Three-dimensional colour reconstruction of aviation spiral bevel gear tooth surface through fusion of image and point cloud information

Contact pattern measurement is commonly applied to assess gear transmission and meshing performance in aviation spiral bevel gear (ASBG) manufacturing enterprises. However, these patterns cannot be directly segmented and obtained from point clouds or images because each tooth of the spiral bevel gear has complex 3D spiral surface and texture information. Moreover, research on the high-precision 3D colour reconstruction of spiral gear tooth surfaces is relatively rare. Aimed at these problems, the current work proposed a high-precision 3D colour reconstruction method of spiral bevel gear. This method is based on the fusion of the image and point-cloud information. It includes two core steps to satisfy the practical demands of high precision and high efficiency. First, dense point clouds of the 3D calibration block are converted to a plane using the bird’s eye view method for corner detection. Second, the corners are quickly and accurately detected using a two-stage corner detection algorithm based on the inherent geometric features of the calibration block. The identified corners are then used to solve the transformation matrix from the pixel coordinate system to the line laser coordinate system. Image textures can be precisely projected and fused onto a 3D geometry for the coloured reconstruction of the gear tooth surface on the basis of this transformation matrix. The proposed method was validated by applying it to the 3D colour reconstruction of tooth surfaces of 10 distinct types of ASBGs. The experimental results demonstrated that the re-projection error of the proposed method is less than 0.1 millimetres. The minimal margin of error enables high-precision 3D colour reconstruction of the spiral bevel gear tooth surface. Compared to other classic 3D colour reconstruction methods, the proposed method achieves superior accuracy and efficiency. An experimental device was also developed for the 3D colour reconstruction of the tooth surface of ASBGs, as illustrated in figure 1.