Research On Processing Accuracy Of Freeform Surfaces Based On Discrete Detection Point Cloud Three-dimensional Reconstruction

With the rapid development of science and technology,3D point cloud data processing technology has been widely used in the high and new fields such as computer vision,scientific computing,virtual reality and so on,and it plays a more and more important role in various fields.Model reconstruction based on 3D point cloud data is a very important part of3 D point cloud data processing technology,and is an important basis for a series of operations and applications.In view of a large number of three dimensional point cloud data,a more fine point detection algorithm is developed to accurately realize 3D reconstruction of the free surface model.It is of great theoretical significance and engineering application value for the application of 3D point cloud data.Therefore,this paper will study the model reconstruction based on 3D point cloud data,the way of free surface detection and the precision of reconstruction.The main research contents are as follows:First of all,this thesis discusses the research status of 3D data acquisition and 3D surface reconstruction technology at home and abroad,and introduces the basic theory of 3D point cloud data processing.On this basis,the related knowledge of the isometric method is further introduced,and the mathematical models of three algorithms are set up,namely,the isometric point detection method,the triangle point detection method and the curvature based point detection method,which provide the theoretical basis for the following three algorithms.Secondly,the free surface model is designed,the actual workpiece surface is processed and the point cloud data is detected.Based on the extracted detection data,the Matlab is used as the tool to fit and reconstruct the free-form surface based on the Delaunay algorithm fitting method,the polynomial fitting method and the local weighted regression method,and the corresponding residual graph is drawn.The DT algorithm is used to fit the free-form surface for 3D surface.Thirdly,according to the mathematical model and the point taking principle of the three kinds of point extraction algorithms proposed in this paper,a variety of different point extraction schemes are designed.The three-dimensional surface of the free surface under the corresponding scheme is taken and reconstructed on the determined detection surface.According to the ICP algorithm,the three dimensional surface and the design surface are completed respectively.Registration.According to the registration information,the deviation precision between the three dimensional surface and the design surface corresponding to all the schemes is given.In addition,the influence of the detection of the different length width ratio and the angle of different angles on the detection of the triangle point is also analyzed.Based on the above contents,the following conclusions can be drawn if the number of points is the same.(1)when using the isometric point detection algorithm,the square width ratio isometric point algorithm is better than the other length and width ratio algorithm.(2)when the triangle point detection algorithm is used,the equilateral triangle fetching detection algorithm is better than the other triangles detection algorithm;(3)the isometric point and the triangle point are compared.The detection algorithm of the equilateral triangle detection algorithm is better than the square equidistant point detection algorithm.(4)further analysis shows that the equilateral triangle detection algorithm based on the curvature change is not better than the equilateral triangle sampling detection algorithm without the change of curvature.Therefore,in the actual industrial environment,the equilateral triangle point detection algorithm will get the best result.In the product digital modeling engineering,the precision processing technology of 3D data processing precision information will play a more and more important role.Through the conclusion and method verified in this paper,it can meet the needs of practical engineering application,and can help realize the more accurate reconstruction of the 3D model,and apply it to the actual industrial processing and field.Production,paperless design and R & D and other fields have important theoretical significance and industrial economic value.