对于温度灵敏度优于10 mK的长波红外相机, 如何精确测量表征其灵敏度的指标-噪声等效温差(Noise Equivalent Temperature Difference, NETD), 是一项重要的工作。首先, 依照尽量缩短标准辐射传递链路减少误差项的原则, 对比不同的测量方法, 选取“黑体直接测量法”; 其次, 基于相机噪声理论模型, 对不同温度点下的实测噪声分析, 提出噪声修正方法对噪声进行修正, 以此减小环境影响带来的测量误差; 最后, 基于NETD测量计算公式及不确定度分析理论对测试结果的不确定度进行分析评定。结果表明: 针对甚高灵敏度长波红外相机所采用的测试设备及方法, 可满足测试要求, 测试结果相对不确定度在7.7%左右。

For the long-wave infrared camera which has a temperature sensitivity less than 10 mK, it is an important work of testing its noise equivalent temperature difference(NETD) with high accuracy. Firstly, the "black body direct testing method" was chosen based on the principle of shortening the standard radiation transfer link and reducing the error terms after comparing different testing methods; Secondly, based on the theoretical noise model of the long-wave infrared camera, the testing noise data was analyzed at different temperatures, the noise correction method was proposed for reducing the testing error caused by the instability of environment. Finally, the uncertainty of testing results was analyzed based on the NETD calculation formula and analysis theory of uncertainty. The result shows that the testing device and methods are satisfied for the testing requirement of ultra-high sensitive long-wave infrared camera, the testing uncertainty is 7.7%.