Fig. 1. Schematic diagram of ground target thermal boundary

Fig. 2. Contribution rate of different factors

Fig. 3. (a) Diagram of the tank geometry model; (b) Schematic diagram of the tank grid

Fig. 4. Meteorological parameters on April 23, 2020. (a) Air temperature; (b) Air humidity; (c) Wind speed; (d) Solar radiance

Fig. 5. (a) The top-view azimuth temperature nephogram of tank; (b) The right-view azimuth temperature nephogram of tank

Fig. 6. (a) Iterative curves of tank top-view azimuth parameter; (b) Iterative curves of tank right-view azimuth parameter inversion

Fig. 7. Calculation of temperature nephogram at 14 o'clock. (a) Temperature nephogram of top-view azimuth real parameters; (b) Temperature nephogram of top-view azimuth inversion parameters; (c) Temperature nephogram of right-view azimuth real parameters; (d) Temperature nephogram of right-view azimuth inversion parameter

Fig. 8. Calculation of temperature changes throughout the day. (a) Comparison diagram of the calculated temperature of the front armor; (b) Comparison diagram of the calculated temperature of the toolbox; (c) Comparison diagram of the calculated temperature of the fort; (d) Comparison diagram of the calculated temperature of the gun barrel

Fig. 9. (a) Visible light image of CUBI model; (b) Physical model and meshing of CUBI

Fig. 10. Meteorological parameters on April 9, 2021. (a) Air temperature; (b) Air humidity; (c) Wind speed; (d) Solar radiance

Fig. 11. (a) Longwave infrared temperature chart at 9 o'clock on April 9, 2021; (b) Inversion selection survey point map

Fig. 12. Diagram of iterative curves

Fig. 13. (a) Measured long wave infrared temperature at positive east position at 14 o'clock on April 9, 2021; (b) Measured infrared temperature map of positive east position of target; (c) Calculated infrared temperature map of positive east position of target

Fig. 14. Variation characteristics of calculated and measured temperatures on each surface and their errors. (a) Comparison diagram of east temperature; (b) Comparison diagram of north temperature; (c) Comparison diagram of up temperature