Method for establishing coordinate system by using virtual target

Abstract

The invention discloses a method for establishing a coordinate system by using a virtual target, and solves the problem of how to ensure the precision of a point cloud establishment control coordinate system when a whole scanning area cannot be controlled when a measurement entity target is laid. A total station prism-free polar coordinate method is utilized, six point positions are evenly and accurately measured on the top opening of the steel pipe pile farthest away from the trestle side, and the center coordinates of the top opening of the steel pipe pile are calculated in a fitting mode; and then the center of a top opening of the steel pipe pile serves as a virtual target, the virtual target and other entity targets on the trestle jointly control the whole scanning area, and therefore a control coordinate system is established, and the precision of the whole point cloud coordinate is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge engineering surveying, and particularly to a method for establishing a coordinate system using virtual targets. Background Art

[0002] When constructing a cross-sea high-speed railway bridge, a construction trestle is erected in parallel on one side of the line for passage. During the construction process, after the steel pipe piles are sunk, a three-dimensional laser scanning measurement method is used for as-built survey. However, since the trestle is only erected on one side of the line, during the pile foundation construction period, personnel cannot directly access the pile foundation, and the measurement targets can only be arranged on one side of the trestle, unable to completely control the measurement area. As a result, when establishing a coordinate system for the point cloud after three-dimensional laser scanning, only the targets on one side of the trestle can be relied on to control the establishment of the coordinate system. The farther the scanned object is from the target, the greater the error, especially the elevation error. Summary of the Invention

[0003] The present application proposes a method for establishing a coordinate system using virtual targets, which has the advantages of establishing a coordinate system and finally obtaining a point cloud calibrated by the coordinate system, so as to solve the problem that the arranged physical measurement targets cannot control the entire scanning area.

[0004] To achieve the above object, the present application adopts the following technical solutions: A method for establishing a coordinate system using virtual targets includes the following steps: The first step: Install three physical measurement targets on the trestle, then set up a total station, and accurately measure the center coordinates of the three measurement targets by using the total station polar coordinate method. The top of the steel pipe pile is used as the scanning area of the total station, and six points are accurately measured evenly on the top of the steel pipe pile farthest from the trestle. The second step: Import the six points measured on the top of the steel pipe pile into the processing software in point cloud format; use the circle drawing tool to click on the six points in sequence to obtain the three-dimensional coordinates of the center of the top of the steel pipe pile, and this coordinate is the coordinate of the virtual target. The third step: Import the point cloud after splicing and processing into the processing software, use the circle drawing tool to evenly fit the center of the top of the steel pipe pile on the same steel pipe pile, and mark the center of the top of the steel pipe pile in the form of a point. This point will be used as the virtual target in the fourth step. Then, merge the center point of the top of the steel pipe pile with the processed point cloud into a new point cloud, and export the point cloud containing the center point of the top of the steel pipe pile in point cloud formats such as LGS or LAS. The fourth step: Import the new point cloud into the splicing software, import the three-dimensional coordinates of the three physical measurement targets and the virtual target as control point coordinates, calibrate the positions of the three physical measurement targets and the virtual target in the new point cloud in sequence, and then apply control to establish a coordinate system, and finally obtain a point cloud calibrated by the coordinate system.

[0005] Further, the entity measurement targets are respectively measurement target one, measurement target two, and measurement target three.

[0006] Further, the processing software is Cyclone 3DR software.

[0007] Further, the stitching software is Cyclone REGISTER 360 PLUS software.

[0008] The present invention has the following beneficial effects: Through a method for establishing a coordinate system using a virtual target provided by the present application, the problem of how to ensure the accuracy of the control coordinate system established by the point cloud when laying out the measurement entity targets and when the entire scanning area cannot be controlled is solved. Using the total station prism-free polar coordinate method, six points are evenly and accurately measured on the top of the steel pipe pile at the farthest distance from the side of the trestle, and the top center coordinates of the steel pipe pile are calculated by fitting; then, taking the top center of the steel pipe pile as the virtual target and combining it with the entity targets on the rest of the trestle to jointly control the entire scanning area, thereby establishing a control coordinate system and ensuring the accuracy of the entire point cloud coordinates. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings forming a part of the specification depict the embodiments disclosed in the present application and, together with the specification, are used to explain the principles disclosed in the present application.

[0010] Referring to the drawings, the present disclosure can be more clearly understood from the following detailed description, wherein: Figure 1 is a schematic diagram of the operation of the present application; Figure 2 is a schematic diagram of the processing in Step 1 of the present application; Figure 3 is a schematic diagram of the processing in Step 2 of the present application Figure 1 ; Figure 4 is a schematic diagram of the processing in Step 2 of the present application Figure 2 ; Figure 5 is a schematic diagram of the processing in Step 3 of the present application; Figure 6 is a schematic diagram of the processing in Step 4 of the present application.

[0011] In the figure: 1, steel pipe pile; 2, scanning area; 3, trestle; 4, measurement target one; 5, measurement target two; 6, measurement target three; 7, total station; 8, virtual target. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0012] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts belong to the scope of protection of the present application.

[0013] Please refer to Figures 1-6 As shown in the figure, a method for establishing a coordinate system using a virtual target includes the following steps: The first step: Install three physical measurement targets on the trestle 3, namely measurement target one 4, measurement target two 5, and measurement target three 6. Then set up a total station 7, and use the polar coordinate method of the total station to accurately measure the center coordinates of the three measurement targets. The top opening of the steel pipe pile 1 is used as the scanning area 2 of the total station 7, and six points are evenly and accurately measured on the top opening of the steel pipe pile 1 that is farthest from the trestle 3. The second step: Import the six points on the top opening of the measured steel pipe pile 1 into the Cyclone 3DR software in the form of point cloud; use the circle drawing tool to click on the six points in sequence to obtain the three-dimensional coordinates of the center of the top opening of the steel pipe pile 1, and this coordinate is the coordinate of the virtual target 8. The third step: Import the point cloud after splicing and processing into the Cyclone 3DR software, use the circle drawing tool to evenly fit the center of the top opening of the steel pipe pile 1 on the same steel pipe pile 1, and mark the center of the top opening of the steel pipe pile 1 in the form of a point. This point will be used as the virtual target 8 in the fourth step. Then merge the center point of the top opening of the steel pipe pile 1 with the processed point cloud into a new point cloud, and export the point cloud containing the center point of the top opening of the steel pipe pile 1 in the point cloud format such as LGS or LAS. The fourth step: Import the new point cloud into the Cyclone REGISTER 360 PLUS splicing software, import the three-dimensional coordinates of the three physical measurement targets (i.e., measurement target one 4, measurement target two 5, and measurement target three 6) and the virtual target 8 as control point coordinates, calibrate the positions of the three physical measurement targets and the virtual target 8 in the new point cloud in sequence, and then apply control to establish a coordinate system, and finally obtain the point cloud after coordinate system calibration.

[0014] To sum up, in the process of point cloud processing, using a method for establishing a coordinate system using a virtual target can effectively improve the accuracy of point cloud coordinates, and the accuracy is equal to that of the total station, meeting the accuracy requirements of the completion measurement of steel pipe piles. In similar engineering applications, in the case where physical measurement targets cannot be arranged, using a method for establishing a coordinate system using a virtual target can effectively control the accuracy of point cloud coordinates.

Claims

1. A method for establishing a coordinate system using a virtual target, characterized in that, It includes the following steps: The first step: Install three physical measurement targets on the trestle, then set up a total station, and use the polar coordinate method of the total station to accurately measure the center coordinates of the three measurement targets. The top of the steel pipe pile is used as the scanning area of the total station, and six points are evenly and accurately measured on the top of the steel pipe pile farthest from the trestle; The second step: Import the six points on the top of the measured steel pipe pile into the processing software in the form of point cloud; Use the circle drawing tool to click on the six points in sequence to obtain the three-dimensional coordinates of the center of the top of the steel pipe pile, and this coordinate is the coordinate of the virtual target; The third step: Import the point cloud after splicing and processing into the processing software. Use the circle drawing tool to evenly fit the center of the top of the steel pipe pile on the same steel pipe pile, and mark the center of the top of the steel pipe pile in the form of a point. This point will be used as the virtual target in the fourth step. Then, merge the center point of the top of the steel pipe pile with the processed point cloud to form a new point cloud, and export the point cloud containing the center point of the top of the steel pipe pile in the point cloud format such as LGS or LAS; The fourth step: Import the new point cloud into the splicing software, import the three-dimensional coordinates of the three physical measurement targets and the virtual target as the control point coordinates, calibrate the positions of the three physical measurement targets and the virtual target in the new point cloud in sequence, and then apply the control to establish a coordinate system, and finally obtain the point cloud after coordinate system calibration; 2. The method for establishing a coordinate system using a virtual target according to claim 1, characterized in that, The physical measurement targets are respectively Measurement Target 1, Measurement Target 2, and Measurement Target 3.

3. The method for establishing a coordinate system by using a virtual target according to claim 1, wherein The processing software is Cyclone 3DR software.

4. The method for establishing a coordinate system by using a virtual target according to claim 1, wherein, The splicing software is Cyclone REGISTER 360 PLUS software.

Images