Image Processing for Reduction of Background Reflection from Thermal Image

抄録

For the external wall of building, non-destructive inspection is recently needed, because fall accidents of tiles and mortar are increasing. In infrared thermographic testing as this inspection method, background reflection is one of the main causes of false detection. The authors developed image processing program to reduce the background reflection from a thermal image. The program mainly consists of two parts. The first part is the correction of emissivity. The correction of emissivity is carried out for each pixel in the thermal image according to the emissivity theory. The authors confirmed that the first part of this program can correct efficiently the emissivity change for a flat plate and a curved surface. The second part of the program is the reduction of a background reflection. To reduce the reflection, the background heat source should be measured separately. In measuring the reflection, there are two important points about a focus and a specular reflectivity. Consequently, this program can reduce the effect of reflection and extract only the emission of the flaw part from the thermal image including the background reflection.