A monitoring device for displacement and speed of wire rope operation and a method for using the same

Abstract

The invention discloses a monitoring device for the displacement and speed of a steel wire rope and a method for using the same. The device comprises a background plate, a steel wire rope, an industrial camera group, a network cable, a host computer processing module, an auxiliary light source, and an ambient light sensor. The industrial camera group collects images of the surface texture of the steel wire rope in an external triggering manner, and after being processed by the host computer processing module, the values ​​of the displacement and speed of the steel wire rope are settled in real time. The method of the invention can effectively eliminate the error caused by the sliding of the steel wire rope on the drum, so that the measurement result is more accurate. In addition, the system of the invention has a simple structure, a wide range of use, good environmental adaptability, and a strong anti-interference ability.

Description

Technical Field

[0001] The invention belongs to the technical field of mining hoist monitoring, and in particular relates to a method and a device for monitoring the displacement and speed of a steel wire rope. Background Art

[0002] Coal mining is an important basic industry in my country. Coal mining is a dangerous industry. The severe situation of coal mine safety production has always restricted the development of the coal mining industry and seriously threatened the health and life safety of coal miners. The displacement and speed monitoring of the running wire rope plays an important role in the safety of the coal mining industry.

[0003] There are currently two main methods for monitoring the displacement and speed of a running wire rope. The first method uses a shaft encoder, which is placed on the shaft of the drum, and uses the high-counting function of the PLC to monitor the drum, thereby indirectly monitoring the wire rope. The second method is to add a permanent magnet to the drum and use the electromagnetic characteristics of the Hall element to monitor the drum, thereby indirectly monitoring the wire rope.

[0004] Both of the above methods monitor the wire rope indirectly by monitoring the drum, and cannot eliminate the error caused by the sliding of the wire rope relative to the drum. Summary of the invention

[0005] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a monitoring device for the displacement and speed of a wire rope and a method of using the same. The method and device for monitoring the displacement and speed of a wire rope in a mine hoist have a simple system structure, a wide range of use, good environmental adaptability, and strong anti-interference ability. The displacement and speed information of the wire rope at this time can be obtained by identifying the texture features on the surface of the wire rope.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a monitoring device for the displacement and speed of a steel wire rope, comprising a background plate arranged at the rear of the steel wire rope and two vertical brackets corresponding to the steel wire rope, wherein the upper and lower parts of the vertical brackets are both provided with Y-direction slide rail grooves, an upper transverse support plate and a lower transverse support plate which can move along the Y-direction slide rail grooves are installed between the two vertical brackets, an X-direction slide rail groove is correspondingly arranged on the upper transverse support plate and the lower transverse support plate, a Z-direction slide column which can slide along the X-direction slide rail grooves is installed between the upper transverse support plate and the lower transverse support plate, an upper part of the Z-direction slide column extends out of the X-direction slide rail groove of the upper transverse support plate and is connected to a mounting plate, a main camera, an auxiliary light source and an ambient light sensor are installed on the mounting plate, an auxiliary camera which can slide along the Z-direction slide column is installed on the Z-direction slide column, and the main camera and the auxiliary camera are electrically connected to a host computer processing module through a network cable.

[0008] Preferably, the background plate is white, the main camera and auxiliary camera corresponding to a Z-direction sliding column are a group of industrial cameras, and a group of industrial cameras corresponds to a wire rope.

[0009] The present invention also provides a method for using the above device, which specifically comprises the following steps:

[0010] (a) Adjust the positions of the main camera and the auxiliary camera so that they correspond to the wire rope;

[0011] (b) using the main camera and the auxiliary camera to collect images of the wire rope in real time;

[0012] (c) taking out two pictures captured by the main camera and the auxiliary camera respectively, taking the pictures taken at the same time as a group of pictures, and rotating the pictures so that the position of the wire rope in the pictures is in a horizontal state;

[0013] (d) Select the region of interest for the two images in each group, obtain the key points of the region of interest, compare the key points to find the key points that match each other, and finally obtain the rotation and displacement matrices;

[0014] (e) The second image in each group is spliced ​​with the first image according to the rotation displacement matrix to obtain the total image;

[0015] (f) Traverse a row of pixels above and below the wire rope in each group of total images to obtain the position of the first point with a pixel value of 0; where a is the horizontal coordinate of the first point with a pixel value of 0 in the row of pixels above the wire rope, and b is the horizontal coordinate of the first point with a pixel value of 0 in the row of pixels below the wire rope; the average value of the horizontal coordinates of the two pixel points is c = (a + b) / 2;

[0016] (g) The width of the first image in each group is marked as d, and the displacement pixels between the two images relative to the world coordinates is g = cd;

[0017] (h) The actual diameter of the wire rope is marked as H, and the number of pixels occupied by the wire rope in the picture is marked as L; the actual displacement between the two pictures relative to the world coordinates is S = g*H / L;

[0018] (i) The camera acquisition frame rate is set to F; the actual speed of the wire rope at this time is v = S*e / F; e is the frame difference between each set of two pictures;

[0019] (j) Create an index table by associating pixels with displacement and speed; put the video frame number, displacement value and speed value in each cycle into Excel for later retrieval and viewing of related pictures;

[0020] (k) Repeat steps (a)-(j) to obtain the displacement and velocity of the wire rope.

[0021] Preferably, in step (a), the positions of the main camera and the auxiliary camera are adjusted so that the diameter of the wire rope occupies 30%-50% of the width of the image.

[0022] Preferably, in the step (c), after the picture is rotated so that the position of the wire rope in the picture is horizontal, the two rotated pictures in each group are grayed by mapping Y=0.3R+0.59G+0.11B: wherein Y is the gray value, R is the red value, G is the green value, and B is the blue value; [a11, a12, a13; a21, a22, a23; a31, a32, a33] is the unrotated state array, and [a11, a21, a31; a12, a22, a32; a13, a23, a33] is the transposed array after rotation.

[0023] Preferably, in step (i), the initial value of the frame difference e between each group of two pictures is 10, and the subsequent values ​​are determined by the calculated pixel displacement; the specific determination method is to set the standard pixel displacement to S0, when the obtained pixel displacement is less than S0, e=e+5, when the obtained pixel displacement is greater than S0, e=e-5, when e<0, e=0, so as to adapt to the speed change of the wire rope.

[0024] Preferably, in step (d), the entire image is selected for the first matching of the region of interest, and subsequent matching is selected according to the pixel displacement g obtained last time. Assuming that the width of the first image is img1.cols, the image width of the second image is img2.cols, the region of interest of the first image is ROI1, and the region of interest of the second image is ROI2, then the horizontal coordinate of the region of interest ROI1 of the first image is img1.cols / 2+g to img1.cols / 2+2g, the horizontal coordinate of the region of interest ROI2 of the second image is img1.cols / 2 to img1.cols / 2+g, and the vertical coordinate direction selects the total length of the image;

[0025] The method for finding key points in the region of interest is to perform a two-dimensional coordinate gradient operation on each point in the region. The method is that the horizontal gradient of A(x, y) is lx = (px+1-px-1) / 2, the vertical gradient is ly = (py+1-py-1) / 2, the total gradient direction α = ly / lx, the total gradient amplitude, where px+1 and px-1 are the pixel values ​​of the next and previous pixel points in the horizontal direction of point A, and py+1 and py-1 are the pixel values ​​of the next and previous pixel points in the vertical direction of point A. Assuming the gradient threshold is t, when lx and ly are both greater than t, then point A is the key point;

[0026] When matching key points, it is necessary to establish a feature description of the key points, specifically including: performing gradient operations on 8 points in the key point area and itself, and then classifying them by direction into 4 quadrants of a two-dimensional coordinate. The sum of the gradients in each quadrant is the total amplitude of this quadrant. l1, l2, l3, and l4 are the total amplitudes of this key point in the first, second, third, and fourth quadrants respectively; comparing and matching the key points of two pictures. Assume that point A and point B are the key points of two pictures, l1, l2, l3, and l4 are the total amplitudes of point A in the first, second, third, and fourth quadrants, and l5, l6, l7, and l8 are the total amplitudes of point B in the first, second, third, and fourth quadrants. Then the Euclidean distance between the two points. Assume that the amplitude threshold is F. When o < F, these two points are considered to be the same key point.

[0027] Preferably, when splicing the total picture in step (e), the array for placing the panoramic picture constructed consists of 0s. When two pictures are matched and spliced, there will be a slight rotation, and there will be a black area that does not belong to the picture on the right side of the picture. By traversing the pixel values of the first row and the last row of the picture, obtaining the positions of the points with pixel value 0, and cutting off the part on the right of this position, the remaining part is the spliced panoramic picture; when there is no point with pixel value 0 in the row pixels, then the average value c of the abscissa is replaced by the width value of the spliced picture.

[0028] Preferably, when calculating the displacement pixel g in step (g), 3 groups of main cameras and auxiliary cameras corresponding to 3 steel wires are used to obtain 3 groups of displacement pixel values. Subtract the obtained 3 groups of displacement pixel values from each other and take the absolute value. If the sizes of the obtained 3 absolute values do not exceed 2, then take the average value of the 3 absolute values as the true value of the displacement pixel of the steel wire this time. If 1 absolute value is greater than 2, then take the median value of the three values as the true value of the displacement pixel of the steel wire this time. If 2 absolute values are greater than 2, then take the average value of the two pixel values not greater than 2 as the true value of the displacement pixel of the steel wire this time. If all 3 absolute values are greater than 2, then the displacement value of the steel wire obtained this time is inaccurate, and then remove the picture of this time, and calculate the displacement pixel g with the previous picture of this time as the reference picture.

[0029] Preferably, in step (h), when marking the number of pixels occupied by the steel wire in the picture, first use α0 as the threshold for the steel wire image. For the part where the pixel value is greater than α0, change the pixel value to 255, and for the part where the pixel value is less than or equal to α0, change the pixel value to 0. Then traverse the S1 row pixels in the middle of the picture, find the positions of the first and last pixel values of 0 in each row, and subtract the abscissa of the last pixel value of 0 from the abscissa of the first pixel value of 0 to obtain the diameter of the steel wire in this row. Finally, take the average value of the diameter values of these S1 rows to obtain the number of pixels L occupied by the steel wire in the picture.

[0030] The beneficial effects of the present invention are as follows:.

[0031] The present invention sets up a camera on the front of the wire rope to collect images of the wire rope without contact, and does not need to change the original structure of the mine hoist, thereby enhancing practicality; the method of the present invention directly monitors the wire rope instead of indirectly monitoring through a roller, effectively eliminating the error caused by the sliding of the wire rope and increasing the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying creative work.

[0033] Figure 1 It is the main diagram of the device layout of the present invention.

[0034] Figure 2 It is a rear view of the device arrangement of the present invention.

[0035] Figure 3 It is a top view of the device arrangement of the present invention.

[0036] Figure 4 This is a magnified view of the auxiliary light source and ambient light sensor.

[0037] Figure 5 It is a diagram of the method of the present invention for simultaneously measuring multiple steel wire ropes.

[0038] Figure 6 It is a preparation flow chart of the method of the present invention.

[0039] Figure 7 It is a pre-processing flow chart of the method of the present invention.

[0040] Figure 8 It is a key processing flow chart of the method of the present invention.

[0041] Fig. 9 It is a post-processing flow chart of the method of the present invention.

[0042] Among them: 1-background board; 2-wire rope; 3-industrial camera group; 4-network cable; 5-host computer processing module; 6-auxiliary light source; 7-ambient light sensor; 8-Y-axis slide rail groove; 9-X-axis slide rail groove; 10-mounting plate; 11-vertical bracket; 12-upper horizontal support plate; 13-lower horizontal support plate; 14-Z-axis slide column. DETAILED DESCRIPTION

[0043] 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.

[0044] like Figures 1 to 9 As shown, a monitoring device for the displacement and speed of a wire rope and a method for using the same; Figure 1-2 As shown, a monitoring device for the displacement and speed of a wire rope in this example comprises a background plate 1 arranged at the rear of the wire rope, two vertical brackets 11 corresponding to the wire rope, the upper and lower parts of the vertical brackets 11 are both provided with Y-direction slide rail grooves 8, an upper transverse support plate 12 and a lower transverse support plate 13 movable along the Y-direction slide rail grooves 8 are installed between the two vertical brackets 11, an X-direction slide rail groove 9 is correspondingly provided on the upper transverse support plate 12 and the lower transverse support plate 13, a Z-direction slide column 14 capable of sliding along the X-direction slide rail groove 9 is installed between the upper transverse support plate 12 and the lower transverse support plate 13, the upper part of the Z-direction slide column 14 extends out of the X-direction slide rail groove 9 of the upper transverse support plate 12 and is connected to a mounting plate 10, and a main camera 3-1 is installed on the mounting plate 10, Auxiliary light source 6, ambient light sensor 7, the Z-axis sliding column 14 is equipped with an auxiliary camera 3-2 that can slide along the Z-axis sliding column 14, the auxiliary camera 3-2 is fixed to the Z-axis sliding column 14 using the existing fixing method well known to those skilled in the art, which will not be described in detail here, the main camera 3-1 and the auxiliary camera 3-2 are electrically connected to the host computer processing module 5 through the network cable 4, the vertical bracket 11, the main camera 3-1, the auxiliary camera 3-2, the auxiliary light source 6, the ambient light sensor 7, the network cable 4, the host computer processing module 5, the Z-axis sliding column 14, and the mounting plate 10 of this example adopt existing products or structures well known to those skilled in the art, and the way they are connected to each other also adopts the existing connection method well known to those skilled in the art, which will not be described in detail here.

[0045] The X, Y and Z directions of this example are as follows Figure 1 The coordinate system shown defines the X, Y, and Z directions.

[0046] The background plate 1 is fixed on the back of the wire rope in an existing fixing method well known to those skilled in the art and corresponds to the main camera 3-1 and the auxiliary camera 3-2.

[0047] The background plate 1 is white, and the main camera 3-1 and the auxiliary camera 3-2 corresponding to a Z-direction sliding column 14 are a group of industrial cameras, and a group of industrial cameras corresponds to a wire rope.

[0048] This embodiment also provides a method for using the above device, which specifically includes the following steps:

[0049] (a) Adjust the positions of the main camera 3-1 and the auxiliary camera 3-2 so that they correspond to the wire rope; adjust the positions of the main camera 3-1 and the auxiliary camera 3-2 so that the diameter of the wire rope 2 occupies 30%-50% of the width of the picture; the distance between the auxiliary camera 3-2 and the main camera 3-1 is determined by technicians in this field based on the actual situation on site using existing technologies, and no specific restrictions are made here. The distance between the auxiliary camera and the main camera is mainly determined by the running speed of the wire rope on site and various parameters of the camera itself.

[0050] (b) using the main camera 3-1 and the auxiliary camera 3-2 to collect images of the wire rope 2 in real time;

[0051] (c) Take out two pictures taken by the main camera 3-1 and the auxiliary camera 3-2 respectively, and take the pictures taken at the same time as a group of pictures, and rotate the pictures so that the position of the wire rope 2 in the pictures is horizontal; after rotating the pictures so that the position of the wire rope 2 in the pictures is horizontal, the two rotated pictures in each group are grayed by Y=0.3R+0.59G+0.11B mapping: where Y is the gray value, R is the red value, G is the green value, and B is the blue value; [a11, a12, a13; a21, a22, a23; a31, a32, a33] is the unrotated state array, and [a11, a21, a31; a12, a22, a32; a13, a23, a33] is the transposed array after rotation;

[0052] (d) For the two images in each group, a region of interest is selected to obtain key points of the region of interest. The key points are compared to find the key points that match each other, and finally the rotation and displacement matrix is ​​obtained. The entire image is selected for the first matching of the region of interest. The subsequent matching is selected according to the pixel displacement g obtained last time. Assuming that the width of the first image is img1.cols, the image width of the second image is img2.cols, the region of interest of the first image is ROI1, and the region of interest of the second image is ROI2, then the horizontal coordinate of the region of interest ROI1 of the first image is img1.cols / 2+g to img1.cols / 2+2g, and the horizontal coordinate of the region of interest ROI2 of the second image is img1.cols / 2 to img1.cols / 2+g, and the vertical coordinate direction selects the total length of the image;

[0053] The method for finding key points in the region of interest is to perform a gradient operation on the two-dimensional coordinates of each point in the region. The method is as follows: the horizontal gradient lx of A(x, y) is lx = (px+1 - px-1) / 2, the vertical gradient ly is ly = (py+1 - py-1) / 2, the total gradient direction α = ly / lx, and the total gradient amplitude, where px+1 and px-1 are the pixel values of the next and previous pixel points in the horizontal direction of point A, and py+1 and py-1 are the pixel values of the next and previous pixel points in the vertical direction of point A. Assuming the gradient threshold is t, when both lx and ly are greater than t, then point A is a key point;

[0054] When matching key points, it is necessary to establish a feature description of the key points, which specifically includes: performing a gradient operation on 8 points in the neighborhood of the key point and itself, and then classifying them into 4 quadrants of the two-dimensional coordinate according to the direction. The sum of the gradients in each quadrant is the total amplitude of this quadrant. l1, l2, l3, and l4 are the total amplitudes of this key point in the first, second, third, and fourth quadrants respectively; comparing and matching the key points of two pictures. Assuming that point A and point B are the key points of two pictures respectively, l1, l2, l3, and l4 are the total amplitudes of point A in the first, second, third, and fourth quadrants, and l5, l6, l7, and l8 are the total amplitudes of point B in the first, second, third, and fourth quadrants. Then the Euclidean distance between the two points, assuming the amplitude threshold is F, when o < F, it is considered that these two points are the same key point;

[0055] (e) The second picture in each group is spliced with the first picture according to the rotation displacement matrix to obtain the total picture; when splicing the total picture, the array for placing the panoramic picture is composed of 0. There will be a slight rotation when the two pictures are matched and spliced, and there will be a black area that does not belong to the picture on the right side of the picture. By traversing the pixel values of the first row and the last row of the picture, the position of the point with pixel value 0 is obtained, and the part on the right of this position is cut off, and the remaining part is the spliced panoramic picture; when there is no point with pixel value 0 in the row pixels, then the average value c of the abscissa is replaced by the width value of the spliced picture;

[0056] (f) Traverse one row of pixels above and below the steel wire rope in each group of total images to obtain the position of the point where the first pixel value is 0; where a is the abscissa of the point where the first pixel value is 0 in the row pixels above the steel wire rope, and b is the abscissa of the point where the first pixel value is 0 in the row pixels below the steel wire rope; the average value c of the abscissas of the two pixel points is c = (a + b) / 2;

[0057] (g) The width of the first picture in each group is marked as d, and the displacement pixel between the two pictures relative to the world coordinate is g=cd; when calculating the displacement pixel g, three groups of main cameras 3-1 and auxiliary cameras 3-2 are used to correspond to three wire ropes to obtain three groups of displacement pixel values, and the three groups of displacement pixel values ​​are subtracted from each other to obtain the absolute values. If the three absolute values ​​obtained are all less than 2, then the average value of the three absolute values ​​is taken as the true value of the displacement pixel of the wire rope this time. If one absolute value is greater than 2, then the median of the three values ​​is taken as the true value of the displacement pixel of the wire rope this time. If two absolute values ​​are greater than 2, then the average value of the two pixel values ​​not greater than 2 is taken as the true value of the displacement pixel of the wire rope this time. If all three absolute values ​​are greater than 2, then the displacement value of the wire rope obtained this time is inaccurate, and then the picture of this time is removed, and the displacement pixel g is calculated using the previous picture of this time as the reference picture;

[0058] (h) The actual diameter of the steel wire rope is marked as H, and the number of pixels occupied by the steel wire rope in the image is marked as L; the actual displacement between the two images relative to the world coordinates is S = g*H / L; when marking the number of pixels occupied by the steel wire rope in the image, first use α0 as the threshold of the steel wire rope 2 image, change the pixel value of the part with a pixel value greater than α0 to 255, and change the pixel value of the part with a pixel value less than or equal to α0 to 0, then traverse the S1 rows of pixels in the middle of the image, find the positions where the first and last pixel values ​​of each row are 0, subtract the horizontal coordinate of the last pixel value of 0 from the horizontal coordinate of the first pixel value of 0 to obtain the diameter of the steel wire rope 2 in this row, and finally take the average of the diameter values ​​of this S1 row to obtain the number of pixels L occupied by the steel wire rope in the image;

[0059] (i) The camera acquisition frame rate is set to F; at this time, the actual speed of the wire rope v = S*e / F; e is the frame difference between each set of two pictures; the initial value of the frame difference e between each set of two pictures is 10, and the subsequent values ​​are determined by the calculated pixel displacement; the specific determination method is to set the standard pixel displacement to S0, when the obtained pixel displacement is less than S0, e = e+5, when the obtained pixel displacement is greater than S0, e = e-5, when e<0, e = 0, so as to adapt to the speed change of the wire rope;

[0060] (j) Create an index table by associating pixels with displacement and speed; put the video frame number, displacement value and speed value in each cycle into Excel for later retrieval and viewing of related pictures;

[0061] (k) Repeat steps (a)-(j) to obtain the displacement and velocity of the wire rope.

[0062] This embodiment sets up a camera on the front side of the wire rope to capture images of the wire rope without contact, and does not need to change the original structure of the mine hoist, thereby enhancing practicality. The method of the present invention directly monitors the wire rope instead of indirectly monitoring it through a drum, effectively eliminating the error caused by the sliding of the wire rope and increasing the measurement accuracy.

[0063] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for using a device for monitoring the displacement and speed of a wire rope, characterized in that: The device comprises a background plate (1) arranged at the rear of the steel wire rope, and two vertical brackets (11) corresponding to the steel wire rope, wherein the upper and lower parts of the vertical brackets (11) are both provided with Y-direction slide rail grooves (8), an upper transverse support plate (12) and a lower transverse support plate (13) movable along the Y-direction slide rail grooves (8) are installed between the two vertical brackets (11), an X-direction slide rail groove (9) is correspondingly arranged on the upper transverse support plate (12) and the lower transverse support plate (13), and a support plate capable of moving along the X-direction slide rail grooves is installed between the upper transverse support plate (12) and the lower transverse support plate (13). (9) a sliding Z-direction sliding column (14), the upper portion of the Z-direction sliding column (14) extending out of the X-direction sliding rail groove (9) of the upper transverse support plate (12) is connected to the outside of a mounting plate (10), the mounting plate (10) being mounted with a main camera (3-1), an auxiliary light source (6), and an ambient light sensor (7), the Z-direction sliding column (14) being mounted with an auxiliary camera (3-2) capable of sliding along the Z-direction sliding column (14), the main camera (3-1) and the auxiliary camera (3-2) being electrically connected to a host computer processing module (5) via a network cable (4), and the connection specifically comprises the following steps: (a) adjusting the positions of the main camera (3-1) and the auxiliary camera (3-2) so that the main camera (3-1) and the auxiliary camera (3-2) correspond to the wire rope; (b) using a main camera (3-1) and an auxiliary camera (3-2) to collect images of the steel wire rope (2) in real time; (c) taking out two pictures respectively captured by the main camera (3-1) and the auxiliary camera (3-2), taking the pictures captured at the same time as a group of pictures, and rotating the pictures so that the position of the wire rope (2) in the pictures is in a horizontal state; (d) Select the region of interest for the two images in each group, obtain the key points of the region of interest, compare the key points to find the key points that match each other, and finally obtain the rotation and displacement matrices; (e) The second image in each group is concatenated with the first image according to the rotation displacement matrix to obtain the total image; (f) Traverse a row of pixels above and below the wire rope in each group of total images to obtain the position of the first point with a pixel value of 0; where a is the horizontal coordinate of the first point with a pixel value of 0 in the row of pixels above the wire rope, and b is the horizontal coordinate of the first point with a pixel value of 0 in the row of pixels below the wire rope; the average value of the horizontal coordinates of the two pixel points is c=(a+b) / 2; (g) The width of the first image in each group is marked as d, and the displacement pixels between the two images relative to the world coordinates is g=cd; (h) The actual diameter of the wire rope is marked as H, and the number of pixels occupied by the wire rope in the image is marked as L; the actual displacement between the two images relative to the world coordinates is S=g*H / L; (i) The camera acquisition frame rate is set to F; the actual speed of the wire rope at this time is v=S*e / F; e is the frame difference between each set of two pictures; (j) Create an index table by associating pixels with displacement and speed; put the video frame number, displacement value and speed value in each cycle into Excel for later retrieval and viewing of related images; (k) Repeat steps (a)-(j) to obtain the displacement and velocity of the wire rope.

2. The method for using the device for monitoring the displacement and speed of a wire rope according to claim 1, characterized in that: The background plate (1) is white, and the main camera (3-1) and the auxiliary camera (3-2) corresponding to a Z-direction sliding column (14) are a group of industrial cameras, and a group of industrial cameras corresponds to a steel wire rope.

3. The method for using the device for monitoring the displacement and speed of a wire rope as claimed in claim 1, characterized in that: In step (a), the positions of the main camera (3-1) and the auxiliary camera (3-2) are adjusted so that the diameter of the steel wire rope (2) accounts for 30%-50% of the width of the image.

4. The method for using the device for monitoring the displacement and speed of a steel wire rope according to claim 1, characterized in that: In the step (c), after the image is rotated so that the position of the wire rope (2) in the image is horizontal, the two rotated images in each group are grayed using a Y=0.3R+0.59G+0.11B mapping: Y is the gray value, R is the red value, G is the green value, and B is the blue value; [a11, a12, a13; a21, a22, a23; a31, a32, a33] is the unrotated state array, and [a11, a21, a31; a12, a22, a32; a13, a23, a33] is the transposed array after rotation.

5. The method for using the device for monitoring the displacement and speed of a wire rope as claimed in claim 1, characterized in that: In step (i), the initial value of the frame difference e between each group of two pictures is 10, and the subsequent values ​​are determined by the calculated pixel displacement; the specific determination method is to set the standard pixel displacement to S0, when the obtained pixel displacement is less than S0, e=e+5, when the obtained pixel displacement is greater than S0, e=e-5, when e<0, e=0, so as to adapt to the speed change of the wire rope.

6. The method for using the device for monitoring the displacement and speed of a steel wire rope according to claim 1, characterized in that: In step (d), the entire image is selected for the first matching of the region of interest, and the subsequent matching is selected according to the pixel displacement g obtained last time. Assuming that the width of the first image is img1.cols, the image width of the second image is img2.cols, the region of interest of the first image is ROI1, and the region of interest of the second image is ROI2, then the horizontal coordinate of the region of interest ROI1 of the first image is img1.cols / 2+g to img1.cols / 2+2g, and the horizontal coordinate of the region of interest ROI2 of the second image is img1.cols / 2 to img1.cols / 2+g, and the vertical coordinate direction selects the total length of the image; The method for finding key points in the region of interest is to perform a two-dimensional coordinate gradient operation on each point in the region. The method is that the horizontal gradient of A (x, y) is lx=(px+1-px-1) / 2, the vertical gradient is ly=(py+1-py-1) / 2, the total gradient direction is α=ly / lx, and the total gradient amplitude is , where px+1 and px-1 are the pixel values ​​of the next and previous pixels in the horizontal direction of point A, py+1 and py-1 are the pixel values ​​of the next and previous pixels in the vertical direction of point A. Assuming the gradient threshold is t, when lx and ly are both greater than t, then point A is the key point; When matching key points, it is necessary to establish a feature description of the key points, which specifically includes: performing gradient operations on 8 points in the key point area and itself, and then classifying them by direction into 4 quadrants of the two-dimensional coordinate. The sum of the gradients in each quadrant is the total amplitude of this quadrant. l1, l2, l3, and l4 are the total amplitudes of this key point in the first, second, third, and fourth quadrants respectively; comparing and matching the key points of two pictures. Suppose point A and point B are the key points of two pictures, l1, l2, l3, and l4 are the total amplitudes of point A in the first, second, third, and fourth quadrants, and l5, l6, l7, and l8 are the total amplitudes of point B in the first, second, third, and fourth quadrants. Then the Euclidean distance between the two points , assuming that the amplitude threshold is F, when o < F, these two points are considered to be the same key point.

7. The method for using the device for monitoring the displacement and speed of a wire rope as claimed in claim 1, characterized in that: When stitching the total image in step (e), the array of the panoramic image constructed is composed of 0. There will be a slight rotation when the two images are matched and stitched, and a black area that does not belong to the image will appear on the right side of the image. By traversing the pixel values ​​of the first and last rows of the image, the position of the point with a pixel value of 0 is obtained, and the part to the right of this position is cut off, and the remaining part is the stitched panoramic image; when there is no point with a pixel value of 0 in the row of pixels, the average value c of the horizontal axis is replaced by the stitching image width value.

8. The method for using the device for monitoring the displacement and speed of a steel wire rope according to claim 1, characterized in that: When calculating the displacement pixel g in step (g), three groups of main cameras (3-1) and auxiliary cameras (3-2) are used to obtain three groups of displacement pixel values ​​corresponding to the three wire ropes. The three groups of displacement pixel values ​​are subtracted from each other to obtain absolute values. If the three absolute values ​​obtained do not exceed 2, then the average value of the three absolute values ​​is taken as the true value of the displacement pixel of the wire rope this time. If one absolute value is greater than 2, then the median of the three values ​​is taken as the true value of the displacement pixel of the wire rope this time. If two absolute values ​​are greater than 2, then the average value of the two pixel values ​​not greater than 2 is taken as the true value of the displacement pixel of the wire rope this time. If all three absolute values ​​are greater than 2, then the wire rope displacement value obtained this time is inaccurate, and then the current picture is removed, and the displacement pixel g is calculated using the previous picture of this time as the reference picture.

9. The method for using the device for monitoring the displacement and speed of a wire rope as claimed in claim 1, characterized in that: In step (h), when marking the number of pixels occupied by the steel wire rope in the image, firstly, the steel wire rope (2) image is thresholded with α0, and the pixel value of the part with a pixel value greater than α0 is changed to 255, and the pixel value of the part with a pixel value less than or equal to α0 is changed to 0, then the S1 rows of pixels in the middle of the image are traversed to find the positions where the first and last pixel values ​​of each row are 0, and the diameter of the steel wire rope (2) in this row is obtained by subtracting the horizontal coordinate of the last pixel value of 0 from the horizontal coordinate of the first pixel value of 0, and finally the diameter values ​​of this S1 row are averaged to obtain the number of pixels L occupied by the steel wire rope in the image.

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