提出了利用大气修正因子修正大气透过率来提高测量目标红外辐射特性精度的方法。建立了目标红外辐射特性测量模型, 给出了基于大气修正因子的目标红外辐射特性测量方法。该方法将短距离大气透过率实测结果和MODTRAN模拟计算的大气透过率之比定义为基础大气修正因子, 然后依据长距离与短距离的不同数量关系得到增强大气修正因子, 最后利用该因子对MODTRAN计算的长距离大气透过率进行修正并进行目标的辐射反演, 从而获得目标辐射特性。 对中波红外摄像机进行了定标, 利用中波红外摄像机和面源黑体开展了目标红外辐射特性测量实验。实验结果表明, 利用大气修正因子修正大气透过率的目标辐射测量方法得到的目标辐射特性测量精度在8%左右, 高于传统的利用MODTRAN计算方法得到的20%的测量精度。得到的结果显示本文方法较传统方法较大程度地提高了目标辐射特性测量精度。

A method to improve the infrared radiation measurement precision of a target based on correcting atmospheric transmittance by using an atmosphere-corrected coefficient was proposed. A measuring model of infrared radiation characteristics for the target was established, and the measuring method of the infrared radiation characteristics for the target was given. The method defines the ratio between the really-measured atmospheric transmittance at a short distance and the calculated one by using MODTRAN as an atmosphere-corrected coefficient. Then, it obtains the enhanced atmosphere-corrected coefficient according to the different quantitative relationships between the short distance and other distance. Finally, it uses the enhanced atmosphere-corrected coefficient to correct the long distance atmospheric transmittance and to invert the radiation of the target, so that to obtain the radiation characteristics of the target. A middle wavelength infrared camera was calibrated and the measuring experiment of the infrared radiation characteristics for the target was carried out by the middle wavelength infrared camera and a black body. The results show that the radiation measurement precision obtained by using MODTRAN is about 20% and that obtained by the proposed method is about 8%. It demonstrates that the radiation measurement precision has improved greatly as comparing with that of the conventional method.