Abstract:To address the problems of manual experience dependent viewpoint planning, low coverage efficiency, and unstable imaging quality in the inspection of man made structures such as buildings, transmission towers, and bridges, a study was conducted on an automated multi viewpoint planning method for UAV based inspection. A target 3D model was adopted as input, and surface modeling was achieved through voxelization and facet approximation. A candidate viewpoint set was generated by integrating constraints including safety distance, imaging resolution, and attitude, and a facet viewpoint coverage relationship model was subsequently constructed. On this basis, a weighted Next Best View (NBV) strategy was introduced to optimize viewpoint selection while meeting coverage requirements. Experimental results show that, compared with random sampling and regular orbiting flight methods, the proposed method exhibits superior coverage performance and efficiency in inspection tasks of varying complexity. Under the same number of viewpoints, surface coverage increases from 17.09%–72.34% to 86.92%–95.74%, and weighted coverage improves from 11.73%–75.52% to 86.79%–99.30%. Furthermore, the number of viewpoints required to achieve the same coverage target is significantly reduced. Practical application demonstrates that the proposed method satisfies the engineering applicability requirements for complex man made target inspection tasks.