环境温度对中波热成像设备信号传递函数的影响研究

Study of the influence of ambient temperature on MWIR imaging device′s SiTF

信号传递函数(SiTF)是评价热成像设备性能的重要指标,其与噪声之比为NETD,NETD可用于预测热成像设备的外场性能。根据红外成像测试理论,SiTF与环境温度相关,而外场环境温度变化范围大,在宽温度范围内SiTF变化很大,在预测热成像设备的外场性能时,应依据当前环境温度下的SiTF指标,但由于测试宽温度范围下SiTF指标的全军温红外整机测试系统并不普及,热成像设备在出厂时一般只测试室温SiTF值,用户不能获得宽温度范围内的SiTF值,因此当使用室温SiTF值预测设备在外场环境下的性能时由于外场温度与室温相差较大,导致预测结果偏差较大。本文通过分析SiTF随温度的变化规律,建立其随温度的变化关系,基于室温SiTF预测其他不同温度下的SiTF,从而解决采用室温SiTF预测外场环境下热成像设备外场性能时预测偏差较大的问题。

The signal transfer function(SiTF)is a important parameter to evaluate thermal imaging device′s field performance.According to thermal imaging device′s test and evaluate theory,SiTF is related to temperature,and temperature range in outfield is very wide.In such a wide temperature range,SiTF changes greatly,when predicting device′s field performance,we should use SiTF corresponding to the outfield′s temperature.But as the test system used to test SiTF in wide temperature range isn′t common,SiTF in wide temperature range can′t obtained easily.As a result,when we predict thermal imaging device′s field performance using SiTF at room temperature,the deviation of prediction results is relatively large.This paper presents a method to address the above problem by analyzing the relationship of SiTF and temperature,establishing the relationship of SiTF and temperature and predicting the SiTF in wide temperature range using SiTF at room temperature.