Atmospheric transmission simulation and analysis on the polarization system in three infrared wavebands

Compared with traditional infrared imaging, polarization imaging system can detect and identify the man-made or camouflaged target more effectively by using the differences of the degree of polarization between a target and its background. As the polarization transmission is a complex process, it's necessary to study polarization properties of different objects and atmospheric effects, including atmospheric absorption, atmospheric path radiation and scattering of suspended particles in the atmosphere. In this paper, a general expression of polarized radiation control equation was obtained firstly. Secondly, the atmospheric absorption coefficient and path radiation in NIR, MWIR and LWIR were modeled and calculated respectively by using MODTRAN software. The polarization contrast and intensity contrast between the target and background with increasing detection distance were calculated. The results show that in NIR waveband, the reflection intensity is in a dominant position and that in MWIR both intensity and radiation cannot be ignored. While in LWIR, the radiation is in a dominant position and therefore in general polarization imaging has more advantages than intensity imaging. The results are basically consistent with the theoretical analysis. All the work mentioned above provides a reference to the choice of the way in IR detection.