On-line measurement method and system for bar length

Abstract

The present invention provides a method and system for measuring the length of a bar material online, and relates to the technical field of bar materials. The method comprises the following steps: detecting a target multiple-length bar material through a heat detection module; obtaining a detection signal when the head of the target multiple-length bar material reaches the heat detection module; obtaining a detection loss signal when the tail of the target multiple-length bar material passes through the heat detection module; collecting a position image of a target area through a visual module based on the detection signal and the detection loss signal; performing image recognition on the position image through an image processing module to calculate the head position of the target multiple-length bar material; and calculating the actual multiple-length length of the target multiple-length bar material based on the head position. The present invention can collect position images by using a visual module, and process the position images by using an image processing module using image recognition technology, so as to more efficiently and accurately measure and calculate the length of the target multiple-length bar material.

Description

Technical Field

[0001] The invention relates to the technical field of rod materials, and in particular to an online measurement method and system for the length of a rod material. Background Art

[0002] The bar production line is equipped with a multiple length shear between the finished product rack and the cooling bed to shear the bars. During the use of the multiple length shear, the multiple length of the bar needs to be accurately measured to be fed back to the multiple length shear control system to optimize the shearing accuracy of the multiple length shear. However, during the bar production process, the measurement result of the bar length will be affected by factors such as the bar head removal, the acceleration / deceleration change of the roller table, the forward / backward sliding of the rolled piece, the installation position of the detection instrument, and the data processing algorithm, which reduces the accuracy of the measurement result of the actual length of the bar. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide a method and system for online measurement of the length of a bar, which are used to measure the length of the bar online through visual recognition technology to improve the measurement accuracy.

[0004] The above-mentioned object of the present invention can be achieved by adopting the following technical scheme. The present invention provides an online measurement method for the length of a bar, comprising the following steps:

[0005] Detect the target multiple-length bar through the thermal inspection module;

[0006] When the head of the target multiple-length bar reaches the thermal inspection module, a detection signal is obtained;

[0007] When the tail of the target multiple-length bar passes through the thermal inspection module, a detection loss signal is obtained;

[0008] Based on the detected signal and the lost signal, a position image of the target area is collected through a visual module;

[0009] Performing image recognition on the position image through an image processing module to calculate the head position of the target multiple-length bar;

[0010] The actual multiple-length length of the target multiple-length bar is calculated based on the head position.

[0011] In a preferred embodiment of the present invention, before the target multiple-length bar is inspected by the thermal inspection module, the following steps are also included:

[0012] Shearing the rolled piece by a multiple-length shear to obtain the target multiple-length bar;

[0013] The target multiple-length bars are transported to the cooling bed via a bar guide roller;

[0014] During the conveying process of the target multiple-length bar, the target multiple-length bar is detected by the thermal detection module.

[0015] In a preferred embodiment of the present invention, after calculating the actual multiple length of the target multiple length bar based on the head position, the following steps are also included:

[0016] Feeding back the actual multiple length to the multiple shear control system and the continuous casting system;

[0017] The multiple-length shear control system is used to adjust the subsequent shearing length of the rolled piece;

[0018] The continuous casting system is used to adjust the subsequent length of the rolling stock in the direct rolling production process.

[0019] In a preferred embodiment of the present invention, based on the detected signal and the lost signal, collecting the position image of the target area through the visual module comprises the following steps:

[0020] When the detected signal and the lost signal are received in sequence, taking a picture of the target area through a visual module;

[0021] The visual module continuously shoots the target area twice at a fixed frequency to obtain two position images; wherein the position images at least include a background reference image based on the bar guide roller and a bar image based on the target multiple-size bar.

[0022] In a preferred embodiment of the present invention, performing image recognition on the position image by an image processing module to calculate the head position of the target multiple-length bar comprises the following steps:

[0023] Converting the position image into a grayscale image by the image processing module;

[0024] Binarizing the grayscale image to obtain a first grayscale image;

[0025] Performing connected domain analysis on the first grayscale image to obtain a plurality of independent first regions;

[0026] Based on the area feature of each of the first regions, extracting the bar image according to the maximum area feature;

[0027] Binarizing the grayscale image again to obtain a second grayscale image;

[0028] Performing connected domain analysis on the second grayscale image to obtain a plurality of independent second regions;

[0029] Extracting the background reference image based on the area feature of each second region, wherein the background reference image at least includes a roller table gap image;

[0030] Extracting reference object coordinates based on the roller gap image;

[0031] Based on the bar image, the roller gap image and the reference object coordinates, obtaining the head coordinates of the target multiple-scale bar;

[0032] Based on the head coordinates of the target multiple-size rod, the head position of the target multiple-size rod is calculated.

[0033] In a preferred embodiment of the present invention, the grayscale image is binarized using the following formula:

[0034]

[0035] Where Img1(x, y) is the grayscale value of the grayscale image, Img11(x, y) is the grayscale image after binarization, Tmin is the minimum threshold, and Tmax is the maximum threshold.

[0036] In a preferred embodiment of the present invention, based on the head coordinates of the target multiple-size rod, calculating the head position of the target multiple-size rod comprises the following steps:

[0037] Dividing the rod guide roller into a plurality of roller sections, and recording the coordinate position of the front end of each roller section;

[0038] Dividing each of the roller sections into a plurality of calibration intervals, and recording the interval sizes of the calibration intervals;

[0039] The position of the head of the target multiple-size bar is calculated based on the number of roller sections passed by the head of the target multiple-size bar and the number of calibration intervals passed by the head of the target multiple-size bar.

[0040] In a preferred embodiment of the present invention, the calculation formula used to calculate the head position of the target multiple-length bar is as follows:

[0041] Lc=L n +K×Dis

[0042] Where, Lc is the distance between the head of the target multiple-length bar and the multiple-length shear, L n is the distance between the front end of the nth roller end passed by the head of the target multiple-length bar and the multiple-length shear, K is the number of calibrated intervals in the n+1th track segment covered by the head of the target multiple-length bar, and Dis is the interval size of the calibrated interval.

[0043] In a preferred embodiment of the present invention, calculating the actual multiple length of the target multiple length bar based on the head position comprises the following steps:

[0044] Obtaining the installation distance between the thermal inspection module and the multiple-length shears;

[0045] Based on the installation distance and the head position of the target multiple-size bar, the actual multiple-size length of the target multiple-size bar is calculated.

[0046] In a preferred embodiment of the present invention, after calculating the actual multiple length of the target multiple length bar based on the head position, the following steps are also included:

[0047] Error compensation is performed on the actual multiple length of the target multiple length bar, wherein the error compensation at least includes signal delay error compensation and image influence coefficient compensation.

[0048] In a preferred embodiment of the present invention, the calculation formula of the actual multiple length of the target multiple length bar after error compensation is:

[0049] Lmea=Lc-Ls-Atrigger-Aframe

[0050] Wherein, Lmea is the actual multiple-size length of the target multiple-size bar, Lc is the distance between the head of the target multiple-size bar and the multiple-size shear, Ls is the installation distance between the thermal inspection module and the multiple-size shear, Atrigger is the signal delay error compensation distance between the thermal inspection module and the visual module, and Aframe is the compensation distance of the shooting interval between the two position images.

[0051] In a preferred embodiment of the present invention, after the position image of the target area is collected by the visual module, the following step is also included: the position image is transmitted to the image processing module in real time via high-speed Ethernet.

[0052] An embodiment of the present invention further provides a bar length online measurement system, comprising:

[0053] A bar guide roller table arranged between the multiple-length shear and the cooling bed;

[0054] A heat detection module is arranged at the outlet of the multiple-length shear, and is used to emit a pulse signal to detect the bar material to send a detection signal or a detection loss signal;

[0055] A visual module is arranged between the multiple-size shear and the cooling bed, the visual module is electrically connected to the thermal inspection module, and the visual module is used to receive the loss detection signal to collect a position image of the target multiple-size bar;

[0056] An image processing module is electrically connected to the visual module and is used to process the position image to feed back to the multiple-length shear control system and the continuous casting system.

[0057] In a preferred embodiment of the present invention, the visual module includes a plurality of industrial cameras, which are arranged at intervals between the bar guide roller and the cooling bed to capture position images.

[0058] In a preferred embodiment of the present invention, the rod guiding roller comprises a plurality of roller sections, the plurality of roller sections are arranged at intervals, and the roller sections are equally spaced to form a plurality of calibrated intervals.

[0059] In a preferred embodiment of the present invention, the heat detection module includes a hot metal detector, which is arranged at the outlet of the multiple-length shear, and is used to send a pulse signal to detect the target multiple-length bar.

[0060] In a preferred embodiment of the present invention, the thermal detection module includes at least two hot metal detectors, one of which is in working state and the other is in standby state.

[0061] The technical solution of the present invention has the following significant beneficial effects:

[0062] Before using the online measurement method for the length of a bar in the embodiment of the present invention, the rolled piece is sheared by a multiple-length shear to generate a target multiple-length bar, and then the target multiple-length bar is transported to the cooling bed by a bar guide roller. The online measurement method for the length of a bar can measure the length of the target multiple-length bar in the process of transportation online by cooperating with a heat detection module, a visual module and an image processing module. By using the visual module to collect position images, and by using the image processing module to process the position images using image recognition technology, the length of the target multiple-length bar can be measured and calculated more efficiently and accurately.

[0063] The installation distance between the heat detection module and the multiple-length shear can be pre-stored. When the heat detection module obtains the detection signal and the loss signal in sequence, it can be considered that the target multiple-length bar has all passed through the heat detection module. Among them, when the heat detection module obtains the loss signal, it can be considered that the tail of the target multiple-length bar is at the position of the heat detection module. At this time, the loss signal can also be used to control the visual module. When the heat detection module obtains the loss signal, the visual module is triggered to collect the position image of the target area. The tail position of the target multiple-length bar can be obtained through the loss signal of the heat detection module, and the visual module is triggered by the loss signal to collect the position image of the target area. The image processing module uses image recognition technology to process the position image, and the head position of the target multiple-length bar can also be obtained synchronously. The actual length of the target multiple-length bar can be accurately calculated by the head position of the target multiple-length bar and the tail position of the target multiple-length bar. Furthermore, the signal delay of the loss signal during the transmission process can be compensated, thereby further improving the measurement accuracy of the length of the target multiple-length bar.

[0064] After measuring the length of the target multiple-length bar online, the length data of the target multiple-length bar can also be fed back to the multiple-length shear control system and the continuous casting system. The multiple-length shear control system and the continuous casting system can instantly adjust the subsequent shearing length of the rolled piece and the length of the rolled piece billet, thereby better controlling the length accuracy of the target multiple-length bar. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0066] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0067] Figure 1 A flowchart of the steps of the online measurement method for the length of a bar;

[0068] Figure 2 A schematic diagram of a process of binarizing the grayscale image to obtain a first grayscale image;

[0069] Figure 3 A schematic diagram of a process for extracting the bar image;

[0070] Figure 4 A schematic diagram of a process for extracting the background reference image;

[0071] Figure 5 is a structural schematic diagram of the online measurement system for the length of a bar;

[0072] Figure 6 It is a schematic diagram of the installation structure of the bar guide roller and the visual module;

[0073] Figure 7 Schematic diagram of the head position of the target multiple-length rod.

[0074] Reference numerals in the above drawings:

[0075] 1. Multiple-length shear; 2. Cooling bed; 3. Rod guide roller; 31. Roller section; 4. Heat inspection module; 41. Hot metal detector; 5. Vision module; 51. Industrial camera; 52. Switch; 6. Image processing module; 7. Multiple-length shear control system; 8. Continuous casting system; 9. Target multiple-length rod. DETAILED DESCRIPTION

[0076] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0077] Please refer to Figure 1 In an embodiment of the present invention, a method for measuring the length of a bar online is provided, comprising the following steps:

[0078] Step 101: Detect the target multiple-length bar through a thermal detection module;

[0079] Step 102: When the head of the target multiple-length bar reaches the thermal inspection module, a detection signal is obtained;

[0080] Step 103: when the tail of the target multiple-length bar passes through the thermal inspection module, a detection loss signal is obtained;

[0081] Step 104: Based on the detected signal and the lost signal, a position image of the target area is collected by a visual module;

[0082] Step 105: performing image recognition on the position image through an image processing module to calculate the head position of the target multiple-size bar;

[0083] Step 106: Calculate the actual multiple-length of the target multiple-length bar based on the head position.

[0084] In general, the online measurement method for the length of the bar can measure the length of the target multiple-length bar in the process of transportation online by cooperating with the thermal inspection module, the visual module and the image processing module. The position image can be collected by using the visual module, and the position image can be processed by the image processing module using the image recognition technology, so that the head position of the target multiple-length bar can be obtained more intuitively and accurately.

[0085] The installation distance between the thermal inspection module and the multiple-length shear can be pre-stored. When the thermal inspection module obtains the detection signal and the detection loss signal in sequence, it can be considered that all the target multiple-length bars have passed through the thermal inspection module. Among them, when the thermal inspection module obtains the detection loss signal, it can be considered that the tail of the target multiple-length bar is at the position of the thermal inspection module. At this time, the detection loss signal can also be used to control the visual module. When the thermal inspection module obtains the detection loss signal, the visual module is triggered to collect the position image of the target area.

[0086] The tail position of the target multiple-length bar can be obtained through the detection signal of the heat detection module, and the position image of the target area can be collected by the visual module triggered by the detection signal. The position image can be processed by the image processing module using image recognition technology to synchronously obtain the head position of the target multiple-length bar. The length of the target multiple-length bar can be accurately calculated through the head position of the target multiple-length bar and the tail position of the target multiple-length bar.

[0087] In an embodiment of the present invention, before the target multiple-length bar is inspected by the thermal inspection module, the following steps are also included:

[0088] Step 107: Shearing the rolled piece by a multiple-length shear to obtain the target multiple-length bar;

[0089] Step 108: transporting the target multiple-length bars to the cooling bed via a bar guide roller;

[0090] During the conveying process of the target multiple-length bar, the target multiple-length bar is detected by the thermal detection module.

[0091] Specifically, the target multiple-length bar can be obtained by shearing the rolled piece with a multiple-length shear, and the size and parameters of the target multiple-length bar can be adjusted as needed, and there is no limitation here.

[0092] In an embodiment of the present invention, after calculating the actual multiple-length length of the target multiple-length bar based on the head position, the method further includes the following steps:

[0093] Step 109: Feedback the actual multiple length to the multiple shear control system and the continuous casting system;

[0094] Step 110: adjusting the subsequent shearing length of the rolled piece by using the multiple-length shear control system;

[0095] Step 111: The continuous casting system is used to adjust the length of subsequent rolled stock during the direct rolling production process.

[0096] By feeding back the length data of the target multiple-length bar to the multiple-length shear control system and the continuous casting system, the multiple-length shear control system and the continuous casting system can instantly adjust the shear length of the rolled piece and the length of the rolled piece billet, thereby better controlling the shearing accuracy of the target multiple-length bar. Among them, the designer can select the type and structure of the multiple-length shear control system and the continuous casting system according to production needs, and there is no restriction here.

[0097] In an embodiment of the present invention, based on the detected signal and the lost signal, collecting a position image of the target area through a visual module comprises the following steps:

[0098] Step 1041: when the detected signal and the lost signal are received in sequence, taking a photo of the target area through a visual module;

[0099] Step 1042: the visual module continuously photographs the target area twice at a fixed frequency to obtain two position images; wherein the position images at least include a background reference image based on the rod guide roller and a rod image based on the target multiple-size rod.

[0100] Specifically, one of the two position images is imported into the image processing module for image recognition operation, and the other position image can be used as a backup. Among them, the background reference image includes the reference object coordinates preset on the rod guide roller, and the rod image includes the head image of the target multiple-size rod. Of course, the designer can also set the reference object coordinates or other reference structures at other locations, which is not limited here.

[0101] In the embodiments of the present invention, Figure 2 , Figure 3 and Figure 4 , performing image recognition on the position image through an image processing module, and calculating the head position of the target multiple-length bar comprises the following steps:

[0102] Step 1050: converting the position image into a grayscale image by the image processing module;

[0103] Step 1051: binarizing the grayscale image to obtain a first grayscale image;

[0104] Step 1052: performing connected domain analysis on the first grayscale image to obtain a plurality of independent first regions;

[0105] Step 1053: extracting the bar image according to the maximum area feature based on the area feature of each of the first regions;

[0106] Step 1054: binarizing the grayscale image again to obtain a second grayscale image;

[0107] Step 1055: performing connected domain analysis on the second grayscale image to obtain a plurality of independent second regions;

[0108] Step 1056: extracting the background reference image based on the area feature of each of the second regions, wherein the background reference image at least includes a roller table gap image;

[0109] Step 1057: extracting reference object coordinates based on the roller gap image;

[0110] Step 1058: based on the bar image, the roller gap image and the reference object coordinates, obtaining the head coordinates of the target multiple-scale bar;

[0111] Step 1059: Based on the head coordinates of the target multiple-size rod, the head position of the target multiple-size rod is calculated.

[0112] By performing two binarization processes on the grayscale image of the position image, the bar image and the reference coordinates are extracted from the grayscale image, and the head coordinates of the target multiple-scale bar can be obtained by comparing the bar image with the reference coordinates. The installation distance between the reference coordinates and the multiple-scale shear can be pre-stored, so that the head position of the target multiple-scale bar can be calculated through the head coordinates of the target multiple-scale bar.

[0113] Specifically, the grayscale image is binarized using the following formula:

[0114]

[0115] Where Img1(x, y) is the grayscale image, (x, y) is the grayscale value, Img11(x, y) is the binarized grayscale image, Tmin is the minimum threshold, and Tmax is the maximum threshold.

[0116] Specifically, refer to Figure 2 and Figure 3 , the grayscale image can be set to Img1, the rod image can be set to Img2, and the first grayscale image can be set to Img11. When the grayscale image Img1 is binarized to obtain the first grayscale image Img11, Tmin can be 0 and Tmax can be 9, thereby obtaining Figure 2 and Figure 3Of course, designers can also adjust the size of Tmin and Tmax according to image processing needs, and there is no restriction here. By performing connected domain analysis on the first grayscale image Img11, multiple independent first regions are obtained, wherein the first region can be set to CReg11[]. The bar image Img2 is extracted according to the maximum area feature of each CReg11[], thereby obtaining a reference Figure 3 .

[0117] Further, refer to Figure 2 and Figure 4 , the second grayscale image can be set to Img12, and the roller gap image can be set to Img3. Among them, Tmin can be 223, Tmax can be 255, and the grayscale image Img1 is binarized again to obtain the second grayscale image Img12. A plurality of independent second regions are obtained by performing connected domain analysis on the second grayscale image Img12, wherein the second region can be set to CReg12[]. The roller gap image Img3 is extracted according to the area characteristics of each CReg12[], thereby obtaining a reference Figure 4 The roller gaps in the roller gap image Img3 can be used as reference coordinates, and the coordinate positions of the roller gaps can be recorded. The head position of the target multiple-length bar can be calculated using Img2, Img3, and the reference coordinates. Of course, designers can also adjust the size of Tmin and Tmax according to image processing needs, and there is no restriction here.

[0118] In an embodiment of the present invention, based on the head coordinates of the target multiple-size rod, calculating the head position of the target multiple-size rod comprises the following steps:

[0119] Step 10591: Divide the bar guide roller into a plurality of roller sections, and record the coordinate position of the front end of each roller section;

[0120] Step 10592: Divide each of the roller sections into a plurality of calibration intervals, and record the interval sizes of the calibration intervals;

[0121] Step 10593: Calculate the head position of the target multiple-size bar based on the number of roller sections passed by the head of the target multiple-size bar and the number of calibration intervals passed by the head of the target multiple-size bar.

[0122] Specifically, the designer can adjust the size of the calibration interval according to the measurement accuracy requirements, and there is no limitation here. For example, the size of the calibration interval can be set to 10 cm. The smaller the calibration interval is set, the higher the measurement accuracy of the target multiple-length bar length.

[0123] Specifically, the calculation formula used to calculate the head position of the target multiple-length bar is as follows:

[0124] Lc=L n +K×Dis

[0125] Where, Lc is the distance between the head of the target multiple-length bar and the multiple-length shear, L n is the distance between the front end of the nth roller end passed by the head of the target multiple-length bar and the multiple-length shear, K is the number of calibrated intervals in the n+1th track segment covered by the head of the target multiple-length bar, and Dis is the interval size of the calibrated interval.

[0126] In an embodiment of the present invention, calculating the actual multiple-length length of the target multiple-length bar based on the head position comprises the following steps:

[0127] Step 1061: Obtaining the installation distance between the thermal inspection module and the multiple-length shears;

[0128] Step 1062: Calculate the actual multiple-size length of the target multiple-size bar based on the installation distance and the head position of the target multiple-size bar.

[0129] The installation distance between the heat detection module and the multiple-length shear can be pre-stored. When the tail of the target multiple-length bar passes through the heat detection module, the heat detection module obtains a detection loss signal. At this time, it can be considered that the tail of the target multiple-length bar is at the heat detection module position. Therefore, the distance between the heat detection module and the multiple-length shear is equal to the distance between the tail of the target multiple-length bar and the multiple-length shear. Then, the distance between the head of the target multiple-length bar and the multiple-length shear can be calculated through the position of the head of the target multiple-length bar, and then the distance between the tail of the target multiple-length bar and the multiple-length shear is subtracted from the distance between the head of the target multiple-length bar and the multiple-length shear, so as to calculate the actual length of the target multiple-length bar.

[0130] Since there is a signal delay error in the process of the heat detection module acquiring the lost detection signal and controlling the visual module through the lost detection signal, the target multiple-length bar will continue to move along the bar guide roller during the signal delay error, thus affecting the measurement accuracy of the target multiple-length bar length. Therefore, it is necessary to compensate for the signal delay error.

[0131] Furthermore, when multiple position images are captured by the visual module, there will be a shooting interval between two consecutive position images due to the influence of the interval between the number of frames captured by the visual module. During the shooting interval, the target multiple-size bar will continue to move along the bar guide roller. Therefore, when the first position image is used, it can be considered that the target multiple-size bar is not affected by the shooting interval, and when the second position image is used, the target multiple-size bar will continue to move a certain distance along the bar guide roller during the shooting interval. Therefore, it is necessary to compensate the measured length of the target multiple-size bar according to the number of frames captured by the position image to improve the measurement accuracy of the length of the target multiple-size bar.

[0132] In an embodiment of the present invention, after calculating the actual multiple-length length of the target multiple-length bar based on the head position, the method further includes the following steps:

[0133] Step 112: performing error compensation on the actual multiple-length of the target multiple-length bar, wherein the error compensation at least includes signal delay error compensation and image influence coefficient compensation.

[0134] Specifically, the calculation formula for the actual multiple length of the target multiple length bar after error compensation is:

[0135] Lmea=Lc-Ls-Atrigger-Aframe

[0136] Wherein, Lmea is the actual multiple length of the target multiple length bar, Lc is the distance between the head of the target multiple length bar and the multiple length shear, Ls is the installation distance between the thermal inspection module and the multiple length shear, Atrigger is the signal delay error compensation distance between the thermal inspection module and the visual module, and Aframe is the compensation distance of the shooting interval between the two position images. When the image processing module uses the first frame position image, Aframe is 0; when the image processing module uses the second frame position image, Aframe needs to be calculated according to the frame rate.

[0137] The frame rate can be determined based on the visual module, and the shooting interval between two position images can be calculated through the frame rate. The moving speed of the target multiple-size bar is obtained based on the conveying speed of the bar guide roller, so that the shooting interval is multiplied by the moving speed of the target multiple-size bar to obtain the compensation distance for the target multiple-size bar.

[0138] For example, the conveying speed of the rod guide roller is set to 18m / s, the shooting frame rate of the visual module is set to 45fps, and the shooting interval of each frame position image is 0.02s. It can be calculated that in one shooting interval, the target multiple-scale rod moves 0.36m along the rod guide roller. Among them, the visual module is composed of multiple industrial cameras, and the field of view is composed of multiple industrial cameras, and the fields of view of each industrial camera do not overlap. For example, when 5 industrial cameras are set, it is calculated that within the signal delay between the industrial camera and the thermal inspection module, the moving distance of the target multiple-scale rod is less than 0.09m. The error of 0.09m is small and has limited impact on the actual length of the target multiple-scale rod. Therefore, Atrigger can be taken as 0.09m for compensation.

[0139] Of course, the user also adjusts the compensation distance according to actual usage, and there is no restriction here.

[0140] In an embodiment of the present invention, after the position image of the target area is collected by the visual module, the following steps are also included:

[0141] Step 113: Transmit the position image to the image processing module in real time via high-speed Ethernet.

[0142] By using high-speed Ethernet to transmit position images, the signal delay error can be reduced, thereby improving the measurement accuracy of the target multiple-length bar length.

[0143] Please refer to Figures 5 to 7 In an embodiment of the present invention, there is also provided an online measurement system for the length of a bar, comprising: a bar guide roller 3 arranged between a multiple-length shear 1 and a cooling bed 2; a heat detection module 4, arranged at the outlet of the multiple-length shear 1, the heat detection module 4 being used to emit a pulse signal to detect the bar to send out a detection signal or a loss signal; a visual module 5, arranged between the multiple-length shear 1 and the cooling bed 2, the visual module 5 being electrically connected to the heat detection module 4, the visual module 5 being used to receive the loss signal to collect a position image of a target multiple-length bar 9; an image processing module 6, being electrically connected to the visual module 5, being used to process the position image to feed back to a multiple-length shear control system 7 and a continuous casting system 8.

[0144] In order to ensure that the image processing module 6 has good processing capabilities, the image processing module 6 at least adopts the following configuration: the processor is i7-11700, eight cores, 2.5GHz, and the third-level cache is 16MB. The memory is 16GB, and the hard disk is SSD1T. The graphics card is RTX3060Ti, the video memory capacity is 8GB, and the video memory frequency is 14000MHz. And a gigabit or 10G network card. The image processing module 6 can be connected to the industrial camera 51 through the optical fiber switch 52.

[0145] In an embodiment of the present invention, the visual module 5 includes a plurality of industrial cameras 51 , which are arranged at intervals between the bar guide roller 3 and the cooling bed 2 for capturing position images.

[0146] Specifically, five industrial cameras 51 may be provided, and the five industrial cameras 51 are arranged in sequence, and the fields of view of the industrial cameras 51 do not overlap. The industrial cameras 51 may support hard triggering to cooperate with the thermal inspection module 4. The industrial cameras 51 may use CMOS sensors with a total pixel greater than 10 million, a maximum frame rate greater than 45fps, and an input voltage of 5V to 12V. Among them, a water cooling or air cooling protection device may also be provided on the industrial camera 51, so that the working temperature of the industrial camera 51 is between 0°C and 50°C, and the working humidity is between 20%RH and 80%RH, so as to ensure the best use state of the industrial camera 51. Each industrial camera 51 may be connected to the image processing module 6 via a switch 52.

[0147] In an embodiment of the present invention, the bar guiding roller 3 comprises a plurality of roller sections 31 , the plurality of roller sections 31 are arranged at intervals, and the roller sections 31 are equally spaced to form a plurality of calibrated intervals.

[0148] For details, please refer to Figure 7 The roller sections 31 are divided into those with covers and those without covers. The roller sections 31 closer to the cooling bed 2 may not be provided with covers, so that the industrial camera 51 can capture the target multiple-length bars 9 located in the roller sections 31. The length of the roller sections 31 without covers can be greater than 30m. The width of the cooling bed 2 can be set to about 120m, and the distance from the multiple-length shear 1 to the entrance of the cooling bed 2 can be set to about 90m.

[0149] During installation, three industrial cameras 51 can be arranged in sequence on the top of the roller section 31 without a cover plate, so that the industrial cameras 51 can photograph the target multiple-size bars 9 in the roller section 31. Another two industrial cameras 51 are arranged on the entrance side of the cooling bed 2, so that the industrial cameras 51 can photograph the target multiple-size bars 9 in the unloading roller of the cooling bed 2. The field of view of each industrial camera 51 can cover a length of 9m, and a total length of 45m, which can meet the measurement requirements of a length range of 70m to 11m.

[0150] In an embodiment of the present invention, the heat detection module 4 includes a hot metal detector 41 , which is disposed at the outlet of the multiple-length shear 1 , and is used to send a pulse signal to detect the target multiple-length bar 9 .

[0151] Specifically, the hot metal detector 41 can be a scanning hot metal detector, the scanning angle of the scanning hot metal detector is greater than or equal to 30°, and the response time is less than 10ms. Of course, the designer can also adjust the type of detector according to the use needs, and there is no restriction here.

[0152] Furthermore, the heat detection module 4 includes at least two hot metal detectors 41 , wherein one of the hot metal detectors 41A is in working state, and the other hot metal detector 41B is in standby state.

[0153] Specifically, the working hot metal detector 41A can be installed 3m from the outlet of the multiple-length shear 1, and the standby hot metal detector 41B can be installed about 0.3m downstream of the working hot metal detector 41A. Each hot metal detector 41 can be directly connected to each industrial camera 51 through a hard line to control the delay between the hot metal detector 41 and the industrial camera 51 to less than 5ms.

[0154] The technical problem solved by the on-line measuring system for the length of a bar in the embodiment of the present invention is similar to that of the on-line measuring method for the length of a bar mentioned above. Therefore, the use process of the on-line measuring system for the length of a bar can refer to the on-line measuring method for the length of a bar in the embodiment mentioned above, and will not be repeated here.

[0155] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for various purposes. The term "consisting essentially of ... " describing a combination should include determined elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel features of the combination. The use of the terms "comprising" or "including" to describe the combination of elements, ingredients, parts or steps here also contemplates the implementation method consisting essentially of these elements, ingredients, parts or steps. Here, by using the term "may", it is intended to illustrate that any attribute described that "may" includes is optional. Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "one" used to describe an element, ingredient, part or step is not said to exclude other elements, ingredients, parts or steps.

[0156] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. The above embodiments are only for illustrating the technical concept and features of the present invention. The purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for measuring the length of a bar online, characterized in that: The steps include: Detect the target multiple-length bar through the thermal inspection module; When the head of the target multiple-length bar reaches the thermal inspection module, a detection signal is obtained; When the tail of the target multiple-length bar passes through the thermal inspection module, a detection loss signal is obtained; Based on the detected signal and the lost signal, a position image of the target area is collected through a visual module; wherein the position image at least includes a background reference image based on a rod guide roller and a rod image based on the target multiple-size rod; The image processing module performs image recognition on the position image to calculate the head position of the target multiple-scale rod: the image processing module converts the position image into a grayscale image; the grayscale image is binarized to obtain a first grayscale image; the first grayscale image is connected domain analysis to obtain a plurality of independent first regions; based on the area feature of each first region, the rod image is extracted according to the maximum area feature; the grayscale image is binarized again to obtain a second grayscale image; the second grayscale image is connected domain analysis to obtain a plurality of independent second regions; based on the area feature of each second region, the background reference image is extracted, wherein the background reference image at least includes a roller gap image; based on the roller gap image, the reference object coordinates are extracted; based on the rod image, the roller gap image and the reference object coordinates, the head coordinates of the target multiple-scale rod are obtained; based on the head coordinates of the target multiple-scale rod, the head position of the target multiple-scale rod is calculated; The actual multiple-length length of the target multiple-length bar is calculated based on the head position.

2. The method for measuring the length of a bar online according to claim 1, characterized in that: Before the target multiple-length bar is inspected by the thermal inspection module, the following steps are also included: Shearing the rolled piece by a multiple-length shear to obtain the target multiple-length bar; The target multiple-length bars are transported to the cooling bed via a bar guide roller; During the conveying process of the target multiple-length bar, the target multiple-length bar is detected by the thermal detection module.

3. The method for measuring the length of a bar online according to claim 2, characterized in that: After calculating the actual multiple length of the target multiple length bar based on the head position, the method further includes the following steps: Feeding back the actual multiple length to the multiple shear control system and the continuous casting system; The multiple-length shear control system is used to adjust the subsequent shearing length of the rolled piece; The continuous casting system is used to adjust the subsequent length of the rolling stock in the direct rolling production process.

4. The method for measuring the length of a bar online according to claim 3, characterized in that: Based on the detected signal and the lost signal, collecting a position image of the target area through a visual module comprises the following steps: When the detected signal and the lost signal are received in sequence, taking a picture of the target area through a visual module; The visual module continuously photographs the target area twice at a fixed frequency to obtain two position images.

5. The method for online measuring the length of a bar according to claim 1, characterized in that: The following formula is used to perform binarization processing on the grayscale image: Where Img1(x, y) is the grayscale value of the grayscale image, Img11(x, y) is the grayscale image after binarization, Tmin is the minimum threshold, and Tmax is the maximum threshold.

6. The method for measuring the length of a bar online according to claim 5, characterized in that: Based on the head coordinates of the target multiple-size bar, calculating the head position of the target multiple-size bar includes the following steps: Dividing the rod guide roller into a plurality of roller sections, and recording the coordinate position of the front end of each roller section; Dividing each of the roller sections into a plurality of calibration intervals, and recording the interval sizes of the calibration intervals; The position of the head of the target multiple-size bar is calculated based on the number of roller sections passed by the head of the target multiple-size bar and the number of calibration intervals passed by the head of the target multiple-size bar.

7. The method for measuring the length of a bar online according to claim 6, characterized in that: The calculation formula used to calculate the head position of the target multiple-length bar is as follows: Lc=L n +K×Dis Where Lc is the distance between the head of the target multiple-length bar and the multiple-length shear, L n is the distance between the front end of the nth roller end passed by the head of the target multiple-length bar and the multiple-length shear, K is the number of calibrated intervals in the n+1th track segment covered by the head of the target multiple-length bar, and Dis is the interval size of the calibrated interval.

8. The method for measuring the length of a bar online according to claim 7, characterized in that: Calculating the actual multiple length of the target multiple length bar based on the head position comprises the following steps: Obtaining the installation distance between the thermal inspection module and the multiple-length shears; Based on the installation distance and the head position of the target multiple-size bar, the actual multiple-size length of the target multiple-size bar is calculated.

9. The method for measuring the length of a bar online according to claim 8, characterized in that: After calculating the actual multiple length of the target multiple length bar based on the head position, the method further includes the following steps: Error compensation is performed on the actual multiple length of the target multiple length bar, wherein the error compensation at least includes signal delay error compensation and image influence coefficient compensation.

10. The method for measuring the length of a bar online according to claim 9, characterized in that: The calculation formula of the actual multiple length of the target multiple length bar after error compensation is: Lmea=Lc-Ls-Atrigger-Aframe Wherein, Lmea is the actual multiple-size length of the target multiple-size bar, Lc is the distance between the head of the target multiple-size bar and the multiple-size shear, Ls is the installation distance between the thermal inspection module and the multiple-size shear, Atrigger is the signal delay error compensation distance between the thermal inspection module and the visual module, and Aframe is the compensation distance of the shooting interval between the two position images.

11. The method for measuring the length of a bar online according to claim 1, characterized in that: After the position image of the target area is collected by the visual module, the method further includes the following steps: transmitting the position image to the image processing module in real time via high-speed Ethernet.

12. An online measuring system for the length of a bar, characterized in that: For realizing the on-line measurement method of the length of a bar as claimed in claim 1, the on-line measurement system of the length of a bar comprises: A bar guide roller table arranged between the multiple-length shear and the cooling bed; A heat detection module is arranged at the outlet of the multiple-length shear, and is used to emit a pulse signal to detect the bar material to send a detection signal or a detection loss signal; A visual module is arranged between the multiple-size shear and the cooling bed, the visual module is electrically connected to the thermal inspection module, and the visual module is used to receive the loss detection signal to collect a position image of the target multiple-size bar; An image processing module is electrically connected to the visual module and is used to process the position image to feed back to the multiple-length shear control system and the continuous casting system.

13. The on-line measuring system for rod length according to claim 12, characterized in that: The visual module includes a plurality of industrial cameras, which are arranged at intervals between the bar guide roller and the cooling bed and are used to capture position images.

14. The on-line measuring system for rod length according to claim 13, characterized in that: The rod guide roller comprises a plurality of roller sections, the plurality of roller sections are arranged in an interval, and the roller sections are divided into a plurality of calibrated intervals at equal intervals.

15. The on-line measuring system for rod length according to claim 12, characterized in that: The heat detection module comprises a hot metal detector, which is arranged at the outlet of the multiple-length shear and is used to send a pulse signal to detect the target multiple-length bar.

16. The on-line measuring system for rod length according to claim 15, characterized in that: The thermal detection module includes at least two hot metal detectors, one of which is in working state, and the other hot metal detectors are in standby state.

Images