An online width measuring method for super strong steel thick plate based on monochromatic visible light irradiation
By using monochromatic visible light to irradiate the steel plates during the rolling process, the four edges of the thick steel plates are measured in real time. The plate width is then calculated using long-distance linear regression, which solves the problem of inaccuracy in measuring the width of ultra-strong thick steel plates and achieves stable and accurate plate width data output.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LUOYANG INST OF SCI & TECH
- Filing Date
- 2026-03-13
- Publication Date
- 2026-06-02
Smart Images
Figure CN121829337B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of steel rolling technology, and in particular to product dimension measurement technology in the steel rolling process, specifically a method for online width measurement of ultra-strong steel thick plates based on monochromatic visible light irradiation. Background Technology
[0002] During the rolling of ultra-strong steel thick plates, the width of the finished product fluctuates due to uneven metal deformation and flow, as well as the rolling process. The sides of the thick plates exhibit varying degrees of arc-shaped bulges, known in the industry as "bulging," due to differences in plasticity and rolling process parameters. Real-time monitoring of the plate width during online rolling helps obtain plates with accurate width dimensions, effectively avoiding exceeding allowable tolerances due to uneven width distribution, and preventing the need for secondary processing, which would result in significant material waste and increased costs. Because the thick plates move at high speeds during rolling, mechanical contact-based online width measurement is prone to large errors and is no longer practically meaningful. Lasers are commonly used as measuring tools for non-contact width measurement. However, the common conditions in rolling mills, such as smoke, water vapor, and debris splashing, lead to frequent laser damage and replacement. Furthermore, conventional linear lasers used for point-to-point measurement only measure the width of the thick plate at a specific point on the workpiece. The jitter and oscillation during output from the thick plate cause significant fluctuations in the output data as the travel distance changes. When machines learn on their own or humans judge whether something exceeds the tolerance range, they are prone to misjudgment, leading to unnecessary pressure adjustments or unnecessary shutdowns.
[0003] Chinese patent CN202511188435.8 discloses an online slab width measurement device and method. It utilizes three measuring modules arranged in a right-angled triangle. The slab width is calculated based on the distance from the edge of the slab to each measuring module, combined with the principle that the sum of the squares of the legs of a right triangle equals the square of the hypotenuse. This method can achieve online width measurement to some extent, avoiding direct manual contact. However, it is still a point-to-point measurement, resulting in significant fluctuations in the measurement results. While this method can still obtain the slab width when the slab is tilted, it fails to correct the width error caused by the tilt. When measuring thick slabs, this method cannot avoid the error caused by the "bulge" portion in the measurement results.
[0004] Chinese patent CN201710356004.7 discloses a dynamic slab width detection device based on FPGA and laser triangulation, including a roller conveyor, two laser triangulation rangefinders, and a centralized slab width measurement controller with FPGA as the core. The two laser triangulation rangefinders are installed on both sides of the roller conveyor, and the slab width value is obtained through data analysis. This method is also a point-to-point measurement, and the measurement results fluctuate greatly, especially during thick plate rolling, causing the rolling mill to generate unnecessary self-adjustments during the self-learning process. This is because the measurement results are affected by impurities such as large iron filings adhering to the side of the thick plate, causing dimensional measurement errors and misjudgments. Furthermore, the lasers are easily damaged in rolling workshops with high humidity and dust.
[0005] Chinese patent CN202310206328.8 discloses an intelligent online strip width measurement device based on multi-station operation, which solves the problems of offline strip width measurement and single calibration plate, and realizes accurate laser width measurement calibration for strips with different width requirements, and completes online measurement of their width. It uses a method that identifies the strip edge as "half-lit, half-obscured" when the laser spot illuminates the strip edge, thus obtaining the original data. Therefore, the size of the laser spot has a significant impact on the measurement accuracy error, and it is a point-to-point measurement, which is not suitable for high-strength thick plates or extra-thick plates. This method is mainly used to measure the width of general thin plates. For extra-thick steel plates, the two sides form a "bulge" phenomenon due to rolling. When measuring thick plates using this method, the measured data is the edge after the "bulge," which is not the actual effective thickness portion of the plate. Summary of the Invention
[0006] To overcome the shortcomings of the prior art, the present invention aims to provide an online width measurement method for ultra-thick steel plates based on monochromatic visible light irradiation. This method can measure the effective width of thick steel plates in real time during the rolling process, providing measurement data for automated production control. The present invention avoids measurement errors caused by bulging phenomena through diagonal measurement, and avoids abrupt changes caused by common point-to-point measurements. Using monochromatic parallel light is less expensive than lasers and less prone to damage. By employing a long-distance linear regression method to obtain the plate width, a stable output plate width value is achieved.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A method for online width measurement of ultra-strong thick steel plates based on monochromatic visible light illumination includes the following steps:
[0009] Step 1: Install a roller conveyor outside the mill exit, so that the length direction of the steel plate is parallel to the conveying direction of the roller conveyor, and the steel plate is conveyed along the roller conveyor.
[0010] Step 2: On both sides of the steel plate conveying direction, four monochromatic parallel light sources and four photosensitive plates are respectively set. The four monochromatic parallel light sources correspond one-to-one with the four edges of the steel plate parallel to the length direction, and the four photosensitive plates also correspond one-to-one with the four edges of the steel plate parallel to the length direction.
[0011] When the steel plate is being transported, four monochromatic parallel light sources are used to obliquely illuminate the corresponding edges. When the parallel light from each monochromatic parallel light source passes through the corresponding edge, a portion of the light is blocked by the corresponding edge, creating a projection area on the corresponding photosensitive plate. Based on the projection area generated on each photosensitive plate, the projection image data of the corresponding edge is obtained.
[0012] Step 3: Based on the projected image data of the four edges, establish the equation for each edge;
[0013] Step 4: Obtain the lengths of the two diagonals of the steel plate cross-section based on the equations of the four edges;
[0014] Step 5: Based on the lengths of the two diagonals of the steel plate cross-section obtained in Step 4, and in combination with the thickness of the steel plate, obtain the first plate width value AC and the second plate width value BD of the steel plate.
[0015] Step 6: Based on the first plate width value AC and the second plate width value BD, obtain the error value according to (AC-BD) / AC. When the error value is less than or equal to α, take (AC+BD) / 2 as the final plate width value of the steel plate; α is the error threshold preset according to the project needs.
[0016] In step 2, when the four monochromatic parallel light sources obliquely illuminate the corresponding edges, the following strategy is adopted: Let the four edges of the steel plate parallel to its length direction be edge A, edge B, edge C, and edge D; edge A is located at the upper left corner of the steel plate's cross-section, edge B is located at the lower left corner, edge C is located at the lower right corner, and edge D is located at the upper right corner; let the four monochromatic parallel light sources be the first monochromatic parallel light source, the second monochromatic parallel light source, the third monochromatic parallel light source, and the fourth monochromatic parallel light source, and the four photosensitive plates be the first photosensitive plate, the second photosensitive plate, the third photosensitive plate, and the fourth photosensitive plate; the first monochromatic parallel light source corresponds to edge B of the first photosensitive plate, the second... A monochromatic parallel light source corresponds to edge D of the second photosensitive plate, a third monochromatic parallel light source corresponds to edge A of the third photosensitive plate, and a fourth monochromatic parallel light source corresponds to edge C of the fourth photosensitive plate. The first, second, third, and fourth monochromatic parallel light sources are respectively positioned above the steel plate, and the first, second, third, and fourth photosensitive plates are respectively positioned below the steel plate. The first photosensitive plate receives the parallel light emitted by the first monochromatic parallel light source, the second photosensitive plate receives the parallel light emitted by the second monochromatic parallel light source, the third photosensitive plate receives the parallel light emitted by the third monochromatic parallel light source, and the fourth photosensitive plate receives the parallel light emitted by the fourth monochromatic parallel light source.
[0017] In step 2, when the four monochromatic parallel light sources obliquely illuminate the corresponding edges, the following strategy is also adopted: the axis of the first monochromatic parallel light source is parallel to edge B of the first photosensitive plate, and the light emitted by the first monochromatic parallel light source is perpendicular to the first photosensitive plate; the axis of the second monochromatic parallel light source is parallel to edge D of the second photosensitive plate, and the light emitted by the second monochromatic parallel light source is perpendicular to the second photosensitive plate; the axis of the third monochromatic parallel light source is parallel to edge A of the third photosensitive plate, and the light emitted by the third monochromatic parallel light source is perpendicular to the third photosensitive plate; the axis of the fourth monochromatic parallel light source is parallel to edge C of the fourth photosensitive plate, and the light emitted by the fourth monochromatic parallel light source is perpendicular to the fourth photosensitive plate.
[0018] In step 2, when the four monochromatic parallel light sources obliquely illuminate the corresponding edges, the following strategy is also adopted: the light emitted by the second monochromatic parallel light source is parallel to the light emitted by the first monochromatic parallel light source, and the light emitted by the fourth monochromatic parallel light source is parallel to the light emitted by the third monochromatic parallel light source.
[0019] In step 2, the four monochromatic parallel light sources and the four photosensitive plates are respectively connected to angle adjustment mechanisms, and are connected to the external support truss through the angle adjustment mechanisms.
[0020] In step 2, the light emitted by the four monochromatic parallel light sources is all violet light.
[0021] In step 3, the equation for each edge is established using the following method: A set of Y coordinates of the steel plate is obtained along its length. Based on the projected image data of each edge, corresponding to each Y coordinate, the projection area on each edge is divided into a white area, a transition area, and a black area along the cross-sectional direction of the steel plate. The values of the red, blue, and green primary colors of any pixel in the projection area of each edge are added together and recorded as the total value. Then, the total values of every two pixels are divided. If the quotient is less than 0.25, the pixel containing the molecule is considered to be located at the edge adjacent to the black area and the transition area. At this time, the coordinates of the pixel containing the molecule are extracted as the X coordinate corresponding to the Y coordinate of that edge. The X coordinates corresponding to a set of Y coordinates for each edge are obtained. Based on the coordinates of each edge, a univariate linear regression is performed on each edge to obtain the equation for each edge.
[0022] In step 4, when obtaining the lengths of the two diagonals of the steel plate cross section, it is also necessary to perform slope accuracy processing on the equations of the four edges to ensure that the equations of the four edges satisfy the condition of mutual parallelism.
[0023] In step 6, based on the first plate width value AC and the second plate width value BD, the error value is obtained according to (AC-BD) / AC. When the error value is greater than or equal to α, it is determined that the steel plate has cross-sectional distortion.
[0024] The beneficial effects of this invention are as follows: This invention uses a long-distance linear regression method to measure the width of ultra-strong steel plates in real time during the rolling process, providing measurement data for automated production control. This invention avoids the "bulging" area that occurs during the rolling of steel plates, and the final value of the plate width obtained is stable and accurate, and its accuracy fully meets the engineering requirements. Attached Figure Description
[0025] Figure 1 This is a three-dimensional schematic diagram of the measurement principle of the present invention.
[0026] Figure 2 This is a planar schematic diagram of the testing principle of the present invention.
[0027] Figure 3 A schematic diagram of the projection image of edge A of a thick steel plate exported from a photosensitive plate.
[0028] Figure 4 for Figure 2 Side view.
[0029] In the figure, 1. First monochromatic parallel light source, 2. Second monochromatic parallel light source, 3. Third monochromatic parallel light source, 4. Fourth monochromatic parallel light source, 5. Steel plate, 6. Conveyor roller, 7. Third photosensitive plate, 8. First photosensitive plate, 9. Fourth photosensitive plate, 10. Second photosensitive plate, 11. Angle adjustment mechanism, 12. Protrusion, 13. White area, 14. Transition area, 15. Black area. Detailed Implementation
[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0031] like Figure 1 , Figure 2 , Figure 4 As shown, this invention provides an online width measurement method for ultra-strong thick steel plates based on monochromatic visible light illumination, comprising the following steps:
[0032] Step 1: Install a roller conveyor outside the mill exit, so that the length direction of the steel plate 5 is parallel to the conveying direction of the roller conveyor, and the steel plate 5 is conveyed along the roller conveyor.
[0033] Step 2: On both sides of the conveying direction of the steel plate 5, four monochromatic parallel light sources and four photosensitive plates are respectively set. The four monochromatic parallel light sources correspond one-to-one with the four edges of the steel plate 5 parallel to the length direction, and the four photosensitive plates also correspond one-to-one with the four edges of the steel plate 5 parallel to the length direction.
[0034] When the steel plate 5 is conveyed, four monochromatic parallel light sources are used to obliquely illuminate the corresponding edges. When the parallel light from each monochromatic parallel light source passes through the corresponding edge, part of the light is blocked by the corresponding edge, and a projection area is generated on the corresponding photosensitive plate. Based on the projection area generated on each photosensitive plate, the projection image data of the corresponding edge is obtained.
[0035] Step 3: Based on the projected image data of the four edges, establish the equation for each edge;
[0036] Step 4: Based on the equations of the four edges, obtain the lengths of the two diagonals of the cross section of the steel plate 5;
[0037] Step 5: Based on the lengths of the two diagonals of the cross section of the steel plate 5 obtained in Step 4, and in combination with the thickness of the steel plate 5, obtain the first plate width value AC and the second plate width value BD of the steel plate 5.
[0038] Step 6: Based on the first plate width value AC and the second plate width value BD, obtain the error value according to (AC-BD) / AC. When the error value is less than or equal to α, take (AC+BD) / 2 as the final plate width value of the steel plate; α is the error threshold preset according to the project needs.
[0039] In step 2, the roller conveyor consists of multiple conveyor rollers 6; four monochromatic parallel light sources include a first monochromatic parallel light source 1, a second monochromatic parallel light source 2, a third monochromatic parallel light source 3, and a fourth monochromatic parallel light source 4; four photosensitive plates include a third photosensitive plate 7, a first photosensitive plate 8, a fourth photosensitive plate 9, and a second photosensitive plate 10. The four photosensitive plates and the four monochromatic parallel light sources are connected to an external support truss via an angle adjustment mechanism 11. The first monochromatic parallel light source 1, the second monochromatic parallel light source 2, the third monochromatic parallel light source 3, and the fourth monochromatic parallel light source 4 are all elongated structures, and the axes along the length of the four monochromatic parallel light sources are parallel to each other and parallel to the conveying direction of the rolled steel plate 5 on the roller conveyor. The four monochromatic parallel light sources are located after the first conveyor roller 6 outside the mill exit.
[0040] The light emitted by the first monochromatic parallel light source 1 and the second monochromatic parallel light source 2 is parallel in direction, and the light emitted by the third monochromatic parallel light source 3 and the fourth monochromatic parallel light source 4 is parallel in direction. The light emitted by the first monochromatic parallel light source 1 and the second monochromatic parallel light source 2 is not parallel in direction to the light emitted by the third monochromatic parallel light source 3 and the fourth monochromatic parallel light source 4 (symmetrically distributed and at a certain angle), so that each monochromatic parallel light source obliquely illuminates the four edges of the steel plate 5 parallel to its length direction. The light emitted by the four monochromatic parallel light sources passes through the corresponding four edges of the steel plate 5 and reaches the first photosensitive plate 8, the second photosensitive plate 10, the third photosensitive plate 7, and the fourth photosensitive plate 9, respectively.
[0041] In step 2, the projected image data corresponding to the edges is obtained by a computer. The computer acquires the projection area information of the photosensitive plate through the information acquisition unit, thereby obtaining the corresponding projected image data. This part is prior art and will not be described in detail further.
[0042] The steel plate 5 and the conveyor roller 6 are used to illustrate the relative positions of the various components of the present invention during actual production, and are not unique to the present invention and are not subject to protection. This invention uses four monochromatic parallel light sources to illuminate the four edges of a thick steel plate 5 parallel to its length, and projects them onto four photosensitive plates. Based on the principle that opposite sides of a parallelogram are equal, the four edges of the thick steel plate 5 parallel to its length are designated as edges A, B, C, and D. Edge A is located at the upper left corner of the cross-section of the thick steel plate 5, edge B at the lower left corner, edge C at the lower right corner, and edge D at the upper right corner. The diagonal connecting edges A and C is designated as the first diagonal, and the diagonal connecting edges B and D as the second diagonal. The first monochromatic parallel light source 1 corresponds to edge B on the first photosensitive plate 8, the second monochromatic parallel light source 2 corresponds to edge D on the second photosensitive plate 10, the third monochromatic parallel light source 3 corresponds to edge A on the third photosensitive plate 7, and the fourth monochromatic parallel light source 8 corresponds to edge D on the second photosensitive plate 10. The light source 4 corresponds to edge C of the fourth photosensitive plate 9. Therefore, based on the projection of edge B obtained from the first photosensitive plate 8 and the projection of edge D obtained from the second photosensitive plate 10, the length of the second diagonal can be calculated (the length of the second diagonal is equal to the distance between the projected edge line of edge B and the projected edge line of edge D). Based on the projection of edge A obtained from the third photosensitive plate 7 and the projection of edge C obtained from the fourth photosensitive plate 9, the length of the first diagonal can be calculated (the length of the first diagonal is equal to the distance between the projected edge line of edge A and the projected edge line of edge C). Based on the thickness of the steel plate 5 set for each rolling pass, the first width value AC of the steel plate 5 can be obtained by combining the side length function relationship of a right triangle with the length of the first diagonal. Similarly, the second width value BD of the steel plate 5 can be obtained by combining the length of the second diagonal.
[0043] Because the parallel light emitted by the four monochromatic parallel light sources does not shine vertically downwards onto the steel plate 5, it avoids the "bulging" area that occurs during the rolling of the steel plate 5 (i.e., Figure 2 The effective plate width excluding the bulge area is accurately obtained by comparing the first width value AC with the second width value BD. It can be determined whether the steel plate 5 has undergone cross-sectional distortion during rolling. The ideal situation is that AC=BD. If the difference between AC and BD exceeds the specified limit, the deviation should be corrected by adjusting the roll reduction.
[0044] In one embodiment of the present invention, the angle adjustment mechanism 11 is a cylindrical rotary hinge, and there are a total of 16 cylindrical rotary hinges. Each monochromatic parallel light source is connected to an external support truss at both ends via a corresponding cylindrical rotary hinge; the cylindrical rotary hinges are existing technology, with one end of each hinge connected to the corresponding monochromatic parallel light source and the other end fixed to the external support truss. Similarly, each photosensitive plate is connected to the external support truss at both ends via corresponding cylindrical rotary hinges. The cylindrical rotary hinges are located at the center of the photosensitive plate.
[0045] In one embodiment of the present invention, an external support truss for mounting four monochromatic parallel light sources is fixedly installed on the ceiling, and an external support truss for mounting four photosensitive plates is fixedly installed on the floor. During installation, the light-emitting panel of each monochromatic parallel light source is parallel to and centered with the panel of the corresponding photosensitive plate, so that the light emitted by each monochromatic parallel light source is perpendicular to the panel of the corresponding photosensitive plate.
[0046] The angle adjustment mechanism 11 can fine-tune the emission angle of the light and the receiving angle of the photosensitive plate, enabling the measurement of the width of steel plates 5 with different thicknesses and widths on the same rolling mill. The four monochromatic parallel light sources located above the conveyor rollers, mounted on the same external support truss, reduce the thermal expansion and contraction caused by seasonal and ambient temperature changes. Furthermore, the external support truss should be similar in material and thermal expansion coefficient to the rolling mill frame, conveyor rollers, and the rolled steel plate 5, thus improving measurement accuracy. During installation, keeping the emitting panels of the monochromatic parallel light sources parallel and centered on the photosensitive plate allows for fine-tuning to achieve a wider measurement range for the width of the steel plate 5.
[0047] In one embodiment of the present invention, the first monochromatic parallel light source 1, the second monochromatic parallel light source 2, the third monochromatic parallel light source 3, and the fourth monochromatic parallel light source 4 are all violet light. The wavelength range of the seven colors of light is approximately between 380 nanometers and 750 nanometers, among which violet light has the shortest wavelength, approximately 400 nanometers, resulting in a short diffraction ripple distance and the highest measurement accuracy.
[0048] It should be noted that the effective photosensitive areas of the third photosensitive plate 7, the first photosensitive plate 8, the fourth photosensitive plate 9, and the second photosensitive plate 10 should avoid the projection area of the conveyor roller 6 itself. Therefore, they should be set in the light-transmitting part between every two conveyor rollers 6.
[0049] Photosensitive plates are relatively expensive products and are generally composed of multiple sections. It is not practical to place an effective photosensitive area directly below the conveyor roller 6, because the light emitted by the light source is blocked by the conveyor roller and cannot reach the photosensitive plate. Segmentation saves costs; therefore, each photosensitive plate can also be divided into multiple segments, evenly distributed among multiple conveyor rollers 6.
[0050] In this invention, the equation for each edge is established using the following method: A set of Y-coordinates of the steel plate 5 is obtained along its length. Based on the projected image data of each edge, corresponding to each Y-coordinate, as shown below... Figure 3 As shown, the projected area on each edge along the cross-section of the steel plate 5 is divided into a white area 13, a transition area 14, and a black area 15. The values of the red, blue, and green primary colors of any pixel in the projected area of each edge are added together and recorded as the total value. Then, the total values of every two pixels are divided. If the quotient is less than 0.25, the pixel containing the molecule can be considered to be located on the edge adjacent to the black area 15 and the transition area 14. At this time, the coordinates of the pixel containing the molecule are extracted as the X coordinate of the corresponding Y coordinate of that edge. The X coordinates of each edge corresponding to a set of Y coordinates are obtained. Based on the coordinates of each edge, a univariate linear regression is performed on each edge to obtain the equation of each edge. The principle of the above method is: according to the RGB color mode, the values of the red, blue, and green primary colors of the black area 15 are: 0,0,0, and the values of the red, blue, and green primary colors of the white area 13 are: 255,255,255. If the value of the three primary colors of a pixel is larger, the color is lighter; conversely, if the value of the three primary colors of a pixel is smaller, the color is darker. The darker the color, the smaller the sum of the three primary colors of the pixels. Dividing this by the sum of the three primary colors of the nearby pixels yields a ratio less than 1. According to the established monochromatic light diffraction, the transition region 14 is generally within 4 pixels. According to experimental results, when the ratio is less than 0.25, the pixel containing the molecule is located at the edge of the black region 15.
[0051] Furthermore, the coordinate values of the four edges of the obtained steel plate 5 are subjected to univariate linear regression to obtain the equation for each edge. However, the regression results are not necessarily parallel. Therefore, the slope accuracy of the equations for the four edges needs to be processed to ensure that the equations for the four edges satisfy the condition of parallelism. In one embodiment of the present invention, the slope and intercept are rounded to four decimal places. According to the design of the present invention, the unit in the equation is mm. For the steel plate 5, the four decimal places represent one-tenth of a micrometer. Even after discarding, the accuracy still fully meets the engineering requirements. Based on the distance between the parallel lines, the distance between edge A and edge C and the distance between edge B and edge D of the steel plate 5 are obtained, that is, the lengths of the two diagonals of the cross-section of the steel plate 5 are obtained. Then, combined with trigonometric function relationships, based on the thickness value of the steel plate 5 in this pass, the two plate width values of the steel plate 5 can be calculated. The following example 1 focuses on illustrating the calculation process of the final plate width value of the present invention. Example 1:
[0052] When performing univariate linear regression, due to projection errors, disturbance errors, and other factors, it is impossible to directly obtain the equations of four parallel lines. For example, when verifying this invention, the linear equations obtained after measuring a 150mm thick steel plate 5 are as follows:
[0053] A: y=1.0000556545x+1612.2586454582;
[0054] B: y=1.0000031253x+1613.1239647819;
[0055] C: y=1.0000058742x+0.1473789521;
[0056] D: y=1.0000012957x+0.1823456586;
[0057] The four equations determined by regression analysis are obviously not parallel to each other, but if the slope is taken to four decimal places, the equations become parallel.
[0058] Based on the equations corresponding to edges A, B, C, and D, and considering the setting to retain four decimal places, the first diagonal is 1612.1112665061 mm, and the second diagonal is 1612.9416191233 mm. Combining this with the plate thickness of 150 mm, the first plate width AC is calculated to be 1605.11767032698 mm, and the second plate width BD is calculated to be 1605.9516389668 mm.
[0059] Furthermore, by comparing the values of AC and BD, the error value is obtained according to (AC-BD) / AC. When the error value is less than or equal to α, (AC+BD) / 2 is taken as the final value of the plate width. When the error value is greater than or equal to α, the value of (AC+BD) / 2 is output and an error message indicating cross-sectional distortion is displayed. Here, α is the error threshold that needs to be defined in the project.
[0060] Generally, the error threshold α is set according to the actual engineering situation. For example, the error value in this embodiment is -0.000519568537084261mm. If the error threshold α set in the engineering design is 0.01mm, then the error requirement is met. The final width of the steel plate 5 can be obtained as 1605.53465464689mm.
[0061] The parts of this invention not described in detail are prior art.
Claims
1. A method for online width measurement of ultra-strong thick steel plates based on monochromatic visible light illumination, characterized in that, Includes the following steps: Step 1: Install a roller conveyor outside the mill exit, so that the length direction of the steel plate is parallel to the conveying direction of the roller conveyor, and the steel plate is conveyed along the roller conveyor; let the four edges of the steel plate parallel to the length direction be edge A, edge B, edge C and edge D; edge A is located at the upper left corner of the cross-section of the steel plate, edge B is located at the lower left corner of the cross-section of the steel plate, edge C is located at the lower right corner of the cross-section of the steel plate, and edge D is located at the upper right corner of the cross-section of the steel plate. Step 2: On both sides of the steel plate conveying direction, four monochromatic parallel light sources and four photosensitive plates are respectively set up. The four monochromatic parallel light sources correspond one-to-one with the four edges of the steel plate parallel to the length direction, and the four photosensitive plates also correspond one-to-one with the four edges of the steel plate parallel to the length direction. When the steel plate is conveyed, the four monochromatic parallel light sources are used to obliquely illuminate the corresponding edges. When the parallel light rays of each monochromatic parallel light source pass through the corresponding edge, part of the light rays are blocked by the corresponding edge, and a projection area is generated on the corresponding photosensitive plate. Based on the projection area generated on each photosensitive plate, the projection image data of the corresponding edge is obtained. Let there be four monochromatic parallel light sources, namely the first monochromatic parallel light source, the second monochromatic parallel light source, the third monochromatic parallel light source, and the fourth monochromatic parallel light source, and four photosensitive plates, namely the first photosensitive plate, the second photosensitive plate, the third photosensitive plate, and the fourth photosensitive plate. The first monochromatic parallel light source corresponds to edge B of the first photosensitive plate, the second monochromatic parallel light source corresponds to edge D of the second photosensitive plate, the third monochromatic parallel light source corresponds to edge A of the third photosensitive plate, and the fourth monochromatic parallel light source corresponds to edge C of the fourth photosensitive plate. The axis of the first monochromatic parallel light source is parallel to edge B of the first photosensitive plate, and the light emitted by the first monochromatic parallel light source is perpendicular to the first photosensitive plate. The axis of the second monochromatic parallel light source is parallel to edge D of the second photosensitive plate, and the light emitted by the second monochromatic parallel light source is perpendicular to the second photosensitive plate. The axis of the third monochromatic parallel light source is parallel to edge A of the third photosensitive plate, and the light emitted by the third monochromatic parallel light source is perpendicular to the third photosensitive plate. The axis of the fourth monochromatic parallel light source is parallel to edge C of the fourth photosensitive plate, and the light emitted by the fourth monochromatic parallel light source is perpendicular to the fourth photosensitive plate. Step 3: Based on the projected image data of the four edges, establish the equation for each edge; Step 4: Obtain the lengths of the two diagonals of the steel plate cross-section based on the equations of the four edges; Step 5: Based on the lengths of the two diagonals of the steel plate cross section obtained in Step 4, and in combination with the thickness of the steel plate, obtain the first plate width value AD and the second plate width value BC of the steel plate. Step 6: Based on the first plate width value AD and the second plate width value BC, obtain the error value according to (AD-BC) / AD. When the error value is less than or equal to α, take (AD+BC) / 2 as the final plate width value of the steel plate; α is the error threshold set in advance according to the project requirements.
2. The method for online width measurement of ultra-strong thick steel plates based on monochromatic visible light illumination as described in claim 1, characterized in that, In step 2, when the four monochromatic parallel light sources obliquely illuminate the corresponding edges, the following strategy is also adopted: the first monochromatic parallel light source, the second monochromatic parallel light source, the third monochromatic parallel light source, and the fourth monochromatic parallel light source are respectively arranged above the steel plate, and the first photosensitive plate, the second photosensitive plate, the third photosensitive plate, and the fourth photosensitive plate are respectively arranged below the steel plate. The first photosensitive plate receives the parallel light emitted by the first monochromatic parallel light source, the second photosensitive plate receives the parallel light emitted by the second monochromatic parallel light source, the third photosensitive plate receives the parallel light emitted by the third monochromatic parallel light source, and the fourth photosensitive plate receives the parallel light emitted by the fourth monochromatic parallel light source.
3. The method for online width measurement of ultra-strong thick steel plates based on monochromatic visible light illumination as described in claim 2, characterized in that, In step 2, when the four monochromatic parallel light sources obliquely illuminate the corresponding edges, the following strategy is also adopted: the light emitted by the second monochromatic parallel light source is parallel to the light emitted by the first monochromatic parallel light source, and the light emitted by the fourth monochromatic parallel light source is parallel to the light emitted by the third monochromatic parallel light source.
4. The method for online width measurement of ultra-strong steel thick plates based on monochromatic visible light illumination as described in claim 2, characterized in that, In step 2, the four monochromatic parallel light sources and the four photosensitive plates are respectively connected to angle adjustment mechanisms, and are connected to the external support truss through the angle adjustment mechanisms.
5. The method for online width measurement of ultra-strong steel thick plates based on monochromatic visible light illumination as described in claim 2, characterized in that, In step 2, the light emitted by the four monochromatic parallel light sources is all violet light.
6. The method for online width measurement of ultra-strong thick steel plates based on monochromatic visible light irradiation as described in claim 1, characterized in that, In step 3, the equation for each edge is established using the following method: A set of Y coordinates of the steel plate is obtained along its length. Based on the projected image data of each edge, corresponding to each Y coordinate, the projection area on each edge is divided into a white area, a transition area, and a black area along the cross-sectional direction of the steel plate. The values of the red, blue, and green primary colors of any pixel in the projection area of each edge are added together and recorded as the total value. Then, the total values of every two pixels are divided. If the quotient is less than 0.25, the pixel containing the molecule is considered to be located at the edge adjacent to the black area and the transition area. At this time, the coordinates of the pixel containing the molecule are extracted as the X coordinate corresponding to the Y coordinate of that edge. The X coordinates corresponding to a set of Y coordinates for each edge are obtained. Based on the coordinates of each edge, a univariate linear regression is performed on each edge to obtain the equation for each edge.
7. The method for online width measurement of ultra-strong thick steel plates based on monochromatic visible light illumination as described in claim 1, characterized in that, In step 4, when obtaining the lengths of the two diagonals of the steel plate cross section, it is also necessary to perform slope accuracy processing on the equations of the four edges to ensure that the equations of the four edges satisfy the condition of mutual parallelism.
8. The method for online width measurement of ultra-strong thick steel plates based on monochromatic visible light illumination as described in claim 1, characterized in that, In step 6, based on the first plate width value AD and the second plate width value BC, the error value is obtained according to (AD-BC) / AD. When the error value is greater than or equal to α, it is determined that there is cross-sectional distortion in the steel plate.