Researchand Implementation Of 3D Point Cloud Hole Repairalgorithm

Engineering and technical personnel in the use of three-dimensional scanning equipment to collect three-dimensional point cloud raw data,due to object surface reflections,line of sight obscuration and equipment jitter,etc.,may appear point cloud local data missing situation that the holes in this paper,and three-dimensional point cloud raw data in the formation of triangular grid point cloud through triangulation will also form holes due to local data missing.These holes will directly affect the downstream work such as target detection,medical imaging and 3D reconstruction,so the missing point cloud data should be repaired.For the holes in 3D point cloud raw data,this paper proposes a hole repair method based on invalid point array point cloud holes and a hole repair method based on profile degree scattered point cloud holes.For the holes in the triangular mesh point cloud formed by the original 3D point cloud data,this paper proposes a triangular mesh hole repair method based on wavefront method.Finally,for better visualization,this paper develops a client based on Win Form platform.For the problems such as poor quality of repair triangles in triangular mesh point cloud hole repair method,this paper proposes a triangular mesh hole repair method based on wavefront method.Firstly,the set of hole edges is screened according to the hole edge characteristics,and then the set of hole edges is classified to find the first and last connected holes;after locating the hole location,the hole is to be interpolated and repaired by using the advancing wavefront method based on the four minimum angle principles;finally,the triangle formed by the interpolated points is checked by Delaunay criterion,and if it does not satisfy,the diagonals of the triangle are exchanged.For the problems of noise introduction,slow speed and poor repair quality in array point cloud hole repair,this paper proposes a hole repair method based on invalid point array point cloud.Firstly,the median filtering is improved based on the characteristics of the invalid values generated by the line laser camera and the histogram principle.The improved method is to create a histogram of the z-values of the array point cloud and quickly find the median by counting the frequency of the z-values of each point of the array point cloud,which greatly increases the speed of filtering;then,based on the point cloud normal vector information,the neighboring points of each invalid value are found and the plane is fitted with the least squares method,and the new points are interpolated from the invalid points and interpolate the new points from the invalid points and the plane;finally,the method is accelerated by using AMP-GPU to further improve the speed.For the problems of poor repair quality and difficult repair in scattered point cloud hole repair,this paper proposes a contour-degree based scattered point cloud hole repair method.The profile degree refers to the variation of the measured actual contour relative to the ideal contour,and this paper repairs the holes in the scattered point cloud by analogy with the profile degree principle.Firstly,the general alignment method is improved,the key points are extracted by ISS algorithm and described by 3DSC descriptors,and the ISS-3DSC features are formed and then coarse alignment is performed by RANSAC algorithm and fine alignment is performed by ICP algorithm;after finishing the alignment,the missing hole points in the source point cloud are calculated by thresholding based on the profile degree principle.In order to verify the effectiveness of the method in this paper,multiple sets of experimental analyses were conducted on Stanford data as well as data scanned by ourselves.In the triangular mesh hole repair method based on wavefront method,the evaluation function μ value of triangles repaired by this paper is generally higher,and the average percentage of this paper’s method is 18.9% in the region of higher evaluation index(0.9,1),which is much larger than 4.3% of the common method,effectively improving the quality of triangles.In the repair method based on invalid point array point cloud hole repair method,this paper compares the time of median filtering,when the number of points reaches about 500,000,this paper’s method is only 0.225 times of the traditional method,as the number of points increases,the more obvious the advantage of this paper’s method,meanwhile,the error analysis of the repaired data is carried out,and the calculated RMSE=0.37,the experiment shows that the repair quality is better.In the contour-based scattered point cloud hole repair method,this paper compares three key point detection methods,the ISS algorithm extracts about 7 times more key points than 3D-Harris when the time is approximately the same,and also compares three alignment methods,this paper has better alignment effect,and the hole repair effect can be obtained from the experiment has a great relationship with the set threshold value,in rabit,Armadill data with H=3.5 or so has the best repair effect,and in the Apple 11 phone case with H=2.1 has the best repair effect.