Fig. 1. Research technology road map

Fig. 2. Process diagram of Zhang Zhengyou camera calibration method realized by Matlab2020 program algorithm. (a) Checkerboard images obtained from different directions; (b) origin determination and corner detection of image coordinates; (c) positions of 17 checkerboard images in the image coordinate system; (d) parameter test accuracy of 17 checkerboard images

Fig. 3. Schematic of working mode of equipment integration installation

Fig. 4. Initial parameter registration effect. (a) Key frame position and shooting direction; (b) point cloud data backprojecting to key frames of video images

Fig. 5. Accurate registration effect of the iterative method of weight selection based on Robust estimation. (a) Registration effect without using Robust method to improve the accuracy of registration parameters; (b) registration effect using Robust method to improve the accuracy of registration parameters; (c) video image point cloud and laser point cloud registration fusion effect

Fig. 6. Schematic of point cloud 3D model reconstruction using the proposed method. (a) Laser point cloud of the base of the national flagpole; (b) point cloud of the national flagpole after registration;(c) reconstruction of 3D models of video images and laser point clouds

Table 1. Camera calibration parameter table

Table 2. Relevant parameters of experimental instruments

Table 3. Accuracy test of registration results

Table 4. Comparison between the measured values and those of the 3D model