环境辐射对热像仪测温的影响

不同于传统的离散光谱测温，热像仪测温的实质是一种在一定波段范围内的基于探测器光谱响应的连续光谱测温。除了目标的发射率会影响热像仪所测温度与真实温度的关系外，反射的环境辐射也是热像仪测温结果的重要影响因素。目前的热像仪测温精度研究在对目标反射环境辐射的处理中，大都把环境辐射看做是均匀入射的或者是把目标看做了镜面反射体，这样做虽然可以大大简化模型，但是却远远不符合实际情况。针对这一现状，利用辐射度学原理和热像仪探测器的光谱响应特性，建立了在环境辐射非均匀入射条件下的热像仪对漫射目标的测温模型，结果表明:环境辐射对热像仪测温的影响，除了与目标的反射率和环境辐射源的温度有关外，还与环境辐射源对目标所张的投影立体角有关。根据所得模型，分析了热像仪测温的影响因素，重点对几种典型环境辐射条件下对热像仪测温的影响进行了定量计算和分析，并进行了实验验证。相关结果一方面可以为热像仪测温设计提供参考，另一方面可以为复杂环境条件下热像仪测温与真实温度的误差估算提供理论依据。

Influence of environmental radiation on temperature measurement of thermal imager

Different from the traditional discrete spectrum temperature measurement, the essence of thermal imager temperature measurement is a kind of continuous spectrum temperature measurement based on the spectral response of detector in a certain band. In addition to the emissivity of the target will affect the relationship between the temperature measured by the thermal imager and the real temperature, the reflected environmental radiation is also an important factor affecting the temperature measurement results of the thermal imager. The current research on the temperature measurement accuracy of thermal imager, in the processing of the environmental radiation reflected by the target, mostly regard the incident environmental radiation as uniform or the target as a mirror reflector. Although this can greatly simplify the model, it is far from the actual situation. Based on the principle of radiometry and the spectral response characteristics of thermal imager detector, the temperature measurement model of the thermal imager for the diffuse target was established. The results show that the influence of environmental radiation on the temperature measurement of thermal imager is not only related to the reflectivity of the target and the temperature of the environmental radiation source, but also related to the projection solid angle of the environmental radiation source on the target. According to the model, the influencing factors of the temperature measurement of the thermal imager were analyzed. Then the influence of several typical environmental radiation conditions on the temperature measurement of the thermal imager was calculated and analyzed, and the experimental verification was carried out. On the one hand, the results can provide a reference for the design of temperature measurement of thermal imager, on the other hand, it can provide a theoretical basis for the error estimation between temperature measurement of thermal imager and real temperature under complex environmental conditions.