Fig. 1. Working diagrams of laser surveillance camera and laser footprint camera^[25]

Fig. 2. Gaofen-7 surveillance spot image and footprint spot images. (a) Surveillance spot image; (b) image of footprint spot 1; (c) image of footprint spot 2

Fig. 3. Method in this paper

Fig. 4. Simulated spot energy distributions. (a) Ideal simulated spot energy distribution; (b) simulated spot energy distribution with random deformation and random noise

Fig. 5. Relationship between laser footprint camera and ground optical projection and footprint spot images. (a) Relationship between laser footprint camera and ground optical projection; (b) image of footprint spot 1; (c) image of footprint spot 2

Fig. 6. Relationship between laser surveillance camera and ground optical projection, and surveillance spot image. (a) Relationship between laser surveillance camera and ground optical projection; (b) surveillance spot image

Fig. 7. Statistics of spot centroid extracted by LS-GCM. (a) x direction; (b) y direction

Fig. 8. Statistics of spot centroid results extracted by GCM. (a) x direction; (b) y direction

Fig. 9. Statistics of spot centroid results extracted by GFM. (a) x direction; (b) y direction

Fig. 10. Average of 30 track footprint spot centroid coordinates. Average of centroid of footprint spot 1 of (a) x coordinate and (b) y coordinate; average of centroid of footprint spot 2 of (c) x coordinate and (d) y coordinate