热成像系统中的视在温差研究

Research on Apparent Temperature Difference in Infrared Imaging System

温度的差异是决定目标红外图像特征的一个重要因素,热成像系统的主要性能参数也都与温差有着直接的关系,红外伪装效能评估也与温差密切相关。研究热成像中的温差问题对研究目标的红外图像特征、热像仪的实际性能和红外对抗等都有着重要的意义。讨论了大气衰减对辐射温差的影响;通过引入等效环境辐射温度的概念,分析了热成像的原理;得到了热成像中视在温度表达式;推导出了热成像中视在温差的理论计算公式。结果表明热像仪上的视在温差,不仅与目标本身温度和发射率有关,还和目标与背景(或目标不同部位)的温差和发射率差、大气透过率、等效环境辐射温度以及探测器有关。

Temperature difference is an important factor to determine the characteristic of the target infrared image.The main performance parameters of thermal imaging system have direct relation to temperature difference.The effectiveness evaluation for infrared camouflage is also correlated to temperature difference.It is an important issue to study the problem on the temperature difference in infrared imaging for the research of target infrared image characteristic,the practical performance of thermal imaging system and the infrared countermeasure.The effect of atmospheric attenuation on infrared radiation was discussed;the principle of thermal imaging was analyzed after the concept of equivalent ambient radiation temperature was introduced into thermal imaging;the expression of apparent temperature in infrared imaging was gained;the theoretical calculation formula of apparent temperature difference in infrared imaging was deduced.The investigated results show that the apparent temperature difference is related to the target temperature and emissivity,the difference of temperature and emissivity between the target and the background （or different parts of target）,the aerosphere transmissivity,the equivalent ambient radiation temperature and the detector.