WO2022105676A1

WO2022105676A1 - Method and system for measuring wear of workpiece plane

Info

Publication number: WO2022105676A1
Application number: PCT/CN2021/130178
Authority: WO
Inventors: 王维林
Original assignee: 深圳市道通科技股份有限公司
Priority date: 2020-11-17
Filing date: 2021-11-12
Publication date: 2022-05-27
Also published as: CN112284256B; CN112284256A

Abstract

A method and system for measuring the wear of a workpiece plane. The method comprises: projecting laser rays onto a workpiece plane to be tested, and acquiring an image containing the laser rays (101); acquiring, according to the image, point cloud data related to the laser rays (102); determining, from the point cloud data, a consistency point set DSn located in a wear region, wherein DSn is a subset of Dn (103); performing fitting according to the consistency point set to obtain a reference line f(x,y) for representing the wear region (104); determining a rotation reference line f'(x',y') according to the slope of the reference line f(x,y) with respect to an x-axis, so that the slope of the rotation reference line f'(x',y'), with respect to the x-axis, is within an interval containing 0 (105); and determining the degree of wear of said workpiece plane according to the rotation reference line (106).

Description

Method and system for measuring plane wear of workpiece

This application claims the priority of the Chinese patent application filed on November 17, 2020 with the application number 202011287507.1 and the application title "A Method and System for Measuring Flat Wear of Workpieces", the entire contents of which are incorporated by reference in in this application.

technical field

The present application relates to the technical field of workpiece measurement, and in particular, to a method and system for measuring plane wear of a workpiece.

Background technique

Workpieces that are in contact with each other and move relative to each other often experience wear, for example, between a brake disc and a brake pad, and triangulation monocular laser ranging can be used to detect such wear. The specific detection principle is: the monocular laser ranging first shoots the target laser line through the camera, then extracts the laser line from the camera image, converts the image pixel coordinates into 3D point cloud data through projection transformation, and then analyzes the point cloud data. The measured distance information of the target is displayed. In point cloud data analysis, the position of the unworn point is usually used as the reference point, and the difference in laser projection depth between the worn area and the reference point is compared to obtain the wear information.

Since the method of determining the wear area from the point cloud data affects the accuracy of measuring the wear information of the brake disc, at present, how to accurately determine the wear area has become a technical problem to be solved urgently by those skilled in the art.

SUMMARY OF THE INVENTION

The purpose of the embodiments of the present invention is to provide a method and system for measuring the plane wear of a workpiece, which can accurately determine the unworn points and wear areas, thereby improving the measurement accuracy of the plane wear degree of the workpiece.

In a first aspect, an embodiment of the present invention provides a method for measuring plane wear of a workpiece, the method comprising:

Projecting a laser line to the plane of the workpiece to be inspected, and acquiring an image containing the laser line;

Acquire point cloud data related to the laser line according to the image; the point cloud data is the coordinate data sequence D _n projected by the laser line on the plane of the workpiece to be detected; wherein D _n ={d ₁ (x ₁ , y ₁ )...d _n (x _n , y _n )}, n is a positive integer, d _n (x _n , y _n ) indicates that the laser point d _n on the laser line is projected on the workpiece to be inspected The coordinates of the plane, x _n represents the x-axis coordinate corresponding to the laser point d _n when the length direction of the laser line is taken as the x-axis, and y _n represents the depth direction of the laser line set on the plane of the workpiece to be detected as the x-axis. On the y-axis, the y-axis coordinate corresponding to the laser point d _n ;

Determine the consistent point set DS _n in the wear area in the point cloud data; wherein, DS _n is a subset of D _n ;

Fitting a reference line f(x, y) for representing the wear area according to the set of consistency points;

According to the slope of the reference line f(x, y) with respect to the x-axis, the rotation reference line f'(x', y') is determined so that the rotation reference line f'(x', y') the slope with respect to the x-axis is in an interval containing 0;

According to the rotation reference line, the degree of wear of the plane of the workpiece to be measured is determined.

In some embodiments, the determined rotation reference line is calculated according to a rotation formula, and the rotation formula is:

in,

is the coordinate of each point in the rotation reference line f'(x', y'),

is the coordinate of each point in the reference line f(x, y), k is the slope of the reference line f(x, y) relative to the x-axis, θ is the reference line f(x, y) The angle of rotation relative to the x-axis.

In some embodiments, determining the degree of wear of the plane of the workpiece to be measured according to the rotation reference line includes:

determining an unworn point in the area where the rotation reference line is located;

Based on the unworn point and the rotation reference line, the depth of wear is determined.

In some embodiments, the determining an unworn point in the area where the rotation reference line is located includes:

The lowest point of the area below the rotation reference line is searched as the unworn point.

In some embodiments, determining the wear depth according to the unworn point and the rotation reference line includes:

From the unworn point, search to the center of the consistent point set, and use the point within the preset range of the rotation reference line as the wear point;

According to the worn point and the unworn point, the wear depth is determined.

In some embodiments, the determining of the wear depth according to the worn points and the unworn points includes:

According to the unworn point and the worn point, at least one of a maximum wear degree, an average wear degree or a wear consistency is determined.

In some embodiments, the determining wear consistency includes:

According to the wear point, determine the wear area;

determining the wear consistency information according to the curvature of the reference line and the discreteness of the point set corresponding to the wear area;

The wear consistency information is output.

In some embodiments, the determining the maximum degree of wear comprises:

obtain the coordinate information of the wear point;

When the ordinate of the wear point is the maximum value, determining the wear point as the maximum wear point;

The coordinate information corresponding to the maximum wear point is output as the maximum wear information.

In some embodiments, after determining the wear depth according to the unworn point and the rotation reference line, the method further includes:

When the wear depth exceeds a preset wear degree, output prompt information prompting the user to replace the workpiece to be inspected.

In some embodiments, the determining, in the point cloud data, a set of consistent points located in the wear area includes:

Searching for a continuous segment in the point cloud data whose loss function is less than a preset value and conforms to a preset length as a busbar;

Expand the coincidence point according to the busbar;

Eliminate singular points in the consistent points to obtain an initial point set;

Using the loss function to evaluate the consistency of the initial point set;

When the initial point set passes the consistency evaluation, the initial point set is used as the consistency point set.

In some embodiments, the step of searching the point cloud data for continuous segments whose loss function is smaller than a preset value and conforms to a preset length as a busbar includes:

In the point cloud data, start from the center of the point cloud data to both ends or from the two ends of the point cloud data to the center to search for continuous segments whose loss function is less than a preset value and conforms to a preset length as a busbar.

In some embodiments, expanding the coincidence point according to the bus includes:

Within the preset range of the busbar, calculate the Euclidean distance from the point within the preset range of the busbar to the busbar;

If the Euclidean distance is less than the preset distance, the corresponding point is combined with the bus bar to obtain a consistent point.

In some embodiments, the culling of singular points in the consistent points to obtain an initial set of points, including:

At least one singular point including discrete points and hole twill interference points in the consistent points is eliminated to obtain the initial point set.

In a second aspect, an embodiment of the present invention provides a system for measuring plane wear of a workpiece, the system comprising:

bracket;

a laser, which is fixed on the bracket, and the laser projects a laser line to the plane of the workpiece to be inspected;

a camera, fixed on the bracket, and the camera is used to collect an image containing the laser line;

at least one processor, and

a memory in communication with the at least one processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the at least one processor to cause the at least one processor The processor is capable of performing any of the methods described above.

In a third aspect, embodiments of the present invention provide a non-volatile computer-readable storage medium, where the computer-readable storage medium stores computer-executable instructions, when the computer-executable instructions are worn by the workpiece plane measurement system When executed, the measurement system for flat wear of the workpiece executes the method as described above.

The method and system for measuring plane wear of a workpiece according to the embodiments of the present invention use laser measurement technology to determine a set of consistent points located in the wear area in point cloud data, and fit a set of points representing the wear area according to the set of consistent points. and according to the slope of the reference line relative to the x-axis, determine the rotation reference line, so that the slope of the rotation reference line relative to the x-axis is within the interval including 0, and the effective and precise rotation Reference line; fit the wear area according to the rotation reference line, and determine the wear degree of the workpiece plane to be measured, thereby greatly improving the measurement accuracy.

Description of drawings

One or more embodiments are exemplified by the pictures in the corresponding drawings, and these exemplifications do not constitute limitations of the embodiments, and elements with the same reference numerals in the drawings are denoted as similar elements, Unless otherwise stated, the figures in the accompanying drawings do not constitute a scale limitation.

1 is a schematic structural diagram of a measuring system for plane wear of a workpiece according to an embodiment of the present invention;

2 is a schematic flow chart of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

3 is a schematic structural diagram of a laser line image of an embodiment of the method for measuring plane wear of a workpiece of the present invention;

4a is a schematic structural diagram of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

4b is a schematic structural diagram of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

5 is a schematic structural diagram of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

6a is a schematic structural diagram of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

6b is a schematic structural diagram of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

7a is a schematic structural diagram of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

7b is a schematic structural diagram of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

7c is a schematic structural diagram of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

8 is a schematic structural diagram of an embodiment of a method for measuring plane wear of a workpiece of the present invention;

FIG. 9 is a schematic diagram of the hardware structure of the controller in an embodiment of the workpiece plane wear measurement system of the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

A schematic structural diagram of a measurement system for workpiece plane wear provided by an embodiment of the present invention. As shown in FIG. 1 , the measurement system 10 for the plane wear of the workpiece includes a bracket; a laser 14 is fixed on the bracket, and the laser 14 projects a laser line to the plane of the workpiece to be inspected;

The camera 15 is fixed on the bracket, and the camera 15 is used for collecting images including the laser lines.

The measurement system 10 of workpiece plane wear may also include a display device 16 for displaying the degree of wear;

The power supply 17 is used to supply power to the laser 14, the camera 15 and the main control center.

It can be understood that the workpiece plane wear measurement system 10 can be implemented in various environments such as PCs, embedded systems, handheld devices, industrial control machines, etc. The workpiece plane wear measurement system 10 is provided with a controller as the main control center. , Accurate non-wear points and wear areas, thereby improving the measurement accuracy of the level of wear on the workpiece plane.

Please refer to FIG. 2. FIG. 2 is a schematic flowchart of a method for measuring plane wear of a workpiece provided by an embodiment of the present invention. The method can be executed by the controller 13 in the measuring system 10 for plane wear of a workpiece, and the method includes:

101: Project a laser line to the plane of the workpiece to be inspected, and acquire an image including the laser line.

When the workpiece plane wear measurement is performed on the workpiece to be inspected, a laser is used to project a laser line to the plane of the workpiece to be inspected, and a camera is used to capture an image including the laser line. The workpieces to be detected include brake discs and other workpieces that have wear characteristics after long-term use. The surface to be inspected in the workpiece to be inspected is substantially flat.

102: Acquire point cloud data related to the laser line according to the image; the point cloud data is the coordinate data sequence Dn projected by the laser line on the plane of the workpiece to be detected; wherein, Dn={d ₁ (x ₁ , y ₁ )...dn(x _n , y _n )}, n is a positive integer, d _n (x _n , y _n ) indicates that the laser point d _n on the laser line is projected on the plane of the workpiece to be detected x _n represents the x-axis coordinate corresponding to the laser point d _n when the length direction of the laser line is taken as the x-axis, y _n represents the depth direction of the laser line set on the plane of the workpiece to be detected as y axis, the y-axis coordinate corresponding to the laser point d _n .

In some embodiments, the acquired image including the laser line is shown in FIG. 3 , the image includes a black background area and a highlighted laser line area that is different from the black background area, and is determined according to the highlighted laser line area Point cloud data used to represent laser line coordinates.

In some embodiments, the highlighted laser line area can be divided into an edge area and a measurement area, and the edge area can also be called an edge interference area, as shown in FIG. 4a, wherein the laser line in the edge area is to be tested for the wear degree of the workpiece Therefore, the laser line area can be further processed, the edge area can be identified and eliminated, and only the measurement area is reserved for subsequent wear degree determination. The pixel points in the edge area can be eliminated by the adjacent point distance judgment method, the sorting method, the rebound detection method, and the like.

Specifically, in the method of judging the distance between adjacent points, since the distance between the edge area and the measurement area is relatively far in the projection direction of the laser line, the change is relatively severe. In the point cloud data obtained from the laser line area, the edge area is usually larger than the measurement area. The distance is usually smaller inside the measurement section, so the edge section can be separated by the distance difference.

In the sorting method, since the order of the coordinates of the points in the abscissa direction of the edge section is inconsistent with the order of the point sets in the measurement area in the abscissa direction, the edge section can be separated by this feature, as shown in Figure 4a, Separate the left edge segment.

In the rebound detection method, as shown in Figure 4b, the first lowest point lower than the reference line is usually not the reference point, but the interference data generated by the edge interference in the background laser line, which needs to be eliminated.

After removing the edge interference data, it can be determined that the effective reference point is close to the center of the point cloud, and has the feature of large rebound in the ordinate direction. According to this feature, the effective reference point as shown in Figure 4b can be identified.

As shown on the right side of Figure 6b, there are still incomplete reference points. When the reference point is not completely captured, the point cloud data is incomplete and incomplete. The position of the incomplete reference point is usually at the edge of the point cloud data sequence, and the point cloud data is incomplete. The longitudinal distance between them is relatively large, and the adjacent points are relatively small. The incomplete reference points can be identified according to the above characteristics. After the incomplete reference points are identified, the incomplete reference points cannot be used as the reference point for point cloud wear detection. Similarly, need to be removed.

In Fig. 4a and Fig. 4b, the image is mapped to the coordinate system in which the abscissa is the length direction of the laser line, and the ordinate is the depth of the laser line on the plane of the workpiece to be inspected. After the measurement area is determined, only the image of the measurement area can be processed and analyzed to determine the point cloud data of the laser line in the measurement area mapped in the coordinate system. Specifically, for example, the gray-scale centroid method can be used to analyze the pixel coordinates of the laser line in the measurement area. For the calculation formula of the pixel coordinates, refer to Formula 1:

Among them, W(i, j) represents the grayscale weight of the image pixel, i, j represent the horizontal and vertical coordinates of the pixel respectively, S represents the target area, and S(x ₀ , y ₀ ) represents the center of the target area. Pixel coordinates, k is a positive integer, indicating the kth point.

The gray-scale centroid method can be regarded as a weighted centroid method with the gray square as the weight. Using the gray-scale centroid method does not need to binarize the image, and has good results when the target and the background have a large grayscale gap. positioning effect.

It can be understood that the extraction of the laser line is not limited to the extraction by the gray-scale centroid method, and other methods other than the gray-scale centroid method, such as the centroid method, can also be used.

After the pixel coordinates S(x ₀ , y ₀ ) are extracted from the image, the pixel coordinates are converted into camera coordinates through projection transformation, so as to be converted into coordinates where the laser line is located, with reference to formula 2:

in,

Represents the three coordinates of the camera coordinates in the 3D plane, A represents the camera internal parameter matrix, C represents the camera coordinates, u represents the horizontal direction of the pixel coordinates, v represents the vertical direction of the pixel coordinates, and both u and v are scalars.

The direction of the projection transformation can be changed, the reference point is above, and the wear area is below, as shown in Figure 7a.

After getting the camera coordinates, convert the camera coordinates into laser coordinates, as shown in Equation 3:

in,

Three coordinates representing the camera coordinate system,

Represents the three coordinates of the laser coordinate system, R represents the rotation change matrix, C represents the camera coordinate system, L represents the laser coordinate system, and the camera coordinate system and the laser coordinate system coordinate origin coincide.

After converting to laser coordinates, since the point cloud data is a 3D laser coordinate system, based on the 3d laser coordinate system, only the coordinates of the laser line direction and the laser projection direction are retained, and the 2d point cloud data is obtained, as shown in Figure 5. The coordinate data sequence D _n of the laser line projected on the plane of the workpiece to be detected; wherein, Dn={d ₁ (x ₁ , y ₁ )...d _n (x _n , y _n )}, n is a positive integer, d _n (x _n , y _n ) represents the coordinates of the laser point d _n on the laser line projected on the plane of the workpiece to be detected, and x _n represents the laser point d _n when the length direction of the laser line is taken as the x-axis The corresponding x-axis coordinate, y _n represents the y-axis coordinate corresponding to the laser point d _n when the depth direction of the laser line is set on the plane of the workpiece to be detected as the y-axis. For example, as shown in FIG. 5, the horizontal direction identifies the x-axis direction, and the vertical direction identifies the y-axis direction. Among them, the mapping relationship between the image and the horizontal and vertical coordinates in Figure 4a, or the coordinate diagram in Figure 4b, can be understood as the point cloud map of the point cloud data or the coordinate map of the point cloud data, which is used to indicate the horizontal and vertical coordinates of the point cloud data. value.

103: Determine, in the point cloud data, a set of consistent points DS _n located in the wear area; where DS _n is a subset of D _n .

As shown in Figure 5, since the camera shooting angle may be inclined, in the point cloud image, the point cloud is not parallel to the abscissa axis in the abscissa direction, and it is difficult to find the measurement point and reference point from the original point cloud data. Therefore, , the point cloud data needs to be rotated into data parallel to the abscissa.

In some of the embodiments, the determining, in the point cloud data, a set of consistent points located in the wear area includes:

31: Search for a continuous segment in the point cloud data with a loss function smaller than a preset value and conforming to a preset length as a busbar.

During busbar exploration, since most of the positions in the wear area are relatively close in degree of wear, it can be considered that these points are all near a certain straight line. In the point cloud data, from the center of the point cloud data to the two The end or from the two ends of the point cloud data to the center to search for a continuous segment whose loss function is less than a preset value and conforms to a preset length as a busbar.

Specifically, the loss function is calculated according to Equation 4:

Among them, m and n are both positive integers, representing the mth groove, with n points, the shortest average Euclidean distance from the point to the straight line is calculated as the evaluation criterion, k represents the slope of the straight line fitted by the point set, through y=kx+ Point b obliquely represents the fitted straight line. The busbar is generally preferred to the point near the center of the point cloud position, because the degree of wear at this position is generally close. If there is no suitable busbar near the center of the wear area, you can search from both ends of the point cloud data. The initial length of the busbar is also critical. If it is too short, the consistency will be poor. If it is too long, the search failure probability will be high. In this scheme, the preset search length is preferably 10mm.

32: Expand the coincidence point according to the busbar.

In some of these embodiments, according to the bus expansion consistency, it may include:

A search range can be defined as the preset range of the bus, and then the Euclidean distance from the points within the preset range to the bus is calculated. If the Euclidean distance is less than the preset distance, the corresponding point and the bus will be combined. If the Euclidean distance If it is greater than the preset distance, it means that the points are farther apart, and then these points are crossed.

According to the Euclidean distance and the preset distance, a point with good consistency with the busbar within the preset range is searched, so as to effectively expand the consistent point.

It is understandable that other methods of non-average Euclidean distance can also be used when expanding the consistent points. As long as the methods can effectively expand the consistent points, they are all simple deformations and transformations of this case, and fall within the scope of protection in this case.

33: Eliminate singular points in the consistent points to obtain an initial point set.

In practical applications, the worn area may contain holes, patterns, or singularities such as edge reflections, which will cause distortion of the point cloud data. Therefore, when searching for consistent points, at least one singular point including discrete points and hole twill interference points in the consistent points is eliminated to obtain the initial point set.

As shown in Figure 6a and Figure 7c, discrete points may be misjudged as reference points due to uneven plane of the workpiece to be detected, target reflection, clutter, etc. The point cloud data may be misjudged as a reference point. The culling principle is usually considered based on factors such as the number of point sets, gradient changes, and data locations.

As shown in Figures 7b and 7c, the interference of the hole twill, usually the hole or pattern of the worn plane in the plane of the workpiece to be detected, will affect the continuity of the laser line, or the point cloud of the laser line will be distorted. Therefore, it needs to be eliminated. Hole twill interference point. The depth of holes or twill lines in the projection direction of the laser line is usually larger than that of the wear area. In the point cloud data, the coordinates are usually above the reference line, and the width is limited, and the changes are relatively drastic. Through the above characteristics, holes or twill lines can be identified. Then remove the hole twill interference point.

34: Use the loss function to perform consistency evaluation on the initial point set.

After obtaining the initial point set, use the loss function to evaluate the consistency of the initial point set, calculate the average Euclidean distance between each point in the initial point set and the bus, and determine whether the points in the initial point set pass the consistency evaluation according to the average Euclidean distance.

35: When the initial point set passes the consistency evaluation, use the initial point set as the consistency point set.

When the average Euclidean distance between each point in the initial point set and the busbar conforms to the preset distance, it can be determined that the initial point set passes the consistency evaluation, so that the initial point set that passes the consistency evaluation is used as the consistency point set.

When the average Euclidean distance between the points in the initial point set and the bus bar does not meet the preset distance, the steps of eliminating singular points in the consistent points are looped until all the points in the initial point set pass the consistency evaluation.

104: Fit a reference line f(x, y) for representing the wear area according to the set of consistency points.

After finding the consistent point set, the reference line f(x, y) used to represent the wear area is calculated by fitting. Usually the reference line f(x,y) is a straight line or a quadratic curve. In one case, since the camera shooting angle may be inclined, the reference line f(x,y) may have an included angle compared with the x-axis, that is, the reference line f(x,y) has a slope k, and the slope has May affect the accuracy of determining the degree of wear such as depth of wear, so before determining the degree of wear, the influence of this slope k should be eliminated so that the reference line is roughly parallel to the x-axis.

105: Determine a rotation reference line f'(x', y') according to the slope of the reference line f(x, y) relative to the x-axis, so that the rotation reference line f'(x', y ') with respect to the slope of the x-axis in an interval containing 0.

The reference line f(x, y) used to represent the wear area is calculated by the method of fitting. The slope of the reference line f(x, y) is k, and according to the slope k of the reference line f(x, y) relative to the x-axis, the rotation reference line f'(x', y') is determined according to the rotation formula Calculation, the rotation formula is as formula 5:

in,

is the coordinate of each point in the rotation reference line f'(x', y'),

After the coordinate transformation, the transformed coordinate point set can be used to simulate the rotation reference line, which can be simulated as a quadratic curve or a straight line, which is not limited here. In the simulated rotation reference line, the slope of any line end is 0 or less than the allowable threshold, so that the rotation reference line is roughly parallel to the x-axis of the point cloud.

The rotation reference line, usually a quadratic curve can be used, which is closer to the actual wear situation and meets the application requirements.

As shown in Figure a in Figure 7, it is the rotated point cloud.

106: Determine the wear degree of the plane of the workpiece to be measured according to the rotation reference line.

In some of the embodiments, determining the degree of wear of the plane of the workpiece to be measured according to the rotation reference line may include:

Specifically, as shown in FIG. 7a, the worn area usually occupies a relatively large area, and determining an unworn point in the area where the rotation reference line is located may include: searching for the lowest point of the area lower than the rotation reference line as the unworn point wear point. Then, based on the unworn point and the rotation reference line, the wear depth is determined.

In some of the embodiments, determining the wear depth according to the unworn point and the rotation reference line may include:

Searching from the unworn point to the center of the consistent point set, and taking the point within the preset range of the rotation reference line as the wear point;

According to the worn point and the unworn point, the wear depth is determined.

The worn area usually occupies a relatively large area, and the search starts from the unworn point, that is, the reference line, to the center of the consistency point set, and the point near the rotation reference line or above the rotation reference line is used as the wear point.

In some of the embodiments, the wear depth is determined according to the wear point and the non-wear point, which may include:

In some of these embodiments, determining wear uniformity includes:

According to the wear point, determine the wear area;

The wear consistency information is output.

The set of multiple wear points can be determined as the wear area. The smaller the curvature of the reference line, the better the consistency, and the smaller the discreteness of the point set, the better the consistency. Equation 4 can be used to determine the discreteness of the point set.

After the wear consistency information is determined, the wear consistency information is output so that the user can obtain the consistency information.

In some of these embodiments, determining the maximum degree of wear includes:

obtain the coordinate information of the wear point;

As shown in FIG. 8 , the position with the largest ordinate in FIG. 8 can be considered as the maximum wear point and the corresponding area, then the coordinate information corresponding to the maximum wear point is output, so that the user can obtain the maximum wear point information.

In some of the embodiments, after determining the wear depth according to the unworn point and the rotation reference line, the method further includes:

A preset wear degree can be set. When the preset wear degree exceeds the preset wear degree, it means that the workpiece is too worn and it is inconvenient for continued use, and a prompt message prompting the user to replace the workpiece to be inspected is output.

In the embodiment of the present invention, laser measurement technology is used, and an intelligent method is used to measure plane wear, and a local search method is used to determine the set of consistent points located in the wear area in the point cloud data, and fit the set according to the set of consistent points. The reference line used to represent the wear area is effectively accurate reference line; and the rotation reference line is determined according to the slope of the reference line relative to the x-axis, so that the slope of the rotation reference line relative to the x-axis is within the range including 0. In the interval, the reference line is effectively and accurately rotated; according to the rotation reference line, the wear degree of the workpiece plane to be measured is determined, thereby greatly improving the measurement accuracy, and the embodiment of the present invention can meet the measurement requirements of most scenarios.

9 is a schematic diagram of the hardware structure of the controller in an embodiment of the workpiece plane wear measurement system 10. As shown in FIG. 9, the controller 13 includes:

One or more processors 131 , memory 132 . In FIG. 9 , one processor 131 and one memory 132 are used as examples.

The processor 131 and the memory 132 may be connected by a bus or in other ways, and the connection by a bus is taken as an example in FIG. 9 .

As a non-volatile computer-readable storage medium, the memory 132 can be used to store non-volatile software programs, non-volatile computer-executable programs and modules, such as corresponding to the method for measuring the plane wear of the workpiece in the embodiment of the present application. program instructions/modules. The processor 131 executes various functional applications and data processing of the controller by running the non-volatile software programs, instructions and modules stored in the memory 132, that is, to implement the method for measuring the plane wear of the workpiece in the above method embodiments.

The memory 132 may include a stored program area and a stored data area, wherein the stored program area may store an operating system, an application program required for at least one function; the stored data area may store data created according to the use of a measurement system for workpiece plane wear, etc. . Additionally, memory 132 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device. In some embodiments, the memory 132 may optionally include memory located remotely from the processor 131, and these remote memories may be connected via a network to the workpiece flat wear measurement system. Examples of such networks include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

The one or more modules are stored in the memory 132, and when executed by the one or more processors 131, execute the method for measuring the plane wear of the workpiece in any of the above method embodiments, for example, execute the above-described method Method steps 101 to 106 in FIG. 2 .

The above product can execute the method provided by the embodiments of the present application, and has functional modules and beneficial effects corresponding to the execution method. For technical details not described in detail in this embodiment, reference may be made to the methods provided in the embodiments of this application.

Embodiments of the present application provide a non-volatile computer-readable storage medium, where the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are executed by one or more processors, for example, in FIG. 9 A processor 131 of the above-mentioned one or more processors can execute the method for measuring the plane wear of the workpiece in any of the above-mentioned method embodiments, for example, to execute the above-described method steps 101 to 106 in FIG. 2 .

The device embodiments described above are only illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in One place, or it can be distributed over multiple network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

From the description of the above embodiments, those of ordinary skill in the art can clearly understand that each embodiment can be implemented by means of software plus a general hardware platform, and certainly can also be implemented by hardware. Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and the program can be stored in a computer-readable storage medium. During execution, it may include the processes of the embodiments of the above-mentioned methods. The storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM), or a random access memory (Random Access Memory, RAM) or the like.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, The steps may be carried out in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the invention has been The skilled person should understand that it is still possible to modify the technical solutions recorded in the foregoing embodiments, or to perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the implementation of the present invention. scope of technical solutions.

Claims

A method for measuring plane wear of a workpiece, characterized in that the method comprises:

Projecting a laser line to the plane of the workpiece to be inspected, and acquiring an image containing the laser line;

Acquire point cloud data related to the laser line according to the image; the point cloud data is the coordinate data sequence D n projected by the laser line on the plane of the workpiece to be detected; wherein D n ={d 1 (x 1 , y 1 )...d n (x n , y n )}, n is a positive integer, d n (x n , y n ) indicates that the laser point d n on the laser line is projected on the workpiece to be inspected The coordinates of the plane, x n represents the x-axis coordinate corresponding to the laser point d n when the length direction of the laser line is taken as the x-axis, and y n represents the depth direction of the laser line set on the plane of the workpiece to be detected as the x-axis. On the y-axis, the y-axis coordinate corresponding to the laser point d n ;

Determine the consistent point set DS n in the wear area in the point cloud data; wherein, DS n is a subset of D n ;

Fitting a reference line f(x, y) for representing the wear area according to the set of consistency points;

According to the slope of the reference line f(x, y) with respect to the x-axis, the rotation reference line f'(x', y') is determined so that the rotation reference line f'(x', y') the slope with respect to the x-axis is in an interval containing 0;

According to the rotation reference line, the degree of wear of the plane of the workpiece to be measured is determined.
The method according to claim 1, wherein the determined rotation reference line is calculated according to a rotation formula, and the rotation formula is:

in,
is the coordinate of each point in the rotation reference line f'(x', y'),
is the coordinate of each point in the reference line f(x, y), k is the slope of the reference line f(x, y) relative to the x-axis, θ is the reference line f(x, y) The angle of rotation relative to the x-axis.
The method according to claim 1, wherein the determining the degree of wear of the plane of the workpiece to be measured according to the rotation reference line comprises:

determining an unworn point in the area where the rotation reference line is located;

Based on the unworn point and the rotation reference line, the depth of wear is determined.
The method according to claim 3, wherein the determining an unworn point in the area where the rotation reference line is located comprises:

The lowest point of the area below the rotation reference line is searched as the unworn point.
The method according to claim 3, wherein the determining the wear depth according to the unworn point and the rotation reference line comprises:

From the unworn point, search to the center of the consistent point set, and use the point within the preset range of the rotation reference line as the wear point;

According to the worn point and the unworn point, the wear depth is determined.
The method according to claim 3, wherein the determining the wear depth according to the worn point and the unworn point comprises:

According to the unworn point and the worn point, at least one of a maximum wear degree, an average wear degree or a wear consistency is determined.
The method according to claim 6, wherein the determining the wear consistency comprises:

According to the wear point, determine the wear area;

determining the wear consistency information according to the curvature of the reference line and the discreteness of the point set corresponding to the wear area;

The wear consistency information is output.
The method according to claim 1, wherein the determining the maximum degree of wear comprises:

obtain the coordinate information of the wear point;

When the ordinate of the wear point is the maximum value, determining the wear point as the maximum wear point;

The coordinate information corresponding to the maximum wear point is output as the maximum wear information.
The method according to claim 3, wherein after determining the wear depth according to the unworn point and the rotation reference line, the method further comprises:

When the wear depth exceeds a preset wear degree, output prompt information prompting the user to replace the workpiece to be inspected.
The method according to any one of claims 1 to 9, wherein the determining, in the point cloud data, a set of consistent points located in the wear area comprises:

Searching for a continuous segment in the point cloud data whose loss function is less than a preset value and conforms to a preset length as a busbar;

Expand the coincidence point according to the busbar;

Eliminate singular points in the consistent points to obtain an initial point set;

Using the loss function to evaluate the consistency of the initial point set;

When the initial point set passes the consistency evaluation, the initial point set is used as the consistency point set.
The method according to claim 10, wherein the searching for continuous segments in the point cloud data whose loss function is smaller than a preset value and conforms to a preset length as a busbar comprises:

In the point cloud data, start from the center of the point cloud data to both ends or from the two ends of the point cloud data to the center to search for continuous segments whose loss function is less than a preset value and conforms to a preset length as a busbar.
The method according to claim 10, wherein the expanding the coincidence point according to the bus bar comprises:

Within the preset range of the busbar, calculate the Euclidean distance from the point within the preset range of the busbar to the busbar;

If the Euclidean distance is less than the preset distance, the corresponding point is combined with the bus bar to obtain a consistent point.
The method according to claim 10, wherein the removing singular points in the consistent points to obtain an initial point set, comprising:

At least one singular point including discrete points and hole twill interference points in the consistent points is eliminated to obtain the initial point set.
A measurement system for workpiece plane wear, characterized in that the system comprises:

bracket;

a laser, which is fixed on the bracket, and the laser projects a laser line to the plane of the workpiece to be inspected;

a camera, fixed on the bracket, and the camera is used to collect an image containing the laser line;

at least one processor, and

a memory in communication with the at least one processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the at least one processor to cause the at least one processor The processor is capable of performing the method of any of claims 1-13.
A non-volatile computer-readable storage medium, characterized in that, the computer-readable storage medium stores computer-executable instructions, when the computer-executable instructions are executed by the workpiece plane wear measurement system, make the A measurement system for flat wear of a workpiece performs the method of any one of claims 1-13.