A device and method for detecting the buckle value of a slab hot rolling outlet
By combining linear laser and cross laser with an image processing system, discrete points at the end of the slab are extracted and fitted to fit the warp curve, solving the problem of large warp value detection error in existing technologies and achieving high-precision warp value detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANSHAN UNIV
- Filing Date
- 2023-06-14
- Publication Date
- 2026-05-29
AI Technical Summary
In the existing technology, the machine vision-based method for detecting the overhang value at the hot rolling exit of slabs is prone to misextracting the end curve as the side edge, resulting in incorrect overhang value calculation and failing to accurately reflect the true degree of overhang of the strip.
A single-line laser and a cross laser are emitted perpendicularly and parallel to the side edge of the slab, respectively. Combined with an image acquisition system and a processing system, discrete points in the end image are extracted, a warping curve is fitted, and the maximum warping value is determined by the image vanishing point and edge protrusion.
It improves the accuracy of overhang value detection, avoids erroneous judgments caused by incorrect extraction of end curves, and can detect the overhang status of slabs in real time. It is suitable for overhang value detection of slab ends at the exit of hot rolling mills.
Smart Images
Figure CN116713332B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of intelligent rolling technology, and in particular to a device and method for detecting the warpage value at the exit of hot-rolled slabs. Background Technology
[0002] During hot rolling, slabs frequently exhibit shape defects such as head and tail bending. Upward bending is called "head curling," and downward bending is called "head buckling." Both are common in rolling production and pose significant hazards. When head curling occurs, the slab head may collide with the outer guard plate of the roller table, the protective plate, or on-site monitoring instruments. Severe head curling may prevent the slab from entering the subsequent rolling mill, causing a steel pile-up accident. When head buckling occurs, the slab head may collide with the mill stand rolls or the roller table. In severe cases, this can cause the slab to damage the roller table's perforated frame or even crawl under the roller table, causing varying degrees of damage to the production line. Failure to control head curling and head buckling during rolling production can lead to numerous production problems. Therefore, a real-time online method for detecting head curling and head buckling values is needed to promptly detect these defects and prevent accidents.
[0003] The main cause of warping is the asymmetrical deformation that occurs during rolling. The main factors causing asymmetrical deformation include the temperature difference between the upper and lower surfaces, the difference in diameter of the work rolls, the difference in speed of the work rolls, the height of the binding wire, and the amount of reduction. Under the combined influence of these factors, warping occurs when the extension of the lower surface is greater than that of the upper surface; warping occurs when the extension of the upper surface is greater than that of the lower surface.
[0004] Currently, traditional machine vision-based detection methods use the side edges of the slab as the warp curve. However, after hot rolling, due to temperature differences and uneven thickness in the width direction, the head and tail of the slab are usually not regular rectangles, but rather have slightly irregular arcs. The head is slightly convex, resembling a "tongue," and the tail is slightly concave, resembling a "fish tail." In the acquired images, the side edges and end edges form a smooth curve. This leads to the extraction of the end curve when extracting the side edge curve, incorrectly treating the end edge as part of the side edge, ultimately causing errors in judging the warp head. Furthermore, the degree of warp is uneven in the width direction, meaning the side edge cannot accurately represent the true warp degree of the entire strip, resulting in inaccurate warp values calculated based on the side edge. Therefore, how to avoid incorrectly extracting the end curve and causing errors in warp value calculation is a pressing problem that needs to be solved. Summary of the Invention
[0005] Based on this, embodiments of the present invention provide a device and method for detecting the overhang value at the hot-rolled exit of slabs, so as to avoid errors in the calculation of the overhang value caused by the incorrect extraction of the end curve, and improve the accuracy of detecting the overhang value at the hot-rolled exit of slabs.
[0006] To achieve the above objectives, embodiments of the present invention provide the following solutions:
[0007] A device for detecting the warpage value at the exit of hot-rolled slabs includes:
[0008] The first laser generator is used for:
[0009] A linear laser beam is emitted toward the surface of the target slab; the linear laser beam is perpendicular to the side edge of the target slab.
[0010] The second laser generator is used for:
[0011] A cross-shaped laser is emitted toward the surface of a target slab; the cross-shaped laser includes: a second laser perpendicular to the side edge of the target slab and a third laser parallel to the side edge of the target slab;
[0012] Image acquisition system, used for:
[0013] After the single-line laser and the cross laser irradiate the end of the target slab, an image of the end of the target slab is acquired;
[0014] The image processing system is connected to the image acquisition system and is used for:
[0015] Extract discrete points of the first laser line in the end image, and fit the warping curve of the end of the target slab based on the discrete points; the first laser line is the laser line that the third laser irradiates to the end of the target slab.
[0016] The vanishing point of the end image is determined based on the parallel laser line group, and the maximum lifting value of the end of the target slab is determined based on the vanishing point, the edge protrusion of the end image, and the lifting curve.
[0017] The maximum warping value is used to characterize the maximum warping degree of the end of the target slab; the parallel laser line group includes: the laser line irradiating the end of the target slab by the single laser and the laser line irradiating the end of the target slab by the second laser.
[0018] Optionally, the image processing system, in determining the maximum warp value at the end of the target slab based on the image vanishing point, the edge protrusion of the end image, and the warp curve, is specifically used for:
[0019] The intersection points of each edge protrusion of the end image with the buckle curve are determined to obtain the intersection point group;
[0020] The point with the largest pixel value in the image column is selected from the group of intersection points to obtain the point of maximum warping.
[0021] The first height is determined based on the vanishing point of the image and the maximum warping point; the first height is the height of the target slab on the plane captured by the image processing system.
[0022] Based on the first height and the angle between the image processing system and the vertical plane, the second height is calculated and determined as the maximum overhang value of the end of the target slab; the second height is the height of the target slab in world coordinates.
[0023] Optionally, the image processing system, in extracting discrete points of the first laser line in the end image, is specifically used for:
[0024] The end image is subjected to image processing operations to obtain a processed image; the image processing operations include: image preprocessing, image binarization, image segmentation, and feature extraction;
[0025] Extract the outline of the first laser line from the processed image;
[0026] Discrete points of the first laser line are extracted on the contour at equal intervals.
[0027] Optionally, the image processing system, in calculating the second height based on the first height and the angle between the image processing system and the vertical plane, is specifically used for:
[0028] According to the formula Calculate the second height; h1 represents the first height; h0 represents the second height; α represents the angle between the image processing system and the vertical plane.
[0029] Optionally, the image acquisition system is at a height of 20cm or more above the surface of the target slab; the length of the target slab captured by the image acquisition system is greater than 1.5m.
[0030] Optionally, the first laser generator is a line laser; the second laser generator is a cross laser.
[0031] Optionally, the laser emitted by the first laser generator and the second laser generator is a green laser with a wavelength of 520nm or 532nm.
[0032] This invention also provides a method for detecting the warpage value at the exit of hot-rolled slabs, comprising:
[0033] After the line laser and cross laser irradiate the end of the target slab, an image of the end of the target slab is acquired;
[0034] The vanishing point of the end image is determined based on the parallel laser line group;
[0035] The maximum warp value at the end of the target slab is determined based on the vanishing point of the image, the edge protrusion of the end image, and the warp curve.
[0036] The single-line laser is a laser emitted by a first laser generator toward the surface of the target slab and perpendicular to the side edge of the target slab; the cross laser includes: a second laser emitted by a second laser generator toward the target slab and perpendicular to the side edge of the target slab, and a third laser parallel to the side edge of the target slab.
[0037] The maximum warping value is used to characterize the maximum warping degree of the end of the target slab; the parallel laser line group includes: the laser line irradiated by the first laser to the end of the target slab and the laser line irradiated by the second laser to the end of the target slab.
[0038] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:
[0039] Compared with traditional image edge detection methods, this invention uses the laser line irradiated on the slab as the benchmark for measuring the warp value, avoiding the problem of extracting the end edge and side edge together, which leads to incorrect judgment of the warp head. At the same time, the laser line array measurement method can detect the true warp condition on the slab surface, avoiding the problem of inaccurate detection caused by the unevenness of warp in the width of the slab. Therefore, this invention can perform real-time detection of the end (head and / or tail) of the slab at the exit of the hot rolling mill, avoiding the error in calculating the warp value caused by the mis-extraction of the end curve, and improving the accuracy of the warp value detection at the hot rolling exit of the slab. Attached Figure Description
[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0041] Figure 1 This is a schematic diagram of the shape of the head of the target slab after hot rolling, provided in an embodiment of the present invention.
[0042] Figure 2 This is a schematic diagram of the shape of the tail of the target slab after hot rolling, provided in an embodiment of the present invention.
[0043] Figure 3 This is a schematic diagram of the slab hot-rolled exit warp value detection device provided in an embodiment of the present invention;
[0044] Figure 4A schematic diagram of the target slab on the projection plane captured by the image acquisition system;
[0045] Figure 5 A schematic diagram illustrating the degree of slab warping provided in an embodiment of the present invention;
[0046] Figure 6 This is a schematic diagram illustrating the determination of the degree of slab buckling provided in an embodiment of the present invention;
[0047] Figure 7 The warpage values and image diagrams of the slab after each rolling pass when the slab head warpage control system is not used, as provided in the embodiments of the present invention;
[0048] Figure 8 The image shows the warpage value and image diagram of the slab after each rolling pass, provided by the slab head warpage control system in the embodiments of the present invention.
[0049] Symbol explanation:
[0050] Support roller—1, working roller—2, first laser generator—3, second laser generator—4, target slab—5, image acquisition system—6, projection plane—7. Detailed Implementation
[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0052] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0053] After hot rolling, slabs often develop shape defects at their ends, such as upward or downward curling, collectively known as curling or buckling. When curling occurs, the slab head may collide with the outer guard plate of the roller table, the protective plate, or on-site monitoring instruments. Severe curling may prevent the slab from biting into the subsequent rolling mill, causing a steel pile-up accident. When buckling occurs, the slab head may collide with the mill stand rolls or the roller table. In severe cases, this can cause the slab to damage the flower rack on the roller table or even crawl under the roller table, causing varying degrees of damage to the production line. The head and tail ends of hot-rolled slabs are usually irregularly curved, such as... Figure 1 As shown, the head protrudes slightly outward, resembling a "tongue," and its side edges and end edges form a curve, as... Figure 2As shown, the tail end is also slightly concave, resembling a "fish tail". If the side edge of the strip is directly extracted to detect the buckle value, the edge of the end will often be extracted together, forming an incorrect edge curve. This will ultimately lead to misjudgment of the buckle head and incorrect calculation of the buckle value.
[0054] To achieve machine vision-based detection of slab warpage value while avoiding edge extraction errors, this invention provides a slab hot-rolling exit warpage value detection device. (See also...) Figure 3 The slab hot-rolled exit warp value detection device of this embodiment includes:
[0055] The first laser generator 3 is used to: emit a line laser beam onto the surface of the target slab 5; the line laser beam is perpendicular to the side edge of the target slab 5.
[0056] The second laser generator 4 is used to emit a cross laser onto the surface of the target slab 5; the cross laser includes a second laser perpendicular to the side edge of the target slab 5 and a third laser parallel to the side edge of the target slab 5.
[0057] Image acquisition system 6 is used to acquire an image of the end of the target slab 5 after the linear laser and the cross laser illuminate the end (head and / or tail) of the target slab 5. Figure 3 As shown, an image acquisition system 6 can be installed at the side of the hot rolling mill exit for the target slab 5. The hot rolling mill includes a support roll 1 and a work roll 2. The arrow indicates the direction of movement of the target slab 5 during the hot rolling process.
[0058] The image processing system is connected to the image acquisition system 6 and is used for:
[0059] Extract discrete points of the first laser line in the end image, and fit the warping curve of the end of the target slab 5 based on the discrete points; the first laser line is the laser line that the third laser irradiates to the end of the target slab 5.
[0060] The vanishing point of the end image is determined based on the parallel laser line group, and the maximum knockout value of the end of the target slab 5 is determined based on the vanishing point, the edge protrusion of the end image, and the knockout curve.
[0061] The maximum warping value is used to characterize the maximum warping degree of the end of the target slab 5; the parallel laser line group includes: the laser line that the single laser irradiates the end of the target slab 5 and the laser line that the second laser irradiates the end of the target slab 5.
[0062] In one example, the image processing system is specifically used to determine the maximum warp value at the end of the target slab 5 based on the image vanishing point, the edge protrusion of the end image, and the warp curve:
[0063] The intersection points of each edge protrusion of the end image with the warp curve are determined to obtain an intersection point group. The intersection point with the largest pixel value in the image column is selected from the intersection point group to obtain the maximum warp point. A first height is determined based on the image vanishing point and the maximum warp point; the first height is the height of the target slab 5 on the plane captured by the image processing system. A second height is calculated based on the first height and the angle between the image processing system and the vertical plane, and the second height is determined as the maximum warp value of the end of the target slab 5; the second height is the height of the target slab 5 in world coordinates.
[0064] In one example, the image processing system, in extracting discrete points of the first laser line in the end image, specifically involves: performing image processing operations on the end image to obtain a processed image; the image processing operations include: image preprocessing, image binarization, image segmentation, and feature extraction. The contour of the first laser line is extracted from the processed image. Discrete points of the first laser line are extracted on the contour at equal intervals.
[0065] In one example, the image processing system, in calculating the second height based on the first height and the angle between the image processing system and the vertical plane, specifically uses the following formula: Calculate the second height; h1 represents the first height; h0 represents the second height; α represents the angle between the image processing system and the vertical plane.
[0066] In one example, the image acquisition system 6 includes: a high-precision industrial camera and optical components such as a lens, as well as adjustment components. The distance between the camera and the roughing mill is greater than 2m. The length of the target slab 5 captured by the camera is greater than 1.5m. The height of the camera from the surface of the target slab 5 is greater than or equal to 20cm. A guardrail is installed around the image processing system.
[0067] In one example, the first laser generator 3 is a line laser; the second laser generator 4 is a cross laser. The lasers emitted by the first laser generator 3 and the second laser generator 4 are green lasers with wavelengths of 520nm or 532nm.
[0068] In one example, the image processing system is further configured to: construct a correction model for the upper and lower roll speed ratio based on warpage influencing factors and the maximum warpage value; the correction model is used to correct the upper and lower roll speed ratio of the hot rolling mill during the hot rolling process of the target slab 5 based on the detected maximum warpage value. The warpage influencing factors include: entrance thickness, reduction amount, upper roll linear speed, upper and lower roll speed ratio, upper roll diameter, lower roll diameter, upper surface temperature, upper and lower surface temperature difference, and slab width.
[0069] In this example, a specific construction process of the roll speed ratio correction model is as follows: A dual-hidden-layer neural network model is established. The warpage influencing factors are used as the input to the dual-hidden-layer neural network model, and the maximum warpage value is used as the output for training. The trained dual-hidden-layer neural network model is then determined as the upper and lower roll speed ratio correction model.
[0070] The following section describes a more specific implementation process of the above-mentioned slab hot rolling exit warp value detection device, based on the working process of the hot rolling mill in practical applications.
[0071] A line laser generator and a cross laser generator are set above the target slab 5 to irradiate the surface of the target slab 5 with laser lines parallel to the side edge of the slab. Since the hot-rolled strip is usually red-hot after passing through the rolling mill, in order to avoid the laser lines being obscured by the red light of the strip, the laser generators should use green lasers with wavelengths of 520nm or 532nm to improve contrast and facilitate the detection of laser lines by the vision system. Figure 3 The laser emits two laser lines. The cross laser illuminates the middle of the slab, with the laser beam perpendicular to the slab and parallel to the side edge of the slab. The line laser illuminates the surface of the slab, with the laser beam perpendicular to the side edge of the slab.
[0072] Support roll 1 supports work roll 2 and transmits rolling force for detection, such as... Figure 3 As shown, when the head of the target slab 5 reaches the field of view of the image acquisition system 6, the laser is in the first position, and the image acquisition system 6 is in the second position. The laser line strikes the surface of the slab head perpendicularly, acquiring an image of the slab head. The target slab 5 moves with the roller conveyor. When the tail of the target slab 5 reaches the field of view of the image acquisition system 6, the laser is in the first position, and the image acquisition system 6 is in the second position, acquiring an image of the tail of the target slab 5. The target slab 5 on the projection plane 7 captured by the camera in the image acquisition system 6 is shown below. Figure 4 As shown, the angle between the camera and the vertical plane is α.
[0073] Image processing is performed on the acquired images, including image preprocessing, image binarization, image segmentation, and feature extraction, to obtain the contour of the laser line at the head and tail of the target slab 5. Discrete points are extracted at equal intervals within a 1.5m range starting from the head or tail of the target slab 5 along the laser line in the image. These discrete points can reflect the warping of the target slab 5, thus allowing the warping curve of the target slab 5 to be plotted. Figure 5 and Figure 6 As shown.
[0074] See Figure 5 and Figure 6 First, a set of parallel laser lines is extended in the image to obtain the vanishing points. Then, the warping curve y = f(x) of the slab is fitted from the discrete points on the laser lines. Several convex points on the edge of the target slab 5 intersect the fitted warping curve to form several intersection points. The horizontal coordinate of the intersection point is the number of rows of pixels, and the vertical coordinate is the number of columns of pixels. The intersection point with the largest column pixel value in the image (the maximum warping point) is the position where the fitted curve warps most severely, which is the position where the target slab 5 has the most severe warping. By connecting the vanishing points to the maximum warping point and combining the expression of the fitted warping curve, the maximum warping value h0 at the end of the target slab 5 can be indirectly calculated. Figure 5 and Figure 6 The leftmost point is the initial point, which is the starting point of the fitted warp curve. In the image, the number of pixels occupied by the upper and lower ends l of the slab are different, but the length of l is equal in world coordinates. The distance between every two pixels in the row containing the upper and lower ends l can be obtained. By using the similarity principle and the number of pixels occupied by l1 in the row direction of the image, the length of l1 in world coordinates can be calculated. Combined with the expression of the fitted warp curve, the warp value h1 of the slab can be obtained.
[0075] It is worth noting that the h1 value calculated at this time is not the maximum warpage value h0 at the end of the slab in world coordinates, but rather an h1 on the projection plane. The expression for calculating h0 is: α is the angle between the camera and the vertical plane (rad); h1 is the height of the target slab 5 on the plane captured by the camera (mm), i.e., the first height; h0 is the height of the target slab 5 in world coordinates (mm), i.e., the second height; l is the distance between two parallel lines on the slab in world coordinates (mm); l1 is the lateral distance between the warped point and the initial point in world coordinates (mm).
[0076] Based on a hot strip mill production line, taking S610L-P steel as an example in the rolling specifications, the slab dimensions are: width 1325mm, thickness 237mm, and length 7300mm. Without using a slab head warpage control system, the warpage height values and images of the slab at each pass through the roughing mill on this hot strip mill are as follows: Figure 7 As shown, Figure 7Part (a) in the diagram represents the first rolling process without control. Figure 7 Part (b) in the diagram represents the second rolling process without control. Figure 7 Part (c) in the diagram represents the third rolling pass without control; after the hot continuous rolling production line uses the slab head warp control system, the slab inspection results are as follows: Figure 8 As shown, Figure 8 Part (a) in the diagram represents the first rolling process after control. Figure 8 Part (b) in the diagram represents the second rolling process after control. Figure 8 Part (c) in the diagram represents the third rolling pass after control. The comparison results show that the hot continuous rolling production line significantly reduced the warping degree of the slab after roughing mill rolling after using the slab head and tail warping control system.
[0077] The slab warpage detection device at the hot-rolled exit of this embodiment includes an image acquisition system at the hot-rolled exit and a laser generator above the slab. The laser line is irradiated onto the slab surface, acquiring images of the slab's head and tail. The acquired images are processed, and discrete points on the laser line are extracted. A warpage curve is obtained by fitting these points and extending it outwards. First, a set of parallel laser lines is used to obtain image vanishing points. Several protrusions on the slab's upper surface intersect the fitted curve to form several intersection points. The point with the largest pixel value in the image is then connected to the vanishing points; this point represents the location of the most severe warpage. The warpage curve is quantified, and the maximum warpage value at the slab end is calculated. Combining the parameters affecting the slab head warpage and the warpage value, a neural network model is used to predict the warpage amount at the head of the hot-rolled rough-rolled slab. This model is then used to calculate an adjustable SKI (Skimming Indicator) recommended value, i.e., the ratio of the upper roll speed to the lower roll speed. This device has the following advantages:
[0078] Machine vision technology is used to quantitatively detect the warp value at the head and tail of hot-rolled slabs. This method offers high speed and accuracy, enabling online detection and timely identification of warp head defects, which is beneficial for subsequent rolling processes. Machine vision is a non-contact detection method with high stability and wide applicability. Compared to traditional image-based edge detection methods, this embodiment uses a laser line as the reference for measuring the warp value, replacing the traditional method that uses the upper edge of the slab as the reference. This avoids the problem of extracting the end edge and side edge together, which could lead to incorrect judgment of the warp head condition. Furthermore, the laser line array measurement method can detect the true warp condition on the strip surface, avoiding inaccurate detection caused by uneven warp distribution across the strip width. Therefore, this invention can improve the detection accuracy of warp values in hot-rolled slabs.
[0079] This invention also provides a method for detecting the warpage value at the exit of hot-rolled slabs, comprising:
[0080] (1) After the line laser and cross laser irradiate the end of the target slab, the end image of the target slab is acquired.
[0081] (2) Determine the image vanishing point of the end image based on the parallel laser line group.
[0082] (3) Determine the maximum buckling value of the end of the target slab based on the vanishing point of the image, the edge protrusion of the end image, and the buckling curve.
[0083] The single-line laser is a laser emitted by a first laser generator toward the surface of the target slab and perpendicular to the side edge of the target slab; the cross laser includes: a second laser emitted by a second laser generator toward the target slab and perpendicular to the side edge of the target slab, and a third laser parallel to the side edge of the target slab.
[0084] The maximum warping value is used to characterize the maximum warping degree of the end of the target slab; the parallel laser line group includes: the laser line irradiated by the first laser to the end of the target slab and the laser line irradiated by the second laser to the end of the target slab.
[0085] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Regarding the methods disclosed in the embodiments, since they correspond to the apparatus disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the apparatus description.
[0086] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.
Claims
1. A device for detecting the warpage value at the exit of hot-rolled slabs, characterized in that, include: The first laser generator is used for: A linear laser beam is emitted toward the surface of the target slab; the linear laser beam is perpendicular to the side edge of the target slab. The second laser generator is used for: A cross-shaped laser is emitted toward the surface of a target slab; the cross-shaped laser includes: a second laser perpendicular to the side edge of the target slab and a third laser parallel to the side edge of the target slab; Image acquisition system, used for: After the single-line laser and the cross laser irradiate the end of the target slab, an image of the end of the target slab is acquired; An image processing system, connected to the image acquisition system, is used for: Extract discrete points of the first laser line in the end image, and fit the warping curve of the end of the target slab based on the discrete points; the first laser line is the laser line that the third laser irradiates to the end of the target slab. The vanishing point of the end image is determined based on the parallel laser line group, and the maximum lifting value of the end of the target slab is determined based on the vanishing point, the edge protrusion of the end image, and the lifting curve. The maximum warping value is used to characterize the maximum warping degree of the end of the target slab; the parallel laser line group includes: the laser line that the single laser irradiates the end of the target slab and the laser line that the second laser irradiates the end of the target slab; The image processing system is specifically used for determining the maximum warp value at the end of the target slab based on the image vanishing point, the edge protrusion of the end image, and the warp curve: The intersection points of each edge protrusion of the end image with the buckle curve are determined to obtain the intersection point group; The point with the largest pixel value in the image column is selected from the group of intersection points to obtain the point of maximum warping. The first height is determined based on the vanishing point of the image and the maximum warping point; the first height is the height of the target slab on the plane captured by the image processing system. Based on the first height and the angle between the image processing system and the vertical plane, the second height is calculated and determined as the maximum overhang value of the end of the target slab; the second height is the height of the target slab in world coordinates.
2. The slab hot-rolled exit warp value detection device according to claim 1, characterized in that, The image processing system, in extracting discrete points of the first laser line in the end image, is specifically used for: The end image is subjected to image processing operations to obtain a processed image; the image processing operations include: image preprocessing, image binarization, image segmentation, and feature extraction; Extract the outline of the first laser line from the processed image; Discrete points of the first laser line are extracted on the contour at equal intervals.
3. The slab hot-rolled exit warp value detection device according to claim 1, characterized in that, The image processing system, in calculating the second height based on the first height and the angle between the image processing system and the vertical plane, is specifically used for: According to the formula Calculate the second altitude; Indicates the first altitude; Indicates the second altitude; This indicates the angle between the image processing system and the vertical plane.
4. The slab hot-rolled exit warp value detection device according to claim 1, characterized in that, The image acquisition system is at a height of 20cm or more above the surface of the target slab; the length of the target slab captured by the image acquisition system is greater than 1.5m.
5. The slab hot-rolled exit warp value detection device according to claim 1, characterized in that, The first laser generator is a line laser; the second laser generator is a cross laser.
6. The slab hot-rolled exit warp value detection device according to claim 1, characterized in that, The lasers emitted by the first laser generator and the second laser generator are green lasers with wavelengths of 520nm or 532nm.
7. A method for detecting the warpage value at the exit of hot-rolled slabs, characterized in that, The method for detecting the overhang value at the hot-rolled exit of a slab is used in any one of the slab overhang value detection devices according to claims 1-6, and the method for detecting the overhang value at the hot-rolled exit of a slab includes: After the line laser and cross laser irradiate the end of the target slab, an image of the end of the target slab is acquired; The vanishing point of the end image is determined based on the parallel laser line group; The maximum warp value at the end of the target slab is determined based on the vanishing point of the image, the edge protrusions of the end image, and the warp curve. The single-line laser is a laser emitted by a first laser generator toward the surface of the target slab and perpendicular to the side edge of the target slab; the cross laser includes: a second laser emitted by a second laser generator toward the target slab and perpendicular to the side edge of the target slab, and a third laser parallel to the side edge of the target slab. The maximum warping value is used to characterize the maximum warping degree of the end of the target slab; the parallel laser line group includes: the laser line irradiated by the first laser to the end of the target slab and the laser line irradiated by the second laser to the end of the target slab.