Elevator guide rail straightness measurement device and method

Abstract

The present application discloses a device and method for measuring the straightness of an elevator guide rail, and relates to the field of elevator detection technology. The device comprises: a laser plumb line, a laser receiving board, an image acquisition module and an image processing module. The laser plumb line is arranged at the top of the elevator guide rail, the laser receiving board and the image acquisition module are arranged on the top of the car, the laser plumb line is used to emit a vertical laser, and the vertical laser is irradiated onto the laser receiving board to form a laser spot, the image acquisition module is used to continuously shoot a target image containing a laser spot and an elevator guide rail as the car moves, and the image processing module is used to sequentially extract the distance between the laser spot and the elevator guide rail in each of the target images, and determine the straightness of the elevator guide rail according to the change of each distance. The present application improves the detection accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of elevator detection, and in particular to a device and method for measuring the straightness of an elevator guide rail. Background Art

[0002] Elevators have become an indispensable special equipment in people's production and life, and the guide rails of elevators are an important part of elevators. In the long-term use process, the deformation of elevator guide rails is an important factor affecting the safe and stable operation of elevators. The traditional method of measuring the deformation of elevator guide rails mainly adopts the hanging wire measurement method, which uses the heavy hammer line of the wire as the straight line reference, and measures manually in sections. The number of measurement points is small, the measurement is difficult, and the measurement results are easily affected by wind force and subjective factors of operators.

[0003] In recent years, laser beams have been used instead of heavy hammer wires to improve detection accuracy and reduce detection difficulty. However, operators are still required to read the data, and the measurement results are easily affected by the operator's technical level. Summary of the invention

[0004] The purpose of the present application is to provide a device and method for measuring the straightness of an elevator guide rail, thereby improving the detection accuracy.

[0005] To achieve the above-mentioned purpose, the present application provides the following solutions: In the first aspect, the present application provides a device for measuring the straightness of an elevator guide rail, comprising: a laser plumb line, a laser receiving plate, an image acquisition module and an image processing module, wherein the laser plumb line is arranged at the top of the elevator guide rail, the laser receiving plate and the image acquisition module are arranged on the top of the car, the laser plumb line is used to emit a vertical laser, the vertical laser is irradiated onto the laser receiving plate to form a laser spot, the image acquisition module is used to continuously shoot a target image containing a laser spot and an elevator guide rail as the car moves, and the image processing module is used to sequentially extract the distance between the laser spot and the elevator guide rail in each of the target images, and determine the straightness of the elevator guide rail according to the change of each distance;

[0006] The image processing module includes an area of ​​interest determination unit, an edge detection unit, a false edge elimination unit and a distance calculation unit;

[0007] The region of interest determination unit is used to determine the laser region of interest and the elevator guide rail region of interest in the target image;

[0008] The edge detection unit is used to perform sub-pixel edge detection on the laser region of interest to obtain a first sub-pixel edge, and perform sub-pixel edge detection on the elevator guide rail region of interest to obtain a second sub-pixel edge;

[0009] The false edge elimination unit is used to convert the sub-pixel inner edge straight line coefficient in the pixel coordinate system in the first sub-pixel edge into the parameter of the point in the polar coordinate system through the coordinate space change to obtain a first group of points, and delete the noise points in the first group of points according to the Gaussian normal distribution characteristics of the first group of points to obtain a first set of remaining points; convert the sub-pixel inner edge straight line coefficient in the pixel coordinate system in the second sub-pixel edge into the parameter of the point in the polar coordinate system through the coordinate space change to obtain a second group of points, and delete the noise points in the second group of points according to the Gaussian normal distribution characteristics of the second group of points to obtain a second set of remaining points; fit the points in the first set of remaining points to obtain a first edge contour, and fit the points in the second set of remaining points to obtain a second edge contour;

[0010] The distance calculation unit is used to determine the distance between the center of the laser spot and the elevator guide rail in the horizontal direction of the center according to the first edge profile and the second edge profile.

[0011] In a second aspect, the present application provides a method for measuring the straightness of an elevator guide rail, which uses a device for measuring the straightness of an elevator guide rail, and comprises: continuously photographing a target image including a laser spot and an elevator guide rail as the elevator moves through an image acquisition module; extracting the distance between the laser spot and the elevator guide rail in each of the target images in turn through an image processing module, and determining the straightness of the elevator guide rail according to changes in each distance.

[0012] According to the specific embodiments provided by the present application, the present application discloses the following technical effects: the present application provides a device and method for measuring the straightness of an elevator guide rail, wherein a vertical laser is emitted by a laser plumb instrument to form a laser spot on a laser receiving plate, and an image acquisition module continuously shoots a target image containing a laser spot and an elevator guide rail as the elevator moves, and an image processing module sequentially extracts the distance between the laser spot and the elevator guide rail in each of the target images, and determines the straightness of the elevator guide rail according to the change in each distance, and performs image processing by edge detection and Gaussian normal distribution to remove noise pixels, thereby obtaining the straightness of the elevator guide rail and improving the detection accuracy. The method can realize automatic detection of the straightness of the elevator guide rail, reduce the influence of subjective factors of operators in manual measurement, realize high-precision measurement of the straightness of the guide rail, have strong data continuity, high restoration of the straightness of the guide rail, and operators do not need to perform detection when the car moves up and down, which is safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 A schematic diagram of the structure of a device for measuring the straightness of an elevator guide rail provided in one embodiment of the present application.

[0015] Figure 2 A schematic diagram of a region of interest provided in an embodiment of the present application.

[0016] Figure 3 A schematic diagram of the edge detection principle provided in one embodiment of the present application.

[0017] Figure 4 A schematic diagram of the position of a sub-pixel edge line provided in an embodiment of the present application.

[0018] Figure 5 A schematic diagram of coordinate system conversion provided in one embodiment of the present application.

[0019] Figure 6 A schematic flow chart of a method for measuring the straightness of an elevator guide rail provided in one embodiment of the present application.

[0020] Figure numerals: 1-laser plumb line, 2-elevator guide rail, 3-laser receiving board, 4-high-speed camera, 5-car, 6-elevator shaft civil structure. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0023] The present application provides a device for measuring the straightness of an elevator guide rail. Figure 1As shown, the measuring device for the straightness of the elevator guide rail includes: a laser plumb line 1, a laser receiving plate 3, an image acquisition module and an image processing module. The laser plumb line 1 is arranged at the top of the elevator guide rail 2, and the laser receiving plate 3 and the image acquisition module are arranged on the top of the car 5. The laser plumb line 1 is used to emit a vertical laser, and the vertical laser is irradiated on the laser receiving plate 3 to form a laser spot. The image acquisition module is used to continuously shoot a target image containing a laser spot and the elevator guide rail 2 as the car 5 moves. The image processing module is used to sequentially extract the distance between the laser spot and the elevator guide rail 2 in each of the target images, and determine the straightness of the elevator guide rail 2 according to the change of each distance.

[0024] The elevator guide rails 2 and the car 5 are both arranged in the elevator shaft civil structure 6.

[0025] In an exemplary embodiment, the image acquisition module is a high-speed camera 4. The laser spot received by the laser receiving plate 3 is circular. The distance between the laser spot and the elevator guide rail 2 in the target image is specifically the vertical distance between the laser spot and the elevator guide rail. The movement of the car 5 is a constant speed movement, and the image acquisition module continuously captures the target image containing the laser spot and the elevator guide rail 2 at a preset frequency. The specific position information of the elevator guide rail 2 can be obtained according to the time of capturing the image or other distance measuring instruments.

[0026] The present application uses a laser plumb meter 1 to emit a vertical laser to form a laser spot on a laser receiving plate 3. The image acquisition module continuously captures a target image including the laser spot and the elevator guide rail 2 as the elevator moves. The image processing module sequentially extracts the distance between the laser spot and the elevator guide rail 2 in each of the target images, and determines the straightness of the elevator guide rail 2 according to the change in each distance. The detection is convenient and simple, which solves the technical difficulties of the difficulty in continuous on-site measurement of the elevator guide rail 2 and the large measurement error in the prior art, reduces the influence of the operation risk and the technical level of the operator on the measurement result, can realize the continuous and automatic measurement of the guide rail straightness, shortens the detection time, and improves the work efficiency.

[0027] The specific process of using the elevator guide rail straightness measuring device of the present application to detect the elevator guide rail 2 is as follows: a laser plumb line 1 is installed at the top of the elevator guide rail 2 to be detected, the car 5 is parked at the other end of the elevator guide rail 2, and a laser receiving plate 3 is installed on the top of the elevator car 5. The laser receiving plate 3 is located on one side of the elevator guide rail 2. The straightness of the elevator guide rail 2 is subsequently measured according to the distance between the laser spot and the elevator guide rail 2; the position of the laser plumb line 1 and the receiving plate is adjusted so that the end of the vertical laser is irradiated on the laser receiving plate 3 and a circular laser spot is formed. A high-speed camera 4 is set up, and the parameters of the high-speed camera 4 are adjusted to obtain a clear image including the laser spot on the laser receiving plate 3 and the elevator guide rail 2, that is, the target image; as the car 5 moves at a constant speed, the high-speed camera 4 continuously collects the target image of the laser spot and the elevator guide rail 2, performs image processing on the area of ​​interest in the acquired target image, calculates the distance between the laser spot and the elevator guide rail 2 in real time, and obtains the continuous value of the straightness of the elevator guide rail 2.

[0028] The image processing module includes an area of ​​interest determination unit, an edge detection unit, a false edge elimination unit and a distance calculation unit.

[0029] The region of interest determination unit is used to determine a laser region of interest (ROI-Laser, RL) and an elevator guide rail region of interest (ROI-Guide rail, RG) in the target image. Figure 2 As shown in part (a), the elevator rail area of ​​interest is as follows Figure 2 As shown in part (b), by selecting two regions of interest and calculating the position of the laser spot center and the elevator guide rail 2 at the same time, the image processing efficiency is improved.

[0030] The edge detection unit is used to perform sub-pixel edge detection on the laser region of interest to obtain a first sub-pixel edge, and to perform sub-pixel edge detection on the elevator guide rail region of interest to obtain a second sub-pixel edge.

[0031] The edge detection unit of the present application performs edge detection on two regions of interest respectively. The pixel element is a light integration device. The main principle is to integrate the light intensity projected on a pixel of a fixed size area within a fixed time interval, and the output result is a sampled value of the light intensity. Pixel elements are, for example, charge coupled devices (CCD) or complementary metal oxide semiconductors (CMOS). Ideally, the edge projection of an object will divide the sub-pixel unit in which it is located into two parts with different light intensities, such as Figure 3 As shown in part (a), Figure 3The red dotted line in part (a) is the region of interest (ROI). So a reasonable assumption is that the light intensity of the sub-pixel unit through which the edge line passes conforms to the area-weighted average principle, which can be expressed as: .

[0032] in, is the area corresponding to the part with light intensity value C in the sub-pixel unit, is the area corresponding to the part with light intensity of O in the sub-pixel unit, h is the side length of the sub-pixel unit, . Further arrangement can be obtained: .

[0033] in, Sub-pixel The gray value of .

[0034] Based on the above principles, this application proposes an image sub-pixel edge detection algorithm. Before applying sub-pixel-based edge detection, the single edge pixel of the image is calculated using a traditional derivative mask, such as a partial derivative. After obtaining the single edge pixel of the image, the row differential of each sub-pixel is calculated. and column difference . Then according to , The size relationship of the pixels in the original image is intercepted to determine the intermediate parameters C, O, , , The value of finally determines the coefficient of the edge line and the specific position of the sub-pixel.

[0035] Assume that the expression of the edge line is: .

[0036] In an exemplary embodiment, in performing sub-pixel edge detection on the laser region of interest to obtain a first sub-pixel edge, the edge detection unit is specifically used to: extract a single edge pixel in the laser region of interest to obtain a first single edge pixel. Calculate the row difference and column difference of each sub-pixel in the first single edge pixel. According to the size relationship between the row difference and the column difference, pixel matrices of different specifications are intercepted from the corresponding position of the sub-pixel in the target image. Determine the coefficient of the edge line in the sub-pixel and the sub-pixel position of the edge line according to the pixel matrix, and each sub-pixel position constitutes a first sub-pixel edge.

[0037] According to the size relationship between the difference on the row and the difference on the column, pixel matrices of different specifications are intercepted from the corresponding position of the sub-pixel in the target image, specifically including: if , is the difference on the row, is the difference on the column, then the slope of the straight line is For the convenience of introduction, assume that the slope of the straight line is between (0, 1) and the sub-pixel points to be detected are , then the sub-pixel A 3×5 pixel matrix (i.e. Figure 3 ROI), establish Figure 3 In the coordinate system shown in part (b), the edge straight line divides the edge sub-pixel into two parts, with grayscale values ​​of C and O respectively, as shown in Figure 3 As shown in part (c).

[0038] Assumptions , , The sum of the grayscale values ​​of each column of pixels in the ROI satisfies the equation: , and 。

[0039] in, is the sum of the grayscale values ​​of the sub-pixels in the first column of the pixel matrix, is the sum of the grayscale values ​​of the sub-pixels in the second column of the pixel matrix, is the sum of the grayscale values ​​of the sub-pixels in the third column of the pixel matrix, is the coordinate of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, h is the side length of the sub-pixel unit, O is the first light intensity value, C is the second light intensity value, is the area on the side of the second light intensity value of the edge straight line in the first column of sub-pixels, is the area on the side of the second light intensity value of the edge straight line in the second column of sub-pixels, is the area on one side of the second light intensity value of the edge straight line in the third column of sub-pixels.

[0040] in, , , Respectively represent the area under the straight line of the sub-pixel edge of each column of the three columns of pixels in the ROI, then: ; ; .

[0041] According to the above formula, the coefficient can be calculated and The expression of ; .

[0042] Among them, the edge line is expressed as: , and are the coefficients of the edge lines, is the horizontal coordinate of the edge line, is the ordinate of the edge line.

[0043] Among them, C and O are unknown. Because the edge is affected by optical effects, the pixels at the edge of the structure are not two clear parts, and the pixel values ​​have a change process, such as Figure 3 As shown in (a) and (b). So the values ​​of C and O are obtained by the three pixels at the diagonal edges of the pixel matrix using the following method: ; .

[0044] like , at this time the slope of the straight line is , when the line is perpendicular to the horizontal axis, the slope b is infinite. For the convenience of calculation, a horizontal window is selected within this interval, and a 5×3 pixel matrix is ​​intercepted from the target image with the sub-pixel as the center. At this time, the edge line expression is: . Edge line expression The parameter calculation method is consistent with the above method.

[0045] In summary, according to the above calculation method and combined with pixel information, the coefficient of the edge line in each edge sub-pixel can be obtained. After obtaining the expression of the edge line, the intersection of the edge line and the y-axis is used as the corresponding sub-pixel position, such as Figure 4 As shown, the y-axis is The y-axis of the coordinate system with the origin at that point.

[0046] The method of performing sub-pixel edge detection on the elevator guide rail region of interest to obtain the second sub-pixel edge is the same as the method of performing sub-pixel edge detection on the laser spot region of interest to obtain the first sub-pixel edge.

[0047] Due to the influence of image noise and uneven background, the position of the edge line within the sub-pixel will rotate or shift to form a false edge, which affects the fitting of the real edge position of the structure. In the image space, the coefficient of the edge line within the sub-pixel (slope and intercept) changes little, and it is difficult to directly eliminate the false edge with existing methods. Therefore, the present application proposes a method for eliminating false edges within the sub-pixel of the image edge. In this method, the coefficient of the edge line within the sub-pixel in the pixel coordinate system in the image plane is converted into the parameters of the internal point of the polar coordinate system (polar angle and polar diameter) through the change of the coordinate space, and then the Gaussian normal distribution characteristics of the false edge of the image are combined to eliminate the false edge, thereby improving the accuracy of edge detection.

[0048] The false edge elimination unit is used to convert the sub-pixel inner edge straight line coefficients in the pixel coordinate system in the first sub-pixel edge into parameters of points in the polar coordinate system through a change in coordinate space to obtain a first group of points, and delete the noise points in the first group of points according to the Gaussian normal distribution characteristics of the first group of points to obtain a first set of remaining points; convert the sub-pixel inner edge straight line coefficients in the pixel coordinate system in the second sub-pixel edge into parameters of points in the polar coordinate system through a change in coordinate space to obtain a second group of points, and delete the noise points in the second group of points according to the Gaussian normal distribution characteristics of the second group of points to obtain a second set of remaining points; fit the points in the first set of remaining points to obtain a first edge contour, and fit the points in the second set of remaining points to obtain a second edge contour. The parameters of the points in the polar coordinate system include the polar angle θ and polar diameter ρ .

[0049] The specific principle of edge contour extraction by the false edge elimination unit is as follows: According to the Hough transform principle, the features of a straight line in the image space can be mapped to a point set in the parameter space under the polar coordinate system. In the image plane, the straight line in each sub-pixel can be expressed in the pixel coordinate system using the following formula: .

[0050] in, is the coordinate of the point in the pixel coordinate system, m and c are the slope and intercept of the straight line.

[0051] Then the formula Can be converted into the equation .

[0052] Each line in the image plane corresponds to a single point in parameter space These points in parameter space represent straight lines in the image plane. But there is a problem. It is impossible to describe a straight line perpendicular to the x-axis, i.e. . Parameters of a line in the image plane can be expressed in polar coordinates. m The angle between the straight line and the coordinate axis can be θ express, θ It is called the polar angle; intercept c The distance from the straight line to the origin in the polar coordinate system ρ express, ρ It is called the polar diameter.

[0053] By using the above method, the set of straight lines in the image plane is transformed into a set of points in the polar coordinate system, such as Figure 5 As shown. Figure 5 As shown in part (a), the straight line in the image space With straight line ,straight line He Zhi The slope and intercept of are quite different and intersect each other. Figure 5 As shown in part (b), the straight line in polar coordinate space ,straight line ,straight line He Zhi are converted to points ,point ,point and Point ,point With point ,point and Point It is divided into two areas (black dashed square area and black solid square area). Among them, the points formed by the straight lines with similar slope and intercept in the polar coordinate space More focused, called the normal point; point Areas far from normal points are called outliers. This provides a basis for eliminating false edges in the next step. So far, the false edges in the image space have been converted into outliers in the polar coordinate space.

[0054] Uneven background and image noise are the main factors that cause false edges in images, and the uneven background and image noise pixels are random variables and conform to the normal distribution law. Therefore, the offset and rotation angle of the edge line in the pixel caused by the noise also conform to the normal distribution. Therefore, the distribution law of points in the polar coordinate space obtained earlier also conforms to the normal distribution law. Assume that in the one-element array there is Number According to the properties of normal distribution, the mean of this one-element array is μ and variance δ It can be expressed as: ; .

[0055] According to the characteristics of normal distribution, The area contains 99.7% of the data. Therefore, it can be considered that the points not in this area are noise points.

[0056] In a two-dimensional array, the edge line parameters within the sub-pixel can be converted to polar angles through the coordinate space and polar diameter A two-dimensional array, and and It conforms to the normal distribution law, and the two-dimensional array is specifically the first group of points or the second group of points. Assume , ; , , m is the amount of data in the two-dimensional array. Then the joint probability density of the parameters of any edge line inside the region of interest is It is expressed as: .

[0057] in, All calculated and The formula is calculated as follows: Polar angle The mean of The polar diameter The mean of Polar angle The variance of The polar diameter The variance of .

[0058] According to the size of the probability value, it can be judged whether any point in the two-dimensional array is an outlier. Specifically, Points outside the region are noise points. Eliminating the outliers can eliminate the false edges caused by noise. After the false edges are eliminated, the sub-pixel edge lines of the structure are composed of the remaining points.

[0059] The first edge profile is a circular profile of the laser spot.

[0060] In the edge detection process, due to the influence of image noise, false edges are detected, which affects the accurate positioning of the laser and the guide rail. Therefore, a method for eliminating false edges in the edge detection process is proposed to improve the positioning accuracy.

[0061] The distance calculation unit is used to determine the distance between the center of the laser spot and the elevator guide rail 2 in the horizontal direction of the center according to the first edge contour and the second edge contour, specifically including respectively calculating the pixel average values ​​of the first edge contour and the second edge contour, and then calculating the real distance between the edges of the two regions of interest by the proportional factor method, determining the center of the laser spot according to the first edge contour, the pixel average value from the center of the laser spot to the second edge contour is the distance from the center of the laser spot to the elevator guide rail, determining the real distance according to the proportional factor, and determining the straightness by continuous real distances based on the center of the laser spot.

[0062] Since the elevator guide rail 2 includes two edges, the distance includes the distance between the center of the laser spot and one edge of the elevator guide rail 2, and the distance between the center of the laser spot and the other edge of the elevator guide rail 2. After calculating the distance between the center of the laser spot and the elevator guide rail 2 in the horizontal direction of the center, the actual distance is calculated using the proportional factor method, and a continuous curve of the straightness change is displayed through the actual distance calculated in real time.

[0063] The elevator guide rail straightness measuring device also includes a magnetic frame, which is attached to the elevator guide rail 2, and the laser plumb line 1 is installed on the magnetic frame, and the magnetic frame is used to adjust the direction of the laser output by the laser plumb line 1. The magnetic frame is a bracket with a magnetic suction cup, and the magnetic suction cup is tightly attached to the surface of the guide rail through magnetic force.

[0064] The laser receiving plate 3 is a back plate whose color is in sharp contrast with the color of the laser. For example, when the color of the laser output by the laser vertical collimator 1 is red, the color of the laser receiving plate 3 is white.

[0065] In an exemplary embodiment, the present application uses a laser spot as a straight line reference, and adopts a high-speed camera 4 installed on the top of the elevator car 5 and moving with the car 5 to continuously measure the target image. The image processing module calculates the distance from the laser spot to the elevator guide rail 2 in real time according to the target image captured by the image acquisition module in real time, thereby obtaining the continuous change of the straightness of the elevator guide rail 2 in real time.

[0066] Based on the same inventive concept, the embodiment of the present application also provides a method for measuring the straightness of an elevator guide rail used to implement the above-mentioned device for measuring the straightness of an elevator guide rail. The implementation scheme for solving the problem provided by the method is similar to the implementation scheme recorded in the above-mentioned device, so the specific limitations of one or more embodiments of the method for measuring the straightness of an elevator guide rail provided below can refer to the limitations of the device for measuring the straightness of an elevator guide rail above, and will not be repeated here.

[0067] In an exemplary embodiment, Figure 6As shown, a method for measuring the straightness of an elevator guide rail is provided. The method for measuring the straightness of an elevator guide rail uses the device for measuring the straightness of an elevator guide rail. The method for measuring the straightness of an elevator guide rail includes step 101 and step 102.

[0068] Step 101: Continuously capture target images including the laser spot and the elevator guide rails through an image acquisition module as the elevator moves.

[0069] Step 102: extracting the distance between the laser spot and the elevator guide rail in each of the target images in turn through an image processing module, and determining the straightness of the elevator guide rail according to the change of each distance.

[0070] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A device for measuring the straightness of an elevator guide rail, characterized in that: The device for measuring the straightness of the elevator guide rail comprises: a laser plumb line, a laser receiving plate, an image acquisition module and an image processing module, wherein the laser plumb line is arranged at the top of the elevator guide rail, the laser receiving plate and the image acquisition module are arranged on the top of the car, the laser plumb line is used to emit a vertical laser, the vertical laser is irradiated onto the laser receiving plate to form a laser spot, the image acquisition module is used to continuously shoot a target image containing a laser spot and the elevator guide rail as the car moves, and the image processing module is used to sequentially extract the distance between the laser spot and the elevator guide rail in each of the target images, and determine the straightness of the elevator guide rail according to the change of each distance; The image processing module includes an area of ​​interest determination unit, an edge detection unit, a false edge elimination unit and a distance calculation unit; The region of interest determination unit is used to determine the laser region of interest and the elevator guide rail region of interest in the target image; The edge detection unit is used to perform sub-pixel edge detection on the laser region of interest to obtain a first sub-pixel edge, and perform sub-pixel edge detection on the elevator guide rail region of interest to obtain a second sub-pixel edge; The false edge elimination unit is used to convert the sub-pixel inner edge straight line coefficient in the pixel coordinate system in the first sub-pixel edge into the parameter of the point in the polar coordinate system through the coordinate space change to obtain a first group of points, and delete the noise points in the first group of points according to the Gaussian normal distribution characteristics of the first group of points to obtain a first set of remaining points; convert the sub-pixel inner edge straight line coefficient in the pixel coordinate system in the second sub-pixel edge into the parameter of the point in the polar coordinate system through the coordinate space change to obtain a second group of points, and delete the noise points in the second group of points according to the Gaussian normal distribution characteristics of the second group of points to obtain a second set of remaining points; fit the points in the first set of remaining points to obtain a first edge contour, and fit the points in the second set of remaining points to obtain a second edge contour; The distance calculation unit is used to determine the distance between the center of the laser spot and the elevator guide rail in the horizontal direction of the center according to the first edge profile and the second edge profile.

2. The elevator guide rail straightness measuring device according to claim 1, characterized in that: In terms of performing sub-pixel edge detection on the laser region of interest to obtain a first sub-pixel edge, the edge detection unit is specifically used to: Extracting a single edge pixel in the laser region of interest to obtain a first single edge pixel; Calculating the row difference and column difference of each sub-pixel in the first single edge pixel; According to the magnitude relationship between the difference on the row and the difference on the column, pixel matrices of different specifications are intercepted from the corresponding position of the sub-pixel in the target image; The coefficients of the edge line in the sub-pixel and the sub-pixel positions of the edge line are determined according to the pixel matrix, and each sub-pixel position constitutes a first sub-pixel edge.

3. The device for measuring the straightness of elevator guide rails according to claim 2, characterized in that: According to the magnitude relationship between the difference on the row and the difference on the column, pixel matrices of different specifications are intercepted from the corresponding position of the sub-pixel in the target image, specifically including: like , then a 3×5 pixel matrix is ​​intercepted from the target image with the sub-pixel as the center; wherein, is the difference on the row, is the difference on the columns; like , a 5×3 pixel matrix is ​​intercepted from the target image with the sub-pixel as the center.

4. The device for measuring the straightness of elevator guide rails according to claim 3, characterized in that: when When determining the coefficient of the edge line in the sub-pixel and the sub-pixel position of the edge line according to the pixel matrix, specifically includes: The calculation formula of the coefficient of the edge line within the sub-pixel is: , ; Among them, the edge line is expressed as: , and are the coefficients of the edge lines, is the horizontal coordinate of the edge line, is the ordinate of the edge line; ； ； ； ； ； ； ； ； in, is the sum of the grayscale values ​​of the sub-pixels in the first column of the pixel matrix, is the sum of the grayscale values ​​of the sub-pixels in the second column of the pixel matrix, is the sum of the grayscale values ​​of the sub-pixels in the third column of the pixel matrix, is the coordinate of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, The coordinates are The grayscale value of the sub-pixel, h is the side length of the sub-pixel unit, O is the first light intensity value, C is the second light intensity value, is the area on the side of the second light intensity value of the edge straight line in the first column of sub-pixels, is the area on the side of the second light intensity value of the edge straight line in the second column of sub-pixels, is the area on one side of the second light intensity value of the edge straight line in the third column of sub-pixels; The intersection of the edge line and the y-axis is taken as the corresponding sub-pixel position. The y-axis of the coordinate system with the origin at that point.

5. The device for measuring the straightness of elevator guide rails according to claim 1, characterized in that: The device for measuring the straightness of the elevator guide rail also includes a magnetic frame, which is pasted on the elevator guide rail. The laser plumb line is installed on the magnetic frame, and the magnetic frame is used to adjust the direction of the laser output by the laser plumb line.

6. The device for measuring the straightness of elevator guide rails according to claim 1, characterized in that: When the color of the laser output by the laser plumb line instrument is red, the color of the laser receiving plate is white.

7. The device for measuring the straightness of elevator guide rails according to claim 1, characterized in that: The laser spot received by the laser receiving plate is circular.

8. The device for measuring the straightness of elevator guide rails according to claim 1, characterized in that: The image acquisition module is a high-speed camera.

9. A method for measuring the straightness of an elevator guide rail, characterized in that: The elevator guide rail straightness measurement method applies the elevator guide rail straightness measurement device according to any one of claims 1 to 8, and the elevator guide rail straightness measurement method comprises: The image acquisition module continuously captures the target image including the laser spot and the elevator guide rail as the elevator moves; The distance between the laser spot and the elevator guide rail in each target image is extracted in sequence by an image processing module, and the straightness of the elevator guide rail is determined according to the change of each distance.

Images