Steel structure size measurement method and system based on combination of three-dimensional laser and total station

Abstract

The invention discloses a steel structure size measurement method and system based on combination of three-dimensional laser and a total station, and the method comprises the steps: scanning a steel structure through a three-dimensional laser scanner, and obtaining the point cloud data of the surface of the steel structure; measuring the key points on the steel structure by using a total station to obtain three-dimensional coordinates of the key points; converting the point cloud data acquired by the three-dimensional laser scanner into a coordinate system of the total station to realize unification of the point cloud data and the measurement data of the total station; key feature points of the steel structure are extracted from the converted point cloud data; calculating each size of the steel structure according to the extracted key feature points and the three-dimensional coordinates of the key points measured by the total station; and outputting the measured size data of the steel structure as a report in the forms of graphs and tables. The advantages of two measurement technologies are combined, the measurement precision and efficiency are improved, and powerful technical support is provided for manufacturing, installation and detection of the steel structure.

Description

Technical Field

[0001] The present invention relates to the technical field of building measurement, and in particular to a steel structure dimension measurement method and system based on the combination of three-dimensional laser and total station. Background Art

[0002] With the continuous development of construction technology, steel structures have been widely used in high-rise buildings, bridges, factories and other fields due to their advantages such as high strength, light weight and short construction period. However, the dimensional measurement of steel structures has always been one of the difficulties in the construction process. Traditional measurement methods have problems such as low measurement accuracy and low efficiency, and cannot meet the needs of modern construction. Although traditional steel structure dimension measurement methods, such as manual measurement and optical rangefinder, have met the needs of foundation construction to a certain extent, their inherent limitations are becoming increasingly prominent. First, the measurement accuracy is limited by human operation errors, changes in environmental factors and the accuracy limitations of measuring tools, resulting in deviations in the measurement results, which makes it difficult to meet the standards of modern high-precision construction. Secondly, traditional measurement methods are inefficient, especially when facing complex and changeable steel structure forms. The measurement work is time-consuming and laborious, which not only prolongs the construction period, but also increases labor costs. Therefore, it is necessary to propose a steel structure dimension measurement method and system based on the combination of three-dimensional laser and total station to solve the above problems. Summary of the invention

[0003] The present invention provides a steel structure dimension measurement method and system based on the combination of three-dimensional laser and total station, so as to solve the problems of low measurement accuracy and low efficiency of traditional measurement methods.

[0004] In a first aspect, the present invention provides a steel structure dimension measurement method based on a combination of three-dimensional laser and total station, comprising: Use a 3D laser scanner to scan the steel structure and obtain point cloud data on the surface of the steel structure; use a total station to measure key points on the steel structure and obtain the 3D coordinates of the key points; Convert the point cloud data obtained by the 3D laser scanner into the coordinate system of the total station to unify the point cloud data with the measurement data of the total station; The key feature points of the steel structure are extracted from the converted point cloud data; the local geometric features of the point cloud surface are reflected by the normal vector, and the normal vector of the point cloud is calculated using the principal component analysis method; the change rate of the normal vector of the point cloud is calculated; it is determined whether the change rate of the normal vector is greater than a preset threshold, and the points whose change rate is greater than the preset threshold are taken as key feature points; the curvature of the point cloud surface is described by the curvature, and the key feature points of the steel structure are extracted by calculating the local curvature of the point cloud; it is determined whether the curvature is greater than a preset threshold, and the points whose curvature is greater than the preset threshold are taken as key feature points; Calculate the dimensions of the steel structure based on the extracted key feature points and the three-dimensional coordinates of the key points measured by the total station; The measured steel structure dimension data is output as a report in the form of graphics and tables.

[0005] Furthermore, before converting the point cloud data acquired by the three-dimensional laser scanner into the coordinate system of the total station, the method further includes: filtering, denoising and smoothing the point cloud data acquired by the three-dimensional laser scanner.

[0006] Furthermore, the point cloud data acquired by the 3D laser scanner is converted into the coordinate system of the total station using the following formula:

[0007] in, is the azimuth of the point cloud based on the reference system, is the rotation matrix, is the scaling matrix, is the translation matrix, is the original coordinate matrix;

[0008] in, is the transformed coordinate.

[0009] In a second aspect, the present invention provides a steel structure dimension measurement system based on a combination of three-dimensional laser and total station, comprising: a three-dimensional laser scanner, a total station, a data processing unit and an output device; The three-dimensional laser scanner is used to scan the steel structure and obtain point cloud data on the surface of the steel structure; The total station is used to measure key points on the steel structure and obtain the three-dimensional coordinates of the key points; The data processing unit is used to convert the point cloud data acquired by the three-dimensional laser scanner into the coordinate system of the total station to achieve the unification of the point cloud data and the total station measurement data; in the converted point cloud data, the key feature points of the steel structure are extracted; wherein the local geometric features of the point cloud surface are reflected by the normal vector, and the normal vector of the point cloud is calculated using the principal component analysis method; the rate of change of the normal vector of the point cloud is calculated; it is determined whether the rate of change of the normal vector is greater than a preset threshold, and the points with a rate of change greater than the preset threshold are taken as key feature points; the curvature of the point cloud surface is described by the curvature, and the key feature points of the steel structure are extracted by calculating the local curvature of the point cloud; it is determined whether the curvature is greater than a preset threshold, and the points with a curvature greater than the preset threshold are taken as key feature points; various dimensions of the steel structure are calculated according to the extracted key feature points and the three-dimensional coordinates of the key points measured by the total station; The output device is used to output the measured steel structure dimension data as a report in the form of graphics or tables.

[0010] Furthermore, the data processing unit also includes a user interface, which allows a user to input parameters, view measurement data and perform data analysis.

[0011] Furthermore, the system also includes: The data storage unit is used to store the measured steel structure dimension data.

[0012] The present invention has the following beneficial effects: The present invention provides a steel structure dimension measurement method and system based on the combination of three-dimensional laser and total station, which realizes accurate measurement of steel structure dimensions by combining the advantages of the two measurement technologies. The method has the advantages of high measurement accuracy, high measurement efficiency, strong applicability, etc., and provides strong technical support for the manufacture, installation and detection of steel structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 The present invention provides a flow chart of a steel structure dimension measurement method based on a combination of three-dimensional laser and total station. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The technical solutions provided by the embodiments of the present invention are described in detail below in conjunction with the drawings.

[0016] See also Figure 1 , a steel structure dimension measurement method based on the combination of three-dimensional laser and total station provided by the present invention, comprising: Step 1: Use a 3D laser scanner to scan the steel structure to obtain point cloud data on the surface of the steel structure; use a total station to measure the key points on the steel structure to obtain the 3D coordinates of the key points.

[0017] The 3D laser scanner uses a non-contact measurement method and can perform accurate measurements without damaging the surface of the steel structure.

[0018] Step 2: Convert the point cloud data obtained by the 3D laser scanner into the coordinate system of the total station to unify the point cloud data with the measurement data of the total station.

[0019] Specifically, before converting the point cloud data acquired by the three-dimensional laser scanner into the coordinate system of the total station, the method further includes: filtering, denoising and smoothing the point cloud data acquired by the three-dimensional laser scanner to improve the measurement accuracy.

[0020] In this embodiment, the point cloud data acquired by the 3D laser scanner is converted into the coordinate system of the total station using the following formula:

[0021] in, is the azimuth of the point cloud based on the reference system, is the rotation matrix, is the scaling matrix, is the translation matrix, A is the original coordinate matrix;

[0022] in, is the transformed coordinate.

[0023] Step three: extract the key feature points of the steel structure from the converted point cloud data.

[0024] Specifically, the key feature points of the steel structure are extracted from the converted point cloud data, including: The normal vector reflects the local geometric features of the point cloud surface, and the principal component analysis method is used to calculate the normal vector of the point cloud; the change rate of the normal vector of the point cloud is calculated; it is determined whether the change rate of the normal vector is greater than the preset threshold, and the points with a change rate greater than the preset threshold are used as key feature points. The curvature describes the curvature of the point cloud surface, and the key feature points of the steel structure are extracted by calculating the local curvature of the point cloud; it is determined whether the curvature is greater than the preset threshold, and the points with a curvature greater than the preset threshold are used as key feature points.

[0025] The normal vector can reflect the local geometric features of the point cloud surface, and methods such as principal component analysis (PCA) can be used to calculate the normal vector of the point cloud. Curvature can describe the degree of bending of the point cloud surface. The key feature points of the steel structure can be extracted by calculating the local curvature of the point cloud. Commonly used curvature calculation methods include curvature calculation based on normal vector change, curvature calculation based on the least squares method, etc. Points with larger curvatures usually correspond to key feature points such as the edges and corners of the steel structure. A curvature threshold can be set, and points with curvatures greater than the threshold are taken as key feature points. Points with large changes in the normal vector may also be key feature points. The change rate of the normal vector of the point cloud can be calculated, and points with a large change rate are taken as key feature points. Such as corner points, edge lines, etc., and these feature points will be used as the basis for subsequent dimension measurement.

[0026] Step 4: Calculate the dimensions of the steel structure according to the extracted key feature points and the three-dimensional coordinates of the key points measured by the total station.

[0027] Calculate the dimensions of the steel structure, such as length, width, height, angle, etc., according to the extracted feature points and the coordinates of the key points measured by the total station.

[0028] For the surfaces of columns and beams, since they usually have large planar parts, the random sample consensus (RANSAC) algorithm can be used for plane fitting. Randomly extract a small number of points from the point cloud, such as 3 points; assume a plane equation, and then calculate the number of points in the point cloud within a certain distance range of the plane, such as setting the threshold as t; repeat this process multiple times to find the plane containing the most points. Based on the normal vector and position information of the fitted plane, preliminarily judge the direction and position of the structural components. For example, the plane normal vector of a column is usually perpendicular to the ground, and there is a specific angular relationship between the plane normal vector of a beam and the plane normal vector of the column.

[0029] Calculate the local curvature of the point cloud. Determine the curvature by calculating the geometric shape change of the neighborhood of each point, such as the k-nearest neighbor points. At the nodes, due to the complexity of their structural shapes, the curvature is usually large; while the curvature of the main parts of beams and columns is relatively small. Different curvature thresholds can be set to distinguish different structural components. For example, points with curvatures greater than C1 may be points in the node area, and points with curvatures less than C2 (C2 < C1) may belong to the surfaces of beams or columns.

[0030] For the identification of columns, look for structural components with relatively large heights and basically the same cross-sectional shape in the vertical direction. By slicing the fitted plane in the vertical direction and analyzing the shape and area changes of each slice, if within a certain height range, such as the shape and area changes of the H shape are within the allowable range, such as setting the relative change rate as p, it can be determined as a column.

[0031] The identification of beams can be based on their slender shape characteristics. By calculating the length and width in the extension direction of the point cloud, the principal component analysis is used to determine the longest direction and calculate the length in this direction. The width is the maximum dimension perpendicular to the longest direction. If the ratio of length (L) to width (W) L / W is greater than the set threshold, such as L / W>5, it may be a beam.

[0032] Nodes are the connecting parts of beams and columns. By analyzing the connection relationship of the point cloud, we can find the areas that are connected to multiple structural components with different directions at the same time. For example, we first identify beams and columns, and then for each point, we count the number of points adjacent to it that belong to different structural components. Different structural components are distinguished by the previous shape recognition; if the number is greater than the set connection number threshold, the area where the point is located may be a node. And use these features to build a 3D model of the steel structure.

[0033] Step 5: Output the measured steel structure dimension data in the form of graphics and tables as a report.

[0034] It can be seen from the above embodiments that the steel structure dimension measurement method based on the combination of three-dimensional laser and total station of the present invention has the following advantages: High measurement accuracy: Combining 3D laser scanning and total station measurement technology improves the measurement accuracy of steel structure dimensions.

[0035] High measurement efficiency: Through automated data processing and feature extraction technology, manual operations are reduced and measurement efficiency is improved.

[0036] Strong applicability: This method is suitable for measuring the dimensions of steel structures of various complex shapes and has strong versatility and flexibility.

[0037] Data visualization: The measurement results are output in the form of graphs, tables, etc., which is convenient for users to view and analyze.

[0038] The embodiment of the present invention also provides a steel structure dimension measurement system based on the combination of three-dimensional laser and total station, including: a three-dimensional laser scanner, a total station, a data processing unit and an output device.

[0039] 3D laser scanner, used to scan the steel structure and obtain point cloud data of the steel structure surface; Total station, used to measure key points on the steel structure and obtain the three-dimensional coordinates of the key points; The data processing unit is used to convert the point cloud data acquired by the 3D laser scanner into the coordinate system of the total station to unify the point cloud data with the total station measurement data; extract the key feature points of the steel structure from the converted point cloud data; calculate the dimensions of the steel structure based on the extracted key feature points and the 3D coordinates of the key points measured by the total station; Output device, used to output the measured steel structure dimension data as a report in the form of graphics or tables.

[0040] In this embodiment, the data processing unit further includes a user interface, which allows a user to input parameters, view measurement data, and perform data analysis.

[0041] In this embodiment, the steel structure dimension measurement system based on the combination of three-dimensional laser and total station also includes: The data storage unit is used to store the measured steel structure dimension data.

[0042] The embodiment of the present invention further provides a storage medium, in which a computer program is stored, and when the computer program is executed by a processor, some or all of the steps in each embodiment of the steel structure dimension measurement method based on the combination of three-dimensional laser and total station provided by the present invention are implemented. The storage medium can be a magnetic disk, an optical disk, a read-only memory (English: Read-Only Memory, abbreviated: ROM) or a random access memory (English: Random Access Memory, abbreviated: RAM), etc.

[0043] Those skilled in the art can clearly understand that the technology in the embodiments of the present invention can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution in the embodiments of the present invention can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present invention or certain parts of the embodiments.

[0044] In this specification, the same or similar parts between the various embodiments can be referred to each other. In particular, for the steel structure dimension measurement system embodiment based on the combination of three-dimensional laser and total station, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description in the method embodiment.

[0045] The above-described embodiments of the present invention do not limit the protection scope of the present invention.

Claims

1. A steel structure dimension measurement method based on the combination of three-dimensional laser and total station, characterized in that: include: Use a 3D laser scanner to scan the steel structure and obtain point cloud data on the surface of the steel structure; Use the total station to measure the key points on the steel structure and obtain the three-dimensional coordinates of the key points; Convert the point cloud data obtained by the 3D laser scanner into the coordinate system of the total station to unify the point cloud data with the measurement data of the total station; The key feature points of the steel structure are extracted from the converted point cloud data; the local geometric features of the point cloud surface are reflected by the normal vector, and the normal vector of the point cloud is calculated using the principal component analysis method; the change rate of the normal vector of the point cloud is calculated; it is determined whether the change rate of the normal vector is greater than a preset threshold, and the points whose change rate is greater than the preset threshold are taken as key feature points; the curvature of the point cloud surface is described by the curvature, and the key feature points of the steel structure are extracted by calculating the local curvature of the point cloud; it is determined whether the curvature is greater than a preset threshold, and the points whose curvature is greater than the preset threshold are taken as key feature points; Calculate the dimensions of the steel structure based on the extracted key feature points and the three-dimensional coordinates of the key points measured by the total station; The measured steel structure dimension data is output as a report in the form of graphics and tables.

2. The steel structure dimension measurement method based on the combination of three-dimensional laser and total station as claimed in claim 1 is characterized in that: Before converting the point cloud data acquired by the three-dimensional laser scanner into the coordinate system of the total station, the method further includes: filtering, denoising and smoothing the point cloud data acquired by the three-dimensional laser scanner.

3. The steel structure dimension measurement method based on the combination of three-dimensional laser and total station as claimed in claim 1 is characterized in that: The point cloud data obtained by the 3D laser scanner is converted to the coordinate system of the total station using the following formula: ； in, is the azimuth of the point cloud based on the reference system, is the rotation matrix, is the scaling matrix, is the translation matrix, is the original coordinate matrix; ； in, is the transformed coordinate.

4. A steel structure dimension measurement system based on the combination of three-dimensional laser and total station, characterized in that: include: 3D laser scanners, total stations, data processing units and output devices; The three-dimensional laser scanner is used to scan the steel structure and obtain point cloud data on the surface of the steel structure; The total station is used to measure key points on the steel structure and obtain the three-dimensional coordinates of the key points; The data processing unit is used to convert the point cloud data acquired by the three-dimensional laser scanner into the coordinate system of the total station to achieve the unification of the point cloud data and the total station measurement data; in the converted point cloud data, the key feature points of the steel structure are extracted; wherein the local geometric features of the point cloud surface are reflected by the normal vector, and the normal vector of the point cloud is calculated using the principal component analysis method; the rate of change of the normal vector of the point cloud is calculated; it is determined whether the rate of change of the normal vector is greater than a preset threshold, and the points with a rate of change greater than the preset threshold are taken as key feature points; the curvature of the point cloud surface is described by the curvature, and the key feature points of the steel structure are extracted by calculating the local curvature of the point cloud; it is determined whether the curvature is greater than a preset threshold, and the points with a curvature greater than the preset threshold are taken as key feature points; various dimensions of the steel structure are calculated according to the extracted key feature points and the three-dimensional coordinates of the key points measured by the total station; The output device is used to output the measured steel structure dimension data as a report in the form of graphics or tables.

5. The steel structure dimension measurement system based on the combination of three-dimensional laser and total station as claimed in claim 4, characterized in that: The data processing unit also includes a user interface that allows a user to input parameters, view measurement data, and perform data analysis.

6. The steel structure dimension measurement system based on the combination of three-dimensional laser and total station as claimed in claim 5, characterized in that: Also includes: The data storage unit is used to store the measured steel structure dimension data.

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