Three-dimensional laser imaging with a variable scanning spot and scanning trajectory

Traditional lidar scans the target with a fixed-size scanning spot and scanning trajectory. Therefore, it can only obtain the depth image with the same pixels as the number of scanning points. In order to obtain a high-resolution depth image with a few scanning points, we propose a scanning and depth image reconstruction method with a variable scanning spot and scanning trajectory. Based on the range information and the proportion of the area of each target (PAET) contained in the multi echoes, the region with multi echoes (RME) is selected and a new scanning trajectory and smaller scanning spot are used to obtain a finer depth image. According to the range and PAET obtained by scanning, the RME is segmented and filled to realize the super-resolution reconstruction of the depth image. By using this method, the experiments of two overlapped plates in space are carried out. By scanning the target with only forty-three points, the super-resolution depth image of the target with 160 × 160 pixels is obtained. Compared with the real depth image of the target, the accuracy of area representation (AOAR) and structural similarity (SSIM) of the reconstructed depth image is 99.89% and 98.94%, respectively. The method proposed in this paper can effectively reduce the number of scanning points and improve the scanning efficiency of the three-dimensional laser imaging system.