烟幕对红外热成像干扰效果评价

Evaluation of interference effects of smokescreen on IR imaging

烟幕是对抗红外侦察与制导的有效手段。为了定量评估和评价烟幕对红外热成像干扰的效果,从理论和实验两方面进行了研究。理论上,依据作用距离准则,从辐射对比度入手,建立了烟幕干扰下的红外热成像视距方程,从而可以通过估算干扰前后热成像系统作用距离的变化来分析评价烟幕干扰的效果。实验中,首先测定了烟幕对不同波段辐射的透过率。然后以人体作为观察目标,基于相似度准则,引入归一化互信息指标作为评价标准,并和直接观察结合来分析红外热成像效果受烟幕干扰的情况。结果表明,在烟幕干扰下,当红外热成像系统无法达到识别要求时,目标与背景表观对比度下降到固有对比度的4%以下,对应的烟幕透过率为55%,且理论计算与实验分析相符。

Smokescreen is effective to counter infrared reconnoiter and guide.In order to assess and evaluate the ability of smokescreen to interfere IR imaging quantificationally,study was carried out both in theory and in experiment.Firstly,based on discrimination distance rule,the equation to calculate the view range of IR imaging under the interference of smokescreen was built from the aspect of radiation contrast,which made the analysis and evaluation of interference effect of smokescreen available from assessing the variation of view range of IR imaging before and after the interference.Secondly,transmissivity of smokescreen to different wavebands was measured in experiment.And then human body was selected as the target to observe.Normalized mutual information was selected as criterion based on correlativity rule and direct observation was used to analyze the interference effect of smokescreen on IR imaging in experiment.The results show that under the action of smokescreen,the apparent contrast between the target and background has dropped to less than4%of their inherent contrast when the IR imaging system can′t satisfy the demand of recognition.The corresponding transmissivity of smokescreen was55%,and the theoretical calculation was consistent with the experimental analysis.