制冷型HgCdTe红外推扫系统噪声等效温差精测与结果分析

Precision Measurement and Results Analysis of Noise Equivalent Temperature Difference of Cooled HgCdTe Infrared Push-Broom System

指出传统噪声等效温差(NETD)测试中的不足之处;从噪声等效温差测试原理出发,推导测试中常用噪声等效温差公式;提出实验室条件下的精确测量方法,并对测试结果进行修正;对制冷型HgCdTe红外推扫系统采用不同波段、不同光学镜头组合测试噪声等效温差值,对测试得到4组数据进行对比分析。根据探测器本身温度响应特性及中波与长波波段的黑体辐射特性,从理论上解释了不同测试条件下噪声等效温差的测试结果差异;同时,实验结果表明同一波段,不同口径的噪声等效温差相差不大,而不同波段相同口径的噪声等效温差相差很大。实验结果同时证实了光学系统只有F数与噪声等效温差有关。

The inadequacies of traditional noise equivalent temperature difference （NETD） test are pointed out; the commonly used NETD test formula is derivatived from the principle of NETD test. The accurate measurement methods under laboratory conditions are raised and test results are corrected; NETD of cooled HgCdTe infrared pushbroom system with different bands, different optical lens are tested and four sets of data on the test are got and contrast analysis is given to them. According to the detector temperature response characteristics and blackbody radiation characteristics of the medium wave and long wave band, the reasons for NETD test result differences under different test conditions are explained theoretically. At the same time, experimental result shows that NETD with the same band and the different optical calibers change little, while NETD with different bands and the same optical caliber change very much. The experimental results also confirm that only the F number in all the parameters of the optical system, is relative to NETD.