Research On Scattered Point Cloud Model Hole Filling Technology In Reverse Engineering

With the maturity of three-dimensional point cloud data acquisition technology,advanced measurement equipment can be used to rapidly acquire high-precision mass point cloud data on the surface of an object in a short time.Moreover,point cloud models are widely used in reverse engineering,topographic mapping,virtual scene construction,medical diagnosis and other fields due to their low cost and convenient storage.A perfect point cloud model is the basis for downstream applications.However,in the actual point cloud data collection process,due to various factors such as operation technology,physical objects and measurement environment,the measured point cloud data are incomplete and various holes are formed in the point cloud model.The existence of holes in the point cloud model not only affects the display effect of the model,but also has a great impact on subsequent point cloud data processing and analysis operations.Therefore,it is necessary to repair holes in the point cloud model so as to ensure the integrity of the point cloud data and lay a foundation for downstream model reconstruction,rapid prototyping and simulation analysis.After a large number of literature research,this paper focuses on the hole repair technology of 3D scattered point cloud model from the following three aspects on the basis of analyzing the causes of hole formation in point cloud model and existing hole repair methods:(1)Intelligent patching:The holes in point cloud models are classified.BP neural network,RBF neural network,ELM neural network and reverse software hole repair methods are applied to different types of artificial holes in different models respectively.By comparing the deviation of repair point cloud obtained by various hole repair methods and the running time of programs,repair strategies for different types of holes are summarized,which can provide reference for intelligent repair of natural holes in other point cloud models.(2)Parallel repair: To solve the problem that the repair of point cloud models with a large number of holes takes a lot of time,based on the existing hole repair methods of scattered point cloud models,parallel computing technology based on multi-core CPU is applied in the hole repair process of point cloud models to realize parallel repair of multiple holes of point cloud models.On the premise of ensuring the hole repair accuracy,the hole repair time of point cloud models is reduced,and the hole repair efficiency is improved.(3)Automatic patching: In order to solve the problem that many links in the hole repair process of scattered point cloud models need to be completed through human-computer interaction and the steps are tedious and time consuming,the hole identification,hole region interpolation and hole repair are combined through computer programming to realize automatic hole repair from incomplete point cloud models to complete point cloud models,which greatly reduces the workload of human-computer interaction,improves the automation degree of point cloud model repair,and makes the hole repair of point cloud models more convenient and efficient.In addition,due to the adoption of the interpolation point selection method for the hole region with equal step length growth,the obtained interpolation points are more uniform in density than those selected by the traditional method,have better matching with the density of the point cloud around the hole,and contribute to improving the hole repair quality of the point cloud model to a certain extent.In order to verify the practicality of the above-mentioned point cloud model hole repair method,multiple point cloud models are used to verify it.The experimental results show that: in the point cloud model hole repair process,the above hole repair method is better than the traditional hole repair in some aspects method.At the same time,it summarizes the innovations and shortcomings of this paper,and looks forward to the future development trend of the point cloud model hole repair technology,which provides a useful reference for the further improvement of the point cloud model hole repair technology.