CN212963223U - Diameter measurement and surface defect detection system for seamless steel pipe - Google Patents
Diameter measurement and surface defect detection system for seamless steel pipe Download PDFInfo
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- CN212963223U CN212963223U CN202021726500.0U CN202021726500U CN212963223U CN 212963223 U CN212963223 U CN 212963223U CN 202021726500 U CN202021726500 U CN 202021726500U CN 212963223 U CN212963223 U CN 212963223U
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Abstract
The utility model relates to a seamless steel pipe diameter measurement and surface defect detection system, which comprises a rack, a first guide rail, a first bar light source, a second bar light source, a parallel light source, an area-array camera, a second guide rail, an auxiliary rotating shaft, a driving rotating shaft, a display screen, an image processing device and a motor, wherein the first guide rail is arranged at the top of the rack; the first strip-shaped light source, the second strip-shaped light source and the area-array camera are all arranged on the first guide rail and can slide left and right along the first guide rail; the end part of the driving rotating shaft is connected with a motor, and the motor drives the driving rotating shaft to rotate; the driving rotating shaft further drives the auxiliary rotating shaft and the seamless steel tube to rotate; the area-array camera is respectively connected with the display screen and the image processing device through data lines, so that the image shot by the area-array camera is transmitted to the image processing device for processing while the image shot by the area-array camera is displayed on the display screen.
Description
Technical Field
The utility model relates to a seamless steel pipe's detection technology field, concretely relates to seamless steel pipe diameter measurement and surface defect detecting system.
Background
The seamless steel pipe is a section steel with high practicability, and has great demand in production and life, such as the fields of petroleum, boilers, power stations, ships, machinery manufacturing, automobiles, aviation, aerospace, energy, geology, buildings, military industry and the like. The diameter and surface defect information of the seamless steel pipe are important standards for judging the quality of the seamless steel pipe and are the most concerned parts of enterprises and customers. Thirteen-five planning is carried out, the market demand for seamless steel pipes is increasing, and the traditional seamless steel pipe detection method is difficult to meet the production requirements of enterprises.
Disclosure of Invention
The utility model aims at providing a seamless steel pipe diameter measurement and surface defect detecting system, the technical problem that solve include how to accomplish the size measurement of diameter and surface defect's detection simultaneously through the single collection.
The utility model aims at solving the defects of the prior art and providing a seamless steel tube diameter measurement and surface defect detection system, which comprises a rack, a first guide rail, a first bar light source, a second bar light source, a parallel light source, an area array camera, a second guide rail, an auxiliary rotating shaft, a driving rotating shaft, a display screen, an image processing device and a motor, wherein the first guide rail is arranged at the top of the rack; the first strip-shaped light source, the second strip-shaped light source and the area-array camera are all arranged on the first guide rail and can slide left and right along the first guide rail; the auxiliary rotating shaft is rotatably arranged on one side of the rack, the driving rotating shaft is rotatably arranged on the other side of the rack, and the seamless steel tube to be detected is arranged and clamped between the auxiliary rotating shaft and the driving rotating shaft; the end part of the driving rotating shaft is connected with a motor, and the motor drives the driving rotating shaft to rotate; the driving rotating shaft further drives the auxiliary rotating shaft and the seamless steel tube to rotate; the area-array camera is respectively connected with the display screen and the image processing device through data lines, so that images shot by the area-array camera are transmitted to the image processing device for processing while the images shot by the area-array camera are displayed on the display screen.
Preferably, the first guide rail and the second guide rail are arranged in parallel to the central axis of the seamless steel pipe.
The first strip-shaped light source and the second strip-shaped light source are symmetrically arranged on the left side and the right side of the area-array camera respectively.
The optical axis directions of the first strip-shaped light source and the second strip-shaped light source form an angle of 25-60 degrees with the surface of the seamless steel pipe.
The central axes of the auxiliary rotating shaft, the driving rotating shaft and the seamless steel tube are coincided into the same straight line.
The first strip light source and the second strip light source are arranged above the seamless steel tube, light emitted by the first strip light source and the second strip light source is irradiated on the seamless steel tube and then reflected by the seamless steel tube, and the reflected light enters the area array camera.
The parallel light source is arranged below the seamless steel pipe.
Advantageous effects
Compared with the prior art, the beneficial effects of the utility model are that: seamless steel pipe diameter measurement uses single area array camera to combine rotatory scheme of advancing to accomplish the seamless steel pipe image acquisition of columnar order with surface defect detecting system, can gather the size measurement of accomplishing the diameter simultaneously and surface defect's detection through the single. The problem of steel pipe surface reflection of light and reservation boundary information is solved to the combination light source that constitutes through adopting two strip light sources and parallel light source, has still increased simultaneously and has adopted like device's stability and expansibility, guarantees that the image has clear profile and guarantees that the surface characteristic of image is obvious simultaneously. Adopt seamless steel pipe diameter measurement and surface defect detecting system, the detectable rate that measuring error of diameter is less than 0.01mm, surface defect is at the size more than 0.2mm is higher than 95%, all satisfies the production requirement to seamless steel pipe diameter's measurement and surface defect's detection effect.
Drawings
The accompanying drawings are included to provide a further understanding of the embodiments of the present invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention and not to limit the embodiments of the invention.
Fig. 1 is a flow chart of a method for manufacturing the system for measuring the diameter of the seamless steel pipe and detecting the surface defects of the seamless steel pipe.
Fig. 2 is a schematic diagram of the second order differential curve.
FIG. 3 is a schematic diagram of fitting of left and right boundaries of a collected image of a seamless steel pipe to be detected.
Detailed Description
The present invention is described in more detail below to facilitate an understanding of the invention.
As shown in fig. 1 and fig. 2, the system for measuring the diameter of a seamless steel pipe and detecting surface defects of the seamless steel pipe of the present invention comprises a rack 1, a first guide rail 3, a first bar-shaped light source 4, a second bar-shaped light source 5, a parallel light source 6, an area-array camera 7, a second guide rail 8, an auxiliary rotating shaft 9, a driving rotating shaft 10, a display screen 11, an image processing device 12 and a motor 13, wherein the first guide rail 3 is arranged at the top of the rack 1; the first strip-shaped light source 4, the second strip-shaped light source 5 and the area array camera 7 are all arranged on the first guide rail 3 and can slide left and right along the first guide rail; the auxiliary rotating shaft 9 is rotatably arranged on one side of the rack, the driving rotating shaft 10 is rotatably arranged on the other side of the rack, and the seamless steel tube 2 to be detected is arranged and clamped between the auxiliary rotating shaft 9 and the driving rotating shaft 10; the end part of the driving rotating shaft 10 is connected with a motor 13, and the motor 13 drives the driving rotating shaft 10 to rotate; the driving rotating shaft 10 further drives the auxiliary rotating shaft 9 and the seamless steel tube 2 to rotate; the area-array camera 7 is respectively connected with the display screen 11 and the image processing device 12 through data lines, so that images shot by the area-array camera 7 are transmitted to the image processing device 12 for processing while being displayed by the display screen 11; the image processing device 12 performs second differentiation on the brightness value of the image of the seamless steel pipe shot by the area array camera 7 to generate a second differential image; at the same time, the image processing device 12 generates a second order differential curve L for each of a plurality of virtual mark lines in the second order differential image, the virtual mark lines being closed circular lines H surrounding the seamless steel pipe on the second order differential image, the surfaces of the circular lines being perpendicular to the central axis of the seamless steel pipe; the second order differential curve represents the change of the second order differential value on the imaginary mark line in the second order differential image; the image processing apparatus 12 further counts a first reference number n1, which is the number of times the second order differential curve L intersects the first limit B1 on the annular line H; the image processing apparatus 12 further counts a second reference number n2, which is the number of times the second order differential curve L intersects with a second limit B2 on the annular line H.
The first limit value B1 and the second limit value B2, which are the luminance values of the second order differential image, correspond to the extreme values of the defect depth that is used as the boundary line between the defect surface and the normal surface that can be tolerated in the surface defect inspection, and the second limit value corresponds to the extreme values of the surface roughness of the seamless steel pipe to be inspected that can be tolerated in the surface defect inspection.
The second limit B2 is less than the first limit B1.
The applicant found in the experimental process that if there is a defect on the surface of the seamless steel pipe to be detected, the second order differential value of the luminance value in the actual image becomes large at a position deep in the defect. That is, by comparing the second derivative value of each luminance value with the first limit value B1 which is relatively large, it is possible to detect whether a defect exists. In addition, in the actual inspection process, the applicant found that the brightness value in the actual image is also affected by the surface roughness of the seamless steel pipe. By comparing the second derivative value of each luminance value with a relatively small second limit value B2, the actual effect of the surface roughness of the seamless steel pipe on the detection of the surface defects of the seamless steel pipe can be detected.
The image processing apparatus 12 further counts a first reference total number of times N1 and a second reference total number of times N2, which is a sum of the first reference number of times N1 of the plurality of virtual mark lines; the second reference total number of times is a sum of the second reference number of times n2 of the plurality of imaginary mark lines.
The image processing device 12 calculates the first reference total times N1 divided by the second reference total times N2, and if N1/N2 is more than or equal to V, the defect is determined to exist; if N1/N2< V, where V is a constant specified by the technician as a function of allowable defect size, then it is determined that no defect is present.
As an example, when the allowable defect is larger than 0.2mm × 0.2mm, V is taken to be 4; when the allowable defect is less than or equal to 0.2mm × 0.2mm, V is taken to be 2.
The diameter measurement of the seamless steel pipe generally comprises two methods of acquiring images of the end part of the seamless steel pipe and acquiring images of the side wall of the seamless steel pipe. The area-array cameras are required to be arranged at the end parts of the seamless steel pipes independently for acquiring images of the end parts of the seamless steel pipes, so that the diameter measurement and surface defect detection system of the seamless steel pipes needs at least two area-array cameras, each camera needs an independent optical lens, and the manufacturing cost of the detection system is greatly increased. In addition, since the diameter of the seamless steel pipe varies along the length direction (i.e., the direction of the central axis), measuring the diameter of the end portion alone is not sufficient to characterize the actual diameter of the entire seamless steel pipe.
The side wall of the seamless steel pipe is shot by using an area-array camera from top to bottom, a rectangular figure is shown on the image, and the diameter of the seamless steel pipe can be obtained by measuring the width of the rectangle. The measuring method only needs one area array camera arranged above the seamless steel pipe, and the manufacturing cost of the seamless steel pipe diameter measuring and surface defect detecting system is reduced. In addition, the area-array camera arranged above the seamless steel pipe can move along the length direction (namely the direction of the central axis) of the seamless steel pipe, so that the actual diameter condition of the whole seamless steel pipe can be accurately displayed.
The diameter measurement of the seamless steel tube is carried out on the collected image of the side wall of the seamless steel tube, and the boundary positioning is carried out on the collected image, specifically:
since the diameter of the seamless steel pipe in the longitudinal direction is not a uniform fixed value as shown in fig. 3, the actual left and right boundaries of the seamless steel pipe are not strictly straight lines, and the above-mentioned figure is requiredThe image processing device 12 fits the collected left and right boundaries of the seamless steel pipe 2 to be detected into a left boundary L1And a right boundary L2：
L1：y＝k1x+b1
L2：y＝k2x+b2；
Wherein k is1、k2、b1And b2The specific numerical value is a least square estimation value obtained by utilizing a least square method to fit a straight line for calculation;
as shown in FIG. 3, let (x)1，y1) And (x)2，y2) Indicates the left boundary L1Two end points of (x)1’， y1') and (x)2’，y2') indicates the right boundary L2The two end points of (a) are obtained according to a distance formula from the point to the straight line1，y1) To the right boundary L2Distance L of12Comprises the following steps:
calculated in the same way to obtain (x)2，y2) To the right boundary L2Distance L of22、(x1’，y1') to the left boundary L1Distance L 'of'21And (x)2’，y2') to the left boundary L1Distance L 'of'22Theoretical L12、 L22、L'21And L'22Can represent the left boundary L1And a right boundary L2The distance between, but due to the actual calculation of the left boundary L1And a right boundary L2Not absolutely parallel straight lines, so the left boundary L1And a right boundary L2There is actually a very small included angle between them, and to reduce the error, L is taken12、L22、L'21And L'22As the diameter d of the seamless steel pipe, i.e.:
preferably, the first guide rail 3 and the second guide rail 8 are both arranged parallel to the central axis of the seamless steel tube 2.
The first strip-shaped light source 4 and the second strip-shaped light source 5 are respectively and symmetrically arranged at the left side and the right side of the area array camera 7.
The optical axis directions of the first strip-shaped light source 4 and the second strip-shaped light source 5 form an angle of 25-60 degrees with the surface of the seamless steel pipe 2. The angle enables the overall image of the seamless steel pipe 2 shot by the area-array camera 7 to be brighter, and the contour and the uneven area of the surface of the seamless steel pipe 2 can be highlighted.
The central axes of the auxiliary rotating shaft 9, the driving rotating shaft 10 and the seamless steel tube 2 are coincided to form a same straight line.
The first strip-shaped light source 4 and the second strip-shaped light source 5 are arranged above the seamless steel tube 2, light emitted by the first strip-shaped light source 4 and the second strip-shaped light source 5 is irradiated on the seamless steel tube 2 and then reflected by the seamless steel tube 2, and the reflected light enters the area array camera 7.
The parallel light source 6 is arranged below the seamless steel tube 2. Thus, the backlight polishing effect is realized, so that the image profile shot by the area-array camera 7 is clear, and the dimension measurement is convenient.
The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. Modifications and variations of the embodiments disclosed herein may be made by those skilled in the art without departing from the scope and spirit of the invention.
Claims (7)
1. A seamless steel pipe diameter measurement and surface defect detection system is characterized by comprising a rack, a first guide rail, a first strip light source, a second strip light source, a parallel light source, an area array camera, a second guide rail, an auxiliary rotating shaft, a driving rotating shaft, a display screen, an image processing device and a motor, wherein the first guide rail is arranged at the top of the rack; the first strip-shaped light source, the second strip-shaped light source and the area-array camera are all arranged on the first guide rail and can slide left and right along the first guide rail; the auxiliary rotating shaft is rotatably arranged on one side of the rack, the driving rotating shaft is rotatably arranged on the other side of the rack, and the seamless steel tube to be detected is arranged and clamped between the auxiliary rotating shaft and the driving rotating shaft; the end part of the driving rotating shaft is connected with a motor, and the motor drives the driving rotating shaft to rotate; the driving rotating shaft further drives the auxiliary rotating shaft and the seamless steel tube to rotate; the area-array camera is respectively connected with the display screen and the image processing device through data lines, so that images shot by the area-array camera are transmitted to the image processing device for processing while the images shot by the area-array camera are displayed on the display screen.
2. The seamless steel tube diameter measuring and surface defect detecting system according to claim 1, wherein the first guide rail and the second guide rail are both arranged parallel to a central axis of the seamless steel tube.
3. The system for measuring the diameter and detecting the surface defects of the seamless steel tube according to claim 1, wherein the first strip light source and the second strip light source are respectively and symmetrically arranged at the left side and the right side of the area-array camera.
4. The system for measuring the diameter and detecting the surface defects of the seamless steel pipe according to claim 1, wherein the directions of the optical axes of the first and second strip light sources form an angle of 25 ° to 60 ° with the surface of the seamless steel pipe.
5. The system for measuring the diameter of the seamless steel tube and detecting the surface defects as claimed in claim 1, wherein the central axes of the auxiliary rotating shaft, the driving rotating shaft and the seamless steel tube coincide to form a straight line.
6. The system for measuring the diameter and detecting the surface defects of the seamless steel tube according to claim 1, wherein the first strip light source and the second strip light source are arranged above the seamless steel tube, light emitted by the first strip light source and the second strip light source is reflected by the seamless steel tube after being irradiated onto the seamless steel tube, and the reflected light enters the area-array camera.
7. The system according to claim 1, wherein the collimated light source is disposed below the seamless steel pipe.
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| CN202021726500.0U CN212963223U (en) | 2020-08-18 | 2020-08-18 | Diameter measurement and surface defect detection system for seamless steel pipe |
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| CN202021726500.0U CN212963223U (en) | 2020-08-18 | 2020-08-18 | Diameter measurement and surface defect detection system for seamless steel pipe |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112945972A (en) * | 2021-01-29 | 2021-06-11 | 徐州科瑞矿业科技有限公司 | Steel wire rope state detection device and method based on machine vision |
| CN113739859A (en) * | 2021-09-27 | 2021-12-03 | 浙江立潮工程科技股份有限公司 | Drain pipe detection equipment and using method thereof |
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2020
- 2020-08-18 CN CN202021726500.0U patent/CN212963223U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112945972A (en) * | 2021-01-29 | 2021-06-11 | 徐州科瑞矿业科技有限公司 | Steel wire rope state detection device and method based on machine vision |
| CN112945972B (en) * | 2021-01-29 | 2022-04-15 | 徐州科瑞矿业科技有限公司 | Steel wire rope state detection device and method based on machine vision |
| CN113739859A (en) * | 2021-09-27 | 2021-12-03 | 浙江立潮工程科技股份有限公司 | Drain pipe detection equipment and using method thereof |
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