Research On Surface Reconstruction Method Of Poisson Target Body Based On Multi-grid

Geological interpretation based on the geological study and geological oil field has been widely used,including geological tectonics,geological stratigraphy.And the three dimensional geological curved surface reconstruction process is within the scope of the work area is very important in the process of the geological interpretation of a link,it can be collected in geological scattered points which was more image approach is presented to geological analysis,and a better understanding of the earth's surface under geological form to make an accurate analysis,and judgment.At this stage for three dimensional point cloud surface reconstruction,there are two solutions: the first method is to use the 3 d visual modeling software Petrel of each point on the use of point cloud surface such as a scalar function recovers surface;The second method is the method of using the normal vector at every point cloud reconstruction of 3d point cloud surface,for example by marching cube algorithm of triangles in the classification method to extract the level to restore the surface of the object being sampled.In the actual sampling process of 3d geological surface,often with a large number of big noise and redundant points,where to point cloud surface reconstruction,first carries on the pretreatment.However,the existing solutions are all parts of the point cloud area as no thickness and uniform distribution,and there is no combination can reflect the information of topological characteristics of point cloud data,so the effect of surface recovers often has a certain gap and the actual demand.According to the practical situation of geological surface,this thesis puts forward the corresponding the point cloud pretreatment and its surface reconstruction based on multiple grid method,and by using the geological surface information in the actual work area of the proposed scheme is verified.The main work accomplished in the thesis is as follows:1.In common three-dimensional geometry in geological samples with noise and redundant points in the process of and the phenomenon of repeated sampling,which leads to the sectional area of closed surface point cloud,there will be a certain thickness and thickness is uneven,for this kind of situation,combining with the idea of multiple grid and mapping between each point to each grid point cloud of thought is put forward based on the Poisson equation of curved surface reconstruction method.First of all,with the thickness of the closed surface point cloud to streamline processing,including in three-dimensional space grid structure cube,all point to point cloud to each unit grid mapping,structure for the grid of double step length and the method of tectonic structure elements for a series of concise point cloud.Simplified point cloud,the use of covariance method to point cloud of each point vector and make it toward the same direction.Then the adjusted the divergence of the normal vector into 3d multi-grid iteration solving Poisson equation.Finally using marching cube algorithm pick up the contour surface.2.In the geological exploration of common open surface sampling process,easy to mix a lot of noise points,causes the sampling to get open surface point cloud surface is not smooth.In order to get a satisfactory effect after surface reconstruction,so we need to split surface to smooth processing,point cloud concrete steps include: within the work area of geological mesh dissection on open surface,the curvature at every point calculation point cloud information,construct the two-dimensional Poisson equation of point cloud coordinates the multi-grid iteration.Smooth after the point cloud,the use of covariance method to calculate the normal vector at every point cloud information and uniformity,adjustment,and will be adjusted the divergence of the normal vector into 3d multi-grid iteration solving Poisson equation,finally using marching cube algorithm extract the level.3.In this thesis,combined with the actual work area,the above proposed different geological curved surface reconstruction scheme applied to the real geological curved surface are simulated,the reconstruction of surface shape,founding reconstruction results meet the practical requirements.