
The scanned point cloud is first downsampled using voxel grid filtering to reduce density and suppress noise. Subsequently, Scale-Invariant Feature Transform (SIFT) is employed to extract scale-invariant keypoints, and their Fast Point Feature Histograms (FPFH) descriptors are computed to represent local geometric features. Based on these keypoint features, Sample Consensus Initial Alignment (SAC-IA) is performed for global coarse registration. This algorithm achieves stable initial correspondences and estimates the initial transformation by searching for random consensus within the FPFH feature space. Following this, Iterative Closest Point (ICP) is used for local fine registration, iteratively minimizing the distance to the nearest points to obtain high-precision pose estimation. To enhance robustness and convergence, adaptive downsampling and normal constraints are incorporated into the ICP process. The final transformation is obtained by multiplying the coarse and fine registration matrices, achieving high-precision alignment between the scanned point cloud and the CAD point cloud, thus providing a reliable foundation for workpiece pose estimation and subsequent path mapping.
Drawing a network structure diagram of the algorithm. The fo...