Fig. 1. Illustrative example of the multi-depth fast-denoising method

Fig. 2. Depth images and 3D point clouds of s of geometric shapes under different PPP and SBR. (a) Surfaces per pixel on geometric shapes; (b) Depth image estimated by MLE under PPP=11.12, SBR=3.40; (c)-(e) Depth images estimated by the proposed method respectively under PPP=11.12 and SBR=3.40, PPP=2.33 and SBR=0.99, PPP=1.08 and SBR=0.13, and (f)-(i) the corresponding 3D point clouds

Fig. 3. Depth images of the art scene. (a) Reference; (b)-(g) MLE, FDTCP, Rapp, SPISTA, ManiPOP, and proposed method, respectively

Fig. 4. 3D point clouds of the art scene. (a) Reference; (b)-(g) MLE, FDTCP, Rapp, SPISTA, ManiPOP, and proposed method, respectively

Fig. 5. Schematic diagram of long-range single-photon lidar system

Fig. 6. Complex buildings at 1 km. (a) Visible-band image; (b) Histogram of test dataset

Fig. 7. Depth images of complex buildings. (a) Reference; (b)-(g) MLE, FDTCP, Rapp, SPISTA, ManiPOP, and proposed method, respectively

Fig. 8. 3D point clouds of complex buildings. (a) Reference; (b)-(g) MLE, FDTCP, Rapp, SPISTA, ManiPOP, and proposed method, respectively