Visual characterization method of cracks based on laser 3D scanning

Structural crack is a common damage form for aircraft. Laser 3D scanning technology can realize 3D reconstruction of structural parameters by obtaining point cloud data, but it is faced with the cross scale effect between local crack and structure size when applied to crack detection and identification. To address this issue, based on the difficulty of visual inspection, four cracks of artificial crack, crack propagating to edge of the sample, visible crack, and barely visible crack were selected as objects, and three reconstruction parameters of crack length, crack width and height difference on both sides of crack were extracted to characterize crack characteristics, and the parameters were quantitatively measured using optical microscope. Then, the laser 3D scanning crack modeling test was carried out on the four cracks,and the effects of reconstruction parameters on the crack characteristics recognition and modeling accuracy were analyzed. The results show that the laser 3D scanning technology was able to accurately identify and characterize the characteristics of cracks, which might provides a novel technical means for the visual characterization of aircraft structure cracks.