Aircraft skin gap and flush measurement based on seam region extraction from 3D point cloud

Gap and flush measurement is a challenging task in the process of aircraft assembly, which significantly affects the reliability of aircraft aerodynamic shape. To ensure the quality of aircraft assembly, an accurate gap and flush measurement method is essential. This paper presents a novel simple yet effective method, which is suitable for various kinds of scanner data. Given an unstructured scanned point cloud, our method first detects and segments the seam area based on the local point density discrepancy. In the second stage, a projection operation is applied based on the segmentation results to convert 3D measurement to 2D measurement to reduce the computational complexity and improve the accuracy of the measurement. According to the geometric distribution of the projection points generated in stage two, the feature points defined by the gap and flush calculation model are extracted to complete the computation. Experimental results show that the accuracy is comparable to some state-of-the-art methods. Concerning the robustness to different types of scanner devices data, the proposed method clearly outperforms the others. •A fully automatic gap and flush measurement framework is proposed.•A density variation-aware seam extraction method is designed to extract seam area.•An optimization algorithm is devised to ensure the correctness of cross sections.