# Optimization of the 3D Point Cloud Registration Algorithm Based on FPFH Features
## 5 Conclusions  
An improved point cloud registration method is proposed in this paper. In the rough registration stage, ISS feature point extraction, which combined the feature points extraction algorithm based on octree methods and the noise points filtering algorithm, is used to verify the feasibility of the proposed method. Finally, the mismatching point pairs are eliminated by combining the edge feature point removal algorithm with the RANSAC algorithm. In the precise registration stage, a new nearest neighbor selection method is proposed, and the ICP algorithm precise registration algorithm is improved by using curvature and FPFH features, which are verified by experiment. Compared with the traditional algorithm, the speed and accuracy of registration in this paper have been improved. The research conclusions are as follows:  
1) In the rough registration stage, this paper improves the point cloud feature point extraction method and point cloud filtering method and then verifies it through experiments. From the data in Table 1, it can be seen that the removal rates of noise points on the 3D cloud data sets reached 95.3%, 98.6%, and 93.5%, respectively, and the accuracy and robustness of rough registration have been improved.  
2) In the precise registration stage, the feasibility of this method was verified by experiments. Taking the Stanford bunny and the free-form surface as examples, it can be seen that the error of the improved algorithm is reduced by 40.16% and 36.27%, respectively, and the number of iterations is reduced by 42.9% and 37.14%, respectively. Compared with the traditional ICP algorithm, the improved algorithm has higher registration accuracy, a faster running speed, and stronger versatility.  
The point cloud registration method is proposed in this paper, which can improve the registration accuracy and iteration rate of complex surface grinding and polishing precision machining, and has a good registration effect. The matching analysis between complex surface parts, which includes not only machined blanks but also semi-finished parts and theoretical models, can be completed in the precise machining process of complex surface grinding and polishing, and the machining allowance of each position of complex surface grinding and polishing parts can be obtained, which optimizes the subsequent machining process parameters and process planning; this further improves the machining accuracy and efficiency of complex surface grinding and polishing. This study has good theoretical  
Figure 12: Fine registration results.  
significance and important engineering application value for the future development of grinding and polishing through the precision machining of complex surfaces.  
Project administration, E.Z.; writing--original draft preparation, R.S., H.L. and Z.F.; supervision, D.M., S.J. and Z.Z.; data curation, R.S., H.L. and Z.F.; All authors have read and agreed to the published version of the manuscript.  
In this paper: the general project of Jilin Natural Science Foundation (project number 20230101336 JC) \"Research on the new method of airbag polishing for composite free-form surface robot\", the key research and development project of Jilin Science and Technology Department (project number 20220201035 GX) \"Manufacturing theory and key technology of preci-sion performance-driven composite mirror\" and the key research and development project of Jilin Science and Technology Department (project number 20200401121 GX) \"Research on New Technology and Equipment of Adaptive Grinding and Polishing of Complex Curved Surface\" were obtained.  
Not applicable.  
All the data given in this paper is available at corresponding websites.  
The authors are grateful to the anonymous reviewers and the editor for their valuable comments and suggestions for improving this paper.  
The author(s) declare no potential conflict of interest concerning the research, authorship, and/or publication of this article.