红外热像仪精确测温技术

Accurate measuring temperature with infrared thermal imager

为实现红外热像仪对温度的精确测量，根据热辐射理论和红外热像仪的测温原理，推导了计算被测物体表面真实温度的通用计算公式；讨论了发射率对测温精度的影响。分析了用红外热像仪进行精确测温的条件，探讨了环境、大气和热像仪本身对测量精度的影响，并绘制了各种因素对测温精度影响的理论曲线。结果表明：发射率为0．7时，真实温度为50℃，发射率偏离0．1时，对于3～5μm热像仪来说。测温结果偏离真实温度0．76～0．89℃；对于8～14μm热像仪来说，测温结果偏离真实温度1．56～1．87℃。本研究结果对提高热像仪测量温度和表面发射率的准确性，减小不必要的测量误差具有实际意义。

In order to measure the temperature accurately using infrared thermal imager the interpolation of true surface temperature and the influence factors were studied. Based on the principles of thermal radiation and temperature measurement with infrared thermal imager, a general formula for computing the true surface temperature of objects was given. The influence of emissivity on accurate temperature measurement was discussed mainly, the conditions of accurate temperature measurement with infrared thermal imager were analyzed, and the influence factors from the surroundings, the atmosphere and the thermal imager were investigated too. Finally, the theoretical curves of the various factors influencing on the accuracy of measuring temperature were given. The results show that when emissivity is 0.7, the true temperature is 50℃, as deflected emissivity is 0. 1, the measuring result of true temperature fluctuating is 0.76～0.89℃ for a 3～5μm thermal imager; and 1.56～1.87℃ for a 8～14 μm thermal imager. It is shown that proposed method can provide a feasibility for improving the accuracy of measuring temperatrue and surface emissivity and reducing measuring errors.