曲面红外测温方向性误差分析与修正方法

Research on error analysis and correction of infrared temperature measurement for curved surface

通过实验验证与理论分析,探讨了曲面特征的红外辐射测温特性.研究结果表明:曲面红外辐射测温在本质上与平面辐射测温相同,满足同一数学表达式;出现曲面红外测温失真的根本原因是被测表面等效面出现了不满足表面漫射条件假设的状况,这主要是由被测表面法向与测量方向夹角过大导致的;通过测量当地表面发射率可以校正因等效面不满足漫射条件假设造成的红外测温结果失真.

Experiments and theory analysis were carried out to investigate the character- istics of temperature measurement using thermal imager for curved surface. According to the theory of infrared thermometry techniques, the infrared radiation characteristics of curved surface essentially have no difference with flat surface,both of which can be described by the same mathematics expression. The essential reason which induces the measuring error of infrared thermal imagery for curved surface is that equivalent face of the measured surface no longer satisfies the diffuse body hypothesis, owing to too large included angle of the normal direction of curved surface and the measuring direction of infrared thermal imagery. The temperature measuring accuracy can be improved by measuring the local emissivity for the region where the diffuse body hypothesis is invalid for its equivalent face.