Steel structure dimension measurement method and system based on the combination of 3D laser and total station

Abstract

The present invention discloses a steel structure dimension measurement method and system based on the combination of three-dimensional laser and total station, the method comprising: using a three-dimensional laser scanner to scan the steel structure to obtain point cloud data on the surface of the steel structure; using the total station to measure key points on the steel structure to obtain the three-dimensional coordinates of the key points; converting the point cloud data obtained by the three-dimensional laser scanner to the coordinate system of the total station to achieve the unification of the point cloud data and the total station measurement data; extracting the key feature points of the steel structure in the converted point cloud data; calculating the various 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; and outputting the measured steel structure dimension data in the form of graphics and tables as a report. The present invention combines the advantages of the two measurement technologies, improves the measurement accuracy and efficiency, and provides strong technical support for the manufacture, installation and detection of steel structures.

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:

[0005] 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;

[0006] 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;

[0007] 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;

[0008] 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;

[0009] The measured steel structure dimension data is output as a report in the form of graphics and tables.

[0010] 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.

[0011] 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:

[0012]

[0013] 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;

[0014]

[0015] in, is the transformed coordinate.

[0016] 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;

[0017] The three-dimensional laser scanner is used to scan the steel structure and obtain point cloud data on the surface of the steel structure;

[0018] The total station is used to measure key points on the steel structure and obtain the three-dimensional coordinates of the key points;

[0019] 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;

[0020] The output device is used to output the measured steel structure dimension data as a report in the form of graphics or tables.

[0021] Furthermore, the data processing unit also includes a user interface, which allows a user to input parameters, view measurement data and perform data analysis.

[0022] Furthermore, the system also includes:

[0023] The data storage unit is used to store the measured steel structure dimension data.

[0024] 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

[0025] 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 paying any creative labor.

[0026] 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

[0027] 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.

[0028] 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:

[0029] 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.

[0030] The 3D laser scanner uses a non-contact measurement method and can perform accurate measurements without damaging the surface of the steel structure.

[0031] 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.

[0032] 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.

[0033] 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:

[0034]

[0035] 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;

[0036]

[0037] in, is the transformed coordinate.

[0038] Step three: extract the key feature points of the steel structure from the converted point cloud data.

[0039] Specifically, the key feature points of the steel structure are extracted from the converted point cloud data, including:

[0040] 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.

[0041] The normal vector can reflect the local geometric features of the point cloud surface. The normal vector of the point cloud can be calculated using methods such as principal component analysis (PCA). Curvature can describe the degree of curvature 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. Common curvature calculation methods include curvature calculation based on normal vector change and curvature calculation based on least squares method. Points with large curvature usually correspond to key feature points such as edges and corners of steel structures. A curvature threshold can be set to take points with curvature greater than the threshold as key feature points. Points with large normal vector changes may also be key feature points. The normal vector change rate of the point cloud can be calculated, and points with large change rates can be taken as key feature points. Such as corner points, sidelines, etc., these feature points will serve as the basis for subsequent dimensional measurement.

[0042] Step 4: 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.

[0043] According to the extracted feature points and the coordinates of the key points measured by the total station, the various dimensions of the steel structure, such as length, width, height, angle, etc., are calculated.

[0044] For the surfaces of columns and beams, since they usually have large planar parts, the random sampling consensus (RANSAC) algorithm can be used for plane fitting. A small number of points, such as 3 points, are randomly selected from the point cloud; a plane equation is assumed, and then the number of points in the point cloud within a certain distance range of the plane is calculated, such as setting a threshold value of t; this process is repeated many times to find the plane containing the most points. The direction and position of the structural component are preliminarily determined based on the normal vector and position information of the fitted plane. For example, the plane normal vector of the column is usually perpendicular to the ground, while the plane normal vector of the beam has a specific angle relationship with the plane normal vector of the column.

[0045] Calculate the local curvature of the point cloud. The curvature is determined by calculating the geometric shape change of the neighborhood of each point, such as the k-nearest neighbors. For nodes, due to the complexity of their structural shapes, the curvature is usually large; while for the main parts of beams and columns, the curvature is relatively small. Different curvature thresholds can be set to distinguish different structural components. For example, points with a curvature greater than C1 may be points in the node area, and points with a curvature less than C2 (C2 < C1) may belong to the surface of beams or columns.

[0046] For the identification of columns, look for structural components with relatively large height and basically consistent cross-sectional shapes 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, and a relative change rate of p is set, then it can be determined as a column.

[0047] 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, using principal component analysis to determine the longest direction and calculate the length in this direction, and the width is the maximum dimension perpendicular to the longest direction. If the ratio of the length (L) to the width (W), L / W, is greater than the set threshold, such as L / W > 5, then it may be a beam.

[0048] Nodes are the connection parts of beams and columns. By analyzing the connection relationship of the point cloud, find the areas that are connected to multiple structural components with different directions at the same time. For example, first identify the beams and columns, and then for each point, count the number of points adjacent to it and belonging 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, then the area where the point is located may be a node. And use these features to construct a three-dimensional model of the steel structure.

[0049] Step five, output the measured steel structure dimension data in the form of graphics and tables as a report.

[0050] As can be seen from the above embodiments, 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:

[0051] High measurement accuracy: By combining three-dimensional laser scanning and total station measurement technologies, the measurement accuracy of the steel structure dimensions is improved.

[0052] High measurement efficiency: Through automated data processing and feature extraction technologies, manual operations are reduced, and the measurement efficiency is improved.

[0053] Strong applicability: This method is applicable to the measurement of steel structure dimensions with various complex shapes, and has strong versatility and flexibility.

[0054] Data visualization: The measurement results are output in the form of graphics, tables, etc., which is convenient for users to view and analyze.

[0055] 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.

[0056] 3D laser scanner, used to scan the steel structure and obtain point cloud data of the steel structure surface;

[0057] Total station, used to measure key points on the steel structure and obtain the three-dimensional coordinates of the key points;

[0058] 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;

[0059] Output device, used to output the measured steel structure dimension data as a report in the form of graphics or tables.

[0060] 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.

[0061] In this embodiment, the steel structure dimension measurement system based on the combination of three-dimensional laser and total station also includes:

[0062] The data storage unit is used to store the measured steel structure dimension data.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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; Filter, denoise and smooth the point cloud data obtained by the 3D laser scanner; The point cloud data obtained by the 3D laser scanner is converted to the coordinate system of the total station to achieve the unification of the point cloud data and the total station measurement data; the point cloud data obtained by the 3D laser scanner is converted to the coordinate system of the total station using the following formula: ； Among them, θ is the azimuth of the point cloud based on the reference system, R is the rotation matrix, S is the scaling matrix, T is the translation matrix, and A is the original coordinate matrix; ； in, is the transformed coordinate; 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. 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 filter, denoise and smooth the point cloud data obtained by the three-dimensional laser scanner; convert the point cloud data obtained 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 measurement data of the total station; the point cloud data obtained by the three-dimensional laser scanner is converted into the coordinate system of the total station using the following formula: ； Among them, θ is the azimuth of the point cloud based on the reference system, R is the rotation matrix, S is the scaling matrix, T is the translation matrix, and A is the original coordinate matrix; ； in, is the converted coordinate; 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 whose rate of change 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; 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; The data processing unit further comprises a user interface, which allows the user to input parameters, view measurement data and perform data analysis; 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.

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