中文摘要：

为了更方便理解红外辐射对比度的含义，针对目前红外辐射对比度计算使用的物理量和公式比较混乱的情况，从红外探测的实现方法出发，分析指出对比度衡量的标准物理量应该为在探测器处的红外辐射照度。当目标与背景不在同一位置且与探测器相距较远时，用辐射亮度、辐射出射度计算对比度分析探测效果是不恰当的。相对对比度应该使用目标与背景在探测器处的红外辐射照度差值的绝对值除以目标与背景的红外辐射照度平均值作计算。

英文摘要：

In view of the present disordered situation of using physics quantity and formula for infrared con trast calculation, the paper presents that the criterion of physics quantity used to evaluate the contrast should be infrared irradiance at the detector surface by analyzing the purpose and the actualized measures of infrared detection. When the object and background are in different positions, and both of them are far a way from the detector, it is improper to calculate contrast by radiance or radiant emission. In order to make the contrast of infrared target and background represent effectively the infrared feature differences of the targetbackground, the infrared radiation relative contrast is defined by the ratio of the absolute value of the target and background difference in infrared irradiance at the detector surface to their mean value.