Method, device and storage medium for surveying and mapping bridge arch rib linear shape

Abstract

The present invention relates to the technical field of bridge surveying and mapping, and discloses a method, device, and storage medium for surveying and mapping the arch rib linear shape of a bridge. The surveying and mapping method comprises: obtaining original arch rib point cloud data; obtaining downsampled arch rib point cloud data, extracting skeleton points of the downsampled arch rib point cloud; calculating a coarse fitting curve of the arch rib linear shape of the bridge, and dividing the downsampled arch rib point cloud into a plurality of arch rib segments using the coarse fitting curve; constructing a constraint model of the arch rib segment using the downsampled arch rib point cloud, identifying undownsampled point cloud segments under the constraints of the constraint model, and obtaining linear feature points of the undownsampled point cloud segments; and integrating the linear feature points of the plurality of undownsampled point cloud segments to obtain a complete linear feature point set containing the arch rib linear shape. The present invention obtains the arch rib linear curve of the bridge under survey by fitting the linear feature point set containing the arch rib linear shape, thereby having high surveying and mapping accuracy and replacing manual surveying and mapping.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge surveying and mapping, and in particular to a method, device and storage medium for surveying and mapping the linear shape of a bridge arch rib. Background Art

[0002] The safety and stability of bridges are key factors in ensuring the normal operation of transportation. As an important part of bridge surveying and mapping projects, the surveying of bridge arch rib lines is of great importance for the structural evaluation and maintenance of bridges.

[0003] Currently, the arch rib alignment of bridges is mostly measured manually. However, the arch ribs of some bridges have large spans, making manual measurement difficult. As a result, the accuracy of the arch rib alignment obtained by manual measurement is not high.

[0004] In view of this, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method, device and storage medium for surveying the linear shape of bridge arch ribs, aiming to improve the surveying accuracy of the linear shape of bridge arch ribs.

[0006] The technical solutions adopted by the present invention to solve the technical problems are as follows:

[0007] In a first aspect, the present invention provides a method for surveying and mapping the linear shape of a bridge arch rib, the method comprising:

[0008] Obtaining original point cloud data of the arch rib linear shape of the bridge, and performing segmentation processing on the obtained original point cloud data to obtain original arch rib point cloud data;

[0009] The original arch rib point cloud data is downsampled to obtain downsampled arch rib point cloud data, and skeleton points of the downsampled arch rib point cloud are extracted;

[0010] A rough fitting curve of the arch rib line shape of the bridge is calculated by downsampling the skeleton points of the arch rib point cloud, and the downsampling arch rib point cloud is divided into several arch rib segments by the rough fitting curve;

[0011] A constraint model of the arch rib segment is constructed by downsampling the arch rib point cloud, and the undownsampled point cloud segment is identified under the constraint conditions of the constraint model. The arch rib component point cloud containing the arch rib linear shape is extracted from the undownsampled point cloud segment of each arch rib segment, and the arch rib component point cloud is transformed into a coordinate system to obtain the linear feature points of the undownsampled point cloud segment;

[0012] By integrating the linear feature points of several un-downsampled point cloud segments, a complete linear feature point set containing the arch rib linear shape is obtained.

[0013] In one implementation, obtaining the original point cloud data of the arch rib linear shape of the bridge specifically includes:

[0014] The arch ribs of the bridge are laser scanned using a 3D laser scanner to record the original point cloud data of the arch rib linear shape of the bridge.

[0015] In one implementation, downsampling the original arch rib point cloud data to obtain downsampled arch rib point cloud data, and extracting skeleton points of the downsampled arch rib point cloud, specifically includes:

[0016] The downsampled arch rib point cloud data is obtained by eliminating data other than the arch rib point cloud data having original features from the original arch rib point cloud data;

[0017] Establish a spatial rectangular coordinate system OXYZ and perform coordinate system transformation on the downsampled arch rib point cloud;

[0018] The downsampled arch rib point cloud is coarsely segmented along the longitudinal direction, and the centroid point of each coarse segment is extracted as the skeleton point of the downsampled arch rib point cloud.

[0019] In one implementation, a coarse fitting curve of the arch rib line shape of the bridge is calculated by downsampling the skeleton points of the arch rib point cloud, and the downsampling arch rib point cloud is divided into a plurality of arch rib segments by the coarse fitting curve, specifically including:

[0020] By performing plane projection on the skeleton points of the downsampled arch rib point cloud, the two-dimensional points of the downsampled arch rib point cloud are obtained, and function fitting is performed on the two-dimensional points of the downsampled arch rib point cloud. The expression of the fitting function is:

[0021] Z=aX 2 +bX+c,

[0022] Where Z represents the vertical coordinate value, X represents the longitudinal coordinate value, a represents the quadratic term coefficient of the fitting function, b represents the linear term coefficient of the fitting function, and c represents the constant of the fitting function;

[0023] A rough fitting curve of the arch rib line shape of the bridge in the spatial rectangular coordinate system OXYZ is obtained by the expression of the fitting function, and the downsampled arch rib point cloud is divided into several arch rib segments of equal length based on the rough fitting curve.

[0024] In one implementation, constructing a constraint model of the arch rib segment by downsampling the arch rib point cloud specifically includes:

[0025] Constraints of the arch rib segment are set by downsampling the arch rib point cloud. The constraints include the type of the arch rib component of the bridge. A constraint model of the arch rib segment is constructed based on the constraints.

[0026] In one implementation, the types of arch rib members of the bridge include arch rib members with a circular cross-section and arch rib members with a rectangular cross-section.

[0027] In one implementation, performing coordinate system conversion on the point cloud of the arch rib component specifically includes:

[0028] The coordinate system transformation formula for the point cloud of an arch rib component with a circular cross section is:

[0029] P'=(P1-T1)·R1,

[0030]

[0031] Among them, P1 represents the point cloud matrix of the lower chord after the point cloud coordinate system of the arch rib component with a circular cross section is transformed; T1 represents the first coordinate translation matrix; R1 represents the first coordinate rotation matrix;

[0032] The coordinate system transformation formula for the point cloud of an arch rib component with a rectangular cross section is:

[0033] P"=(P2-T2)·R2,

[0034]

[0035] Among them, P2 represents the point cloud matrix of the lower surface of the plate arch after the coordinate system of the arch rib component of the rectangular mid-plane mathematical model is transformed; T2 represents the second coordinate translation matrix; R2 represents the second coordinate rotation matrix.

[0036] In one implementation, the surveying method further includes: fitting the arch rib linear curve of the bridge under survey using a complete linear feature point set including the arch rib linear curve.

[0037] In a second aspect, the present invention provides a device for surveying and mapping the linear shape of a bridge arch rib, comprising: a memory and a processor, wherein the memory stores a surveying and mapping program for the linear shape of a bridge arch rib; and when the surveying and mapping program for the linear shape of a bridge arch rib is executed by the processor, it is used to implement the operation of the surveying and mapping method for the linear shape of a bridge arch rib.

[0038] In a third aspect, the present invention provides a storage medium, which includes a computer-readable storage medium, and the storage medium stores a surveying and mapping program for the straight line of a bridge arch rib. When the surveying and mapping program for the straight line of a bridge arch rib is executed by a processor, it is used to implement the operation of the surveying and mapping method for the straight line of a bridge arch rib.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present application provides a method for surveying and mapping the arch rib linear shape of a bridge, wherein the surveying and mapping method comprises the following steps: obtaining original point cloud data of the arch rib linear shape of the bridge, segmenting the obtained original point cloud data to obtain original arch rib point cloud data; performing downsampling processing on the original arch rib point cloud data to obtain downsampled arch rib point cloud data, and extracting skeleton points of the downsampled arch rib point cloud; calculating a coarse fitting curve of the arch rib linear shape of the bridge through the skeleton points of the downsampled arch rib point cloud, and dividing the downsampled arch rib point cloud into the coarse fitting curve; The cloud is divided into several arch rib segments; a constraint model of the arch rib segment is constructed by downsampling the arch rib point cloud, and the undownsampled point cloud segments are identified under the constraints of the constraint model. The arch rib component point cloud containing the arch rib linear shape is extracted from the undownsampled point cloud segment of each arch rib segment, and the arch rib component point cloud is converted into a coordinate system to obtain the linear feature points of the undownsampled point cloud segment; the linear feature points of several undownsampled point cloud segments are integrated to obtain a complete linear feature point set containing the arch rib linear shape. This application obtains the arch rib linear curve of the bridge under measurement by fitting the linear feature point set containing the arch rib linear shape, which has high surveying and mapping accuracy and replaces manual surveying and mapping. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 the structures shown in these drawings without paying any creative work.

[0042] Figure 1 A flow chart of the method for surveying and mapping the bridge arch rib alignment provided by the present invention;

[0043] Figure 2 This is a structural diagram of the bridge;

[0044] Figure 3 Schematic diagram of the structure of a bridge equipped with a 3D laser scanner station and targets, wherein: Figure (a) is a front view of the bridge under measurement, and Figure (b) is a top view of the bridge under measurement;

[0045] Figure 4 This is a schematic diagram of the original point cloud data of the bridge;

[0046] Figure 5 This is a schematic diagram of the coordinate system for the original data of the bridge arch rib line shape;

[0047] Figure 6 Schematic diagram of the coordinate system for the coarse segmentation of the bridge arch rib point cloud along the longitudinal direction;

[0048] Figure 7Schematic diagram of the coordinate system of the skeleton points of the downsampled arch rib point cloud;

[0049] Figure 8 Schematic diagram of the coordinate system of the rough fitting curve of the arch rib line shape of the bridge fitted with skeleton points;

[0050] Figure 9 Schematic diagram of the coordinate system for dividing the downsampled arch rib point cloud into arch rib segments of equal length;

[0051] Figure 10 It is a schematic diagram of the coordinate system of the complete set of linear feature points including the arch rib linear shape;

[0052] Figure 11 This is a schematic diagram of the partial structure of the arch rib component of the bridge;

[0053] Figure 12 This is a schematic diagram of the arch rib line shape of the bridge from the first perspective;

[0054] Figure 13 This is a schematic diagram of the arch rib line shape of the bridge from the second perspective;

[0055] Figure 14 Schematic diagram of identifying arch rib components with circular cross sections from arch rib segment point clouds;

[0056] Figure 15 Schematic diagram of extracting arch rib linear points from the bottom chord point cloud;

[0057] Figure 16 Schematic diagram of extracting arch rib linear points from the lower surface point cloud;

[0058] Figure 17 Schematic diagram of the point cloud of the lower surface of an arch rib component with a rectangular cross section;

[0059] Figure 18 This is a functional principle diagram of the bridge arch rib linear surveying device provided by the present invention.

[0060] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0061] The present application provides a method, device, and storage medium for mapping the alignment of bridge arch ribs. To clarify the purpose, technical solutions, and effects of this application, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are intended only to illustrate this application and are not intended to limit it.

[0062] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, "connected" or "coupled" as used herein may include wireless connections or wireless couplings. The term "and / or" used herein includes all or any units and all combinations of one or more associated listed items.

[0063] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0064] Example

[0065] Exemplary Methods

[0066] Currently, the arch rib alignment of bridges is mostly measured manually. However, the arch ribs of some bridges have large spans, making manual measurement difficult. As a result, the accuracy of the arch rib alignment obtained by manual measurement is not high.

[0067] In response to the technical problems existing in the prior art, a method for surveying the arch rib linear shape of a bridge is provided in this embodiment. The surveying method obtains the arch rib linear curve of the bridge under survey by fitting a set of linear feature points containing the arch rib linear shape. The method has high surveying accuracy for the arch rib linear shape of the bridge and replaces manual surveying.

[0068] like Figure 1 As shown, Figure 1 Flowchart of a method for surveying and mapping the alignment of a bridge arch rib. Specifically, this embodiment provides a method for surveying and mapping the alignment of a bridge arch rib, the method comprising the following steps:

[0069] Step S100: obtaining original point cloud data of the arch rib linear shape of the bridge, and performing segmentation processing on the obtained original point cloud data to obtain original arch rib point cloud data.

[0070] like Figures 2 to 6 As shown, Figure 2This is a structural diagram of the bridge; Figure 3 Schematic diagram of the structure of a bridge equipped with a 3D laser scanner station and targets, wherein: Figure (a) is a front view of the bridge under measurement, and Figure (b) is a top view of the bridge under measurement; Figure 4 This is a schematic diagram of the original point cloud data of the bridge; Figure 5 This is a schematic diagram of the coordinate system for the original data of the bridge arch rib line shape; Figure 6 The following is a schematic diagram of the coordinate system for the longitudinal segmentation of the bridge arch rib point cloud. The following steps are specifically used to obtain the original point cloud data of the bridge arch rib line shape:

[0071] Step S101: performing laser scanning on the arch ribs of the bridge using a three-dimensional laser scanner to record original point cloud data of the arch rib linear shape of the bridge.

[0072] CloudCompare software was used to segment the collected raw point cloud data of the bridge's arch rib alignment. This process removed a significant amount of data unrelated to the arch ribs, such as the ground and trees, while retaining the complete original point cloud data. This segmentation process is essential for subsequent steps. It is simple and quick to perform, requiring minimal accuracy, and facilitates the subsequent accurate extraction of data points for the bridge's arch rib alignment.

[0073] Step S200: downsampling the original arch rib point cloud data to obtain downsampled arch rib point cloud data, and extracting skeleton points of the downsampled arch rib point cloud.

[0074] By downsampling the original arch rib point cloud data, the data volume of the original arch rib point cloud is reduced, the complexity of data calculation is reduced, and the data processing speed is improved while maintaining the geometric and topological characteristics of the original point cloud in the original arch rib point cloud data.

[0075] Step S201: obtaining downsampled arch rib point cloud data by removing data other than the arch rib point cloud data having original features from the original arch rib point cloud data.

[0076] Eliminate data other than those under the condition of maintaining the geometric and topological characteristics of the original point cloud in the original arch rib point cloud data. In other words, divide the original arch rib point cloud data into uniform grids, and then obtain the arch rib point cloud closest to the centroid of each grid as the point cloud retained by the grid, thereby reducing the data volume of the original arch rib point cloud and obtaining the downsampled arch rib point cloud data.

[0077] Step S202: establishing a spatial rectangular coordinate system OXYZ, and performing coordinate system transformation on the downsampled arch rib point cloud.

[0078] Establish a spatial rectangular coordinate system OXYZ, and use the PCA algorithm (principal component analysis) to calculate the direction with the largest variance of the two-dimensional downsampled arch rib point cloud that temporarily excludes the elevation value, that is, the Z axis as the vertical direction; and use the X axis as the longitudinal direction of the arch rib on the horizontal plane. The Y axis perpendicular to the X axis in the horizontal plane is the lateral direction of the arch rib

[0079] Then the downsampled arch rib point cloud is transformed into a coordinate system so that the X axis of the downsampled arch rib point cloud is aligned with the longitudinal direction of the arch rib. Y-axis aligned with the arch rib transverse direction The Z-axis direction remains unchanged, and the origin O is used as the centroid of the downsampled arch rib point cloud.

[0080] Step S203: performing coarse segmentation on the downsampled arch rib point cloud along the longitudinal direction, and extracting the centroid point of each coarse segment as the skeleton point of the downsampled arch rib point cloud.

[0081] Specifically, the longitudinal direction of the arch rib identified by the PCA algorithm The downsampled arch rib point cloud is coarsely segmented. This operation can complete the segmentation by the X-axis coordinate value of the data point in the arch rib point cloud, and obtain the coarse segment length l1, which can be used as the segment width of the arch rib; and extract the centroid point of each coarse segment length l1 as the skeleton point of the downsampled arch rib point cloud. Figure 7 As shown, Figure 7 Schematic diagram of the coordinate system of the skeleton points of the downsampled arch rib point cloud.

[0082] Step S300: calculating a rough fitting curve of the arch rib linear shape of the bridge by using the skeleton points of the downsampled arch rib point cloud, and dividing the downsampled arch rib point cloud into a plurality of arch rib segments by using the rough fitting curve.

[0083] The skeleton points of the downsampled arch rib point cloud are projected onto the converted plane rectangular coordinate system XOZ to obtain the two-dimensional points of the downsampled arch rib point cloud. Function fitting is performed on the two-dimensional points of the downsampled arch rib point cloud, and the expression of the fitting function is obtained as follows:

[0084] Z=aX 2 +bX+c,

[0085] Where Z represents the vertical coordinate value, X represents the longitudinal coordinate value, a represents the quadratic term coefficient of the fitting function, b represents the linear term coefficient of the fitting function, and c represents the constant of the fitting function;

[0086] The rough fitting curve of the bridge arch rib line shape in the spatial rectangular coordinate system OXYZ is obtained by fitting the expression of the function, and the downsampled arch rib point cloud is divided into several arch rib segments of equal length based on the rough fitting curve. Figure 8 and Figure 9 As shown, Figure 8Schematic diagram of the coordinate system of the rough fitting curve of the arch rib line shape of the bridge fitted with skeleton points; Figure 9 Schematic diagram of the coordinate system for dividing the downsampled arch rib point cloud into arch rib segments of equal length.

[0087] The downsampled arch rib point cloud is divided into a number of arch rib segments of equal length based on the coarse fitting curve, which specifically includes the following steps:

[0088] Step S310: Select an appropriate rough fitting curve segment length l2. The rough fitting curve segment length l2 is k times the lateral width of the arch rib. The value range of k is 0.5-1. Since the arch rib is a curved component, the subsequent steps need to assume that the arch rib segments are straight components. Therefore, the shorter the length of the rough fitting curve segment length l2, the more consistent with the assumption. Figure 9 The length is larger for the convenience of display;

[0089] Step S320: Extract the maximum and minimum values ​​of the downsampled arch rib point cloud on the X-axis after coordinate transformation. In the interval between the maximum and minimum values ​​on the X-axis and on the fitting function, sample N segmentation points along the X-axis direction with the segment length as the interval, and obtain the tangent line at the segmentation point. Then, use the segmentation point as a point on the plane and the tangent line of the point as the normal line to segment the plane to obtain N segmentation surfaces.

[0090] Step S330: Select the segmentation plane with the smallest X-axis coordinate value of the segmentation point, traverse all data points of the downsampled arch rib point cloud, and calculate The result,

[0091] in, is the normal of the segmentation surface; P is the data point of the downsampled arch rib point cloud; SP is the segmentation point,

[0092] Extract The points are regarded as point clusters segmented by the segmentation plane from the downsampled arch rib point cloud after coordinate transformation, and the indexes of these point clusters are recorded. These point clusters are then removed from the downsampled arch rib point cloud after coordinate transformation.

[0093] Step S340: Select the next segmentation plane along the X-axis in the positive direction and execute the operation of step S330 to obtain the next segmented point cluster and index until all segmentation planes are traversed;

[0094] Step S350: extracting an arch rib segment point cloud from the downsampled arch rib point cloud that has not undergone coordinate transformation according to the obtained point cluster index.

[0095] Step S400: Construct a constraint model of the arch rib segment by downsampling the arch rib point cloud, identify the non-downsampled point cloud segment under the constraint conditions of the constraint model, extract the arch rib component point cloud containing the arch rib linear shape from the non-downsampled point cloud segment of each arch rib segment, and perform coordinate system transformation on the arch rib component point cloud to obtain the linear feature points of the non-downsampled point cloud segment.

[0096] The constraint model of the arch rib segment is constructed by downsampling the arch rib point cloud, including:

[0097] Step S401: setting constraints of the arch rib segment by downsampling the arch rib point cloud, the constraints including the type of the arch rib component of the bridge, and constructing a constraint model of the arch rib segment based on the constraints.

[0098] The RANSAC algorithm (Random Sample Consensus Algorithm) is used to fit the geometric model. The basic geometric shapes used for fitting include straight lines, circles, etc. This makes it robust to outliers (data points that do not belong to the fitted model). In other words, even in the presence of noise and outliers, it can still find a good fitting model.

[0099] It should be noted that the arch rib components of bridges are divided into two types: arch rib components with circular cross-sections and arch rib components with rectangular cross-sections.

[0100] Recognizing the un-downsampled point cloud fragments under the constraints of the constraint model specifically includes:

[0101] For the steel tube concrete bridge arch rib, the linear arch rib component is the lower chord of the bridge arch rib, and its basic geometric shape can be set to be a cylinder, that is, an arch rib component with a circular cross section.

[0102] Its mathematical model can be expressed by 7 parameters, namely the coordinates of a point on the cylinder axis: (a', b', c'); the unit direction vector of the cylinder axis: The radius of the cylinder is: r.

[0103] It should be noted that for the cylindrical lower chord, its axis is perpendicular to the arch rib's transverse direction. Furthermore, in the arch rib segment point cloud, since this is the lower chord of the bridge arch rib, the elevation of the midpoint of the cylinder's axis is relatively low, lower than the average elevation of the arch rib segment. The a priori constraints for the lower chord of the bridge arch rib include:

[0104]

[0105] (r design -t)≤r≤(r design +t),

[0106] Among them, θ th，1 Indicates the first angle threshold; Z CThe elevation of the cylinder axis representing the bottom chord; represents the elevation of the center of the arch rib segment; r design represents the design radius of the lower chord, and t represents the radius deviation.

[0107] By adding the above prior constraints, the recognition accuracy of the lower chord of the bridge arch rib can be improved. Figure 14 As shown, Figure 14 Schematic diagram of identifying arch rib components with circular cross-sections from the arch rib segment point cloud.

[0108] After incorporating the prior constraints of the bridge, the arch rib component point cloud containing the arch rib line shape is extracted from the un-downsampled point cloud segment of each arch rib segment. The specific steps include:

[0109] Step A1: Select random samples. Randomly select a certain number of data points from the downsampled arch rib segment point cloud.

[0110] Step A2: Fitting the model: A predefined model is fitted using the sampled data points, where the three-dimensional coordinates and normal vectors of the two data points can determine a mathematical model of a cylinder.

[0111] Step A3: Determine the model. If the current cylindrical mathematical model does not meet the prior constraints of the lower chord and Then return to step A1.

[0112] Step A4: Calculate the inliers. Calculate the distance from all data points to the fitted cylinder mathematical model and set the distance less than the threshold d as th，1 The data points are marked as inliers. If the number of inliers is less than the first minimum inlier threshold MinPts1, the process returns to step A1.

[0113] Calculate or update the first iteration threshold k1':

[0114]

[0115] Where P1 represents the probability of successfully finding a cylindrical model that meets the prior constraints in the point cloud data; n represents the number of random samples; and w1 represents the ratio of the number of points inside the cylindrical mathematical model to the number of data points in the downsampled arch rib segment point cloud.

[0116] It should be noted that k1 is a first preset number of iterations set in advance, and the first iteration number threshold k1′ may be smaller than the first preset number of iterations k1 or larger than the first preset number of iterations k1.

[0117] Step A5: Repeated iteration. Repeat step A4 until the number of iterations is less than the first preset number of iterations k1 or the first iteration number threshold k1', then the iteration is stopped.

[0118] Step A6: Select the final model. The cylindrical mathematical model with the largest number of interior points is selected as the final fitting result.

[0119] Step A7: Calculate the distance between each data point in the un-downsampled arch rib segment point cloud and the cylindrical mathematical model, and roughly extract the points whose distance is less than the threshold d. th，2 The data points are used as the point cloud of the arch rib component containing the arch rib line shape.

[0120] Step A8: Obtain the normal of the rough extraction result point cloud, calculate the deviation of each rough extraction result point cloud normal relative to the cylinder mathematical model, and filter out the deviations greater than the second angle threshold θ th，2 point.

[0121] The normal filtering deviation of the rough extraction result point cloud is greater than the second angle threshold θ th，2 The point cloud of the arch rib component containing the arch rib line shape is precisely extracted. For the cylindrical mathematical model, the deviation of the normal line of each rough extraction result point cloud relative to the cylindrical mathematical model must meet the following requirements:

[0122]

[0123] in, Indicates P i Normal of the point; n cyliner Represents the theoretical normal line of the data point as the inner point of the cylinder mathematical model, that is, P i The perpendicular line from a point to the axis of the cylinder mathematical model.

[0124] For the surface point cloud of the lower chord, the arch rib line shape is defined as the lower edge of the arch rib, that is, the lower edge of the lower chord. After obtaining the surface point cloud of the lower chord, the lower edge point cloud of the lower chord can be determined according to the fitted cylindrical mathematical model. Figure 15 As shown, Figure 15 Schematic diagram of extracting arch rib linear points from the bottom chord point cloud.

[0125] The coordinate system of the arch rib point cloud is transformed to obtain the linear feature points of the un-downsampled point cloud fragment, which specifically include:

[0126] For the point cloud of the lower chord surface, the extracted arch rib component point cloud containing the arch rib line shape needs to be transformed into a coordinate system. The new coordinate system takes the coordinates (a', b', c') of a point on the cylinder axis as the origin, and the axis of the cylinder is is the X axis, the arch rib is horizontal The Y axis is perpendicular to the XOY plane and points upwards. The coordinate system transformation formula of the point cloud of the cylindrical arch rib component is:

[0127] P'=(P1-T1)·R1;

[0128]

[0129] Among them, P1 represents the point cloud matrix of the lower chord after the point cloud coordinate system of the arch rib component with a circular cross section is transformed; T1 represents the first coordinate translation matrix; R1 represents the first coordinate rotation matrix.

[0130] Traverse the surface point cloud of the lower chord after coordinate system transformation and extract the points that satisfy the discriminant Y' pi <Z' pi tanθ th，3 The data point cloud is used as the arch rib linear point cloud after coordinate system conversion, and its subscript index = (pi1, pi2, ..., pi N ), extract the point cloud corresponding to the index from the surface point cloud of the lower chord without coordinate transformation as the linear feature point of the non-downsampled point cloud segment.

[0131] Among them, Y' pi Indicates the Y-axis coordinate value; Z' pi Indicates the Z-axis coordinate value; θ th，3 Indicates the third angle threshold.

[0132] For reinforced concrete slab arches, the arch rib component containing the linear shape is the lower surface of the arch rib, and its basic geometric shape can be set as a cuboid, that is, an arch rib component with a rectangular cross-section. The function expression of the mathematical model of the plane in the cuboid is:

[0133] aX+bY+cZ=d,

[0134] Among them, a, b, c, and d represent the mathematical model parameters of the plane in the cuboid.

[0135] The normal direction of the lower surface of the arch rib is perpendicular to the horizontal direction of the arch rib, and the elevation of the lower surface of the arch rib is the lowest among all planes of the arch rib segment point cloud. The prior constraints of the lower surface of the arch rib include:

[0136]

[0137] Among them, θ th，4 represents the fourth angle threshold, Represents the normal vector of the plane mathematical model in the cuboid; Z p Indicates the elevation of the lower surface of the arch rib; Indicates the center elevation of the rib segment that includes the lower surface of the rib.

[0138] By adding the above prior constraints, it is used to improve the recognition accuracy of the arch rib components of the bridge as the lower surface of the arch rib. Figure 16 and Figure 17 As shown, Figure 16 Schematic diagram of extracting arch rib linear points from the lower surface point cloud; Figure 17 Schematic diagram of the point cloud of the lower surface of an arch rib component with a rectangular cross section.

[0139] After incorporating the prior constraints of the bridge, the arch rib component point cloud containing the arch rib line shape is extracted from the un-downsampled point cloud segment of each arch rib segment. The specific steps include:

[0140] Step B1: Select random samples. Randomly select a certain number of data points from the downsampled arch rib segment point cloud.

[0141] Step B2: Fitting the model. A predefined model is fitted using the sampled data points, where the three-dimensional coordinates of the three data points can determine a mathematical model of the mid-plane of a cuboid.

[0142] Step B3: Determine the model. If the current rectangular parallelepiped mid-plane mathematical model does not meet the prior constraints of the arch rib lower surface and Then return to step B1.

[0143] Step B4: Calculate the inliers. Calculate the distances of all data points to the mathematical model of the plane in the fitted cuboid, and set the distances less than the threshold d as th，3 The data points are marked as inliers. If the number of inliers is less than the second minimum inlier threshold MinPts2, the process returns to step B1.

[0144] Calculate or update the second iteration threshold k2':

[0145]

[0146] Among them, P2 represents the probability of successfully finding a rectangular mid-plane mathematical model that meets the prior constraints in the point cloud data; w2 represents the ratio of the number of points in the rectangular mid-plane mathematical model to the number of data points in the downsampled arch rib segment point cloud.

[0147] It should be noted that k2 is a second preset number of iterations set in advance, and the second iteration threshold k2′ may be less than the second preset number of iterations k2 or greater than the second preset number of iterations k2.

[0148] Step B5: Repeated iteration. Repeat step B4 until the number of iterations is less than the second iteration threshold k2' or the second preset iteration number k2, then the iteration is stopped.

[0149] Step B6: Select the final model. The rectangular parallelepiped midplane mathematical model with the largest number of interior points is selected as the final fitting result.

[0150] Step B7: Calculate the distance between each data point in the un-downsampled arch rib segment point cloud and the mid-plane mathematical model of the cuboid, and roughly extract the points whose distance is less than the threshold d. th，4 The data points are used as the point cloud of the arch rib component containing the arch rib line shape.

[0151] Step B8: Obtain the normal of the rough extraction result point cloud, calculate the deviation of each rough extraction result point cloud normal relative to the mathematical model of the cuboid midplane, and filter out the normals whose deviation is greater than the fifth angle threshold θ th，5 point.

[0152] The normal filtering deviation of the point cloud obtained by rough extraction is greater than the fifth angle threshold θ th，5 The point cloud of the arch rib component containing the arch rib line shape is precisely extracted. For the rectangular midplane mathematical model, the deviation of the normal of each rough extraction result point cloud relative to the rectangular midplane mathematical model must satisfy the following requirements:

[0153]

[0154] in, Indicates P j Normal of the point; n plane Represents the normal of the plane mathematical model in the cuboid.

[0155] For the lower surface point cloud of an arch rib component with a rectangular cross-section, the arch rib line shape is defined as the longitudinal centerline of the arch rib bottom surface. After obtaining the lower surface point cloud of the plate arch, the longitudinal centerline of the arch rib bottom surface can be determined based on the fitted rectangular midplane mathematical model.

[0156] For the lower surface point cloud of the arch rib component with a rectangular cross section, it is necessary to perform coordinate system transformation on the precisely extracted point cloud of the arch rib component including the arch rib line shape, and the new coordinate system takes the centroid of the lower surface point cloud of the plate arch as the origin.

[0157] Plane normal The Z axis points upwards, and the arch ribs are horizontal. is the Y axis, and the X axis is perpendicular to the ZOY plane. The coordinate system transformation formula of the arch rib component in the rectangular parallelepiped mid-plane mathematical model is:

[0158] P"=(P2-T2)·R2,

[0159]

[0160] Among them, P2 represents the point cloud matrix of the lower surface of the plate arch after the coordinate system of the arch rib component of the rectangular mid-plane mathematical model is transformed; T2 represents the second coordinate translation matrix; R2 represents the second coordinate rotation matrix.

[0161] For the lower surface point cloud of the arch rib component with a rectangular cross section, the boundary points of the lower surface point cloud of the arch are first obtained based on the angle criterion, and the curve growth algorithm based on the linear structural tensor is used to cluster the lower surface point cloud of the plate arch to identify the two boundary point clouds along the longitudinal direction of the arch rib. Then the Y-axis coordinate mean of the boundary point cloud is calculated and the average of the two Y-axis coordinate means is calculated. As the position of the arch rib bottom surface along the longitudinal center line of the arch rib, and record the Y axis coordinate of the arch bottom surface point cloud after coordinate conversion. The indices of the points within the interval.

[0162] Since the Y axis of the coordinate system is the horizontal direction of the arch rib, the Y axis coordinate is The points within the interval are the point clouds of the centerline of the bottom surface along the longitudinal direction. Finally, based on the recorded index, the point clouds of the centerline of the bottom surface of the arch rib along the longitudinal direction are extracted from the point clouds of the lower surface of the arch rib without coordinate transformation, that is, the arch rib linear point clouds, which are used as the linear feature points of the un-downsampled point cloud segments.

[0163] It should be noted that the linear structure tensor is a three-dimensional local descriptor of a point cloud. j As an example, the linear structure tensor calculation relies on covariance analysis and requires the calculation of P j The eigenvalues ​​of the covariance matrix of the point neighborhood. j The kth nearest neighbor point of a point is Represents the nearest neighbor point. The 3×3 covariance matrix C is shown as follows:

[0164]

[0165] in, Represents neighborhood points The centroid of the covariance matrix C produces three eigenvalues: λ1, λ2, λ3. Specifically, λ1>λ2>λ3, and the eigenvectors V1, V2, V3, λ i (i=1,2,3) neighboring points Along V i The degree of dispersion of the direction, V1 represents the nearest neighbor point The most dispersed direction.

[0166] The linear structure tensor is defined as Therefore, the higher the linear structure tensor, the closer the nearest neighbor point is. The more likely the point cloud is to represent a rectilinear shape.

[0167] In the curve growth algorithm based on linear structure tensor, an empty seed set and an empty cluster are first defined. Then, the point with the largest linear structure tensor L is selected as the starting seed point, and the starting seed point is marked and added to the empty seed set. The kth nearest neighbor point of the starting seed is selected. If the eigenvector V1 deviation between the neighbor point and the starting seed point is less than the sixth angle threshold θ th，6 , the neighborhood points are clustered together with the starting seed point, and the neighborhood point is also marked and added to the initially defined seed set and cluster. After all neighborhood points are judged, the starting seed point is deleted from the seed set.

[0168] Then, a new seed point is selected from the seed set, and the process is repeated if the deviation of the feature vector V1 between the neighboring point and the seed point is less than the sixth angle threshold θ th，6 , delete the seed point from the seed set until the seed set is empty again.

[0169] After that, the above clustering process is repeated for the remaining unlabeled points, and a new seed point is selected from the seed set, that is, if the deviation of the feature vector V1 between the unlabeled point and the seed point is less than the sixth angle threshold θ th，6 , then the unlabeled points are clustered together with the seed points, and the unlabeled points are also labeled and added to the initially defined seed set and cluster. After all unlabeled points are judged, the seed point is deleted from the seed set until all boundary points are processed and linear point clusters are obtained.

[0170] Finally, the point clusters whose number of inliers is less than the preset third minimum inlier threshold value MinPts3 are deleted to obtain the clustered point cloud of the lower surface of the plate arch.

[0171] Step S500: obtaining a complete set of linear feature points including the arch rib linear shape by integrating the linear feature points of a number of non-downsampled point cloud segments.

[0172] The complete set of linear feature points including the arch rib linear shape can be found in Figure 10 、 Figure 12 and Figure 13 As shown, Figure 10 It is a schematic diagram of the coordinate system of the complete set of linear feature points including the arch rib linear shape; Figure 12 This is a schematic diagram of the arch rib line shape of the bridge from the first perspective; Figure 13 A schematic diagram of the arch rib line shape of the bridge from the second perspective.

[0173] As an implementation method in this embodiment, after obtaining a complete set of linear feature points including the arch rib linear shape, the surveying and mapping method further includes:

[0174] Step S600: fitting the arch rib linear curve of the bridge under measurement through a complete linear feature point set including the arch rib linear curve.

[0175] Can get reference Figure 11 The linear curve of the arch rib of the bridge, Figure 11 Schematic diagram of the partial structure of the arch rib components of the bridge.

[0176] Specifically, the bridge arch rib alignment surveying method provided in this embodiment has at least the following beneficial effects:

[0177] (1) By fitting the linear feature point set containing the arch rib linear shape, the arch rib linear curve of the bridge under survey is obtained, which has high surveying accuracy and replaces manual surveying;

[0178] (2) Using a three-dimensional laser scanner to perform laser scanning on the arch ribs of the bridge, without direct contact with the bridge structure, the linear data of the bridge arch ribs can be quickly and accurately obtained, which greatly saves measurement time and labor costs, reduces safety risks during the measurement process, and ensures the integrity of the bridge structure;

[0179] (3) Identify the fitting model of the target point cloud in the downsampled arch rib point cloud data, and extract the target point cloud from the original point cloud data, ensuring that the linear feature points of the extracted target point cloud fragments are not lost in resolution, thereby improving processing efficiency;

[0180] (4) It is not affected by the structural shape and size of the bridge to be tested and can be applied to bridges of various forms and sizes. It has high versatility and applicability, and provides reliable technical support for the design, evaluation and maintenance of bridge projects.

[0181] Taking Bridge A as an example, the specific situation of Bridge A is as follows:

[0182] Bridge A has a span arrangement of 30+148+30m for a railway tied-arch continuous beam bridge. The arch rib alignment of Bridge A was quickly surveyed and mapped using a 3D laser scanner. The details are as follows:

[0183] Record the original point cloud data of the arch rib alignment of Bridge A: First, set control targets for subsequent comparison with the total station measurement results. Four control targets were glued to the bridge deck with resin glue. Then, set four registration targets to align the point cloud data from different 3D laser scanner stations.

[0184] There are 7 3D laser scanner stations on the bridge deck and 6 3D laser scanner stations under the bridge. The specific layout is as follows: Figure 3As shown. The arch ribs of Bridge A are laser scanned at each 3D laser scanner station to obtain the original point cloud data of the arch rib linear shape of Bridge A. The point cloud data of each 3D laser scanner station is then aligned into a complete point cloud using the registration target in the Leica cyclone software. The accuracy of the registration target center is 2-50000mm. The accuracy of the point cloud data obtained through TLS (Secure Transport Layer Protocol) reaches 1-3mm. The original point cloud data of the arch rib linear shape of Bridge A can be found in the original point cloud data. Figure 4 shown.

[0185] Preprocess the original point cloud data of the arch rib line shape of Bridge A: Use CloudCompare software to segment the collected original point cloud data of Bridge A to obtain the original arch rib point cloud data of Bridge A. The extraction results are as follows: Figure 5 As shown in FIG, the original arch rib point cloud data of Bridge A is obtained and used as the subsequent input point cloud.

[0186] The original arch rib point cloud data was downsampled, and the pre-processed point cloud data was downsampled using the voxel grid method, where the voxel size was 50 mm. The downsampled arch rib point cloud data was identified using the PCA algorithm. After the downsampled arch rib point cloud was converted into a coordinate system, the downsampled arch rib point cloud was coarsely segmented along the longitudinal direction with a coarse segment length of 1 m. The coarse segmentation of the arch rib point cloud of Bridge A is as follows: Figure 6 shown.

[0187] Extract the skeleton points of the downsampled arch rib point cloud, as follows Figure 7 shown.

[0188] The rough fitting curve of the arch rib line shape of Bridge A is fitted by downsampling the skeleton points of the arch rib point cloud. Figure 8 As shown in the figure. The segmentation points and segmentation planes are determined on the rough fitting curve, and the downsampled arch rib point cloud is divided into several arch rib segments of equal length based on the rough fitting curve. The length of the arch rib segment is 0.25m. The original arch rib point cloud data without downsampling is also segmented according to the same segmentation points and segmentation planes, as shown in the figure. Figure 9 shown.

[0189] The arch rib component type of Bridge A is a circular arch rib component with the following constraints set:

[0190]

[0191] (r design -t)≤r≤(r design +t),

[0192] The first allowable angle threshold θ where the cylinder axis is perpendicular to the arch rib is th，1The deviation is 7.5°, and the allowable deviation t of the lower chord radius r is 0.01m.

[0193] The RANSAC algorithm that incorporates the prior constraints of Bridge A is used to fit the cylindrical mathematical model from the downsampled arch rib point cloud. th，1 The minimum number of internal points MinPts1 of the cylindrical mathematical model is 10. The probability P1 of successfully finding a cylindrical model that meets the prior constraints in the point cloud data is expected to be 0.99. The first preset iteration number threshold k1 is 1,000,000 times. The cylindrical mathematical model is identified from the arch rib segment point cloud. Figure 14 As shown. The point cloud of the arch rib component including the arch rib line shape is roughly extracted by fitting the cylindrical mathematical model, and the threshold d of the rough extraction is set. th，2 0.05m, and then the normal of the rough extraction result point cloud is filtered out with deviation greater than the second angle threshold θ th，2 The second angle threshold θ th，2 is 5°.

[0194] The extracted arch rib component point cloud containing the arch rib linear shape is transformed into a coordinate system, and the lower edge point cloud of the lower chord is extracted as the linear feature point of the point cloud segment. th，3 The linear feature points of the point cloud segment are extracted from the lower edge point cloud of the lower chord of the steel tube concrete bridge arch rib. Figure 15 shown.

[0195] Finally, the linear feature points of the point cloud fragments are integrated to obtain a complete set of linear feature points containing the arch rib line shape, as shown in the following example: Figure 10 shown.

[0196] Exemplary devices

[0197] like Figure 18 As shown, Figure 18 The functional principle diagram of the device for surveying and mapping the linear shape of a bridge arch rib is shown in FIG. Based on the above embodiment, this embodiment further provides a device for surveying and mapping the linear shape of a bridge arch rib.

[0198] The bridge arch rib linear surveying and mapping device includes a processor, a memory, an interface and a display screen connected via a system bus; wherein the processor is used to provide computing and control capabilities; the memory includes a storage medium and an internal memory, the storage medium stores an operating system and a computer program, and the internal memory provides an environment for the operation of the operating system and the computer program in the storage medium; the interface is used to connect to external devices, such as mobile terminals and computers; the display screen is used to display the corresponding bridge arch rib linear surveying and mapping information.

[0199] When the computer program is executed by the processor, it is used to implement a method for surveying and mapping the linear shape of a bridge arch rib.

[0200] It will be understood by those skilled in the art that Figure 18 The functional schematic diagram of the bridge arch rib alignment surveying device shown in the figure is merely a block diagram of a portion of the structure related to the present invention and does not limit the bridge arch rib alignment surveying device to which the present invention is applied. Specifically, the bridge arch rib alignment surveying device may include more or fewer components than shown in the figure, combine certain components, or have a different component arrangement.

[0201] In one embodiment, a device for surveying and mapping the alignment of a bridge arch rib is provided, comprising a memory and a processor; the memory stores a program for surveying and mapping the alignment of a bridge arch rib, and the program for surveying and mapping the alignment of a bridge arch rib is used to implement the operation of the method for surveying and mapping the alignment of a bridge arch rib when executed by the processor.

[0202] In one embodiment, a storage medium is provided, which is a computer-readable storage medium. The storage medium stores a surveying program for the alignment of a bridge arch rib. When the surveying program for the alignment of a bridge arch rib is executed by the processor, it is used to implement the operation of the surveying method for the alignment of a bridge arch rib as described above.

[0203] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile storage medium. When executed, the computer program can include the processes of the various embodiments of the method described above. Any reference to memory, storage, database, or other media used in the various embodiments provided by the present invention can include non-volatile memory and / or volatile memory.

[0204] The present application provides a method for surveying and mapping the arch rib linear shape of a bridge, wherein the surveying and mapping method comprises the following steps: obtaining original point cloud data of the arch rib linear shape of the bridge, segmenting the obtained original point cloud data to obtain original arch rib point cloud data; performing downsampling processing on the original arch rib point cloud data to obtain downsampled arch rib point cloud data, and extracting skeleton points of the downsampled arch rib point cloud; calculating a coarse fitting curve of the arch rib linear shape of the bridge through the skeleton points of the downsampled arch rib point cloud, and dividing the downsampled arch rib point cloud into the coarse fitting curve; The cloud is divided into several arch rib segments; a constraint model of the arch rib segment is constructed by downsampling the arch rib point cloud, and the undownsampled point cloud segments are identified under the constraints of the constraint model. The arch rib component point cloud containing the arch rib linear shape is extracted from the undownsampled point cloud segment of each arch rib segment, and the arch rib component point cloud is converted into a coordinate system to obtain the linear feature points of the undownsampled point cloud segment; the linear feature points of several undownsampled point cloud segments are integrated to obtain a complete linear feature point set containing the arch rib linear shape. This application obtains the arch rib linear curve of the bridge under measurement by fitting the linear feature point set containing the arch rib linear shape, which has high surveying and mapping accuracy and replaces manual surveying and mapping.

[0205] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for surveying and mapping the linear shape of a bridge arch rib, characterized in that: The surveying and mapping method comprises: Obtaining original point cloud data of the arch rib linear shape of the bridge, and performing segmentation processing on the obtained original point cloud data to obtain original arch rib point cloud data; The original arch rib point cloud data is downsampled to obtain downsampled arch rib point cloud data, and skeleton points of the downsampled arch rib point cloud are extracted; The rough fitting curve of the bridge arch rib line shape is calculated by downsampling the skeleton points of the arch rib point cloud, and the downsampling arch rib point cloud is divided into several arch rib segments by the rough fitting curve; specifically, the following steps are performed: By performing plane projection on the skeleton points of the downsampled arch rib point cloud, the two-dimensional points of the downsampled arch rib point cloud are obtained, and function fitting is performed on the two-dimensional points of the downsampled arch rib point cloud. The expression of the fitting function is: ， Where Z represents the vertical coordinate value, X represents the longitudinal coordinate value, a represents the quadratic term coefficient of the fitting function, b represents the linear term coefficient of the fitting function, and c represents the constant of the fitting function; A rough fitting curve of the arch rib line shape of the bridge in the spatial rectangular coordinate system OXYZ is obtained by the expression of the fitting function, and the downsampled arch rib point cloud is divided into several arch rib segments of equal length based on the rough fitting curve; A constraint model of the arch rib segment is constructed by downsampling the arch rib point cloud, and the undownsampled point cloud segment is identified under the constraint conditions of the constraint model. The arch rib component point cloud containing the arch rib linear shape is extracted from the undownsampled point cloud segment of each arch rib segment, and the arch rib component point cloud is transformed into a coordinate system to obtain the linear feature points of the undownsampled point cloud segment; The constraint model of the arch rib segment is constructed by downsampling the arch rib point cloud, including: By downsampling the arch rib point cloud, constraints are set for the arch rib segment. The constraints include the type of arch rib components of the bridge, and a constraint model of the arch rib segment is constructed based on the constraints. The types of arch rib components of the bridge include arch rib components with circular cross sections and arch rib components with rectangular cross sections. The coordinate system transformation of the arch rib point cloud specifically includes: For the point cloud of the lower chord surface, it is necessary to transform the coordinate system of the point cloud of the arch rib component containing the arch rib line shape. The new coordinate system is based on the coordinate of a point on the axis of the cylinder. is the origin, the axis of the cylinder is the X axis, the arch rib is horizontal The Y axis is perpendicular to the XOY plane and points upwards. ； The coordinate system transformation formula for the point cloud of an arch rib component with a circular cross section is: ， ， in, Represents the point cloud matrix of the lower chord after the point cloud coordinate system of the arch rib component with a circular cross section is transformed; represents the first coordinate translation matrix; represents the first coordinate rotation matrix; For the lower surface point cloud of the arch rib component with a rectangular cross section, it is necessary to transform the coordinate system of the arch rib component point cloud containing the arch rib line shape. The new coordinate system takes the centroid of the lower surface point cloud of the plate arch as the origin; the plane normal The Z axis points upwards, and the arch ribs are horizontal. is the Y axis, and the X axis is perpendicular to the ZOY plane. ; The coordinate system transformation formula for the point cloud of an arch rib component with a rectangular cross section is: ， ， in, The point cloud matrix of the lower surface of the plate arch after the coordinate system of the arch rib component of the rectangular parallelepiped mid-plane mathematical model is transformed; represents the second coordinate translation matrix; represents the second coordinate rotation matrix; By integrating the linear feature points of several un-downsampled point cloud fragments, a complete linear feature point set containing the arch rib linear shape is obtained; and the arch rib linear curve of the measured bridge is fitted through the complete linear feature point set containing the arch rib linear shape.

2. The method for surveying and mapping the bridge arch rib line shape according to claim 1, characterized in that: The original point cloud data of the bridge arch rib line shape is obtained by: The arch ribs of the bridge are laser scanned using a 3D laser scanner to record the original point cloud data of the arch rib linear shape of the bridge.

3. The method for surveying and mapping the bridge arch rib line shape according to claim 1, characterized in that: By downsampling the original arch rib point cloud data, the downsampled arch rib point cloud data is obtained, and the skeleton points of the downsampled arch rib point cloud are extracted, specifically including: The downsampled arch rib point cloud data is obtained by eliminating data other than the arch rib point cloud data having original features from the original arch rib point cloud data; Establish a spatial rectangular coordinate system OXYZ and perform coordinate system transformation on the downsampled arch rib point cloud; The downsampled arch rib point cloud is coarsely segmented along the longitudinal direction, and the centroid point of each coarse segment is extracted as the skeleton point of the downsampled arch rib point cloud.

4. A device for surveying and mapping the linear shape of a bridge arch rib, characterized in that: include: A memory and a processor, wherein the memory stores a surveying and mapping program for the alignment of a bridge arch rib; when the surveying and mapping program for the alignment of a bridge arch rib is executed by the processor, it is used to implement the operation of the surveying and mapping method for the alignment of a bridge arch rib as described in any one of claims 1 to 3.

5. A storage medium, characterized in that The storage medium includes a computer-readable storage medium, which stores a bridge arch rib alignment surveying program. When the bridge arch rib alignment surveying program is executed by a processor, it is used to implement the operation of the bridge arch rib alignment surveying method as described in any one of claims 1 to 3.

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