so that the industrial camera 1 can acquire the corresponding detection image.

[0040] S2. Adjust the position of the grating 3 between the glass tube under test and the LED surface light source 4 so that the industrial camera 1 can obtain a clear inspection image;

[0041] S3. The clear detection image shows obvious boundary features on the edge of the glass tube to be tested, and the distance between the two boundary features is the outer diameter D of the glass tube to be tested.

[0042] S4. Adjust the grating 3 away from the glass tube under test. Stop when two equal-width black lines appear on the detection image. The two equal-width black lines correspond to the points where parallel light rays are tangent to the inner diameters on both sides of the glass tube under test. The distance between the two equal-width black lines is the inner diameter d of the glass tube under test. Therefore, using the difference between the outer diameter and the inner diameter of the glass tube under test, the wall thickness t of the glass tube under test can be calculated, i.e., the wall thickness.

[0043] S5. Observe whether the image of the detection image is distorted according to the image of grating 3. Determine whether there are defects in the glass tube under test based on whether the image of grating 3 is distorted.

[0044] If defects exist, move the glass tube under test. The image deformation position shows continuous movement characteristics and perturbation characteristics with boundary changes. Extract these features and determine the type of defect based on feature changes, defect size, and defect grayscale.

[0045] Furthermore, due to the transparency of the glass tube under test, defects can be detected on the entire circumference of the glass tube. However, because the distance between the glass tube and the industrial camera 1 varies at different locations, the pixel size of the industrial camera 1 will differ at different locations on the entire circumference of the glass tube, thus affecting the size of the defects. Therefore, it is necessary to correct for the size of the defects. The length of the defect in the arc direction is calculated using the following formula:

[0046]

[0047] Where: L (x,y) Let denoted as , and let (x, y) be the length of the defective block on the arc surface of the glass tube. Let (x, y) be the coordinates of the centroid of the defective block on the circumference, R be the radius of the outer diameter of the glass tube, x1 be the coordinates of the left boundary of the defective block along the cross-sectional direction of the glass tube in the image, x2 be the coordinates of the right boundary of the defective block along the cross-sectional direction of the glass tube in the image, and δ be the coordinates of the defective block. yThis is the correction value for the image pixel size along the y-direction.

[0048] In practice, the glass tube to be tested is placed between the lens 2 and the grating 3 of the industrial camera 1. The exposure and focal length of the lens 2 are adjusted to obtain a satisfactory imaging effect. The position and orientation of the industrial camera 1 are adjusted so that the image of the industrial camera 1 is orthogonal to and centered with the glass tube to be tested. Then, the brightness of the LED surface light source 4 is adjusted. The parallel light emitted by the LED surface light source 4 passes upward through the grating 3, the glass tube to be tested, and the lens 2 in sequence, so that the industrial camera 1 can acquire the corresponding detection image. The position of the grating 3 between the glass tube to be tested and the LED surface light source 4 is adjusted so that the industrial camera 1 can acquire a clear detection image. The clear detection image shows obvious boundary features corresponding to the edge of the glass tube to be tested. The distance between the two boundary features is the test edge. The outer diameter of the glass tube is determined by adjusting the grating 3 away from the glass tube under test. The test is stopped when two equal-width black lines appear on the image. These two equal-width black lines correspond to parallel light rays tangent to the inner diameters on both sides of the glass tube. The distance between these two equal-width black lines is the inner diameter of the glass tube. Therefore, the wall thickness of the glass tube can be calculated using the difference between its outer and inner diameters. The image corresponding to grating 3 is then observed for distortion. Based on the distortion of grating 3, it is determined whether the glass tube has defects. If defects exist, the glass tube is moved. The image distortion position exhibits continuous movement characteristics accompanied by boundary changes and disturbance characteristics. These features are extracted, and the type of defect is determined based on feature changes, defect size, and defect grayscale.

[0049] In summary, the integrated multi-parameter inspection device and method for glass tube appearance quality of the present invention has the following beneficial effects: by cooperating with an industrial camera 1, lens 2, grating 3, and LED surface light source 4, the outer diameter, inner diameter, wall thickness, and defects of the glass tube under test can be detected simultaneously, resulting in high inspection efficiency and improving the production efficiency of glass tubes; its widespread application has good economic and social benefits. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0050] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A multi-parameter integrated testing device for the appearance quality of glass tubes, characterized in that, It includes at least one set of measurement units, which include an industrial camera (1), a grating (3) and an LED surface light source (4). The industrial camera (1) is located on one side of the glass tube to be tested and the lens (2) of the industrial camera (1) is facing the glass tube to be tested; The LED surface light source (4) is located on the other side of the glass tube to be tested relative to the industrial camera (1) along the radial direction of the glass tube to be tested. The grating (3) is located between the LED surface light source (4) and the glass tube to be tested; the grating (3) is covered with black and white geometric patterns, which are formed by parallel lines; The glass tube appearance quality multi-parameter integrated detection device determines the outer diameter D of the glass tube to be tested based on the distance between the two sides of the obvious boundary features on the edge of the glass tube to be tested in the detection image obtained by the industrial camera (1). When two equal-width black lines appear on the detection image, the integrated multi-parameter detection device for the appearance quality of the glass tube stops controlling the grating (3) to move away from the glass tube to be tested, and determines the distance between the two equal-width black lines as the inner diameter d of the glass tube to be tested, and calculates the wall thickness t of the glass tube to be tested based on the difference between the outer diameter and inner diameter of the glass tube to be tested. The integrated multi-parameter detection device for the appearance quality of glass tubes determines whether there are defects in the glass tube under test based on whether the image of the grating (3) obtained by the industrial camera (1) is deformed. If there are defects, the device extracts the image deformation position when the glass tube under test is moved, which shows continuous movement characteristics and disturbance characteristics accompanied by boundary changes. The device also determines the type of defects based on the feature changes, defect size and defect gray level.

2. The integrated multi-parameter inspection device for the appearance quality of glass tubes according to claim 1, characterized in that: The position of the grating (3) between the glass tube under test and the LED surface light source (4) is adjustable.

3. The integrated multi-parameter inspection device for the appearance quality of glass tubes according to claim 1, characterized in that: The measuring units are configured in three groups and evenly distributed along the circumference of the glass tube to be tested.

4. A testing method for a multi-parameter integrated testing device for the appearance quality of glass tubes as described in any one of claims 1-3, characterized in that: Includes the following steps: S1. Place the glass tube to be tested between the lens (2) and the grating (3), turn on the LED surface light source (4), and the parallel light emitted by the LED surface light source (4) passes through the grating (3), the glass tube to be tested and the lens (2) in sequence, so that the industrial camera (1) can obtain the corresponding detection image. S2. Adjust the position of the grating (3) between the glass tube to be tested and the LED surface light source (4) so ​​that the industrial camera (1) can obtain a clear detection image; S3. The clear detection image shows obvious boundary features on the edge of the glass tube to be tested, and the distance between the two boundary features is the outer diameter D of the glass tube to be tested. S4. Adjust the grating (3) away from the glass tube to be tested. Stop when two equal-width black lines appear on the detection image. The two equal-width black lines correspond to the parallel light rays that are tangent at the inner diameters on both sides of the glass tube to be tested. The distance between the two equal-width black lines is the inner diameter d of the glass tube to be tested. Therefore, the wall thickness t of the glass tube to be tested can be calculated using the difference between the outer diameter and the inner diameter of the glass tube to be tested. ; S5. Observe whether the image of the grating (3) corresponding to the detection image is deformed. Based on whether the image of the grating (3) is deformed, determine whether there are defects in the glass tube to be tested. If there are defects, move the glass tube to be tested. The image deformation position shows continuous movement characteristics and accompanied by boundary change disturbance characteristics. Extract these characteristics and determine the type of defects based on feature changes, defect size and defect gray level.

5. The detection method of the integrated multi-parameter detection device for the appearance quality of glass tubes according to claim 4, characterized in that: The defect size in step S5 is calculated using the following formula: ; in: Let denoted as , and let (x, y) be the length of the defective block on the arc surface of the glass tube. Let (x, y) be the coordinates of the centroid of the defective block on the circumference, R be the radius of the outer diameter of the glass tube, x1 be the coordinates of the left boundary of the defective block along the cross-sectional direction of the glass tube in the image, x2 be the coordinates of the right boundary of the defective block along the cross-sectional direction of the glass tube in the image, and δ be the coordinates of the defective block. y This is the correction value for the image pixel size along the y-direction.

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