PCB红外热像辐射率校准的非线性滤波方法

Non-Linear Filtering Method for Emissivity Correction of PCB Infrared Thermal Images

在印制电路板 (PCB)的红外辐射诊断中 ,为了获得PCB表面温度的真实分布 ,须对PCB红外热像进行辐射率校准 .将PCB表面温度的测量波形看作真实温度分布与辐射率分布的混合波形 ,提出一种非线性滤波方法 ,利用二者连续性的差异将其区分开来 .讨论了作为该方法关键步骤的红外热像突变点检测的小波变换实现问题 .实验结果表明该方法能够准确地估计PCB表面温度的真实分布波形 .

In the diagnosis of Printed Circuit Board (PCB) based on infrared radiation, emissivity correction must be performed on the thermal image to retrieve the true temperature distribution on the PCB surface. Taking the measured PCB surface temperature as a combination of its true temperature distribution and its emissivity distribution, a non linear filtering method was proposed to separate the true temperature from this combination based on the differences in the continuity of these two contributions. As a key step of the proposed method, the wavelet implementation of discontinuities detection in thermal image was also discussed. Experimental results indicated that the true temperature distribution can be estimated precisely by the proposed method. It is also shown that the proposed method can be used in other applications such as heat source recognition on PCB infrared thermal image and emissivity estimation of unknown materials.