Research On Karst Cave Point Cloud Data Registration And Filtering Processing Technology

With the rapid development of spatial information acquisition technology,the two-dimensional surveying and mapping results are far from meeting the development requirements,and people have gradually turned to the research of three-dimensional surveying and mapping technology.Terrestrial Laser Scanning(TLS)is another major breakthrough in spatial information collection.It is a non-contact measurement method with high efficiency and precision,and has been widely used in topographic survey,cultural relic protection,deformation monitoring,digital city and geological disaster management.With the change of spatial data acquisition mode,field measurement technology has developed rapidly,while the processing technology of collected point cloud data has developed relatively slowly,and a set of fast,accurate and highly automated data processing method is urgently needed to promote the development of 3D laser scanning technology and make this technology more widely used in production and life.Firstly,based on the study of the principle,application field and scanner equipment of three-dimensional laser scanning technology on the ground,based on the point cloud data acquisition of karst caves,and according to the point cloud data registration principle,three different point cloud data registration technologies based on feature features,combination of feature features and feature surfaces,and automatic registration based on ICP iteration are organized respectively.Through the experimental study and the comparative analysis of the three registration techniques,the application of the core technology of karst cave point cloud data matching processing is obtained.The results show that,on the whole,the accuracy of Root Meam Square(RMS)values of the matching results under three different registration modes can reach the millimeter level,but in particular,the accuracy of RMS values can reach the millimeter level.Compared with the application of the three registration methods,the ICP iterative automatic registration method has higher accuracy and less workload,and is more recommended for the registration of karst cave point cloud data.Secondly,in the research of point cloud data filtering and processing technology for karst cave shape modeling,based on the study and comparison of the current mainstream point cloud filtering and denoising methods,according to the characteristics of karst cave point cloud in the experimental area,a filtering method using area-growing encryption triangular network is proposed to apply to the filtering and processing of karst cave point cloud data.Combining with Visual Studio 2012 software platform,the method is applied to the filtering and processing of karst cave point cloud data.The point cloud data in the survey area is divided into regional grids,and the lowest point in each grid is extracted as the initial ground point.The regional growth of point cloud data is achieved by setting a threshold.Using I-Site Studio software platform,the experimental study of point cloud data filtering for karst caves is carried out.The results show that when the region grows to the third time,the algorithm has filtered out the noise points and part of the object points,and retained the geometric features of the terrain well.Compared with other filtering methods,the method is more suitable for filtering point cloud data with complex topography and landform.It can also provide a better data base for the surface construction of point cloud data in the later stage.Finally,in order to ensure the integrity of data information,the data of karst cave point cloud is roughly divided into two parts,which are based on two different software platforms for surface construction.One is based on topographic data of I-Site Studio software platform,the other is based on the number of objects in Geomagic Studio software platform.According to the surface construction,the final integration of model data to obtain a high-precision and complete three-dimensional model.The experimental results show that I-Site Studio software is more suitable for surface construction of topographic data.When the requirement for surface fitting is high,Geomagic Studio software platform is used for surface fitting.Combining the two methods of surface fitting,a model data with high accuracy can be obtained.Different data fitting methods for different surface fitting objects are more suitable for Karst cave point cloud.A model construction of data.