Research On Hydraulic Model Measurement Technology Based On New 3D Laser Scanning Device

At present,the construction of dams on rivers has blocked natural river channels,resulting in changes in the flow regimes of the river channels,which in turn has led to changes in the hydrological characteristics of the upper and lower reaches and estuaries of the entire river.The phenomena of convection,diffusion,sedimentation,and resuspension of sediment are three-dimensional physical processes.Therefore,to accurately describe the process of sediment movement,three-dimensional numerical model of sediment must be the development direction of sediment research.Traditional DEM construction methods,such as field control measurement methods,have large work intensity,high cost,time consuming,and are easily limited by the field of view.They are not suitable for large-scale data collection;such as topographic map scanning digital methods,high efficiency,simple data collection operations,and collection Low cost,it is the main data source for constructing geographic information database,but the mapping accuracy is low,there are problems in vectorization and data processing process;close-range digital photogrammetry,the acquisition process is complex,the mapping cycle is long,the cost is high,and the scope of application is difficult Generalized,the experimental area covered by the checkpoint,the DEM landslide model constructed can hardly conform to the actual terrain surface of the experimental site.Compared with the traditional surveying and mapping technology,the 3D laser scanning technology on the ground has a large amount of collected data,a wide scanning area,convenient operation,and high data accuracy.In this paper,a high-precision DEM model of the experimental area is established by a fixed-station 3D laser scanning method.The processing of point cloud data in the experimental area and determining the optimal interpolation method and grid resolution are the important topics of this paper.The main research contents are as follows:1.Put forward the research background and significance of this article.The reasons and harms of sediment deposition and the development of laser scanning ranging technology are briefly introduced;the current status of research development at home and abroad is elaborated;this article is planned on the basis of summarizing the research of DEM interpolation and grid resolution at home and abroad today.Research ideas and goals.2.A new method of point cloud data collection in the experimental area.For the existing tripod stand,the human error of high centering and amount of alignment,as well as the indoor orbit mounting method,bridge crane mounting method,and other equipment are too huge and cumbersome,and cannot be moved,disassembled,assembled,and swept.The method is relatively single and cannot perform multi-row and multi-column scanning.This invention discloses a three-dimensional laser scanner carrying lifting system and its optimal tilt angle adjustment method,which can lift the three-dimensional laser scanner to a predetermined height and assemble it.Simple,easy to move stations,convenient for multi-station measurement.The lens tilt measurement of the 3D laser scanner collects point cloud data,which solves the problems of low data collection efficiency and low accuracy caused by the scanning line being blocked.3.Multi-site cloud data denoising and splicing processing.First,perform multi-site cloud data splicing processing,and perform data splicing processing on the multi-station and multi-view block point cloud data in the experimental area to obtain a complete surface point cloud of the experimental area;secondly,perform point cloud denoising processing,Elimination of outliers and non-experimental point cloud data caused by occlusion and other issues;Finally,point cloud thinning processing is performed to save data processing time and disk space and improve experimental efficiency while ensuring that the model characteristics of the experimental area are well preserved effect.4.Research on DEM construction method and error model.This paper introduces and compares traditional DEM data acquisition methods and new 3D laser scanning technologies,methods for establishing digital terrain surface models,DEM error classification,source analysis,and accuracy analysis.This paper uses 3D laser scanning technology to collect point cloud data on the surface of the experimental area.Based on the grid surface modeling,a suitable DEM accuracy analysis method is selected.5.Determine the optimal interpolation method and grid resolution.Data processing and information extraction were performed using Surfer and Arcgis software.Several common interpolation methods provided by surfer software are used to interpolate according to terrain features,perform qualitative and quantitative analysis to select the best interpolation method,and based on the basic principle of elevation information entropy,the linearity of the DEM grid spacing and the error in the DEM points is obtained.relationship.The slope topographic factors of the DEM model in the experimental area are analyzed,and the slope and aspect data are extracted through the DEM obtained in the experimental area for comparative analysis.The relationship between the slope,the aspect and the resolution of the DEM grid is studied.Finally,the best grid spacing is obtained.