基于方向发射率校正的红外测温补偿方法

An infrared temperature compensation method based on directional emissivity correction

红外热成像仪具有实时在线、非接触获取被测对象二维温度分布等优点,在钢铁、农业、电力电子等众多领域应用广泛。但是,红外测温结果容易受到干扰因素的影响。针对方向发射率变化引起的红外测温误差,本文提出了基于方向发射率校正的红外测温补偿方法。首先,基于红外测温原理,构建了针对方向发射率变化的红外测温补偿模型。其次,为确定补偿模型中的方向发射率,利用红外热像仪和激光扫描仪构建的三维热成像系统,提出了基于参考体的方向发射率校正方法。然后,通过多项式拟合确定方向发射率随视角变化的规律。实验结果表明所提红外测温补偿方法可以有效降低方向发射率变化造成的红外测温误差,经过补偿温度后,红外测温最大误差由9.64℃降低为2.97℃,标准差由3.57℃降低为0.71℃。

The infrared thermal imager has advantages of real-time on-line, non-contact acquisition of the two-dimensional temperature distribution of the measured object, which is widely used in steel, agriculture, power electronics and other fields. However, infrared temperature measurement results are easily affected by interference factors. To address the infrared temperature measurement error caused by the change of directional emissivity, a temperature compensation method based on directional emissivity correction is proposed in this article. Firstly, based on the principle of infrared temperature measurement, an infrared temperature measurement compensation model for the change of directional emissivity is formulated. Secondly, to determine the directional emissivity in the compensation model, a 3 D thermal imaging system constructed with an infrared thermal imager and a laser scanner is used, and a reference body-based directional emissivity correction method is proposed. Then, the law of the directional emissivity changing with the viewing angle is determined by polynomial fitting. Experimental results show that the proposed infrared temperature measurement compensation method is effective in reducing the infrared temperature measurement error caused by the change of directional emissivity. After temperature compensation, the maximum error of infrared temperature measurement is reduced from 9.64℃ to 2.97℃, and the standard deviation is reduced from 3.57℃ to 0.71℃.