Separation of Temperature and Emissivity from Thermal Infrared Images: Analysis of their Application/Restriction

Remote Sensing data coming from the Thermal InfraRed (TIR) channel of electromagnetic spectrum has several applications in remote sensing, geology, climatology, biological process analysis, geophysical process analysis, disaster assessment and change detection analysis. In the TIR region, the emission of the targets is dominant when compared with reflection. This radiation is a function of two unknowns - the emissivity and the temperature of the target. To study TIR, it is necessary estimate the temperature and/or emissivity from de measured radiation with precision. This process is usually difficult due to a non-linear relationship between these two unknowns and the measured radiation. Therefore, in the last 40 years, several researchers have developed approaches to minimize this problem. However, all these methods have constraints in their applications. This study try to review the main methods available in the literature, facilitating their understanding and replication and creating a summary that allows the reader to choose the most suitable method in their own application.

Keywords :
TIR; TES; temperature measurement; emissivity