Research In Target Recognition Employing Polarization Signatures Of Thermal Emission

Target-detection technique employing polarization characteristics of the infrared radiation is especially good at true-false target recognition, which enables it a promising military future. Given the fact that lots of factors will change some characteristics of infrared radiation, it is difficult for optimal detection. We try to make it clear that which factor effects the polarization characteristics of the thermal radiation most in this study, so the major work is focused on analyzing the polarization characteristics of thermal emission of targets, in which the major work are introduced as follows.First, the generation mechanism of polarization characteristics was explained based on the wave equation of light. The commonly used ways to describe polarization characteristics were analyzed as well as the measure ways and measure devices.Second, the polarization characteristics of the thermal emission from smooth surfaces were modeled and analyzed. On the basis of wave equations of light, the degree of polarization was calculated using emissivity. This model agreed well with the existing knowledge that emission radiation was indeed polarized. Additionally, such a model showed us the variation tendency of the degree of polarization with the emission angle of the radiation and the difference between various materials.At last, this paper formalized a polarization model for thermal emission general to dielectric and metal rough surfaces, which was based on a micro-facet model of rough surfaces. As the key step, the micro-facet model transformed the polarization components of all the micro-facets to a uniform coordinate system. After that the degree of polarization was calculated, and the results turned out to be of great value in identifying different types of materials which could further recognize military targets.This paper has studied polarization characteristics of thermal emission from both smooth and rough surfaces. It is clear that future work on thermal emission polarization should be focused on other effects such as transmission in atmosphere for more accurate results.