Application of point cloud intelligent drawing in intelligent construction site

Application of point cloud intelligent painting in intelligent construction site

The point cloud obtained by airborne lidar and image-based dense matching technology can be used to monitor the construction progress of construction site and calculate the filling and excavation , Pictured 1 Shown .

chart 1 Display of point cloud data of construction site obtained by airborne laser radar point cloud

01 Technical process
Users get multiple phases （ At least two phases ） Behind the point cloud , be based on PCA The software can process point cloud data according to the following process .

This case contains two phases of point cloud data and one shapefile Format of two site outline polygon files , Pictured 2 Shown . The point cloud data of the two phases are photogrammetric point clouds , The experimental area is located in the Hong Kong Special Administrative Region of China .

（a） Point cloud data of the previous phase

（b） Point cloud data of the latter phase

（c） Polygonal boundary of two construction sites

chart 2 Two phase point cloud and site polygon

（1） Crop out the point cloud data of the region of interest
For two phases of point cloud data , Using the cloud pictures respectively “ cutting ” The tool obtains the point cloud data of the site area of interest .“ cutting ” In the tools , Choose to use “ Block according to the following chart ” The pattern of , Allow users to take advantage of shapefile Format polygon file to cut the original point cloud data , Pictured 3 Shown .

chart 3 “ cutting ” Tools

Obtain the data of the region of interest of the two phase point cloud, as shown in the figure 4 Shown .

chart 4 Before the region of interest （ Left ） after （ Right ） Two phases of point cloud data , The point cloud data of each issue includes the following 、 The next two construction sites

（2） Gross error elimination （ Optional ）
If there is a rough handicap in the point cloud , It is recommended to eliminate noise . The shape and spatial distribution characteristics of the noise are different , The user needs to select the appropriate noise elimination method according to the actual situation . If the user is a beginner , It is recommended that users use figure 5 in “SOR filter ”.

chart 5 Noise removal tool in cloud image

（3） Point cloud filtering （ Fine terrain extraction ）
It is suggested to use Yunxiang's “ One click plain fine terrain extraction （ No reference ）” Filter the point cloud data to distinguish the ground points in the point cloud 、 Non ground point .“ One click plain fine terrain extraction （ No reference ）” The position of the tool is shown in the figure 6 Shown .

chart 6 “ One click plain fine terrain extraction （ No reference ）” The location of the tool

The ground points obtained by filtering the point cloud data of the region of interest in the previous and subsequent phases of the two construction sites are shown in the figure 7 Shown .

chart 7 Before the region of interest （ Left ） after （ Right ） Ground points of the two phases

（4） Calculation of earthwork volume for filling and excavation
Select the point cloud data to be processed before and after a construction site , adopt “ Calculation of earthwork volume for filling and excavation ” Tool to calculate earthwork volume ,“ Calculation of earthwork volume for filling and excavation ” The tool position is shown in the figure 8 Shown .

chart 8 “ Calculation of earthwork volume for filling and excavation ” Tool location

Click on “ Calculation of earthwork volume for filling and excavation ” On the tool interface “ to update ” Button can automatically calculate the volume 、 Fill volume 、 Excavation volume , The interface is as shown in the figure 9 Shown .

chart 9 Volume 、 Fill volume 、 Result diagram of excavation volume

The key parameters are set as shown in the figure 10 Shown . Be careful ,“ step ” The smaller it is , The more precise the volume calculation is , But not too small , Recommended setting is 0.5 Rice or so .

chart 10 Setting of key parameters

construction site 1 Volume 、 Fill volume 、 The specific contents related to statistical indicators such as excavation volume are as follows ：

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Volume ：-7,347.073 Cubic meters

Surface area : 156,882.500 Square meters

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Fill volume ：(+)16,180.567 Cubic meters

Excavation volume ：(-)23,527.639 Cubic meters

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construction site 2 Volume 、 Fill volume 、 The specific contents related to statistical indicators such as excavation volume are as follows ：

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Volume ：-26,717.922 Cubic meters

Surface area : 151,144.750 Square meters

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Fill volume ：(+)7,477.177 Cubic meters

Excavation volume ：(-)34,195.099 Cubic meters

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in addition ,PCA The software also allows users to pass through “ Export grid as point cloud ” Button to export the change detection results , It is convenient for users to directly understand the general situation of the construction site , Where was the earth dug , Which places are filled with earth , Pictured 11 Shown .

chart 11 construction site 2 The change detection results show that

02 summary
Use PCA The software can process multi-phase point cloud data of the same building site , Locate the fill at the site 、 Excavation 、 Location of cut and fill , Accurately calculate mass haul volume data , And visually display the change results . in addition , The technical process of this paper can also be used for multi-stage point cloud panel coal 、 Landslide and debris flow detection 、 Earthwork calculation, etc .