Study on camouflage effect of targets with different characteristics under typical background

With the rapid development of infrared detecting and homing technology, it is important for us to analyze infrared camouflage effect of ground targets to improve the survivability. In the paper, factors such as the effect of atmosphere between detectors and targets, characteristics of targets and background and atmospheric radiance including directly transmitted solar irradiance are taken into account in long-distance detecting. The concept of RARD (relative apparent radiance difference) between targets and background is proposed and the camouflage effect of ground targets can be evaluated precisely. MODTRAN 4.0 is used to analyze the camouflage effect of targets. In MODTRAN, solar zenith angle, common background, emissivity and temperature of targets are selected to calculate RARD under certain atmosphere condition. Simulation results show that RARD is affected by the solar zenith angle significantly in middle infrared wavelength region, but hardly in long-wave infrared region. Under the special background, according to the target temperature, proper coating with unchanged emissivity is selected to camouflage the target all day in long-wave infrared region. However, for the changing background, the stealth coating with variable emissivity should be adopted. In addition, for the same target, it is even more difficult to achieve good camouflage effect at both medium infrared band and long wave infrared band.