Error in solid surface emissivity determination by an IC camera

Determination of temperature by IR thermal cameras depends significantly on the knowledge about the emissivity of solids in question. Solids emissivity data can be found in handbooks but can also considerably differ from real values. It is therefore necessary to obtain emissivity data by measurements taken on real materials. Solids emissivity can be determined by the same IR system used for temperature determination. A mathematical model for emissivity determination is derived in the paper as well as the function of error in determining solid materials emissivity by the 870SWB Agema IR THERMOVISION camera with 2-5 μm spectral range. The standard relative error and partial errors in determining emissivity of solid surfaces are analyzed and the obtained results point out to the possibility to model conditions necessary for acquiring demanded accuracy in emissivity determination.